Saturday, April 20, 2019

Observing asteroid (6) Hebe

From about 03:30 - 05:30 UTC on 19 April 2019, I collected some reflected photons from the main-belt asteroid (6) Hebe.

At the time of the observation, (6) Hebe is in the constellation of Gemini.  The approximate RA and DEC was: 06h 55m 24.3s +19d 38m 20s.

I took 700, 4 second exposures.  Even during the observation, I noted that I probably should have done 3 second exposures.  When I decided on 4s exposures, the tracking was looking really nice.  Maximizing the exposure time improves the signal-to-noise, so being able to do 4s exposures would be better than 3s exposures.  The problem is that the tracking quality kept changing, so much so that many of the star images were short streaks.

So because of the pretty poor tracking, my first run at stacking and making some photometric measurements on the two reference stars in the field-of-view used 544 images.  So that means I've lost 156 images, or 22.3%.  That's a bit much, so I'll need to go back into the data to see if I can modify the parameters in the code to pull out a few more images.

Here's a single image:



Here is the stack of all 544 images (inverted greyscale):

Here's a movie showing the motion of (6) Hebe:

https://youtu.be/HA3sQQUsDLU

There are some strange things in this dataset that I need to look at carefully.  More on this later...

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