Hemisphere:  Northern  ·  Constellation: Draco (Dra)  ·  Contains:  NGC 5976  ·  NGC 5981  ·  NGC 5982  ·  NGC 5985  ·  NGC 5989
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Revisiting the Draco Trio:  NGC 5981, NGC 5982, NGC 5985, 



    
        

            Patrick Cosgrove
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Revisiting the Draco Trio: NGC 5981, NGC 5982, NGC 5985

Getting plate-solving status, please wait...
Revisiting the Draco Trio:  NGC 5981, NGC 5982, NGC 5985, 



    
        

            Patrick Cosgrove
Powered byPixInsight

Revisiting the Draco Trio: NGC 5981, NGC 5982, NGC 5985

Imaging telescopes or lenses: William Optics FLT 132 Triplet APO f/7

Imaging cameras: ZWO ASI2600mm-pro

Mounts: iOptron Cem60

Guiding telescopes or lenses: SharpStar 61EDPHII

Guiding cameras: ZWO 290MM Mini

Software: Seqence Generator Pro  ·  Pixinsight  ·  phd2

Filters: astronomiks Halpha 6nm 36mm  ·  ZWO EWF 7x36  ·  astronomiks SII 6nm 36mm  ·  astronomiks OIII 6nm 36mm

Accessory: Pegasus Astro Falcon Rotator  ·  Pegasus Astro FocusCube 2  ·  ZWO EAF Focuser  ·  QHYCCD Polemaster


Dates:June 16, 2021

Frames: 172x120" (5h 44')

Integration: 5h 44'

Avg. Moon age: 5.70 days

Avg. Moon phase: 32.44%


RA center: 15h38m55s.353

DEC center: +59°2033.49

Pixel scale: 0.859 arcsec/pixel

Orientation: -24.578 degrees

Field radius: 0.632 degrees

More info:Open 


Resolution: 4226x3192

Locations: Home Observatory (My Driveway), HONEOYE FALLS, NY, United States

Data source: Backyard

Description

The Draco Trio consists of a close grouping of three very different looking galaxies, found in the constellation Draco.

The Spiral galaxy towards the lower right is NGC 5985. Located 140 Million light-years away, this galaxy measures 246,000 light-years across. For comparison, our Milky Way is 185,000 Light years in diameter.

Next up the chain is the fuzzy elliptical galaxy NGC 5982. This galaxy is 130 Million Light Years away and was discovered by Sir William Hershel in 1788. The luminosity of this galaxy comes from very old stars, and the core of the galaxy contains a supermassive black hole.

Finally, we have NGC 5981, which is a spiral galaxy seen edge-on. Located 112 Million Light years away, it is slightly closer than the other two galaxies. If you zoom in on the image you can see prominent dust towards one side.

These galaxies are part of a larger group of galaxies known as the NGC 5982 Cluster.

Frankly, these are galaxies are pretty small and the grouping does not have a great visual impact when seen at this scale. So why bother shooting them?

Well - there are a couple of reasons.

First, these galaxies are pretty far away compared to some - and just to capture some photons that left when Earth was in the Cretaceous Period - when triceratops walked the Earth and Pterosaurs flew in its skies - yeah - that's kind of cool.

Another reason is that when these were taken, due to the time of year and what can be seen through my tree tunnels - there weren't a lot of other targets available - so why not? In fact, I shot this same target almost one year ago - almost to the day. So this is a kind of test to see if I am improving in my technique. Here is a link to that image if you want to compare:

https://astrob.in/i7ntsp/0/

Finally - these are small galaxies and pulling out detail with my scope will be a challenge. How much detail can I resolve? How much can more can advanced image processing reveal? I spent a lot of time doing deconvolution processing to restore detail lost through the optical system - and I was able to pull out more detail than I thought possible.

Anyhow - here is my most recent attempt at this.

Thanks for looking,

Pat



Here are the details for this image:

These were taken over the nights of June 16 & 17

58 x 120 seconds, bin 1x1 @ -15C, unity gain, ZWO Gen II L Filter

38 x 120 seconds, bin 1x1 @ -15C, unity gain, ZWO Gen II R Filter

38 x 120 seconds, bin 1x1 @ -15C, unity gain, ZWO Gen II G Filter

38 x 120 seconds, bin 1x1 @ -15C, unity gain, ZWO Gen II B Filter

Total of 5.7 hours

40 Dark exposures

25 Flat Darks

Flats taken each night of shooting and used to calibrate that night's Lights

30 L Flats

30 R Flats

30 G Flats

40 B Flats

Capture Hardware:

Scope: William Optics 132mm f/7.0 FLT APO refractor

Guide Scope: Sharpstar 61EDPHII

Camera: ZWO ASI1600mm-pro with ZWO Filter wheel with ZWO LRGB filter set,

and Astronomiks 6nm Narrowband filter set

Guide Camera: ZWO ASI290Mini

Focus Motor: Pegasus Astro Focus Cube 2

Camera Rotator: Pegasus Astro Falcon

Mount: Ioptron CEM60

Polar Alignment: Polemaster camera

Software:

Capture Software: PHD2 Guider, Sequence Generator Pro controller

Image Processing: Pixinsight, Photoshop - assisted by Coffee, extensive processing indecision and second-guessing, editor regret and much swearing….. Given the problems on this image, more than the usual whining….

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Revisiting the Draco Trio:  NGC 5981, NGC 5982, NGC 5985, 



    
        

            Patrick Cosgrove