C14 - An Unusual Look For The Double Cluster in Perseus

This lovely star cluster is actually two clusters but since they are so close to one another they are together known as the Double Cluster. Located in the Constellation of Perseus they go by other designations such as h and chi Persei, NGC 869 and NGC 884, and also Caldwell 14 (C14). They are approximately 7,500 light-years away and visible with the naked eye as hazy patches but stars can be resolved with binoculars. Like most open-clusters, C14 contains hot mostly hot young stars which are blue in color but there are some orange stars scattered throughout as shown on the image.

I imaged the Double Cluster in the past which is considered an easy target, but not with the red tinted hydrogen alpha (Ha) clouds in the background. There is a reason there are not many images with the Ha clouds because it is exceedingly faint - this was one of the hardest images I have done, almost a month of collecting data. Twenty three hours of total exposure (138 x 10min) using hyperstar (f/1.9) was used to capture these clouds and this is all I obtained. I tried to capture Ha data last year when I did this object with my AT115 at f/5.6 and there was not even a hint even after 17 hours so I bagged it until I had a faster system. If you do attempt to capture the nebulosity I would recommend a fast system (f/4 or less), at least 10 minute exposures, and dark skies. I have Bortle 5 skies at best here in southern Connecticut and crappy weather so not the best conditions for this.

Capturing itself went fine with the ASIAir and Atlas Pro but I did have difficulty with the star shapes as mentioned from my previous image post, however, after adjusting the corrector plate a second time the stars showed significant improvement. Still not great on the edges but much better.  In addition to trashing a lot of Ha data, my first set of RGB data was taken on one of those 'fake' clear nights so there were halos in the green channel stars plus it was before I readjusted the corrector plate.  Consequently I redid it another night with much better results.  I decided to use Chuck's 15 second approach for collecting f/2 data.  As a backup I collected a third set of RGB data using the Canon 200mm F2.8 II USM and ASI294MC Pro which came out OK but the stars were noticeably better with the hyperstar.

Processing was very difficult as well because although I did get some Ha, it was not good looking, certainly not what one would normally expect with over 20 hrs. with hyperstar. I had to do a lot of stretching and noise reduction to make it look presentable. I had dreams of getting some nebular detail but so far the only person to do that is Andreas (Equinox). Probably was the best idea going after this with my limited experience with the hyperstar but I am satisfied with it and am ready to move on to something not as challenging.

C14 - Double Cluster in Perseus

Dates: 9-10, 9-11, 9-18, 9-19, 9-24, 9-27, 9-30, 10-1, 10-6, 10-7
Camera: ZWO ASI1600MM-Pro 
Telescope: Celestron EdgeHD 800
Barlow: None
Focal Length: 2032mm (native)
F/10 (native) F/1.9 (Hyperstar)
Focal Reducer: Starizona Hyperstar
Mount: Orion Atlas Pro
Filter Adaptor: Starizona Filter Drawer
Filter: Baader Highspeed F/2 Ha CMOS, Optolong R, Optolong G, Optolong B 
Focuser: ZWO EAF
Autoguiding: ASI120 Mini attached to an Agena 50mm Helical Guidescope
Exposure: Ha 138 x 600s, R 99 x 15s, G 98 x 15s, B 99 x 15s
Gain: 139
Offset 20
Temp: 0 C
Processing: Asiair app, PixInsight, Photoshop, Topaz DeNoiseAI.

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