2016a8 20160831 2300 arobertson

I was observing from home (South Norfolk) with my 600mm F4.5 driven Dobsonian. Skies were relatively poor transparency (NELM 5.0, SQM 20.9) with a lot of thin cloud around and thicker cloud reflecting light. Seeing was about Ant III at best.  I started off with a 17mm Ethos giving x159 and a 38’ FOV. At first nothing, then I caught a faint star with a bit of halo around it (comet, clagg or something else?). I put the 8mm Ethos in giving x338 and definitely something (not a faint star) with a stellar core and a faint small roundish halo around it but looking more like a 14th magnitude GX or PN so I decided to check if anything similar in the area. Couldn’t identify anything so looked back in the e/p and it had moved!


So decided to do a sketch of it moving through the field. On my first position I was struggling to get the field star positions in relation to it as I realised it was moving relative to them as I was mentally working out the angles! Field stars in, it was then easy to plot 3 positions at 10 minute intervals although the first one probably a bit out as described above. When it moved over star ‘A’ in my sketch I could barely detect it due to the glare from that star. After my 23:00 plot it clouded over and I thought that was it, but at 23:15 it cleared again so I put the 4.7mm Ethos in giving x575. I had suspected that the core was not central to the halo. At x575 I was now convinced that was the case and I’ve tried to show that in the sketch.

Page last updated: Sun 2 Apr 08:09:05 BST 2023