This entry was posted on November 14, 2017Last modified on November 15, 2017.
Dark horizontal streaks or stripes in the spectrum are caused by dust deposits on the slit plate of the spectrograph. A partial attenuation of the spectrum results from dust spots (“Donuts”) on the camera sensor.
Let's start with the slit plate of the spectrograph. A dust grain deposited on the slit becomes apparent across the spectrum as a horizontal, dark line perpendicular to the spectral lines. The more frequently the DADOS is attached to the telescope, the more dust can penetrate. And dust can also penetrate through the 1 1/4 " nosepiece of the slit viewer when changing the guide camera.
Cleaning is critical and not recommended because wiping on the slit plate would cause serious harm. Gently blow away dust from the slit plate with DRY compressed air, being careful not to let any liquid propellant from the compressed air get onto the slit plate. Never blow on the...
This entry was posted on July 12, 2017
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...
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"?
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....
Please visit our website www.astrosolar.com/en/faqs for many questions and answers on our solar products, such as AstroSolar Film, Solar Viewers and mounted Baader Solar Filters.
Question in Detail:
I just received a Baader 2" Clicklock TAK-adapter M72. After a few uses it's spinning where it shouldn't. If I hold the inside on the bottom near where it threads onto the scope it works. Can you tell me what to do? Can I repair it?
This might be a mistake done here during assembly. Please try this fix. If it does not help please return the Clicklock clamp to us or to your dealer, we apologizie.
Actually the 2"/M72 ClickLock is consisting of the M68 ClickLock and the Adapter M68/M72. There are 6x M2.5 screws underneath the M68/M72 Adapter. These prevent the M68 thread from rotating. It seems that they where not properly tightened. If you grab the very small outer ring on the ClickLock which is part of the M68 Adapter, and remove the M72 Adapter, then you can fasten the M2.5 screws. We...
If you want to create absolutely beautiful color photos of bright deep sky objects (entry level) and wish to work with sophisticated techniques of Astrophotography (and the correct tracking), then your camera is ideal. For advanced working with long exposure times, i.e. with narrowband emission line filters, the DSLR is less suitable.
The reason is partly in the manufacturer’s narrow cut filter that is installed before the camera’s sensor only allows some of the main wavelengths (H-alpha and S II) to penetrate by a fraction over the prolonged exposure time.
Even if this limitation was lifted by conversion to a suitable astro cut filter, which lets through red, colour CCD sensors for photography with narrowband line filters are not ideally suitable as only every fourth pixel is addressing that wavelength.
Cameras (s/w cooled Astro CCD cameras) are already available for exposure times in this tight line area allowing exposure for...
The ACF-/BCF- replacement filter has exactly the same effective optical thickness as the original AA filter. During the conversion process the focus is calibrated to the best of our ability.
In addition: the conversion will not affect the auto-focus function at all. That is one of the advantages of having our professional modification service.
Question: I am interested in the conversion of a Canon 400D / 40D. On their websites you can only find the filter curves and description for the ACF filter, not the BCF filter used for this conversion! What are the differences in the daylight suitability if it is not simply identical with the ACF filter?
Also I noticed that the ACF filter from 1100nm is permeable. Is this a problem?
Answer: The CMOS chips of the EOS series behave like most other chips from different manufacturers, they are from 1050nm rapidly insensitive to light. Therefore, it is pointless to continue to block past 1100nm.
The effect of the BCF filter corresponds exactly to the curve shown on the website! We do not want to publish the design details of how we achieve these spectral characteristics, so there is no graph for the BCF filter, but rather a comparison of the...
No, it is absolutely necessary to use filters with the precise size and thickness to guarantee maximum quality. We cannot rely on unknown filters, in addition we are only specialized in astro modifications.
No, with manual white balance it is easy to recalibrate the images to daylight values. Only when using images for professional applications a second, unmodified body can be useful, cause there will be a slight reduction in dynamic range and slightly more moire effects visible.