M31 Andromeda Galaxy (2022)

 When I first presented this image, back in 2010!, I wrote the following (*):

 "...all this work has allowed me to learn really a lot both from the mistakes I made and from the experimentation with new processing techniques. Unfortunately, even knowing that some exposure time with an Hydrogen alpha filter would improve the pink color, and reprocessing the image from the beginning would eliminate the dark rings, currently I have no time to do it..."

(*) You can see the original post from January 2010 here.

Well, 12 years later!, while I am accumulating exposure in Hydrogen alpha for this image, I have already reprocessed the RGB image from scratch. 

The reprocessed image can be seen on the right: The dark rings have (practically) disappeared, the color balance seems more balanced (Photometric Color Calibration) and the stellar profile has also been improved. Click on the image for a full resolution version (8 Mb).

The second image is a crop of the central area of the galaxy to better appreciate core details. 

The third and fourth images are from Hydrogen alpha filter.  They are a composition of 50 x 1200 second exposures, that is a total accumulated exposure time of 16.6 hours.

They were taken during a heat wave episode with temperatures at night higher than usual, so in many of them the temperature of my camera could only reach 0ºC: at that temperature the obtained result is certainly noisy.

The third image has been processed in the usual way with all the information collected through the narrowband filter (Astrodon 6 nm),

while the fourth image shows a first attempt to subtract the continuum (light coming from light sources emitting a continuous spectrum, mainly stars) from the previous image, in order to obtain a  more accurate view of the Hydrogen alpha emission line (according to the method described by Vicent Peris here).

24/09/2022

Final step in my image of M31:

This is the combination of the previous image, taken this summer with Hydrogen alpha filter, with the LRGB data acquired earlier.

All sub exposures were taken with FSQ-106N and STL-11000M camera. 

LRGB data were taken in presential sessions, while the Hydrogen alpha data have been taken remotely (All of them from my observatory in Àger).  

Click on the images for higher or full resolution versions.

Complete information about exposure data (and also full resolution version) of the images in the Gallery section 

Image processing: Pixinsight

Observatory automation and remote operation with Talon6