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.