I had to wait a while for the skies to clear to continue testing the Gamma Star Tracker. Got off to a really nice start testing the new tracker with the Canon 50mm f/1.8 lens. But now it was time to try Gamma with the Samyang 135mm f/2 light-gathering monster. I have high hopes and expectations for this lens on this tracker. So with a half moon at my back, I pointed the camera in the direction of Cassiopeia to capture the Heart and Soul nebulae with the 135mm. I know this is a target best captured with a modified camera but I have yet to take that plunge with the T3i. Tonight I just want to see what this target really looks like with an unmodified camera.
Just the Facts
I proceeded with my usual setup and got polar aligned. Given the light conditions, I thought it best to stick with shooting at f/4 and an ISO of 1600 with 45-second exposures. This appears to be the sweet spot for my Bortle 6 location. I daydream about darker skies where I could really open things up but I digress. But for now, my plan is just to start shooting and go as long as my camera battery allows.
The night provided another opportunity to test the Astro Photography Tool’s (APT) plate solving and integration with Stellarium. Man, I am so happy that I set this up. I may have to write a post just dedicated to this as it’s saving me gobs of time and a lot of frustration in trying to frame up my target in the sky. Within 7 minutes I had the 135mm aimed right where I wanted in capturing the Heart and Soul nebulae.
I shot for about 3.5 hours and ended up with about 260 light frames along with 40 darks and 25 flats. Once again it got a little soggy later in the evening but not anywhere near as bad as last week. And hey, it’s so nice to finish shooting before midnight for a change. But I am a little conflicted at the moment because the Pleiades and Orion are starting to rise in the East-Southeast sky. Soon. Soon.
Heart and Soul Nebulae at 135mm
I lost 11 photos to a brief wash of clouds. After crawling through the remaining 249 photos, I noticed several things. First, I must have been a little sloppy with my polar alignment. So I definitely drifted a bit over the course of a few hours. Not terribly, but noticeably. And second, the tracking was very good. Out of 249 photos, I was able to keep 210 for stacking, or 84%. Easily the best results I’ve had to date when tracking with the 135mm lens. And that’s saying something since I know I was drifting!
All things considered, this was an encouraging session. I’m actually surprised at how much detail came through in the photos given my camera isn’t capturing much from the hydrogen alpha spectra. Environmental conditions and the moon definitely marginalized my signal-to-noise ratio. It was rather tough to post-process this image with those artifacts which is why you can see even more grain in this scaled image. But as a test using the Samyang 135mm f/2 lens with the Gamma Star Tracker – superb.
On the Horizon
I’ve got a couple of things in the works.
It looks like I may have a few clear nights over the coming week. Excellent opportunity to continue Gamma testing and I think I’m going to pull out the Canon 75-300mm f/4-5.6 telephoto lens. I still have a bit of a bad taste in my mouth over my attempt with the Triangulum galaxy. So maybe it’s time to fix that.
When I’m not shooting I’m working on upgrading my Samyang 135mm lens collar. The plan is to add a focuser using the Arduino Nano 33 IoT chip I have laying around. I have aspirations of writing an ASCOM driver to control this but for now, I’ll just whip up a C# Windows Forms App. I’ve got most of the code already written for this solution which means I can start working on designing the prints. My goal is to finish this by the end of the year as my time allows.
And finally, if Gamma continues to shine I’m thinking of dipping my toes into auto-guiding. I believe my tracker is robust enough to handle it with a few minor modifications. I’ll just take things as they go. At least I have no shortage of things to explore.