An interesting comet picture

This picture has comet ATLAS C/2020 M ATLAS pictured all the way to the edge of this frame. When imaging, I did notice that the comet was not visible around the image center, and I just assumed it to be too dim for it to show up. I did not inspect the whole frame. Not sure why that happened: were the coordinates in CdC not accurate, or was the telescope not accurately pointed? The telescope was aligned using PlateSolve2. The delta is about 0,8 degree which would be a VERY large pointing error.

According to SkySafari the coordinates of Atlas are at that time 05h19m and +38°15′ and CdC gives the same coordinates. So it seems to be a pointing error. Platsolving & syncing of the mount only happened before the slewxing to this object, there was no platesolving done to center.

Only when processing 8 frames taken with the Esprit120 and the ASI2600MC of 120″ each (Gain 0) the comet – with it’s typial greenish color – revealed itself.

SIMBAD was showing no other object on that location. Also Astrometry provided a precise RA and Declination for the image center. In the image center there is a dim reddish nebula clearly visible. That turns out to be IC2120, a 14th magnitude nebula of which “SkySafari” says it is a nonexistent Deep Sky Object. What would you say? 🙂 Further exploration indicates that it’s not classified as a planetary nebula or a small hydrogen region.

Learning how to image Deep Sky again

After many months without Deep-Sky, and with Mars getting smaller and smaller, it’s time to pick up DS imaging again. That did not go smooth! Many issues, and also not that happy with the intermediate result. I should check the sensor distance against the reducer!

Check: stars are bloated due to a lack of UV/IR blocker. An in addition the sensor distance was off by 10,5mm which explain sthe stretched stars in the corners.

M31, 5DEC2020 TS76EDPH F4.5 & ASI183MM Luminance no filters (also not a UV)

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