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What's the actual size of your 2" filters in "mm" with and without frame/ring? What step down adapter is suggested from a 52 mm to "-- mm"?
Question by: Waqas Ahmad on Oct 10, 2016 7:54:00 PM | 1 Answer(s)
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Details
This new generation of Baader CMOS-filters features:
CMOS-optimized Baader Filters- 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
- 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
Further information, test reviews, image results...
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".
... can be found on our detailed Blogpost:
Baader Blogpost:
New CMOS-optimized Baader FiltersThis entry was posted on May 8, 2021 Last modified on May 4, 2022.
Test-report on new Baader dielectric SDSS-filters, sensational evaluation comparing to RGB-scheme
Baader Blogpost:
First Light with Baader SDSS filters by S. ZiegenbalgThis entry was posted on February 23, 2022
Related Articles
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New CMOS-optimized Baader Filters
See results Here you can jump directly to customer images taken with CMOS-optimized Baader Filters Update May 4th, 2022: 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. "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...
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First Light with Baader SDSS filters by S. Ziegenbalg
IntroIris NebulaPleiadesLDN 1495 Attn. click above images for complex content Both, CMOS and CCD cameras designed for (amateur) astronomy typically have a spectral sensitivity from 400nm to more or less 850nm. But RGB filter sets for astronomy only use the range from about 400nm to 700nm and the on-sensor color filter arrays of consumer cameras only cover about 420nm to 640nm. That means, about one third of the spectral bandwidth is wasted. The three central filters used for the Sloan Digital Sky Survey (SDSS) split the the spectral range of interest into three approximately equal parts: G': 410nm to 550nm, R': 555nm to 695nm and I': 695nm to 845nm. So these filters would be a perfect choice for three-color images with modern cameras. That's probably one reason why these filters became quite popular in professional astronomy. But professionals normally use custom-made filters which are out of reach for amateurs. Baader Planetarium is now the first company which offers these SDSS filter to a wider clientele. This article presents tests and first lights of the long awaited SDSS G', R' and I' filters and compares them with RGB shots. All SDSS filter images in this article are taken with QHY600L cameras...
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Baader L-RGB Filters – CMOS-optimized
A brief introduction to the function of CMOS/CCD (L)RGB Filters 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...
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HALOS – viewed without prejudice
The moment you insert any type of filter into the optical setup, which consists of your specific camera, the appropriate flattener/reducer or coma corrector and the telescope, the filter becomes part of this unique optical system. And every optical system is different because many products from different manufacturers are involved. All optical surfaces interact with each other in some way. One possibility is that coatings of the camera reflect unwanted light back into the telescope and onto all optical elements in front of the filter. If there is no other optical surface that will reflect the light back to the filter a second time, then it is perfect. There are no halos other than residual halos or scattering, which are unavoidable, depending on the filter design. That's what we mean by our slogan "no halos, no ghosting, no reflections" on our product pages. A filter rarely produces halos itself, which are created inside the filter by internal reflections (this happened to us once in 2015, but we replaced all of these filters). Because the moment there are other surfaces near the filter, it is much more likely that light will be reflected from one of those surfaces, creating halos that...
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FAQ
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Unmounted Filters – which side should face the telescope?
For our CMOS-optimized filters we have created the following images showing which side of the filter should face the telescope.
LEGACY FAQ for older unmounted CCD-Filters without black outer rim
Question in Detail:
I just bought LRGB 36mm unmounted filters. I have question: which side of filter should be placed towards telescope? Is it better way of distinguish than "more shiny surface towards telescope"?
Answer:
Always put the more reflective side towards the telescope side. To guide you we already put a small arrow on the filter rim, on those filters were the position matters. This arrow indicates which face of the filter should be directed towards the sky (telescope-sided). All cell-mounted filters are already oriented in a way that the most appropriate filter face is facing the sky when the filter would be mounted directly onto the front end of the nosepiece of a camera.
If you mount your filter the other way, any reflected light would have a short way to the camera sensor, resulting in a higher risk of getting some kind of back-reflections inside the camera field. Many sensors have highly reflective areas near to the light sensitive area, also the area with the bonding contacts is sometimes highly reflective.But: this is true only for instruments without optical elements near to the focal plane. If you have f.e. a coma corrector, field flattener, focal reducer, focal extender (to a lower degree due to concave surface), or in extreme cases a whole lens group for more complex field corrections a few centimeters in front of the filter it could be useful to flip the filter against the rule from above (thus having the arrow pointing away from the telescope). Cause in such cases the likelihood of reflections from the sensor could be lesser then fort- and back- reflections from such glass-surfaces. If in doubt, it helps to make some test images from a star field with bright stars, using the filter in both ways for comparison.
Should you really have some reflections with both positions it can be more effective to add a spacer between filter and camera, eventually shifting the reflection out of the image field. With focal correctors having curved surfaces changing the filter-lens distance could help also.
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HALOS – viewed without prejudice
For our CMOS-optimized filters we have created the following images showing which side of the filter should face the telescope.
LEGACY FAQ for older unmounted CCD-Filters without black outer rim
Question in Detail:
I just bought LRGB 36mm unmounted filters. I have question: which side of filter should be placed towards telescope? Is it better way of distinguish than "more shiny surface towards telescope"?
Answer:
Always put the more reflective side towards the telescope side. To guide you we already put a small arrow on the filter rim, on those filters were the position matters. This arrow indicates which face of the filter should be directed towards the sky (telescope-sided). All cell-mounted filters are already oriented in a way that the most appropriate filter face is facing the sky when the filter would be mounted directly onto the front end of the nosepiece of a camera.
If you mount your filter the other way, any reflected light would have a short way to the camera sensor, resulting in a higher risk of getting some kind of back-reflections inside the camera field. Many sensors have highly reflective areas near to the light sensitive area, also the area with the bonding contacts is sometimes highly reflective.But: this is true only for instruments without optical elements near to the focal plane. If you have f.e. a coma corrector, field flattener, focal reducer, focal extender (to a lower degree due to concave surface), or in extreme cases a whole lens group for more complex field corrections a few centimeters in front of the filter it could be useful to flip the filter against the rule from above (thus having the arrow pointing away from the telescope). Cause in such cases the likelihood of reflections from the sensor could be lesser then fort- and back- reflections from such glass-surfaces. If in doubt, it helps to make some test images from a star field with bright stars, using the filter in both ways for comparison.
Should you really have some reflections with both positions it can be more effective to add a spacer between filter and camera, eventually shifting the reflection out of the image field. With focal correctors having curved surfaces changing the filter-lens distance could help also.
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Off-standard single filter sizes from Baader - why not:
Quite often we receive requests for a single filter in an off-standard size. In all cases we are sorry that we must answer as follows:
Sorry (we know it would be so very much cheaper in production - and we would be so much more flexible to fill special requests) - but we have decided long ago to not cut or saw our filters from large plates because this would leave the coating stack open and mutilated (with microscopic cracks) all around, prone to aging and peeling.
Many times we had the chance to inspect our competitors filters after several years of use (due to our 30+years of servicing SBIG-CCD-cameras/and filter wheels) and we realized already 15 years ago how moisture and heat stress can deteriorate even most modern hard coatings, slowly peeling off from the carrying substrate over time, unless the coating stack is sealed all around the filter stack.
As a consequence - in order to create our filters to remain impermeable - we only offer all filter substrates already cut to final shape and run each substrate on an double deck auto-polisher to achieve perfect optical flatness and freedom from cone errors.
Then we do individually coat these substrates in 500 pc per run as minimum to fill a complete coating chamber, in a way that the coating stack (many times 50+ layers) applied onto each filter won't reach to the very edge of the round or square substrate, so that the coating stack remains completely sealed from all sides. In this way we can ensure that our filters will not age at all.The sad effect is that we cannot offer other sizes unless the inquired production quantity were in the range of 250 to 500 pc (depending on size) and the tooling rings or square holders will be paid for, which serve to precisely center each individual filter substrate within the rotating calotte inside the coating chamber. Sorry - as explained above - we just will not coat onto large plates and cut any shape from them, also because such large plates cannot be polished optically flat in the same way we do it.
For your most urgent need and for single piece solutions we can only recommend to order the next larger size of our respective filter and have that cut to shape by an ophtalmologist locally. We can supply the round filters without the metal cell in such cases; square filters come without cell in any case.
