2016u1 20161227 0555 arobertson

my first chance to get on both this comet. Set the 24” up during the day and was observing from 6pm but skies very claggy against the forecast – NELM of only 5.0 and 20.8 was my best SQM reading. Clouded over at M/N so partially covered up and got a couple of hours sleep in. Woke at 2.45am and clear again, observing by 3.30am but this time very transparent skies although seeing still poor (Ant IV). I looked to see if I could see the mag 5.5 in UMi and immediately noticed the mag 5.8 one! SQM reading was 21.27 – game on!

 



 

C/2016 U1 was much lower so I waited until the last minute to get on it at 0545 hrs. It was very bright looking like a reasonably bright globular cluster with a brighter core and a fainter outer halo – quite roundish. Although that description could fit a GX it looked more like a globular to me – although not resolved (obviously) I suspect there’s a bit of ‘granularity’ that the brain picks up on. I defocussed a slightly orange-ish star in the FOV to the same size as the comet and couldn’t decide which was fainter/brighter so a good match apart from the orangey spectrum of the star. This star I’ve since identified as HD 154477 mag 8.8, spectrum K5. The sketch was made with a 13mm Ethos. I also examined it with a 24mm Panoptic and a 17mm Ethos, also used a 1.25” comet filter in the 13mm & 24mm. I found the comet filter enhanced the size of the coma slightly. With the comet filter I estimated the diameter of the coma to be about the same as the distance between the 2 stars indicated. Without the filter it’s diameter was about ¾ this distance. The 2 stars are; TYC 00976- 04331 & 07061 at a separation of 126”.