A brief introduction to the function of CMOS/CCD (L)RGB Filters
CMOS-optimierte Baader LRGB Filter
Unlike terrestrial objects, astronomical objects shine in discrete emission lines. For this reason, any RGB-filter design with gently raising and falling slopes on either side of the transmitted spectral region generally is undesirable. The stars themselves obey to the laws of physics and shine by their stellar temperature colour - with a smooth, wide spectrum. This richness of colours can be covered nicely when adding an L-filter into the imaging process. However – shades and colour hues such as in earthly objects are not available when imaging the sharply defined emission spectra of deep sky objects. For this reason the slopes on RGB filter curves ought to be produced extremely steep for each colour channel - for maximum energy collection efficiency, while maintaining maximum contrast between the individual spectral emission lines.
Peak transmission of Baader RGB filters are extremely high but at the same time encased tightly within each of the three colour channels – with a very important and deliberate overlap between the B and G spectral region and a calculated wide gap between G and R to exclude a whole family of undesirable terrestrial street light emission lines (just like a UHC nebula filter). Thus colour balance and colour rendition of Baader RGB filters are outstanding, while stray light and reflections are simultaneously reduced to an unprecedented level – causing our filter recipe to having received the worldwide "chinese honour" of being copied by various OEM-marketing companies under a wide variety of trade names. Still our copyists need to prove that they apply the same care onto every aspect of the production process. This also includes selection of highly homogeneous glass-substrates, precision polishing of each individual filter, most expensive evaporation rare earth materials – and a number of other proprietary ideas – to really achieve the same performance on the sky.
Given our precision in filter workmanship, the above mentioned B/G overlap does cleanly separate the key emission lines of H-beta and O III but at the same time allows to double the energy in the O III line. Within the spectral region around 580 nm there is no significant celestial emission line, however a whole family of street lights (mostly Mercury and Sodium vapour lamps) emit their devastating energy within that region. Exactly this spectral area is almost completely suppressed by the Baader RGB filter design. All these design features result in substantially improved colour balance and above all, this design transmits the full extent of energy of these important deep sky emission lines better than any other filter recipe we have analysed. The increased contrast and absence of haze and blurriness is recognized repeatedly by experienced users. In this way Baader RGB filters play a major roll in eliminating light pollution when imaging from flawed, light polluted sites.
When comparing different filter offers, always demand to see the full extent of the spectral area were modern sensors are sensitive, that is – between 300 to 1150 nm at least. Many companies only present a cut-out of the full CCD/CMOS-sensitive spectral area – mainly to hide off band transmission were their inexpensive design has gaps which causes unwanted light to leak onto the image and spoil the data.
Baader-Deep-Sky Filters are completely blocked over a spectral range from 300 to 1150 nm for all wavelengths except the desired transmission ranges, which corresponds to the sensitivity range of current CMOS cameras. Thus, they also serve as UV and IR blocking filters, which could cause further reflections. This ensures that there are no leaks outside the target transmission.
Special emphasis was placed on avoiding reflections as best as possible during filter design. Modern CMOS sensors react more sensitively to reflections on glass surfaces in the vicinity of the filters. In developing this modern generation of filters, we have done everything to ensure that they work just as well on CMOS cameras as they do with CCD-cameras.
Transmission curves of the CMOS-optimized Baader LRGB Filter (Luminance, Red, Green, Blue)
Mechanical Properties
Parfocal and plane polished substrates. Each individual filter is optically fine-polished to 1/4 wave
Baader CMOS-optimized LRGB filters are hard coated individually. This is the only way to achieve sealed coating edges (Life-Coat™) that make them impermeable against ageing because the penetration of moisture is impossible
Baader filters especially are not cut out of large size plate-glass, which is a typical manufacturing process for economy filters (cut-out filters exhibit micro-cracks around all edges. Capillary action between glass and coating layers will lead to premature ageing due to moisture deposition)
Baader filters are being tested repeatedly to comply with MIL-specifications. One common process is to boil the test specimen for one hour in salt water. Baader filters remained completely intact as opposed to filters drilled out of large glass plates
Scratch-resistant Reflex-Blocker™ hard coating, planeoptically polished. Filters can be cleaned repeatedly throughout their entire lifetime as many times as needed – preferably with [product sku="2905009"]
Blackened edges all around, with filter-lead-side-indicator in the form of a telescope-sided black outer rim
Optical Properties
No filter-induced reflections
Balanced RGB-design offer 1:1:1 exposure times for most telescope optical systems – an important benefit when imaging in automated mode
Maximized colour contrast for each of the three RGB channels – achieved through steep slopes at all transmission curves combined with science approved placement of spectral window.
Extremely high transmission of the respective color channel, simultaneously reduces stray light and reflections to an unprecedented level. Reflex-Blocker™ coating for maximum insensitivity to retro-reflection from nearest auxiliary optics, even under the most adverse conditions.
Blackened edges all around, with filter front indicator in the form of a telescope-side black outer rim, to additionally prevent any reflection due to light falling onto the edge of a filter
O III emission line double-weighted in the B and G channel as well, with maximum peak transmission for unparalleled deep sky S/N yield
R-Filter provides maximum transmission of H-alpha and S II emission but at the same time completely blocks all NIR and IR from 680 out to 1200 nm
Blocking of Mercury and Sodium vapour lamps at 580 nm in the G and R filters blackens the sky background and maximizes colour balance and colour separation.
Life-Coat™: coatings that are even harder to provide an aging-resistant coating over an unlimited service life – even in the most adverse environments
Optimized for modern CMOS cameras, equally well suited for classic CCD camera technologies
Temperature controlled H-alpha-filters (lambda = 656,3 nm) with electronic temperature control (combined heating and cooling!)
Such professional filters show an unsurpassed abundance of details by using the full aperture of the telescope and are thus the first choice for semi-professional observers / photographers as well as for scientific use.
Solar Spectrum H-Alpha Filters give you an incomparable view of our Sun's eruptive surface. The SolarSpectrum filters follow the classical design and are placed behind the telescope in the focuser (although this requires a D-ERF energy rejection filter in front of the lens). In combination with a telecentric system tuned to the focal length of the telescopic, between 2/3s of the aperture and the full aperture of the telescope can be used with most refractors and SC telescopes, depending on the telescope's f/ratio! The telecentric system parallels the beam of light and extends the focal ratio of the telescope to the mandatory value of about 1:30.
Other narrow-band H-alpha filters are placed in front of the telescope lens. They are avaiable at affordable prices only up to 90mm diameter. For larger telescopes, the aperture of the telescope is stopped down by the filter. This reduces both light gathering power and resolution of the telescope dramatically!
You can read more about H-alpha observing and photography in these articles on our website www.astrosolar.com:
How does a SolarSpectrum H-alpha-filter work?
The graph shows you schematically the construction of a narrow-band H-alpha filter of the modern generation. First, the light passing through the filter meets an anti-reflection layer (the light intensity of the chromosphere is about 1 million times weaker than that of the photosphere, therefore no or little stray light must occur in the filter). Thereafter, the light passes a filter that removes a large part of the unwanted light from the spectrum.
Next is the core of the filter, a Fabry Pérot Interferometer or Fabry Pérot Etalon.
Subsequently, another filter follows which blocks further wavelengths and isolates the H-alpha line, then another anti-reflection layer. The whole filter block sits in a housing and is heated to a very specific temperature.
The Fabry Pérot Interferometer
The graphic on the left also schematically shows the Fabry Pérot etalon a bit more detailed. The light of the Sun comes from the right, indicated by the spectrum. The first filter is a very broad filter centered around the H-alpha line. Thereafter, the light hits the Fabry Pérot element.
The Fabry Pérot Etalon consists of two parallel and partially transparent glass plates or etalons (special plastics) with an intermediate air layer. Light beams are often reflected in the air gap on the facing glass surfaces. By interferece, most wavelengths are cancelled out.
Depending on the construction and dimensions of the etalon, only the H-Alpha line remains with some secondary maxima, which are filtered out by the last filter (indicated by the vertical red bar). By choosing the thickness of the air gap and the etalons, you can filter out any lines from the spectrum.
The FWHM (full width at half maximum, describing the narrowness of filtering) achieved with such filters is up to 0.2 Å (0.02 nanometer) depending on the effort and construction.
What is the FWHM (full width at half maximum) of an (H-alpha) Filter
DThe graph explains the FWHM or full width at half maximum. On the horizontal axis, the wavelength is specified in nanometers and on the perpendicular the transmission (light transmittance) of a filter. The FWHM is defined as value in nanometers or Ångström at a transmission of T / 2 max.
In order to see surface details in the H-Alpha light, FWHMs <1Å (0.1 Nm) are required. For example: The deep sky H-Alpha filters used by astrophotographers for H-II regions have FWHMs of around 10 to 50 Å (1 to 5 nm).
In addition, of course, the filter must exactly hit the wavelength of the H-alpha line up to a few tenths of nanometers. Therefore, these filters are heated because you can tune the filter exactly to the line via the temperature.
After many customer feedback about our CMOS-Optimized Narrowband filters, we learned that it is necessary to finetune our current f/2 Highspeed filters into two filter categories of Ultra-Highspeed filters for f/2 (working range <f/2.3) and – NEW – f/3 (working range f/2.3 to f/3.4). Further Information about this as well as a detailed whitepaper can be found in our Blogpost Preshift and further Information concerning Baader CMOS-Filters.
Update October 1st: New LRGB-Filters have been added to the line of CMOS-optimized Baader Filters. The post below has been modified to reflect these changes.
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Various Baader Planetarium Print Advertisements from 1966 and later years
"Finding the way" has a long tradition at Baader Planetarium. The slogan got created by our companies founder Claus Baader – in 1966, when "the Baader Planetarium-Orrery" was announced to the world. And within those many years we always tried to find ways for our technical solutions – and the domes – to stand the test of time. The Baader Planetarium Orrery btw. might have the longest product existence in modern industry – we still produce it here in house – unchanged since 1966 (if you like, check a tiny bit of the print material published at that time).
Today we have a similar situation – we worked hard for two years and the "feeling" here is just like way back then. For our new filters:
WE FOUND THE WAY
... to finally and cost-effectively tackle the problem of filters being accused of creating unbearable halos when put into close vincinity of correcting lenses – in conjunction with latest generation CMOS-chips. Hence we introduce our four new families of Baader (Ultra) Narrowband / Highspeed filters:
All these new filters are designated as CMOS-optimized, with the same high quality and engineering you expect from the Baader family of products.
New CMOS-optimized Baader filters
This very problem had almost got us "over the edge". For more than a decade, during the reign of CCD-cameras, our Baader Narrowband-filters had served somewhat as an industry-standard in astro-filter technology. And "all of a sudden", with always newer and revolutionary CMOS-chips hitting the market, people started to complain about halos, whenever a coma-corrector, field-flattener or reducer-corrector would be placed in close vincinity to one of our filters. We studied far and wide and for some time took some soothing from the fact that amateur forums around the world had similar reports for our much higher priced competitors. However, some solution to this just had to be found – but without just have filter prices skyrocketing as was the case everywhere. As a consequence we looked into latest advanced coating technologies and how to use it in ways to address this most severe problem, since nowadays almost any telescope would use such auxillary-optics closely in front of the chip-plane.
Eventually, with significant investment in R&D, we ran from one prototype run into the next for almost all of the years from 2019 until now (middle of 2021). Countless nights were spent under the stars to evaluate so many different coating systems on all new filter families.
However, after much heartship we are absolutely convinced that our new Reflex-Blocker™ coating systems are addressing this severe problem in a very satisfying fashion, with just a moderate increase in price. You will be the judge.[br]
This new generation of Baader CMOS-filters features:
Increased contrast, matched for typical CMOS quantum efficiency and s/n ratio
Reflex-Blocker™ coatings, for largest ever freedom from halos, even under most adverse conditions concerning aux-optics
(Ultra) Narrowband/Highspeed: Ever more narrow passbands
(Ultra) Narrowband/Highspeed: FWHM on each filter category carefully designed to allow for 1:1:1 exposures
Identical filter thickness to existing standards, with utmost care for parfocality
Blackened edges all around, with filter-lead-side-indicator in the form of a telescope-sided black outer rim, to additionally eliminate any reflection due to light falling onto the edge of a filter
Each filter coated individually, with sealed coating edge (NOT cut out of a larger plate with coatings left exposed, read more)
Life-Coat™: evermore hard coatings to enable a non-aging coating for life – even in a most adverse environment
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Don´t be misled.
These all new CMOS-optimized filters work magnificently with all existing digital camera technologies, be it CMOS or CCD. However – an owner of CCD-camera-technology will still find our previous, extremely affordable, narrowband filter technology to be fully apt for excellent imaging. But: "the Better always is enemy to the Good".
We are most confident, anyone using latest CMOS-technology will see the improvement right away – for his/her lifetime! This new CMOS-optimized filter generation is meant to stay and become the new standard in the amateur-word of imagers.
In the future...
Similarly designed Photometric Filters (featuring identical standard thickness alike all our filters as well as all standard sizes) are under preparation for the science world in the form of SLOAN/SDSS and modern BVR (Bessel-conform) filters – likewise using our Reflex-Blocker coating technology, to be fully suitable for 24/7 operation.[br]
Images results and test reviews
UPDATE: Testers of regular production series filters
Markice Stephenson
RASA 8
The Celestron RASA 8 and the Baader High-Speed Ultra-Narrowband filters are a perfect match.
I’ve noticed a couple of things off the bat about these new filters:
1. The narrow bandpasses contributed to stronger and cleaner signal and helped maximize the time under heavily light polluted skies. In only ~4 hours, I was able to pick up the upper tail / H-alpha filaments on the Eastern Veil Nebula that I simply wasn’t able to pick up on any other attempt of this target.
2. That there were no profound halos. 52Cyg is a decently bright star near NGC 6960 and the new Baader H-alpha and [O III] filter handled it well. I didn't see any reflections of my cable router in the images or anything that would warrant further inspection. I should disclose that my sole test of the [O III] filter was on NGC 6960, as I was only slewing to H-alpha objects in Cygnus to avoid switching filters on the RASA. As I began one night on [O III], my luck in clear nights ran out. I intend to test this filter further, but the initial results are incredible.
During the week of imaging, however, I was able to gather over 20 hours total of these 6 Ha images: Butterfly Nebula (IC 1318), Western Veil (NGC 6960), Eastern Veil (NGC 6992), North America Nebula Crop of Cygnus Wall (NGC 7000), The Tulip Nebula (Sh2-101), and The Crescent Nebula (NGC 6888). The shortest of the fully integrated images being the North America Nebula, which was only 1 hour and 18 minutes. The longest of the bunch being the Eastern Veil, which was 5 hours and 8 Minutes.
IC 1318 H-alpha - 122x120s exposures for a total of 4hours 4mins, -10C, 120 Gain; Equipment - RASA 8” Telescope and ZWO 294MM Pro Camera, August 5th 2021
Final Thoughts: Coming from the original Baader F/2 images, I expected the filters to perform well. To produce these quality and quantity of images in only ~20 hours, again, shows the power of these newer filters. I fully endorse them for anyone with fast optics, especially if they are seeking to maximize their time under light polluted skies. Ultimately, the performance met my expectations and I can’t wait to put together more full color images!
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Chris Hendren (Technical Support Manager at Celestron Torrance/CA)
Recently, I lucked out and had clear skies until at least 2 AM for 3 nights in a row from my Bortle 9 back yard sky in overwhelmingly-bright Long Beach, California. That let me test out the new Baader 6.5nm CMOS-optimized high-speed filters with the RASA 8 under very tough conditions. Except for the bright magnitude 2.2 star Sadr (Gamma Cygni) in OIII and a much lesser extent in SII, there were no haloes to be seen on any stars with 5 min exposures at f/2.0. I was able to easily minimize the halo to a level I felt comfortable with in a couple steps in Photoshop. I am extremely happy with this result. Chris Hendren, www.hendrenimaging.net
Image Specs:
Celestron RASA 8-optics and CGX-mount, ZWO ASI2600MM-P, Baader 6.5nm CMOS optimized High Speed Ha, SII, and OIII filters. 38x5 min SII, 35x5 min Ha, 37x5 min OIII at -10 C (550 min total exposure) HaSHO aquired in NINA and processed in Deep Sky Stacker, PixInsight, StarNet++, and Photoshop CC.
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Central Cygnus HA - TPO180, ZWO2600MM, Baader 6.5 nm HA
UPDATE: I tried the Baader 6.5nm High Speed HA filter with an f/4.5 TPO Ultrawide (Askar FMA180 clone) scope just to satisfy my curiosity on how slower scopes worked with the high-speed filter. I binned 2x2 to compensate for the reduced signal and then shot 46 x 2 min exposures unguided near Gamma Cygni. ~72% QE at H-alpha with the ZWO ASI2600MM-P certainly helped. I will likely have a lot more trouble with SII and OIII at the slower f/ratio, but this experiment worked pretty well.
No calibration frames. Processed in DSS, PixInsight, and Photoshop CC.
New images 30th August 2021:
I had two good nights this last weekend, so I decided to try an HOO narrowband combination on IC 1396 as I had no sulfur data. The green channel is actually 25% HA and 75% OIII, while HA is mapped to Red and OIII to blue. This was a nice way to get a “close to RGB color” narrowband image from my Bortle 9 skies with a bright moon up. Celestron CGX and RASA 8, ZWO ASI2600MM-P, the above mentioned Baader filters. 130 min HA and 160 min OIII (5 min subs) at -10C, acquired in NINA. Processed in DSS, PixInsight, and Photoshop CC.
One of our first testers is Andreas Bringmann, owner of a 2.6m Baader Classic Dome and renowned Astro-Photographer – see his images on www.astrobin.com/users/equinoxx/. The all new f/2 Ultra-Highspeed Filters not only lead to amazing images but even enabled the photographic proof of the newly discovered planetary nebula StDr13, check out the detailed test review.
I would like to emphasize, that the opportunity you have given me to test the new CMOS-optimized filters has been for me, an astro-amateur, like winning the lottery! Andreas Bringmann, www.astrobin.com/equinoxx/
Now Mr. Bringmann had the opportunity to test the new CMOS optimized Baader 5.5nm H-Beta filters:
First of all, I would like to thank you very much for allowing me to test the new Baader filters and I can report that the new CMOS-optimized 5.5nm H-beta filter works photographically perfectly even at f/1.9!
{{block type="mageworx_downloads/link" id="1718" title=""}}Our QHY- and filter expert Christoph Kaltseis held a lecture on our new CMOS-optimized Baader (Ultra-)Narrowband and Highspeed Filters at the ATT DIGITAL show on Saturday, May 8th 2021. The lecture was held in german language only, we apologize. Also the presentation material exists only in German (at least so far). In case you're still interested, you can find the PDF to the right.
after almost 1.5 years of constant tests of always new prototype runs of Baader filters in four different filter categories, I do conclude that the outcome superseeds my expectations, especially considering the prices. Christoph Kaltseis, www.cedic.at
After initial testing, I was pleased to find that the new CMOS-optimized Baader filters with reflex blocker coating work great. With the much narrower passages, there is hardly any light pollution, but plenty of signal and contrast. There are also no halos or reflections, even with very bright stars, which I have never seen before on f/2.
I used the freshly arrived highspeed filters for a quick snapshot of NGC7000 with my RASA 8. The image consists of 5x120s O III and 15x120s Ha, so a 40 minutes bicolor image. This definitely shows what can be done with a fast system and good filters. I don't like to expose less than 10h, but with such bright nebulae I would be done after 4-5h. Julian Shroff, Instagram, Youtube
Also a quick first test with the highspeed H-alpha filter on Deneb with 30s, as well as 60s shots shows the difference clearly in my eyes. There is much less unwanted light coming through and also the slight halo, which is present with other filters I have used so far, has completely disappeared even with an extreme stretch.
Last night (03.May 2021) it was clear for a short time. I have now also made a few 30s and 60s exposures of Deneb with the O III filter. On the 30s images the image looks perfect, on the 60s there is a very faint halo - at maximum stretch. Considering that with other O III filters I used to have halos on virtually every even remotely bright star, I find this very satisfying.[br]
Our british customer has been testing our new CMOS-optimized filters in combination with a QHY 268M camera (read more about that here).
I'm very impressed with the Baader UNBs and managed to get some H-alpha data under Bortle 7 skies with my new CMOS camera. Having used previous Baader high speed filters on my RASA 11, I can confirm that these are a step forward in conjunction with the RASA optical configuration, that is putting so many lenses very near in front of the filter. These new UNBs definitely are improving contrast with the RASA and helping me to keep stars under much tighter control. The UNB-OIII filter likewise has improved considerably with the Frontside Reflex-Blocker technology, with no halos recorded in this images data (unfortunately due to the weather the data is incomplete to make a pretty bi-colour picture). Ian Aiken
Revealing the secrets of the cosmos: captivating deep-sky images with cooled QHYCCD cameras
Monochrome camera models
As we gaze into the endless expanses of the night sky, we are overwhelmed by the sheer size of the cosmos. Deep-sky photography allows us to capture the celestial beauty of distant galaxies, shimmering nebulae, and elusive star clusters.
In this blog post, we will introduce the extraordinary capabilities of QHYCCD deep-sky cameras, specifically designed to unlock the wonders of space and take your astronomical photography to a new level.
Unmatched sensitivity for deep sky photography:
QHYCCD deep sky cameras feature state-of-the-art CMOS and CCD sensors designed to provide exceptional sensitivity in low light conditions. These sensors are ideal for capturing the faint details of celestial objects, revealing intricate structures and subtle color variations previously accessible only to professional observatories. With their remarkable signal-to-noise ratio, QHYCCD cameras ensure that even the faintest deep-sky objects can be captured.
Advanced cooling technology:
To minimize the effects of thermal noise in long exposure astrophotography, QHYCCD has incorporated highly efficient cooling systems into its cameras. These cooling systems employ Peltier elements to rapidly lower the temperature of the sensor, allowing longer exposure times without compromising image quality.
Versatile adaptation options:
QHYCCD offers a wide range of deep-sky cameras that are compatible with various telescopes and facilities. Whether you are using a refractor, reflector, or dedicated astrograph, there is a QHYCCD camera for every telescope that will fit seamlessly into your equipment. What's more, these cameras come in a variety of sizes and formats, so you can choose the optimal sensor size for your specific imaging goals, whether it's wide-angle imaging or detailed imaging of galaxies or planetary nebulae.
Our recommendation for getting started with deep sky photography
[product sku="qhy533"]
The QHY533M/C is a very good and affordable entry-level camera. It has everything a modern CMOS camera is expected to do. For amateur astronomers interested in all areas of astronomical photography, the QHY533 M/C can cover a wide range of images. With its BSI Sony sensor, the camera is extremely sensitive and low-noise in the deep sky range. Thanks to its good cooling performance, long exposure times can be realized with it. The pixel size of 3.76 µm x 3.76 µm is optimally adapted to shorter focal lengths of 500 to 750 mm. It also features non-existent amplifier glow, very low dark current and readout noise, and extremely high sensitivity. The IMX 533 is a 9-megapixel CMOS image sensor with a diagonal of 15.97 mm (11.29 mm squared) and 3003 x 3003 pixels which are read out with 14-bit data depth via the AD converter and is available in both monochrome and color versions.
The two older models, the QHY163M and the QHY183M/C, should not go unmentioned.
For some time now, QHY has been offering a good and affordable camera in the form of the [product sku="QHY163"], ), which is equipped with a monochrome 4/3-inch Front Side Illuminated Sensor (FSI). The Panasonic MN34230 sensor achieves a maximum sensitivity of 60% quantum efficiency (QE) and has a sensor size of 21.9mm. With a pixel size of 3.8 µm, the camera achieves a full resolution of 16 megapixels.
Also available is the [product sku="1931086"], which is equipped with a monochrome 1 inch Back Side Illuminated sensor and thus higher sensitivity. Both sensors are technically mature and therefore well suited for beginners. However, many semi-professional deep sky astrophotographers consider the sensor area to be too small; today, 35mm full-frame sensors are increasingly in demand.
In addition, both camera models have only 12-bit analogue digital conversion (12-bit data depth). In order to achieve the low value of 1e- of the read noise, one must either increase the gain and thereby accept losses in the image dynamics, or reduce the gain and then lose precision in the analogue digital conversion. Nevertheless, both models are good cameras for beginners.
QHYCCD cameras for experienced astrophotographers
[product sku="QHY268"]
For experienced astrophotographers, we would like to introduce exceptional deep sky cameras:
The QHY268M/C is a high-resolution, cooled APS-C camera with 26 megapixels (6280 x 4210 pixels), true 16-bit A/D conversion and 3.76 µm pixels. It is available in both a monochrome and single shot colour camera. The sensor size of the Sony IMX571 Back Illuminated Sensor is 23.5 mm x 15.7 mm (28.3 mm diagonal).
It also features non-existent amplifier glow, very low dark current and readout noise combined with extremely high sensitivity. In extended mode, even a full well capacity of up to 75 ke is possible. The round design, the sensor and the pixel size make this camera ideal for the Celestron RASA and Hyperstar systems.
The chip of the QHY268 has the same features as the flagship QHY600.
The QHY 600 sets a new standard for astronomical CMOS cameras. It uses the IMX455, a highly sensitive 60 megapixel back side illuminated full-frame sensor in 35mm format with a square pixel size of 3.76µm and is therefore also very well suited for shorter focal lengths. The camera is available in both monochrome and single shot colour versions. In addition, the QHY 600 also features true 16-bit analogue digital conversion, which was previously reserved for cameras with CCD sensors.
The QHY600 is available in three camera models. The models PH-L(LITE) (only available with monochrome sensor), the QHY 600 - PH (PHOTO) and the QHY 600 - PRO. The PRO version can be optionally equipped supplied with 2x 10 Gigabit fibre optic interfaces and a QHY PCIE kit for faster data download. In addition, the monochrome PRO and PHOTO models are supplied with an industrial (Grade K) class sensor.
For more information about the special versions of the QHY600, please visit the product page
The QHY294M is technically a special case and is supplied by Sony with a fixed pixel binning of a 2x2 matrix as standard. As a result, the Back Side Illuminated Sensor delivers 11.7 megapixels at 4.63 µm and 14-bit data depth in standard mode (readout mode 0).
QHY has managed to switch Sony's "on-chip" binning on and off in the monochrome version of the 294 PRO, thereby enabling two different readout modes. Readout mode 1 "unlocks" the binning to produce 46.8 MP images with 2.315 µm pixel size at 12-bit data depth per pixel. The ability to trigger the 294 PRO with two different pixel sizes also allows it to be used for two different imaging focal lengths to match the optimal resolution of the telescope.
Which cameras are suitable?
The reason for recommending the QHY533 as an entry-level camera and the QHY268 M/C or QHY600 as a full-frame version for experienced astrophotographers is based on the basic requirements for a good deep sky camera. It should have the following features:
Back-Illuminated Sensor: QHYCCD uses back-illuminated sensor technology in all new cameras with Sony sensors, which significantly increases the quantum efficiency of the sensor. This results in higher sensitivity, better signal-to-noise ratio and improved performance when capturing faint astronomical objects.
High Dynamic Range (HDR): Some QHYCCD models (including the QHY533 and QHY268/QHY600) offer HDR capabilities that allow you to capture a wider range of brightness levels in a single image. This feature is particularly beneficial when capturing celestial objects with varying brightness levels, such as nebulae or star clusters. Full Well Capacity: QHYCCD cameras have generous full-well capacities, allowing you to capture bright stars or intense nebulae without saturation. This ensures that you can capture the fine details across the entire dynamic range of your subject, even in high-contrast celestial objects.
Active cooling monitoring: QHYCCD cameras feature a sophisticated temperature control and monitoring system that provides real-time feedback on the temperature of the sensor. This enables precise adjustments and ensures optimal image quality throughout the entire imaging session. QHYCCD's proprietary technology provides significantly better noise reduction than any other astronomy camera on the market.
True RAW Image Output: QHYCCD cameras offer TRUE RAW IMAGE OUTPUT, producing an image that consists only of the original signal, allowing maximum flexibility for astronomical image processing programs after capture. In comparison, the typical DSLR implementation has RAW image output, but it is usually not fully RAW. Upon closer inspection, there is some evidence of noise reduction and hot pixel removal. This can have a negative effect on the image in astrophotography, e.g. the "star eater" effect.
Monochrome or colour: A variety of the QHYCCD camera series are offered with monochrome or colour sensors. Colour sensors allow a colour image to be captured directly and are therefore easier to use than monochrome cameras (which require a number of filters, such as an LRGB set, to reconstruct the image in colour using special processing techniques). However, monochrome cameras have one important advantage: they are more sensitive than the corresponding colour cameras for the same sensor. This not only allows you to capture fainter details with the same exposure time, but more importantly, it allows you to use narrowband filters against light pollution (such as H-alpha, OIII and SII filters), which greatly increase the contrast of the nebula against the sky background (and also reduce the size of the stars so that you can see the framed nebula better), making astrophotography possible even in areas of heavy light pollution.
Software integration and support: QHYCCD deep sky cameras integrate seamlessly with popular astrophotography software for a comprehensive and streamlined imaging experience. Whether you use a dedicated capture software such as N.I.N.A or an image processing software such as PixInsight, QHYCCD cameras are fully supported so you can maximize the potential of your image data.
4164*2796 (11,7 MP) bei 4,63 µm / 14 Bit Datentiefe (Modus 0) 46,8 MP bei 2135 µm / 12 Bit Datentiefe (Modus 1)
6072*4044 (24,6 MP)
6280*4210 (26 MP)
9600*6422 (61 MP)
Pixel Size
2,4 µm
3,76 µm
5,86 µm
4,8 µm
3,8 µm
4,63 / 2.315 µm
5,94 µm
3,76 µm
3,76 µm
Framerate @ Full Resolution
15 fps
18 fps
138 fps
10 fps
22,5 fps
16,5 fps
19,2 fps
6,8 fps
2,5 fps
ADC-Bit-Depth
12 bit
14 bit
12 bit
14 bit
12 bit
12/14 bit
14 bit
16 bit
16 bit
Full-Well Capacity
15,5 ke-
58 ke-
32 ke-
46 ke-
20 ke-
65 ke-
120 ke-
51 ke- / >75 ke
51 ke- / >80 ke
Pixel-Fov (@1000mm)
0,5"
0,78"
1,21"
0,99"
0,78"
0,96/0,48"
1,23"
0,78"
0,78"
Which advantages do the mentioned deep sky cameras have in detail:
The QHY533 is a popular camera among beginners in astrophotography because of its many advantages. Here are some of the main advantages of the QHY533 for beginners:
Sensor performance: Sony's BSI CMOS IMX533 sensor offers excellent sensitivity and low noise. The pixel size of 3.76 µm enables an extended dynamic range and better performance even in low light conditions.
High resolution: With a resolution of 9.1 megapixels, the QHY533 delivers detailed and sharp images. This high resolution allows beginners to capture fine details of celestial objects, including galaxies, nebulae and star clusters.
Versatile field of view: The QHY533 has a relatively large sensor (1-inch format) that allows a wide field of view.
Cooling system: The QHY533 has a built-in cooling system that reduces the temperature of the sensor during long exposures. Cooling the sensor reduces thermal noise, resulting in cleaner, higher quality images.
Fast readout speed: The camera's high-speed USB 3.0 interface and efficient readout system enable fast transfer of image data to your computer.
The QHY533 is available in both colour and monochrome versions. With the colour version, you can capture normal one-shot colour images of galaxies and nebulae. For the monochrome version, we also offer a set with an integrated 7-position filter wheel. This allows the convenient use of multiple filters for narrowband or broadband images.
For the experienced astrophotographer who wants a slightly wider field of view, we recommend the QHY268 or QHY600. These cameras are based on the same Sony sensor technology, but with a much larger sensor area.
For the larger camera models, such as the QHY268 and QHY600, QHYCCD also offers user-selectable readout modes that allow the camera to be perfectly matched to the respective celestial objects and lighting conditions. Different readout modes provide different image results. Each readout mode has its advantages and disadvantages. The main differences are in the maximum full-well capacity, the readout noise and the image dynamics.
Here is an example of how the readout noise behaves in the 6 readout modes and with different gain settings. Many of the modes have a "switching point" for high and low gain. Here, the readout noise decreases from 3.5 e- to 1.5 e- (example: high gain mode 2CMS between gain 55 and 56).
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Special feature QHY294:
[product sku="QHY294Pro"]
The QHY294M is technically a special case and is supplied by Sony with a fixed pixel binning of a 2x2 matrix as standard. As a result, the Back Side Illuminated Sensor delivers 11.7 megapixels at 4.63 µm and 14-bit data depth in standard mode (readout mode 0).
QHY has managed to switch Sony's "on-chip" binning on and off in the monochrome version of the 294 PRO, thereby enabling two different readout modes. Readout mode 1 "unlocks" the binning to produce 46.8 MP images with 2.315 µm pixel size at 12-bit data depth per pixel. The ability to trigger the 294 PRO with two different pixel sizes also allows it to be used for two different imaging focal lengths to match the optimal resolution of the telescope.
The [product sku="2458600" style="imgright"] is optimized for sensors of size 15 x 10 mm and a 9 μm pixel size.
These specifications are met, for example, with the older KAF-1603 CCD sensor.
Thus, our current CMOS camera recommendation is the IMX492-based QHY294M Pro. This sensor has a dimension of 19 x 13mm. Due to 2x2 binning, the resulting pixel size is 9.26 μm.
Regarding our [product sku="2458550" style="imgleft"]: The optical design of the DADOS is designed to illuminate chips with the size of 13.8 x 9.2 mm and 9 μm pixel size.
Detectors with larger chips than 13.8 x 9.2 mm can also be used, but here image quality and resolution will decrease somewhat at the image edge. Classic recommendations include the CCD-based cameras SBIG ST-402ME, STF-8300 and FLI ML1603 - as a modern equivalent, we would also like to recommend the QHY294M Pro here.
QHYCCD scientific cameras offer the latest technology in scientific imaging at reasonable prices. Scientific CMOS image sensors offer extremely low noise, fast frame rates, wide dynamic range, high quantum efficiency, high resolution and a large field of view simultaneously in one image. In this sense, while QHYCCD cameras for astronomy clearly meet the definition of scientific cameras, QHYCCD differentiates its scientific camera models with additional features not found in similar models for astrophotography.
QHYCCD scientific cameras are characterized not only by extremely low noise, high quantum efficiency, and other scientific CMOS features, but by
Large area, high resolution sensors, SWIR sensors, polarized light sensors,
GPS-enabled timing,
external triggers,
field programmable gate arrays,
2x10 GB fiber optic computer interface and water cooling options.
The following scientific models are suitable for microscopy, spectroscopy, multispectral imaging, inspection, bioluminescence imaging, life science applications, and many other laboratory applications.
Ideal for astronomical and biological science research
Very high quantum efficiency, square (Gpixel)
Low & High-Gain readout like QHY4040
Available also as UV sensitive version
Ideal camera for astronomical and biological imaging as well as spectroscopy
Universal high resolution full frame camera with professional connectivity (GPS & fiber optic connections)
also available as photographic version for high-end users (QHY 600 PH)
With GPS PPS Synced High Precision Hardware Stamp
cooled camera with the smallest sensor
Ideal for multi-site, high precision timing of exoplanet light curve measurements and is the for cooperative multi-site imaging of asteroid occultations.
Universal high resolution full frame camera with professional connectivity (GPS & fiber optic connections)
also available as photographic version (QHY 268 PH)
The Andromeda galaxy is an object seen by every amateur astronomer, either with own eyes or as an image. I was particularly fascinated to image our magnificent neighboring galaxy with the RASA 8" - Rowe-Ackermann Schmidt Astrograph(#822252, € 2195,-) under a perfectly dark sky. This was one of the reasons why my way led me to La Palma for one week in October 2019, to do my images at the Athos Centro Astronómico (www.athos.org).
The QHY 163M camera is a perfect fit on the RASA 8" in terms of field size and pixel scale for M31. For a monochrome camera, the [product sku="baaderfcct"] (see also the test report by Michael Jäger: RASA 8" Extreme) was a very important accessory. This special development of a filter changer for the short backfocus of the RASA 8" not only allows a quick exchange of the different filters, but also a sensitive and stable adjustment of the camera against tilting. I used my proven LRGB and UHC-S Baader filters, but added the very first prototypes of the Baader f/2 ULTRA-Highspeed Narrowband Filters.
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Careful cable routing avoids unwanted spikes on the pictures.
Final preparations: Every optical surface must be clean for the highest possible contrast
After arriving with this instrumentation on La Palma, I was able to set up everything on the first day and was ready to take the raw images of M31. During the setup I paid special attention to the position of the USB- as well as the power cable, which were connected to the QHY-camera. Therefore I led both cables as exactly as possible in a 90° angle in front of the optics to the outside. I fixed the cables with the dew cap heating tape. By this careful preparation I was able to ensure that in the final images beautiful and fine spikes around bright stars could be achieved, which are otherwise only known from reflecting telescopes with high-quality secondary mirror spiders.
In the first clear night I could already start with my project. Via the FCCT the system was perfectly adjusted very quickly, for sharp stars right to all four edges. With every filter change I focused again to get the maximum signal with perfect image quality for every shot. My goal was always to get the most out of M31. The new ULTRA Highspeed filters were a very important help for this, to be able to display the depth of color in the galaxy.
For the exposures in Luminance, UHC-S, R, G and B I chose a single exposure time of only 180 seconds each, due to the extremely fast aperture ratio of f/2 - despite the exceptionally dark night sky on La Palma. For the H-alpha and O-III data I exposed 300 seconds each.[br]
f/2 ULTRA-Highspeed O-III 8 x 300 s
f/2 ULTRA-Highspeed H-alpha 8 x 300 s
UHC-S + L-Filter jeweils 13 x 180 s
RGB-CCD Filter je Kanal 13 x 180 s
[br]However, nature did not quite agree with my plan. The following days and nights were marked by clouds and rain, which was very good for the island after a hot, dry summer, but it caused me long waiting hours. This weather is quite normal for this time of the year - this was already clear to me when I planned the trip at the end of October. My hope was that I would be granted at least a few clear nights.
Ready for the night: Camera, heating tape and autoguider at the telescope.
But only when my one-week stay on La Palma was already coming to an end, a very good night followed. The seeing was above expectations and the transparency was only slightly affected by a very light Calima.
The fast RASA 8 made it possible for me to insert all missing filters in one night or to improve the pictures from the first night. To understand: with an aperture ratio of (e.g.) f/5.6 I would have needed 36 hours of exposure time - and every night on the island would have had to be equally good...
All data was processed with dark and bias. I refrained from using flats, because preliminary tests had already shown that an extraordinarily good illumination could be achieved with the chosen setup.
All single images were measured in PixInsight and evaluated regarding FWHM, roundness and signal. I registered all subframes on the best single frame. So I could collect a total of 275 min exposure time at f/2.0, which would correspond onto 550 min at f/2.8, 1100 min at f/4 and 2200 min or 36.6h at f/5.6!
After I had integrated the data for each filter into a sum image, I was able to examine the averaged images in advance. The 3.5nm H-alpha data showed a ring and single HII regions in the M31 galaxy, clear and sharply resolved, and this at only 400mm focal length! The O-III data, however, did not show any special features.
During image processing I first merged the averaged luminance image with the averaged UHC-S image. These two images formed the basis for an enormous depth. The RGB data were calculated into a color sum image and color calibrated (with GAIA + APASS).
Then I merged the luminance and UHC-S data with the RGB data in Adobe Photoshop without any loss of depth or color information. In this image I then embedded the H-Alpha signal into the red channel in such a way that it matched the R. I proceeded in the same way with green channel and the O-III signal.
The balance in depth and the reproduction of the narrow band data was very important and could be done with some knowledge. After that I had a deep recording of M31, which combines UHC-S + Luminance + R + H-alpha + G + O-III + B.
With this I almost finished my M31 shot in Photoshop, and now the final touch was made. To make the very bright center look natural, I overlaid the image with the H-alpha data. That was extremely delicate! But I am more than satisfied with the result, because a lot of details could be brought out at only 400mm focal length.
From my point of view the effort and the strict selection of the data paid off. 275 min exposure time and 400mm focal length, with a very handy and absolutely focus-stable lens – who would have thought this before?!
This image was printed as an A2 poster as part of the poster campaign atwww.sterne-und-weltraum.deand appeared in SuW 02/2020. Have you ever seen it hanging on a wall?
THE EQUIPMENT: Perfectly matched
The vast Andromeda galaxy is ideal for the RASA 8" with 400 mm focal length and a camera with Micro-Fourthirds sensor. With a weight of almost 7.7 kg the telescope is very easy to transport. For this picture an exposure series was made (see above). The stars are sharp up to the edges - for this amount of sharpness a fast camera lens would have to be stopped down.
RASA 8" Astrograph
Celestron RASA 8" f/2,0 Schmidt-Astrograph
The RASA 8 transfers the concept of the fast Schmidt-Camera into the digital age: The camera is mounted at the primary focus of the telescope, a corrector ensures a flat field of view. Thus, with the 8" RASA at 400 mm focal length and 203 mm aperture a very compact and high-quality f/2 astrograph could be built. Since the RASA is based on the Schmidt-Cassegrain design, the price is also very attractive. [br]
Example image: QHY 174 camera
QHY Camera with Baader FCCT
The QHY 163M, a cooled CMOS camera with a micro four-thirds sensor, was used for the shoot. Its compact, lightweight housing is ideal for digital Schmidt cameras where it sits in front of the lens. The monochrome sensor is sensitive across the entire spectrum and shows exceptionally good sensitivity for the finest brightness gradations. Together with the appropriate filters, colour photos with very short exposure times are possible. With the soon available short Baader FCCT (Filter Changer & Camera Tilter) the filters can easily be exchanged and above all the image position of the QHY camera can be adjusted on the fly from the side, while mounted at the telescope, without any problems. Since the image was taken, camera technology has advanced and the QHY 163 is no longer in production. The QHY 294M delivers comparable sensor size and resolution with a modern sensor, and with the FCCT II it can also be connected to the RASA 8.[br]
At an aperture ratio of f/2, normal narrow-band filters no longer work. Due to the extremely oblique incident light cone, with entrance angles of 0 degrees (image center) to 14 degrees (image edge), the filter coating technology is at its very limit. The specially developed Baader f/2 ULTRA-Highspeed filters are designed for fast astrographs with aperture ratios between f/1.8 and f/3.5. They are available for the wavelengths H-Alpha, S-II and O-III in all standard dimensions. With such filters the colors in the star forming regions, e.g. here of M31, can be displayed without any vignetting and with full S/N-ratio.
Old department store telescopes (Quelle Catalogue)
If you are older than 50 years and were interested in astronomy as a child, you'll surely remember the time when there wasn't such a broad astronomy market as today, with lots of dealers and manufacturers. This was not only because there was no internet – there were also simply no products. Smaller telescopes were rare, as there were only a few manufacturers. It is no coincidence that the first "mass production" in Japan began only shortly after the Apollo mission. In the early 80's in Germany, the mail order company Quelle offered the famous 60mm lens telescope with a reflex finder as well as a 114 mm Newtonian made in Japan, both labeled with their house-brand "Revue". Opticians had the same telescopes in their shop-windows, only with other labels. They were good or even excellent optics – unfortunately on very shaky mounts. Nevertheless, many of todays amateur astronomers started their "career" with one of those scopes. At least in Western Germany, there were simply no other options. In Eastern Germany, instead, astronomy was taught in schools, and the Zeiss Telementor was a common "school telescope".
Advertisement with Leonard Nimoy for a Celestron C8 in "Sky and Telescope" in the year 1982
Larger telescopes than a 114mm Newtonian were much too expensive for anybondy with a normal income, and there were no "middle-class-telescopes." The most important manufacturers of expensive telescopes in Europe were Zeiss, Wachter and Lichtenknecker, who also offered the required heavy and precise mounts. But these were telescopes either for wealthy and ambitious amateurs or for public observatories. Around this time, the first orangecolored Celestron C8 with fork mounts crossed the Atlantic Ocean. They were admired by the astronomical community as rare and novel. You could get really jealous when looking into the magazine "Sky & Telescope", which circulated in many of the astronomical clubs and public observatories.
The good thing about this market situation in Europe was that at that time, as a normally situated amateur, there was almost nothing left to do but acquire the knowledge and skills to build or improve your own equipment. That's why there was a lively exchange during the meetings of the many astronomy clubs that were formed as a result of the Apollo euphoria at that time. Those who had learned the basics in these times still profit from it today! Many people discussed optics grinding, or how to develop photographic film and how to build a mount for your telescope. Especially the mount cannot be overestimated for amateur astronomy. Every telescope can only develop its full photographic power if it is sturdy, and if positioning and tracking work with highest precision. ("Each chain is only as strong as the weakest link").
A pioneer in buiding high-quality telescope mounts was certainly the Japanese company Vixen, which brought affordable and sturdy equatorial mounts from mass production to Europe in the 80s. When astronomy became more popular as a hobby in the 70s and 80s – inspired by the Apollo missions – the GoTo technology was still far from being invented. And so amateur astronomers spent most of their valuable clear nights searching for celestial objects with the help of star maps. This was educative, but it took time! The telescope mounts of this time had either no motors at all or only one tracking motor in the R.A. axis, which could do one thing: turn the R.A.-axis with one revolution per day. Electronic controls for the automatic slewing to celestial objects were reserved for the largest telescopes in the world. Especially when you compare electronics and computer technology, you realize how quickly everything has evolved. On their incredible journey to the Moon, the Apollo astronauts had computers on board that seem ridiculous today. The AGC (Apollo Guidance Computer) was developed at MIT in the early 60s. It had 36kb memory of which the program was stored in 32kb ROM, the rest was RAM. The data processing ran with 1Mhz - and the machine weighed an incredible 32kg. Modern smartphone models (which weight less than 200g) have several thousand times the speed and a memory that stores more than two million times as much data as the Apollo computers could.
Von Apollo zu 10Micron - Printanzeige (erscheint in SUW, Astronomie - das Magazin, VDS)
An Apollo astronaut would be as stunned as a 1980's amateur astronomer if you had shown him a 10Micron Mount back in his days. The servo motors of this mount are fast and precise enough to track the ISS or to slew to specific craters on the Moon – so that you can observe them within minutes at highest magnifications.
Now: Special offers to celebrate the 50th anniversary of the lunar landings
If you perform a 3-star-alignment with the mount and add another 11 alignment stars, then you can take images with exposure times of many minutes – without the need for auto- or even manual guiding. The precision of the mount is absolutely stunning, with a deviation of no more than 0.5 arc-seconds. For comparison: Jupiter has got a diameter of ca. 40 arc-seconds when seen from Earth.
Every 10Micron can do all this – from astrophotography to satellite tracking – without an additional computer. Everything is done with the integrated electronics and the hand control. To put it a little sloppily, this mount "knows" that it is an astronomical mount and not a modified robot which might also be used by the automobile industry. It even has "senses": By the integrated encoders, it always knows its exact position, so you can move the axles manually and still see on the display the exact celestial coordinates where it is pointing to. Such a mount with its superb mechanical quality and the integrated computer technology links the "old" space age with today. It can be the end of a long journey for everyone who still remembers the time of Apollo.
In the early space age, the modern technology would have looked like a car in the middle ages – like magic. But nevertheless, the roots of the development of a mount like a 10Micron lie in the time half a century ago, when the broad public developed an interest in astronomy.
We have a lot to thank the Apollo astronauts and technicians for, because this program has inspired people all over the world to look into natural sciences and to develop the technology required for researchers as well as for hobbyists. Just take a look at old space images taken e.g. by the 5m telescope on Mount Palomar in the 1970s and compare them to the much better images taken by amateur astro-photographers today with Celestron, TEC or Planewave telescopes on 10Micron mounts, then you'll easily see how far we have come. Who knows what the future will bring, where technology and the interest in astronomy will lead us to and when mankind will reach for the next stop in space, the planet Mars.
Palomar Gattini-IR telescope. Copyright: Palomar Gattini-IR team
Wtih the [product sku="1351140"], TEC has created a unique instrument for sky surveillance. Thanks to the aperture ratio of f/1.44 and a flat image field of 52mm, large parts of the sky can be photographed very quickly in high resolution.
These special features are now used by a project on the famous Mt. Palomar in California, where a TEC VT 300 scans the northern starry sky every night in the infrared range completely as a mosaic. Thus one hopes to find changes, for example brightness fluctuations of stars, but also new objects like comets or asteroids. The last convulsions of dying stars are as much a goal of the observations as the short flash of light at the collision of neutron stars - and maybe some things you don't even think about yet. In the infrared you can penetrate the large dust clouds in the galaxy and make objects visible that are hiding in them. As is so often the case, a new telescope design allows a new view of the sky.
The Italian manufacturer 10Micron is expanding its range of high-precision mounts to include azimuthal models. Initially based on the GM2000 HPS and the GM4000 HPS the AZ 2000 HPS and the AZ 4000 HPS will be presented at the ATT in Essen.
In the standard configuration, these mounts are designed for one telescope and require counterweights; with the DT (double telescope) option, the mounts can also be operated with two telescopes. The two sides do not have to be perfectly balanced:
AZ 2000 carries a payload of 50 + 35 kg,
AZ 4000 HPS 100 + 150 kg!
Thanks to the azimuthal configuration, compact observatory buildings can be used more efficiently and, above all, the tiresome meridian flip is eliminated. This allows objects to be observed all night long. The mounts provide a stable basis for scientific applications such as satellite tracking, photo- and astrometry, lidar laser applications and much more. With an image field rotator, "classic" astrophotography with the usual 10 micron precision is also possible.[br] The double telescope option can be retrofitted to the AZ 2000 and AZ 4000 at any time, and two telescopes can even be mounted on each side of the AZ 4000.
The standard version allows to assembly the optics to only a side of the mount and is supplied with a short counterweight bar.[br]
You can find all furhter information about the AZ Mounts and the DT Upgrade Kits on our 10micron product page:
