Hull Cabin back in April

Back in April I met Charles and Mike at Hull Cabin, located in the Grand Canyon National Park.  It's one of those park-owned cabins that they rent out to the general public.  It was a nice little cabin with a single bedroom with bunkbeds, a kitchen, and a living room with a fireplace.    The bathroom was located in a separate building which made you think twice about going to the bathroom at night as the temps were in the 30's.  But who am I kidding?  I was awake at night snapping shots of the stars or looking through my scope.

Sometimes you get to a point where you think you'll make a leap forward only to discover that you're still plagued by beginner's mistakes. I had a chance to shoot the Rho Ophiuchus/Antares region in the southern sky.  I had been planning to take the shot for about 5 months as I purchased a decent 135mm lens which frames the area pretty well.

In May of 2013, I tried shooting the area with my 70-200 through my old Canon XT/350D that had been modded by Hap Griffin.  This simple shot was 111 seconds (manually counted by me) on the Celestron CG5 mount.   The F/stop was 2.8 and I set ISO at 1600.

I think I processed the image in Lightroom, but I'm not sure.  Obviously, the focus is off and there is some minor star trailing.   I could never get that CG-5 working well for astrophotography.   No matter how long I spent polar aligning the mount, I always seem to get trailing in exposures greater than 30-40 seconds.

Fast forward to April 2014, I was able to get better results with the Zeiss 135mm lens.  I used the Canon that I had modified a couple months before, shot it at F/3.2 with 1600 ISO.

This shot is a result of 18 x 5 min exposures.  Only bias frames were used during the stacking of the images.  No darks or flats.  But the Zeiss lens is pretty darn impressive without much vignetting noticeable at F/3.2.   Stacked in Deep Sky Stacker.   Brought into Lightroom and Photoshop to bring out better (perhaps too much) color.  And what mount did I use?   The trusty AP900.

What I'm disappointed at is how I can't seem to deal with overly exposed elements in the image.   Both Antares (the bright orange star) and M4 are just too blown out.  And what's up with that halo around Antares?   If you look really close, the fainter stars are not pinpoints, they are elongated.  I guess I could've shot this again at Van Vleck, but I felt I should move on to more targets.   Most of my shots at Van Vleck had perfectly round stars so I'm guessing my polar alignment was to blame.

We also conducted an interesting, short comparison at Hull.   We shot the North American Nebula (NGC 7000) with both my modded Canon T3i and Charles 60Da.   The exposures were identical with identical processing.   Both shots used my Sky-Watcher 66ED with a Williams Optics reducer/flattener. On the left is the 60Da and on the right is the modded T3i.

Both exposures were for 5 minutes at ISO 6400.   Though the shots were autoguided, there was minor trailing.  I was using the CGEM mount.   It's pretty obvious that the modded T3i is letting in more H-alpha light, but the 60Da doesn't do a bad job either.   In a way, I can see why one might be happier with the 60Da.   

At Van Vleck, I discovered that the little Sky-Watcher 66ED had a loose mounting plate.   It made me wonder how long it had been loose as I had been using the 66ED as my autoguiding scope. Luckily, I noticed the loose mounting plate during the first night at Van Vleck.  As a result, I switched to the Orion Miniguider for the week at Van Vleck, which may explain why I never had guiding issues for the week.