SH2-73 is a nebula located in the constellation of Hercules and is cataloged as an Emission Nebula.
This was a mistake in classification. Emission nebulae glow from the light of excitation from a local hot star. However, Sh2-73 is a cold molecular cloud reflecting light from the entire Milky Way galaxy! As such it is really an Integrated Flux Nebula or IFN.
I have tried and failed in the past to capture IFN - it's hard to get enough integration time at my location (damn tree lines!). I thought I would try again.
This image results from 9.8 hours of LRGB exposure taken with my William Optics 132mm FLT APO scope, the ZWO ASI1600MM-Pro camera, and the IOptron CEM60 mount.
While almost 10 hours is a lot for me, other folks have integrated up to 20-30 hours of data and more on this target.
Processing this was also a challenge given the relatively low integration times and the fact that some bright stars are in the field of view. I ended up processing this five different times to get this result!
Is it the most impressive image I have ever done? NO!
Does it have any WOW-factor? NO!
Does it still have some residual imaging issues? YES!
But it did offer some interesting technical challenges, and the project taught me many things along the way - so in that sense it was very worthwhile!
The story behind this image, as well as a complete processing walkthrough showing the unorthodox way I ended processing this image, can be seen at:
https://cosgrovescosmos.com/projects/sh2-73Thanks for looking! Let me know if you have any questions.
Pat
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