Astrophotography gear

I've read a bunch of sites on the web about astrophotography.  I don't understand much about processing the images yet, that will take time to play around with.  I don't have any images worth sharing yet, but the basic process is to take several exposures, call lights or subs.  Using free software called DeepSkyStacker you can combine all of the subs, along with dark, bias, and flat frames (all described on their site) to get a much more detailed image and remove a lot of the noise.  There are several packages to process the image after that.  A lot of people use Photoshop, but I'm cheap, so I'm going to try to use GIMP.  I found an experimental release of version 2.9, which allows processing 16 bit images at http://www.partha.com/.  

While I do that, I'm also trying to develop a good way to take the pictures.

The camera I'm using is a Canon T3i.

Using the 18-55mm kit lens that came with it gives some nice wide views.  At 55mm it can fit the "W" of Cassiopeia, and then some.  To get a bit tighter, I picked up a used Bushnell 135mm f2.8 lens on eBay for about $7 (yes $7).

This lens uses a M42 threaded mount, so I also picked up an inexpensive mount adapter.  The nice thing about a fixed prime lens is that the aperture opens much larger than most zoom lenses.  The f2.8 is much wider than the f5.6 that my kit lens can do at 55mm.  This lets in much more light.  I haven't had much chance to use this lens yet, but in some experiments it appear the lower half of Orion would fit in the frame.

I may get another longer lens later on, but for now, this will be my setup.

I'm not interested in doing star trail photos, so a tracking mount of some sort is needed.  Searching the net, I learned about barn door trackers, which are simple DIY mounts.  So I built one matching Gary Seronik's design.  Here's what mine looks like.

 An inexpensive ball head from eBay is used to mount the camera.  I found the same 4rpm DC motor, but I wouldn't recommend it, as I'll mention below.  I built the voltage control circuit described on Gary's page.  For gears, I found appropriate ones at ServoCity.  It all runs off a 9V battery.

Why don't I recommend this motor?  I found that it has a lot of play in the shaft and I can't seem to get a steady tracking rate.  From one exposure to the next some with have no trails, some short trails, and some longer trails.  It also eats up a 9V battery really fast.

So my next thought was to try a stepper motor and control it via an Arduino microcontroller.  More on that when I get it working.