With a dSLR, you tread in familiar territory -- you have your RAW-converter & post- processing tools. All you need is a T2-adapter to connect the camera's bayonet mount to a (preferably 2") nose-piece and stick it into the rear of a telescope. After that, you could use a simple solution like a cable-release and start shooting.

Above description is a little bit simplified but with these steps you can get your first usable images of deep sky objects. And you wonder, why you want to change that -- "If it ain't broken, don't fix it".

It isn't exactly broken but there are things you can improve
  • Your SLR runs on (smallish) batteries and they often aren't strong enough to support 2 hours of continuous long exposures.
  • 2..3 hours of continuous long exposures also create a lot of heat on the image sensor -- but SLRs don't cool it and that extra heat creates visible noise in the images
  • SLRs are user-friendly and have tons of buttons & switches -- on a telescope you want to control everything remotely to avoid vibrations
  • The mirror that separates the SLR from the point-and-shoot crowd is a disadvantage, as it also causes vibrations (some cameras allow for delays to reduce that problem. Reduce but not eliminate)
  • To further reduce vibrations, I even added a motorized focuser with a simple hand controller (PC control is optional)
  • I mentioned the knobs & switches -- they are vulnerabilities to dew creeping into the camera. All cameras state operating conditions as "non-condensing". they have seals but it is a risk. And beside, that dew will settle and deposit dirt INSIDE these seals.
  • The viewfinder and even LiveView are not much of a help when stargazing -- except for looking at the Moon. Venus & Jupiter also will show.
    There usually is a lot of INCONVENIENCE involved in looking at the rear LCD or viewfinder because of the odd angles the camera is pointing and the close proximity to the ground (usually < 4ft)
  • dSLRs have one advantage, astro-CCD can't yet match -- HIGH ISO. This comes in handy for navigating, not for imaging.

Switching to an astronomy CCD-camera solves many of these issues as they usually are more or less elegant chunks of metal with no user controls and a USB & 12V DC input, sometimes a few extra plugs, like ST4 guider & connectors to more accessories.

As I started out using a plain dSLR + scope setup, I thought, I could do it all without a laptop. A wireless remote timer to control exposures and the mount has a handset at full GOTO & alignment capabilities.
Soon I learned, using a laptop is OPTIONAL -- but HIGHLY RECOMMENDED. You can control the SLR remotely, especially Canon SLRs. To improve results, you want to use an autoguider. And also to reduce slew errors, by capturing images via SLR & analyze them is a great help. And see the results on a "big screen" instead of crawling on the ground to look a the camera's rear LCD also is a big plus.

All these features chipped away some of the advantages I perceived in using a SLR and a "portable" setup..In the end, my setup was sophisticated and required USB cables and external 12V. Making the jump towards a "real" astronomy CCD camera now seemed like a small step. And I was WRONG.

Oh yes, the hardware portion was easy -- swapping a few USB-cables, configure a new 12V DC cable and I was set to go. Even my favorite imaging tool -- "APT" -- supports CCD cameras via ASCOM drivers. So what else could go wrong ?

The one thing that currently drives my crazy is called FITS. The default format in astronomy to store images and lots of other meta-data. FITS is a "container" for many different forms of data and THAT is what can cause confusion, problems and serious incompatibilities. The data from a camera can be stored in the same FITS format but it might be pure monochrome, or a one-shot color image in RGGB format, or a one-shot color image in some other format, or a one-shot color image that has been run through a debayer algorithm. Different tools use different FITS features -- some use "slices" to separate the different colors. Other tools can't handle "slices".

Getting a plug-in to view CR2 & NEF images in a file-browser is a piece of cake. Try find a tool to CORRECTLY display these incarnations of FITS images is a different story.

My first steps were kind of successful. Now I have to find tools that FITS me. And need some Aspirin along the way :
- Starshoot's SW can't read FITS I've captured with APT using the Starshoot SXV694C
- Nebulosity can read FITS I've captured with APT using the SXV694C, but results are extremely blue, very little red.
- AstroTortilla worked once -- but not the second night. Debayer issue ?
- DSS so far works best with no debayer + superpixel

Here a look at some other FITS viewers -- most are for scientific purposes and are not designed to perform debayer interpolation : /stargazer95050/created/2014/01/01

More challenges ahead.


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