Astronomy lessons learned

Visual observing will really only get you so far with typical amature gear.  The problem is that the eye processes each photon it receives in real time… there’s no way to stack data over time to get more detail with the naked eye.  Another problem is that when dark adapted (the rods of the retina take over processing), color sensing is greatly diminished because only the cones of the retina process color.

So, if you want to see more detail, the idea is to increase the aperature of the telescope.  The primary purpose of the scope is simply to gather more light than the human pupil will typically allow (magnification is a nice side-effect).  So, the larger the aperature of the telescope, the more light it collects and funnels into the human eye.  The more light you get in, the more detail you can see (again, mostly black & white since the cones are not really active).

If you want to see color, and the most detail out of any telescope.. you’ll need to switch to using a camera of some sort.  Cameras can be configured to take longer exposures and therefore, stack the protons they receive.  Further, color cameras always process color, unlike the human eye.  The camera you use depends greatly on what you wish to accomplish and the time you have to commit to the process.

If you already have a DSLR or other camera that can swap lenses, then you’re already a good portion of the way there.  The other items you’d need to use your current camera is a T-ring for the camera (Canon T-ring / Nikon T-ring), and a T-ring adapter for your telescope.  The most common and most compatible T-ring adapter is a standard 1.25″ Eyepiece adapter.  A basic version is the Celestron 93625 Universal 1.25″ Camera T-Adapter, but other, more advanced styles (some that allow an eyepiece to be inside the adapter, etc) are available.  This will allow you to slide your camera directly into the telescope (in place of an eyepiece).

A word of caution… Camera use (and extended exposure time) requires much more precise tracking than does visual observing.  Precise tracking takes more time to setup, and more expensive equipment (mounts, auto-guiders, etc), especially when you get into multi-minute exposures.  This is an advanced technique… so sticking with planetary and lunar observing / imaging will be much easier than deep space objects (nebula, galaxies, etc) since the planets are VERY bright objects comparatively.  With planets, instead of long exposures… you actually record video with each frame being a short exposure.  Then, process the video through a program like the free Registax.

Another issue with camera based observing is that depending on your scope / camera / optical path… you may not be able to achieve focus!  CloudyNights Forum and your local astronomy club (Google Search / Club Finder) will help guide you on this front if you choose to go down this path.  Your local astronomy club may even have loaner equipment so you can try out different types of scopes and camera gear before you buy!

The evolution of my equipment….

  • I started with a Celestron NexStar 8 SE Telescope (8″ SCT on a single arm alt-az mount with tracking/go-to).
  • I quickly realized I wanted to image to get the most detail… so I bought a ‘wedge’ to go with my alt-az, and make it behave like a Equatorial mount.
  • With the weight of the scope and my camera (<a href=’’>Canon T1i</a>), the wedge+SE mount combination was simply too shaky for any serious work.
  • I sold the SE mount and wedge and bought a Celestron CG5 mount.  This is a German Equatorial with Go-to / tracking.
  • My tracking wasn’t up to snuff for anything more than about a 30 second exposure, so I bought an Orion Star-Shoot AutoGuider kit w/ 50mm guide scope.
  • After a bit with the CG5 mount, the Celestron Advanced VX Computerized Mount was released, and I upgraded to it, selling my CG5 on CloudyNights classifieds.
  • While in Arizona this winter, I took the plunge to upgrade to a Hyperstar configuration on my 8″ SCT (which I’ve used this whole time) and also bought a scientific grade, cooled, color CCD camera (ATIK 414EX).
  • I also have been interested in Solar observing for a while… I had made my own off-axis solar filter for my 8″ SCT, but this was only functional for white-light observing.. and a lot of the detail I wanted to see was in the Hydrogen-Alpha spectrum.  So, while in Arizona.. I bought a Lunt LS50THa solar telescope.

My astro-photo collection can be seen here:
My Astro-Photo Collection

Details on my Arizona adventures are available at:
Arizona and Astronomy

Some other posts with imaging results from Arizona are at:
First Solar Light
A Little Horsehead Nebula
Flame Nebula and Whirlpool Galaxy

Further help on picking a good telescope can be had at:
Raleigh Astronomy Club: Buying a Telescope.

Also note that there’s nothing wrong with buying used telescope gear. As long as the optics are not broken, and there’s no obvious sign of abuse, astro gear typically just works.

Two classifieds I use:
Cloudy Nights Classifieds – Free service
AstroMart – Paid subscription required to see prices

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