The Clouds Just Wouldn’t Quit
I really wasn’t kidding about Krakow weather. It hasn’t been terribly bad over the past 10 days, just completely overcast. Not a happy situation when I’m itching like mad to get outside and test the latest version of my tracker. But as you’ll see, it was well worth the wait as I learned that the Lego Star Tracker V4 actually works!
Besides, the downtime was well spent. I started investigating what I could do to better control my camera while tracking and decided to check out the Astro Photography Tool (APT). Not that I need any additional challenges when I finally do get outside, but this might be able to help as I’ll be able to view my images as they’re being taken and make adjustments on the fly rather than waiting until I get back inside.
Come On, Let’s Go!
I leveled up my table in the backyard and ran an extension cord outside so I’d have power for my computer when the time comes. By that time, Polaris was just starting to wiggle through the twilight. I knew I wasn’t going to have much time tonight because there were still clouds in the sky.
And I decided I was going to point the camera straight up tonight for 2 reasons. First, it would linearly align the camera with the axis of rotation and would perhaps minimize any potential issues. Second, swimming through the sky directly above me is Cygnus. What a shame to have such a nice target brilliantly lined up for me :).
I got focused and turned the tracker on. Again I let it soak for a few minutes to give everything time to engage. And you know what, I’m feeling a bit cocky tonight. I’m going to take 60-second exposures. It’s all or nothing at this point – let’s go!
Shooting
When the first frame popped up on my screen, I was a bit perplexed. Yes, there are still star trails but they are in a completely different direction as last time. For a 60-second exposure though, they’re not terrible. Here is the zoomed-in photo of Deneb right out of the camera.
My first thought was my polar alignment is still off a bit. So I tweaked that a bit and it helped a little but didn’t completely fix my issue. It appears that the tracker is lagging the movement of the stars a bit. So I changed the timing of the tracker a bit to move every 5 seconds, and then every 3 seconds. No joy. Check polar alignment again – right, it’s not perfect but I wouldn’t think it would put this off this much.
What the foggy dog is happen…. Woah.
And just like that, I’m perfectly tracking … The next dozen or so shots were all bang on. I was utterly gobsmacked at that moment. Clouds rolled in though and that was it for the night. Bummer.
Time to Analyze
What happened. Well, first I wasn’t tracking very well (improved for sure, but not very well). Next, without really doing anything I was all of a sudden tracking perfectly. What is going on here?
To be sure, I honestly don’t know. It would be easy to blame my polar alignment but then I wouldn’t have ever seen good tracking. Maybe my base shifted during shooting? Oh, I forgot to mention, I didn’t lock it down tonight, so shifting is a definitely possibility.
I have a theory though. Since I pointed the camera straight up tonight, the center of gravity would have been very nearly aligned on the rotational axis. I wonder if the center of gravity was slightly to the left of this axis, so being pulled up, and then it shifted to the right of the axis or was being back on the downswing. Hmmm. I was wondering if that might happen even before I started testing. I’ll need to investigate this more.
As perplexed as I am at the moment, I really need to just take a step back and tell myself:
IT WORKS – THE LEGO STAR TRACKER ACTUALLY WORKS !!!
Now that I’ve demonstrated I can achieve results with a Lego Star Tracker, I can begin to hone in on the remaining issues to make it work better and more consistently.
The Lego Star Tracker Works, What’s Next?
Well, looks like clear skies tomorrow night so I want to try to get out and continue testing. I don’t want to do any major changes and risk not being able to test.
One thing I can do is tighten up the base a bit more. I think there is some flex with the camera mounted and I may be able to add an additional layer of blocks and another 16 x 16 plate to really stabilize things.
I’m going to take care of that and then get out again tomorrow to keep testing!