Imaging report (and unique chance to test effects of distant light pollution)

[Vega]

Last night was fantastic for imaging in Somerset with zero wind, zero cloud and good seeing. However this co-incided with Bridgwater Fair (one of the largest in the UK). I could clearly see a white glow rising up from my SW sky a good 50 degrees or so (could even hear the screams and music carrying through the air on occasion ). Anyways, I set up my kit on NGC6946 as planned while true darkness approached. Couldn't see the milky way at all. I realised that my target had not yet passed the meridian and the Synscan was in a position where I only had about an hour before the bottom of the tube would hit the tripod legs while tracking :shock: . {Does anyone know how to tell the GOTO to view the object with counterweights on the Western side of the mount in this situation? (without manually slewing)} Anyways the sky still wasn't properly dark and I thought, the later I wait the further from the fair lightglow my target would be. By about 9:30 I set out again and this time the galaxy was far enough over for the synscan to decide to view it with counterweights facing West. I spent quite a bit of time focusing and centering and testing exposure lengths. Then set her up for 60x75 sec exposures I Just couldn't stretch any more than 75secs without hints of star trailing . Went inside to watch Jonathan Ross.

A good hour and a half later I just couldn't resist another crack at M31 with the 70-300mm zoom now that I had PEC correction running. Now that the fair had petered out, the milky way was clearly visible! It was like looking at a different sky, such a difference. I spent ages trying to get the camera the right orientation using an SLR bracket screwed to the top of the scope rings. Once I finally got it all sorted with focusing and centering I set it up for 30x150sec exposures at full zoom (300mm). I realised I could have got away with 180 after trying some later on but hey, I needed to sleep at some point in the night! Probably not ideal but once all the subs had finished it was 3am so I decided to setup and run the darks in the locked shed so I could go to sleep. There wasnt too much of a temperiture difference to outside.

Im processing the two images at the moment. One very very freaky thing is that while looking through them, I noticed about 10 of my 60 shots of NGC6946 suddenly went out of focus (Like proper donuts) then back in to focus again! :shock: . Considering I never touched the setup when it was taking the shots, this has freaked me out a but and I dont really wanna think about it too much . (ImagesPlus just finished alinging 38 out of those 60 NGC6946 shots so gonna go see what I got) Will post up the images sometime today.

Cheers

Matt

[ngc2403]

that sounds very strange, the 10 out of focus shots. were they at the end? or scattered randomly?

looking forward to the results

[Vega]

A block of them about 2/3rds of the way through, last 3rd were back in focus.

Matt