A more colourful Whirlpool Galaxy photograph

Whilst my previous image of M51 was an improvement upon my original attempt from last summer, I felt that it lacked colour & character; so I’ve had another go at it!

Background Info

As mentioned previously, Messier 51 is located in Canes Venatici and is pictured here with its companion galaxy NGC 5195. The pair are in strong gravitational interaction, hence the disturbances effecting the beautiful ‘whirlpool’ shape. NGC5195 is actually orbiting around M51 in a decaying manner and it is thought that they will collide & merge in another 1 or 2 billion years time.

For the record here again are the galaxy’s vital statistics:

  • Visual Brightness: 8.4
  • Distance: 37 million light years
  • App. Size: 11 x 7 arc mins
  • Constellation: Canes Venatici
  • Discovered by Lord Rosse in 1845

Below is a cropped and downsized view of my latest image:

 M51-WhirlpoolGalaxy-2cameramerge Click image for a larger view …

Imaging Info

As mentioned above I wanted to capture some of the colours, to do so I decided to combine data collection from 2 different cameras & optical setups. The seeing was only moderate during both sets of exposures. Imaging details below:

Session 1

Camera
Optics
Focal Length
Focal Ratio
ISO
Mount
Autoguiding
Sub-exposures
Total Exposure
Canon 40D
6" Schmidt Cassegrain
1500mm
f10
1250
CG5 German equatorial
SX Lodestar @ 300mm
45 x 300s
3hrs 45mins

Session 2

Camera
Optics
Focal Length
Focal Ratio
ISO
Mount
Autoguiding
Sub-exposures
Total Exposure
Canon 300D (astro modified)
Canon 500mm f4 L + x2 ext
1000mm
f8
800
CG5 German equatorial
SX Lodestar @ 300mm
28 x 300s
2hrs 20mins

Each session’s data was stacked and preliminarily processed in Iris before being exported to Photoshop. Iris processing included drizzling, wavelet noise reduction & a Richardson Lucy deconvolution for the luminance channel, as well as my standard processing routine. The resulting images were then adjusted for image scale, aligned & combined within Photoshop to produce the  image you see above. Note the feint distant galaxy in the top right corner.

I am not convinced that this two setup method was necessarily the best use of my imaging time but it was an enjoyable experiment. As for the final image, well I’m fairly pleased with it considering the less than brilliant sky conditions. At some point in the future I’d like to image M51 in more close detail but that will definitely require excellent seeing and maybe a bigger scope too.

Further Resources

This pair of galaxies give us an insight into the awesome forces at work in the cosmos, for further information about interacting galaxies take a look at Britannica’s article.

Can’t wait? Would you like that close up view of Messier 51 right now? Then follow this link to Hubble’s view of the Whirlpool.

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