NGC 253 (Sculptor)


David Attié

Abu Dhabi

C11 XLT Fastar + focal reducer 0,63x
CCD Moravian G2-4000 (internal filter wheel)
Off Axis Guider Skytrack made in France by Skyméca + LodestarX2
Mount: Az-Eq6
Baader LRGB filters

I got very good conditions last week end in the desert so I decided to catch a few photons from this fascinating object which is quite low above the horizon. I had to do everything between 40 and 30 degrees elevation. I wish I could have done more colors but unfortunately I have set my tent at the wrong place :-(

Overall, I really like how it came out :-) Nevertheless, I have a wrong distance between the focal reducer and the sensor: I’m too short so that takes me to f7 instead of f6.3 and the coma is very annoying :-( It is also noticeable that the coma is not symmetric (more right than left). I did a very good collimation on the field just before shooting: I achieved a very nice Airy pattern thanks to my planetary camera (QHY5l-IIm), a 2.7x barlow and Metaguide software. Hence, I can’t explain this strong coma on the right side unless I have got a tilt in my imaging chain…