Hemisphere:  Northern  ·  Constellation: Canes Venatici (CVn)  ·  Contains:  IC 4277  ·  M 51  ·  NGC 5194  ·  NGC 5195  ·  Whirlpool Galaxy
Getting plate-solving status, please wait...
M51 in LLRGB, 



    
        

            Tom Gray
M51 in LLRGB
Powered byPixInsight

M51 in LLRGB

Getting plate-solving status, please wait...
M51 in LLRGB, 



    
        

            Tom Gray
M51 in LLRGB
Powered byPixInsight

M51 in LLRGB

Technical card

Imaging telescopes or lenses: Meade 2080 SCT 8" LX5

Imaging cameras: Meade DSI 3 Pro

Mounts: Meade Fork mount w/wedge Meade

Guiding telescopes or lenses: Meade 8x50mm Finder/Guider

Guiding cameras: Orion Starshoot autoguider

Focal reducers: Meade f6.3 focal reducer/field flattener Meade 0.63x Reducer

Software: SiliconFields / Ivo Jager Startools v1.7  ·  Stark Labs Nebulosity v3  ·  PHD2 Guiding V 2.6  ·  Meade Envisage V4.10

Filters: Meade RGB-IR Cut 1.25"  ·  Meade LRGB 1.25"

Accessory: Bahtinov Mask  ·  Homemade ST4 autoguider


Dates:April 13, 2021

Frames:
Meade Blue Filter for CCD: 16x120" (32') bin 1x1
Meade Green Filter for CCD: 10x120" (20') bin 1x1
Meade RGB-IR Cut 1.25": 27x120" (54') bin 1x1
Meade Red Filter for CCD: 9x120" (18') bin 1x1

Integration: 2h 4'

Avg. Moon age: 1.25 days

Avg. Moon phase: 1.76%


Basic astrometry details

Astrometry.net job: 4451848

RA center: 13h 30' 6"

DEC center: +47° 13' 26"

Pixel scale: 1.993 arcsec/pixel

Orientation: 175.632 degrees

Field radius: 0.461 degrees


Resolution: 1337x994

Locations: Home 'observatory' (Bortle 5), Derbyshire, United Kingdom

Data source: Backyard

Description

After getting in a spin with M101, I have gone back to other data that I collected the same night. M51 was surprisingly easy to process once I had figured out how to align frames in ASTAP - many thanks @Rich-sky. [Interestingly I cannot see the 'export to fits' button at maximum screen resolution (1400x1050) and the program does not appear to be scaling, which may be a function of still using Win32 - no complaints as this is a free and powerful astrometric solver, image analysis and stacking program - but I should report it to the author, Hans Klein]. I worked around this by solving the image and creating a new stack (after backing up the original!) The composite image was aligned but not the individual stacks?

Long story short, processing in Startools was fairly straightforward, although still some lingering gradients, which may possibly be due to light leaking around my filter slide - I expect this has caused the split in the blue in the histogram. I pushed these back, losing a little of the faint tidal tail and outer arm of NGC 5195 and 5194 respectively. Using Lee B's excellent image as an exemplar https://www.astrobin.com/p6bz3p/ I was pleased to see the galaxies IC 4277 and 4278 faintly to the left in my image. Now I just need to calm down, carry on and bag some longer exposures before the nights get too short.

Comments

Revisions

  • M51 in LLRGB, 



    
        

            Tom Gray
    Original
  • Final
    M51 in LLRGB, 



    
        

            Tom Gray
    B

B

Description: I still wasn't happy with this image which showed alignment errors between the L and RGB channels. Alignment in ASTAP followed by stacking appears to have resolved this and produced a much better image. Seeing was not great and there is some distortion from incorrect backspacing with my Meade f0.63 reducer on my 8" LX5 SCT. I think the colour is better and shows off those lovely blue star forming regions in the whirlpool as a result of the collision between these iconic galaxies.

Uploaded: ...

Sky plot

Sky plot

Histogram

M51 in LLRGB, 



    
        

            Tom Gray