Saturday, May 12, 2018

Five Newbies And An Old Friend

On the night of May 5th I was able to make it to the observatory for a little over an hour's worth of imaging. On my list of Messier objects left to image (18 remaining), I imaged 5 of the 18. The Old Friend was M13, the globular cluster in Hercules that, with M22, are probably the most impressive clusters in the night sky. I really enjoy them. Unfortunately, Georgia is in the midst of daily smog alerts, so the sky is anything but transparent, and that shows up in the images, or at least in the difficulty is processing the images to reduce the skyglow from the scattered ground based light. At the least, these were more interesting to process for that reason.

This group also includes M40, which has been describes as Messier's one mistake. M40 is a double star in Ursa Major (the Big Dipper). According to Wikipedia, Johannes Hevelius described a nebulosity in the area of M40, which Messier looked for. Not finding any, Messier cataloged the double star instead. Speculation is that the nebulosity that Hevelius saw was NGC 4290, which is a dim galaxy that could be seen in larger telescopes, but perhaps not in Messier's. When I image star clusters or, in this case, a double star, I always take as short an exposure as I can, usually 10 seconds. This is the case for the image showing the double star, which, by the way, is just an optical double, meaning the stars are actually very far from each other and not gravitationaly connected (orbiting each other). The second image is a one minute image which shows not only NGC4290, but NGC4284 as well. The effects of the light pollution are also evident, showing up as the “fog” or gray background in the image. This is the very well known property of light pollution; it essentially removes the black sky, substituting gray and thereby significantly reducing contrast between the dim nebulae and the sky. The result is that the nebulae almost disappears; visually, it actually does disappear.

The rest of the images are as noted under the image. Just the “usual”; galaxies and star clusters. Even though “usual”, I still marvel at God's handy work. All made from the same star stuff, but all different, individual; just like people.

M40 (2 stars near center). Actually NGC4290 IS faintly visible in this 10 Second exposure.

 
M40, single 1 minute exposure with no corrections done. Shows NGC4290 (and NGC4284 to it's left).



 
M68. Globular cluster in Hydra. Compare to M13 further down.

M13. Old Friend. In Hercules, just rising in the east when taken 1 Min exp.


M83. Galaxy also in Hydra. 1 Min exp. Low in southern sky and in heavy light pollution.


M101. Galaxy in Ursa Major. 1 Min exp. This would be in the North, light pollution not as bad.



 
M102,galaxy that's also in Ursa Major.