Link to inverted images
IC 1295 (PNG 025.4-04.7) lies about 4700 light years away on the edge of the Scutum star cloud, a particularly rich patch of the northern hemisphere summer Milky Way. The nebula is about 1.5 arcminutes wide. I found magnitude estimates of 12.7 (Wikipedia), 13 (C Seligman), 14 (Burnham, which incorrectly labels the PN IC 1298) and 15 (Saguaro Astronomy Club) but no sources for any of them. The progenitor of the nebula appears to be the faint blue star near center.
There is actually a second PN in this image. A bit less than halfway to the upper right corner is a fairly small but very blue "star." That's Kohoutek 4-8 (Sanduleak 2-374, PN G 025.3–04.6), a tiny (0.70 × 0.64 arcsecs) PN. Here, in RGB, it shows as a faint star, but in the OIII it is much brighter.
This image uses RGB for the stars and narrowband for the nebula. The narrowband was mapped Ha:0.78*OIII:OIII to R:G:B. This produces an image that matches the blue color that the nebula displayed in the heavily stretched RGB image. I find that bluish color typical for OIII-rich PNs like this one.
Exposure: Total exposure time 18.8 hours, 27:25 x 20 minutes HaOIII, 31:31:32 x 2 minutes LRGB. All bin 1x1. Data collected from April to June of 2021.
Light pollution: SQM ~18.38 (Bortle 7-8, NELM at zenith about 4.5, Red/white zone border.)
Seeing: FWHM of integrated Ha and OIII images both around 2.7 arcsecs
Image scale at capture: 0.6 arcsecs/pixel = f/5.7
Scale of presentation: Full scale.
Equipment:
Scope: C11 (standard, not Edge) with Celestron 0.63 reducer
Mount: Paramount MX+, connected via ASCOM Telescope Driver 6.1 for TheSkyX, with MKS 5000 driver 6.0.0.0
Camera: SXVR-H694, connected via SX ASCOM driver 6.2.1.17140 (SX 1.2.2 also installed)
Filter wheel: Atik EFW2 with 7x1.25 carousel and Artemis 2.4.3.0 driver
Filters: Astrodon Type IIi LRGB
Rotator: Optec Pyxis 2", connected via Andy Galasso's 0.4 driver (Optec Pyxis Rotator AG)
Focuser: Rigel Systems GCUSB nStep motor with driver version 6.0.7 on stock Celestron focuser
OAG: Orion Thin OAG
Guide cam: Lodestar (first generation). 4 second exposures
Automation SW: Sequence Generator Pro 3.1.0.457
Guide SW: PHD 2.6.7, connected to guide cam via native SXV driver
ASCOM: ASCOM 6.3.0.2831
Platesolving: PlateSolve 2, failover to local Astrometry.net 0.19 server
Collimation: Metaguide 3, using ASI120MM connected via ZWO Direct Show driver 3.0.0.2
Processing Software: Pixinisight, Affinity Photo, Photoshop CS2
Processing Workflow by Workspace in PixInsight 1.8.8:
1. Calibration
Calibration with WeightedBatchPreProcessing with flats and bias, using Cosmetic Correction with a master dark
Blink to preview and reject a few frames
Weighting and registration with WBPP
2. Stack and Mure Denoise
Image Integration on each channel
Mure Denoise on each channel
RGB Combination for RGB frames
Dynamic Crop
Dynamic Background Extraction
3. Narrowband Linear Processing
Deconvolution to Sharpen (separately for Ha and OIII):
Dynamic PSF to create PSF image
Deconvolution, using a mask created in Affinity Photo to sharpen the nebula only
4. Narrowband Stretching
On each image: Histo Trans x 2
5. RGB Linear Processing
Photometric Color Calibration, using Average Spiral Galaxy white reference
6. RGB Stretching
Histo Trans
Boost color saturation with Curves
Curves Trans
Aggressive Multiscale Median Transform to reduce background lumpiness
Histo Trans to darken slightly
Mild Deconvolution to tighten stars
7. Color Combination
Map Ha:0.78*OIII:OIII to R:G:B with PixelMath
Range mask on merged narrowband image to highlight only the nebula
Use PixelMath to add nebula to RGB stars image, using the mask so that the nebula background (about 0.06) was not added to the RGB starfield background. A background of 0.06 also was subtracted from the nebula image in the PixelMath merge operation.
8. Final Adjustments
TGVDenoise using a mask to restrict the effect to the nebula
9. Final
ICC Profile Transform to sRGB
Save as JPG
