Link to Inverted Images
This appears to be the first detailed image of Weinberger 1-3 (PN G163.1-00.8, PK 163-00.1). This PN was included in R. Weinberger’s 1977 compendium of 335 objects designated as possible, probable or true planetary nebulae since the closing of the 1967 Perek-Kohoutek PN catalog. The HASH planetary nebula database reports that the object is a true planetary nebula, and is about 2 arcminutes in diameter. It also notes that a faint blue central star was detected, but I see no sign of it in my data. I haven’t seen any magnitude estimate for this object, but found a distance estimate of 2700 ± 300 parsecs based on the distance-extinction method. As the inverted images show, OIII is much weaker in this target than Ha, so I concentrated my limited imaging time on Ha. The background galaxy is LEDA 16272, at 325 million light years.
Exposure: Total exposure time about 12.5 hours, 29 x 20 minutes Ha, 53:52:50 x 2 minutes RGB. All bin 1x1. Data collected from October to December 2022.
Light pollution: SQM ~18.38 (Bortle 7-8, NELM at zenith about 4.5, Red/white zone border.)
Seeing: FWHM of integrated luminance 2.5 (Ha) and 2.3 (OIII) arcsecs
Image scale at capture: 0.6 arcsecs/pixel = f/5.7
Scale of presentation: 0.9 arcsecs/pixel (67% of full scale).
Equipment:
Scope: C11 (standard, not Edge) with Celestron 0.63 reducer
Mount: Paramount MX+, connected via ASCOM Telescope Driver 6.2 for TheSkyX, with MKS 5000 driver 6.0.0.0
Camera: SXVR-H694, connected via SX ASCOM driver 6.2.1.18212 (SX Windows Drivers 15.26.50.450 [i.e., version 1.2.2] also installed)
Filter wheel: Atik EFW2 with 7x1.25 carousel and Artemis 2.4.3.0 driver
Filters: Astrodon Type IIi LRG, 5nm Ha/SII, 3nm OIII; Chroma B
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 4.2
Guide SW: PHD 2.6.11, connected to guide cam via native SXV driver
ASCOM: ASCOM 6.6 SP1
Platesolving: ASTAP, 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, Photoshop CS2
Processing Workflow by Workspace in PixInsight 1.8.9:
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, registration and integration with WBPP
2. Linear Processing
RGB Combination for RGB frames
Dynamic Background Extraction on narrowband and RGB
ImageSolve RGB, then run Spectrophotometric Color Calibration, using Average Spiral Galaxy white reference
BlurXterminator on narrowband and RGB
NoiseXterminator on narrowband and RGB
Create inverted Ha and OIII images: Crop, Invert with Ctrl-I, apply STF to Histo Trans, and Save
3. Narrowband Processing
Histo Trans x 3
Curves Trans
StarXterminator to create starless image
4. Colorization of Narrowband Image
Colorize to red with Curves Trans, pulling up red and pulling down blue and green
TGVDenoise
Final Curves Trans
5. RGB Processing
Histo Trans
Curves Trans to boost saturation
Histo Trans
Curves Trans for brightness
StarXTerminator to create starless and stars-only (star mask) images
Slight convolution to blur starless image. This prevents noise from being subtracted during the next step, to avoid creating a perfectly noiseless – and unrealistic-looking – image.
PixelMath to subtract starless image from RGB image, adding a pedestal. This removes circular artifacts left over from flat calibration, which is caused by imaging with a moving-mirror SCT.
6. Image Combination
PixelMath to blend stars-only image and colorized narrowband image using formula ((1-$T)*(stars_only))+$T. This produces an image of the nebula that includes the stars.
In Photoshop, layer this nebula_plus_stars image onto the RGB starfield image using a mask
7. Final
Final Histogram Transformation
ICC Profile Transform to sRGB
Resample to reduce size to 67%
Save as JPG
