After a ton of lunar and Jupiter data processing, I can finally start processing my C14 Hyperstar DSO stuff captured in September 2023. A quick, bright project to use the clear nights during full moon was Pickerings Triangle. I already captured this target in 2020, however my first attempt suffered from too short exposure times (~ 1h per OIII and Ha channel), collimation issues of the Hyperstar, clipping of the black levels/highlights and using Topaz Denoise introduced a ton of artificial features.

This time, I captured 6 h Ha and 9.7 h OIII data with a collimated  C14 Hyperstar. During processing, I used BXT for deconvolution, GHS to carefully stretch the linear HOO image without clipping the blacks & highlights, kept contrast and color saturation enhancements to a minimum to achieve a more natural look and finally used NXT instead of Topaz Denoise for noise reduction. In this video, I compare some details in Pickerings Triangle from my first attempt in 2020 with my latest attempt in 2023.

If you want to process the data by yourself, I uploaded the stacks here.

Equipment

ZWO ASI 1600 MM Pro @ -20°C
+ C14 & Starizona Hyperstar v2 @ 675 mm (f/1.9)
+ Baader 2" Ha/OIII Highspeed filters (old versions)
+ Celestron EF
+ Tempest Cooler
+ Omegon Dew Heater
+ Astrozap Dew Shield for C 14 Hyperstar
on CGE-Pro mount

Cable managment to mitigate Hyperstar diffraction spikes.

Autoguiding:
Artesky 70 mm Guidscope (f=400 mm)
ZWO ASI 120 MM mini
PhD2 (Multistarguiding)
Dither every 4 subs

light frames:
Ha/OIII (gain=139, offset=21)

acquired with N.I.N.A.

Average FWHM: 2.2" - 3"

Post-Processing (PixInsight)

HaOIII (linear & non-linear stage)

- automatic rejection of subs with the subframe selector based on number of stars, FWHM and eccentricity
- manual rejection of bad subs
- image calibration (darks only) & image registration with WBPP script
- NSG & image integration for each channel
- dynamic crop
- DBE of each channel
- BXT
- linear fit of Ha channel wrt OIII channel
- create HOO image with channel combination
- Script -> Image Analysis -> Image Solver to obtain astrometric solution
- SPCC in narrowband filters mode, white reference: Average Spiral Galaxy
- GHS
- remove green tint using SCNR (Color to remove: Green, Protection Method: Average Neutral, Amount: 1.0)
- color saturation & contrast enhancement using curves transformations

Further contrast enhancements ...

- HDRMT (number of layers:7, scaling function: Gaussian(7), To lightness, Lightness mask)
- create lum mask, apply and invert lum mask
- LocalHistogramEqualization (Kernel Radius: 126, Amount: 0.2, Histogram Resolution 12-bit)
- remove lum mask
- GHS Blackpoint definition
- NXT (Denoise: 0.75)

Location: Schwentinental (Germany)

- CS Daniel