The Elephant Trunk Nebula is a very large emission nebula, actually larger than my field of view. I would need to do a mosaic to fit it all in which might be a project for another day.
This is a total of 7.3 hours of data. Half of the data came from the Almost Heaven Star Party and half came from home. Even with more than three hours from the very dark skies at AHSP this was faint and getting the extra time made it much easier to stretch the image. I’m not sure what the surface brightness of this is but it has to be much lower than M16 since that stretched easily with only 83 minutes from AHSP.
Once I had the extra data this was fairly straightforward to process. I used ABE rather than DBE on the RBG masters since the entire frame was full of nebulosity and though I tried DBE in the dust lanes it didn’t work as well as DBE in this case. After this I combined the RBG data with Channel Combination. Then:
- Dynamic Crop
- Photometric Color Calibration
- Multiscale Linear Transform for luminance and chrominance noise reduction
- Masked Stretch
- Local Histogram Equalization
- Multiscale Linear Transform for mild sharpening
- Adam Block’s star de-emphasis procedure
- Curves for contrast
- Dark Structure Enhance
This catches me up on projects for now though I did get about 30 minutes on the propeller nebula at AHSP on my last night before clouds cut it short. I’m hoping to get more data on that in the next few weeks once we get past full moon week and hopefully get some clear weather.
You can find the image at astrobin.