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Contains:  NGC 5195, Whirlpool galaxy, M 51, NGC 5194
Getting plate-solving status, please wait...
M51 in L-H-S-NIR, 


            Andreas Dietz
M51 in L-H-S-NIR

Technical card

Resolution: 1026x1062

Dates:March 30, 2017March 31, 2017Feb. 24, 2018March 21, 2018

B+W 486 UV/IR block: 314x30" ISO1600
Baader Planetarium Ha 36mm 7nm: 496x30" (gain: 270.00) bin 1x1
Heliopan Infrared RG-780: 228x30" ISO25600
Baader Planetarium SII 36mm 8nm: 406x30" ISO25600

Integration: 12.0 hours

Avg. Moon age: 4.78 days

Avg. Moon phase: 25.91% job: 2017384

RA center: 202.489 degrees

DEC center: 47.229 degrees

Pixel scale: 1.067 arcsec/pixel

Orientation: 357.681 degrees

Field radius: 0.219 degrees

Locations: Home Observatory, Regensburg, Bavaria, Germany

Data source: Backyard


My series with the Whirlpool galaxy as the main actor goes on. Today I'd like to show you my latest project, an unusual combination of my previously acquired channels.
In detail:

L -> Luminance from
Red -> Halpha from
Green -> SII from
Blue -> NIR from

According to Cool Cosmos the amount of NIR light is a bit higher towards the central parts of the galaxy due to older stars in that region. This corresponds to the purple look (i.e. more blue light, hence more NIR) in the center of the main galaxy. It's also interesting that there seems to be a higher emission of SII and Ha light in the outer arms.
C&C appreciated!



Andreas Dietz
License: Attribution-ShareAlike Creative Commons


  • M51 in L-H-S-NIR, 


            Andreas Dietz
  • Final
    M51 in L-H-S-NIR, 


            Andreas Dietz


cropped to same FOV as in the pure VIS version

Sky plot

Sky plot


M51 in L-H-S-NIR, 


            Andreas Dietz