This is the first time I've attempted a mosaic, turns out this makes processing quite a lot trickier!
I spent quite some time fiddling with the parameters on the 'Gradient Merge Mosaic' script in PixInsight before I decided to settle on some settings that I think gave decent results - the large bright stars right in the middle of the merge made it very hard to get right.
The mosaic was 1x2 and each panel received the following under Bortle-6 skies:
- 4th Mar-24: 30 x 300" Lights, 30 x Flats, 30 x Darks, 30 x Dark-Flats and 70 x Bias
- 5th Mar-24: 20 x 300" Lights, 30 x Flats, 30 x Darks, 30 x Dark-Flats and 70 x Bias
- 6th Mar-24: 30 x 300" Lights, 30 x Flats, 30 x Darks, 30 x Dark-Flats and 70 x Bias
So each panel had a total integration time of 6 hours and 40 minutes each, giving a total of 13 hours and 20 minutes across the whole image.
I really wanted to add way more integration time to these panels however Auriga is getting lower to the horizon everyday and with British-Summer-Time and the weather, I've called it quits for now. Maybe I'll return to this and add more when Auriga's back up later in the year.
Processing Details:
- Mosaic panels individually stacked via WBPP (2x Drizzle)
- Panels cropped to the same size.
- Panels ran through GraXpert
- Panels merged via Gradient Merge Mosaic
- Merged panel ran through a light pass in GraXpert again to reduce stitching artefacts
- Merged Panel plate-solved
- Image then ran through Spectrophotometric Colour Calibration (SPCC)
- Image ran through BlurXTerminator and then NoiseXTerminator
- Image then ran through StarXTerminator
- Starless image stretched with Generalised Hyperbolic Stretch (GHS)
- Stars image stretched with GHS and then slight saturation curves to try to bring out a bit of colour
- Starless image ran through Bill Blanshan's HOO Normalisation script to make the most of the L-Enhance filter
- Slight curves adjustments and dark-structure enhancement
- Stars and Starless recombined into final image
- Final image ran through Photoshop to do very slight cosmetics
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