Hemisphere:  Northern  ·  Constellation: Canes Venatici (CVn)  ·  Contains:  NGC 4656  ·  NGC 4657
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NGC4656 LRGB - The Hockey Club Galaxy, 



    
        

            andrea tasselli
NGC4656 LRGB - The Hockey Club Galaxy
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NGC4656 LRGB - The Hockey Club Galaxy

Getting plate-solving status, please wait...
NGC4656 LRGB - The Hockey Club Galaxy, 



    
        

            andrea tasselli
NGC4656 LRGB - The Hockey Club Galaxy
Powered byPixInsight

NGC4656 LRGB - The Hockey Club Galaxy

Technical card

Imaging telescopes or lenses: Intes Micro MK 809

Imaging cameras: starlight xpress SXV-H9

Mounts: Gemini Telescope Design G-41

Guiding telescopes or lenses: Custom Build LZOS 80 mm

Guiding cameras: Starlight Xpress SXV-Autoguider

Focal reducers: Riccardi Custom 0.6x

Software: Christian Buil Iris 5.59  ·  Pleiades Astrophoto PinInsight 1.8.8-x

Filters: Astronomik RGB 1.25" Type IIc  ·  Astronomik Clear 1.25"

Accessory: True Tech 7-positions 1.25" Manual Filter Wheel


Dates:May 4, 2005May 7, 2005May 8, 2005May 9, 2005May 10, 2005May 11, 2005June 7, 2005March 10, 2007April 5, 2007April 7, 2007April 8, 2007April 9, 2007April 25, 2009April 29, 2009May 1, 2009

Frames:
Astronomik Clear 1.25": 73x150" (3h 2' 30") bin 1x1
Astronomik Clear 1.25": 16x300" (1h 20') bin 1x1
Astronomik Clear 1.25": 274x45" (3h 25' 30") bin 1x1
Astronomik Clear 1.25": 42x50" (35') bin 1x1
Astronomik RGB 1.25" Type IIc: 45x180" (2h 15') bin 2x2
Astronomik RGB 1.25" Type IIc: 45x300" (3h 45') bin 2x2
Astronomik RGB 1.25" Type IIc: 81x60" (1h 21') bin 2x2

Integration: 15h 44'

Avg. Moon age: 11.41 days

Avg. Moon phase: 31.91%


Basic astrometry details

Astrometry.net job: 4238271

RA center: 12h 43' 59"

DEC center: +32° 9' 57"

Pixel scale: 0.975 arcsec/pixel

Orientation: 273.589 degrees

Field radius: 0.208 degrees


Resolution: 1228x928

Locations: Home, Lincoln, United Kingdom

Data source: Backyard

Description

This has been (and possibly still is) one of the bugbear of mine. Underestimated the overall faintness of it (complicit the wrongly stated dimensions in the catalog) I went after it in 2005 with a set unguided short exposures that didn't come to too much (weak SNR in the L frame, worse SNR in the colour integrations) taken again in 2007 in the transition between unguided and guided exposures but not enough exposure again to make a satisfying image and then, finally, in 2009 as a last gasp I added even more exposure time. Still the thing isn't budging, as its intrinsic dynamic range is too vast to be comfortably met with the amount of time I dedicated to it.

In the back of my mind I knew I would have needed a lot more exposure than I did and no surprise that the weak outer reaches barely show up at all in the raw final integrations, with gremlins and all.

When I first processed the final integrations (in 2010) I wasn't too pleased but I had enough of it and let it stand. Picking it up again after these many years I could not bring myself up to publish it in that state and attempted, once more, to reprocess the whole lot in PI, which produced the image shown here which is still a far cry from what I meant to create but better than all the previous issues.

This one is chalked up for massive make over once I get same serious aperture to the fore.

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NGC4656 LRGB - The Hockey Club Galaxy, 



    
        

            andrea tasselli