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I agreeImaging telescope or lens:TS Optics APO130f6
Imaging camera:ZWO ASI1600MM-Cool
Mount:Ioptron CEM 120 EC2
Guiding telescope or lens:TS Optics APO130f6
Guiding camera:Starlight Express Lodestar X2 Autoguider
Focal reducer:TS-Optics TSFlat 2
Software:Sequence Generator Pro, PixInsight , PHD Guiding 2.5.0
Filters:AstroDon 5nm Ha filter, AstroDon 5nm SII filter, AstroDon 5nm OIII filter, ZWO new B, ZWO new G, ZWO new R
Accessories:ZWO EFW 31mm 8 positions, QHYCCD PoleMaster, Innovations Foresight ONAG, USB_Focus V3 Usb Focus, USB Stepper Motor Heavy Load
Resolution: 4634x3502
Dates:Sept. 14, 2019
Frames:
AstroDon 5nm Ha filter: 45x600" (gain: 139.00) bin 1x1
AstroDon 5nm OIII filter: 43x600" (gain: 139.00) bin 1x1
AstroDon 5nm SII filter: 39x600" (gain: 139.00) bin 1x1
ZWO new B: 5x120" (gain: 139.00) bin 1x1
ZWO new G: 5x120" (gain: 139.00) bin 1x1
ZWO new R: 5x120" (gain: 139.00) bin 1x1
Integration: 21.7 hours
Darks: ~20
Flats: ~5
Flat darks: ~25
Avg. Moon age: 15.05 days
Avg. Moon phase: 99.91%
Mean SQM: 3.00
Mean FWHM: 19.50
Astrometry.net job: 3003196
RA center: 2h 33' 8"
DEC center: +61° 26' 56"
Pixel scale: 0.909 arcsec/pixel
Orientation: 0.055 degrees
Field radius: 0.733
Locations: Duc, Prayssas, Lot et Garonne, France
Data source: Backyard
This image results from exposures spanning over 8 nights : 14, 15, 16, 17, 188, 19, 20 & 22 of september. As the nights were getting longer in september, I let the scope point to this nice area of the sky during the second half of the night.
Despite the nearly full moon shinning, the NB filters did a nice job. However, flats correction was needed to calibrate SHO frames! This is not necessary (with my equipment) on moonless night.
The cooling of the sensor varied at -12C, -15C & -21C, depending on the outside temperature.
The RGB exposures were only used to give a natural color to the stars.
The processing was performed in PI as follows :
For each S, H, O, R, G, B channels :
- Images Calibration (Dark Substraction)
- Cosmetic Correction
- Image Registration
- Image Integration
- Mure Denoise (for SHO only)
Then :
- Create a super Lum image from S, H & O channels (weights estimated using PI integration on S H O images before noise reduction : 1.0 for Ha, 0.1 for O3 & S2.
- Deconvolution of super Lum masked with 2.3 pixel psf
- Create SHO image using LRGB
- Color balance on nebula and color saturation using mask to protect dark area.
- Create RGB image and color balance and color sat (to be used to color stars in SHO)
- SCNR (G neutral and min)
- Background extraction
- Going NL using HT for SHO & RGB images
- Color Saturation masked (and desaturate bkg)
- Color Saturation masked using stars to desaturate stars
- Apply "a" & "b" color channels of the RGB image under star mask
(this is to apply natural color to the stars)
- Local Histogram Equalisation
- TGV denoise (no mask)
Final image adjustments performed in Iphoto on Imac :
- levels adjustments
- adjust color looking using "selective color"
- boost sharpness
- deflip
- crop
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