NGC7822 - my first ever image using a narrowband filter

[LuckieEddie]

I just bought a couple of Baader filters last week (Ha & Oiii - thanks Francis). Last night was my first ever attempt at capturing something using a narrowband filter.

I choose NGC7822 because of it's apparent FOV and because I can actually see it from my heavily occluded back garden. This was 1½hrs of Ha & 20mins of RGB. Taken with my Olympus E-PL5 (full spectrum modded) using a SkyWatcher N200, EQ-5 & Baader MPCC, unguided.

Processing was an interesting challenge being the first time I've combined data sets. My workflow was:

• Preprocess, register and stack each data set separately in Siril. Then make a sequence of just the two resultant fits, and register those together, again in Siril.
• Photometric colour calibration of the RGB data set in Siril.
• Then into GIMP. Stretch Ha data. Heal the stars diffraction spikes, convert to 16-bit greyscale and export as .tif.
• Run the .tif through Starnet++, bring the result back into GIMP and colour using Colours->Components->Channel Mixer.
• Stretch the RGB data, make a starmask, add the Ha data as a new layer, using Dodge blend mode.
• A final bit of masked stretching with curves, and that was it.

Not the sharpest or most detailed of nebula images but I'm quite happy for a first attempt and the lack of exposure time.