Friday, November 27, 2020

NGC 891 & Abell 347

The main object in this image is of course the edge-on unbarred spiral galaxy, NGC 891 (a.k.a. Caldwell 23 or Silver Sliver Galaxy), 100 thousand light-years across located 30 million LY away in the constellation Andromeda.  It is a member of the NGC 1023 Group of galaxies which in turn is part of the Virgo Supercluster which the Milky Way is part of.  Larger telescopes do a great job of bringing out the detail in this galaxy, however, the dust lane is well defined even in my image.  Surprisingly this region of space was unknown to me until I saw some really cool images on Astrobin from some of my friends.  The really prominent yellow star in the lower center approximately 3545 LY away is HIP 11185 (apparent magnitude 6.7/absolute magnitude).  It was even more prominent but I toned it down a bit.   

I purposely framed it off center as I wanted to show part of the the galaxy cluster Abell 347 located 240 million LY away.  I really wanted to show this object as Abell objects typically are small dinky things too small for my equipment.  The cluster is located in the in the lower right portion of my image and many gorgeous galaxies and interesting looking galaxies which still show some structure even though they 8-times further than NGC 891.  There are numerous other galaxies throughout the entire image and I found myself getting lost trying to spot them.

Imaging this was straight forward and processing went well but would have been easier had it not been for the poor quality of the luminosity data which took quite a bit of extra inventive work.  That was the bad news, the good news is I discovered the cause and fixed it.  Turns out the luminosity filter had something on it.  It was not dust or a typical spot but more of a dendritic pattern in a couple of areas.  Whatever it was came off with the isopropyl alcohol cleaner and the new flats are perfect.  I will keep a close eye on this to see if it happens again but I have been looking to replace my 7nm ZWO 1.25" filter set with the 6 nm Astronomik set or 6.5 nm Optolong set.

Dates: 11-16-20, 11-18-20, 11-20-20



NGC 891 & Abell 347
Dates: 11-16-20, 11-18-20, 11-20-20
Camera: ZWO ASI1600MM-Pro Telescope: Astro-Tech AT115EDT 115mm Refractor Telescope
Barlow: None
Focal Length: 805mm
f/7
Focal Reducer: AstroTech Field Flatterner/Focal Reducer
Mount: Orion Sirius
Filter Wheel: ZWO EFW 8 x 1.25"
Filter: ZWO L, R, G, B
Focuser: ZWO EAF
Autoguiding: ASI120 Mini attached to an Agena 50mm Guide Scope/ZWO 60mm Guidescope
Exposure: L 82 x 90, R 41 x 90, G 34 x 90, B 36 x 90
Gain: 139
Offset 21
Temp: 5 C
Processing: APT, NINA, PixInsight, Photoshop, Topaz DeNoiseAI.

https://kurtzeppetello.smugmug.com/
http://astroquest1.blogspot.com/
https://www.astrobin.com/users/kurtzepp/collections/ 

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