Flying Bat and Squid Nebula in HOORGB

It was very difficult to process this target as I have only got 17 hours of data over 3 separate nights and I understand some other people have collected close to 100 hours of data for this dim target.

Flying bat and squid nebula, Ou4, Sh2-129. It was discovered in 2011 by French astro-imager Nicolas Outters. The red and blue-green color regions are the emission regions from Hydrogen and Oxygen atoms respectively.

The flying bat (red) is too big to fit in the view of my 80mm refractor with 294MM-P camera. The squid part (blue-green) fits my view perfectly.

Location and Bortle Scale: Bortle 7, Southern Ontario

Camera: ASI294MM-P

Scope: SW Evostar 80

Mount: CGEM-DX

Filters: 2” Optolong Ha (7nm), Oiii (6.5nm), R,G,B

ZWO 2”x7 Wheel

Exposures: Oiii: 67x600s, -15C, 400gain; Ha: 67x600s, -5C, 400gain; Each of RGB 7x180s, -5C, 200gain;

Total exposures ~ 17 hours

Darks: 30 @ -15C; 30 @ -5C (it got so warm at night I can’t let the TEC run over 60% constantly)

Flats: 30 Flats EACH for Ha, Oiii, R, G and B.

After referring to various techniques and workflows on the internet and days of processing this picture, for my record, this is what I have done in processing this target. (In case I have more data to add on in the future and I may forget what I have done this time)

-> Stack O, Ha, R, G, B as usual using calibrated frames in DSS. Use the highest score from Ha as a reference frame for all stacked images.

-> In Pixinsight, perform the same dynamic crop to all stacked frames

-> Apply separate DBE to O and H

-> Apply MLT noise reduction to both O and H

-> Stretch using HT to O and Ha

-> Create a starless version of O using StarNet software

-> Reduce the blue halos from O using Photoshop

-> Add O+O_starless using PixelMath in PI

-> Readjust background brightness to match the background brightness of Ha

-> Combine HOO in PI (Go back and forth to readjusting the halos if stars are too “blue” around the centre)

-> Combine RGB in PI, perform ABE, Background and Color calibration.

-> Open HOO in Photoshop, curve and adjust colors in red. Color range (squid) selection, curve and color adjust

-> Space noise reduction from AstronomyTools action pack

-> Make stars smaller using AstronomyTools action pack

-> Select red in color range; copy and paste as another layer

-> Set blending to Overlay

-> Apply High Pass Filter to enhance contrast and details of the Ha region

-> Open RGB in Photoshop, make a copy in black and white.

-> Select color range on the background (background mask)

-> Create a inverted star mask (only select the stars), apply to the color version of RGB

-> Open HOO in Photoshop, Add a layer of stars copied from RGB, Gaussian blurred 4pixels, color blended

-> Touch on imperfect optics from reducer. Create vector masks at 4 corners on 4 duplicated layers

-> Highlight the areas to be touched on. Blending mode: Darken

-> Nudge (move) the vector masks so stars are more point and round

-> Merge all layers

-> Fine tunes on details.