It seems I am becoming a collector within my hobby as I now own another telescope. This one is a self build from components bought individually on Ebay. It is an 80mm APO refractor, i.e. smaller but higher quality than the 6 inch refractor I already own. I have assembled a lens made of Japanese FL-53 (the best), tube with baffles, 2 inch Crayford Focuser, Mount rings and Dovetail bar. It is little over half a metre in length and quite lightweight and would classify as a "grab-and-go" telescope. Focal Length is 600mm (distance from primary lens to point of focus) and Focal ratio is F/7.5 which is medium speed. Original intention was to build a guide scope which this will indeed perform but also produces cracking good pictures of it's own!
Tonight I am going to be very ambitious. I'm going to test it on the beloved Horsehead Nebula. This is very close to the bright star Alnitak, in Orion's belt, and as we know such a star would soon saturate and test a refractors optics. Here is a single 10 minute self guided exposure with the Starlight MX7C single shot colour camera.
Indeed Alnitak did saturate as expected but there is nothing like the blue halos being experienced by the 6 inch scope. Not only do we have the (bloated) star Alnitak but also we can spot the Horesehead nebula as well as the Flame nebula below the primary star. Alot of information in this one picture.
So let's reposition the scope and aim directly at the Horesehead aiming to get Alnitak out of the field of view.
Here is the result of stacking 6 shots of 10 minutes each. The stars are nice and round (good tracking) and the colours are good too. Only problem is with shadows of (probably) dust motes on the lens. I can remove these by way of sky flats. These are images of an evenly illuminated background, in my case I use the sky as it brightens in the morning! However I wasn't aiming to stay up this late to obtain said flats.
Indeed I turned my attention to another object as the night was still young, only 2am.
