That_Telescope_Guy

The mount has two axis of rotation, one (polar axis) is parallel to the earths rotation axis. There is a motor gear drive that turns this axis one revolution per day in the opposite direction of the earths rotation. This nominally keeps the target stationary for long exposures.

Because of other effects including gravity sag/flexure, alignment errors, and atmospheric refraction tweaking of the drive position is continually needed. When I started this hobby some 30 years ago I looked through a guide scope at a star centered in a cross hair and as it drifted would make small corrections to both axis drives. Now this is done using a guide CCD, and software.

The detailed of instructions would take many pages, I will find/post some references that provide the basic information.

As for cost, the hobby at my level is not cheap. The mount is the single most expensive part of the system.My mount is an Astro Physics "1200GTO" which no longer made. The size smaller 900GTO today is $8750, the size larger 1600GTO today is $11500. I believe 10 or more years ago I paid less than $10K for the mount. The telescope itself consists of a purchased mirror and home made truss and support structure. Everything is probably $5K. The imaging cameras are in the $5K range The observatory is very homemade and about $1000 in lumber and concrete. It is called sweat equity. There are many other bits and pieces some made on my lathe some purchased. There is also software some free, some purchased.

All the above being said, I started with a Celestron C8 and low cost mount 25 years ago for of order $1000. The hobby has grown over the decades, not as suddenly dumping 20K in stuff and having a go at it.

Except for the brightest objects, everything looks like a faint grey smudge by eye, ie colorless. I will typically enhance the saturation to increase the color, and may use other techniques to select only the stars (and or nebula) for enhancement so that the sky background does not become too garish! Separately I try to force the sky to a neutral color, not the muddy brown it would otherwise look.

The images are exposed for up to several hours, then forced brighter using a variety of software. I break the total exposure down into 10 minute sub exposures.

Bottom line there is a lot of image manipulation that goes on in producing a single image.

I've been interested in astronomy since I was a kid. Thirty years ago I was starting to get enough money to do something about it.

If you use a conventional "SLR daylight camera" like a Cannon or Nikon etc there is a red cutoff filter that dramatically reduces the astronomical H-alpha wavelength where much nebula detail and color is. I did start taking pictures with a SLR but left the filter in. I now have CCD imagers made for astro-photography that do not have the IR filter.

I would personally be reluctant to remove the IR filter myself for fear of screwing up and destroying the camera.