Uranus
I didn't 'discover' Uranus the same way I 'discovered' Mars or Juno. With those two I saw motion in the animated frames and then identified the object in motion. With Uranus I noticed that it was supposed to be visible in the same frame as my previous Mars observation (see the Stellarium sky view in the Mars detection image 6) and then I went looking for its motion. Since Uranus is considerably farther away than Mars, it moves much slower against the background of stars. You can't see any motion over a couple of nights of observation like you can with Mars. I had to wait over a month from the first frame in order to see even a little bit of motion. But since I knew where Uranus was supposed to be from Stellarium I just looked at that very specific part of the sky. Here are the two frames that demonstrate Uranus' motion.
1. Original, unaligned observation frames (2) from 1/1/2019 and 2/5/2019. These images are processed for bad pixels and undarked.
2. Images set 1 frames aligned.
3. SkyDelta processed frames with stationary stars removed and motion linked. If you look closely you might notice some artificial 'motion' in the top-right region, but that's just border distortions. I'm not processing the border regions for motion for that reason. You'll also notice that big blob that appears in one of the frames. That's Mars just blooping in real quick. It's not in the other frame, so it's not a linkable object. With only two frames to detect stars with there's more noise in these stationary star subtracted frames.
4. Linked object detection translated back to the aligned frames. That's Uranus' apparent motion over 35 days.
5. Here's the frame with Mars in it on 2/5/2019. Uranus is circled. The right angle arrow highlights a star formation that points to Uranus.
6. This is the Stellarium sky view for 2/5/2019. Rotate this image 90 degrees clockwise in your head as you compare it to image 5 for a comparable perspective. Note Mars' position relative to Uranus. The right angle arrow highlights the same star formation as in image 5.
Process notes:
- Same process as Mars and Juno mostly. I added a feature to not link border objects since that region is often distorted. I should write up a general process notes page.
Ideas/Todos:
- Can I find Neptune with this same process using different regions of the same observations?
- I should mask areas of the image that never see enough frames to build a stationary star field. For instance, since this is a two frame observation, the lower right region of the second frame is empty when aligned to the first frame. Thus no stars can be subtracted from that region because they only appear in one frame which is not enough to accumulate a star field from.
Published: June 10, 2019