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Stephan's Quintet with Lucky Imaging, 


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Stephan's Quintet with Lucky Imaging

Acquisition type: Lucky imaging

Imaging telescopes or lenses: Planewave CDK24

Imaging cameras: ZWO ASI6200MM Pro

Mounts: Planewave L600

Guiding cameras: Starlight Xpress Ultrastar

Focal reducers: None

Software: PixInsight 1.8  ·  Sequence Generator Pro  ·  Photoshop CS3  ·  PHD Guiding 2  ·  CCDWare CCD Inspector  ·  Planewave PWI4  ·  Planewave PWI3  ·  Maxim DL6

Filters: Astrodon 50mm B  ·  Astrodon 50mm R  ·  Astrodon 50mm L  ·  Astrodon 50 mm G

Accessory: FLI CFW-5-7  ·  Astrodon Monster MOAG  ·  Hedrick Focuser  ·  Planewave Delta-T  ·  Planewave EFA

Dates:Aug. 18, 2020Aug. 19, 2020Aug. 20, 2020Aug. 21, 2020

Astrodon 50 mm G: 8x300" (gain: 100.00) -5C bin 1x1
Astrodon 50mm B: 19x300" (gain: 100.00) -5C bin 1x1
Astrodon 50mm L: 121x60" (gain: 100.00) -5C bin 1x1
Astrodon 50mm R: 24x300" (gain: 100.00) -5C bin 1x1

Integration: 6.3 hours

Darks: ~40

Flats: ~80

Flat darks: ~80

Bias: ~20

Avg. Moon age: 8.39 days

Avg. Moon phase: 2.87%

Mean SQM: 21.40

Mean FWHM: 1.30

Astrometry.net job: 3794804

RA center: 22h 36' 2"

DEC center: +33° 57' 53"

Pixel scale: 0.195 arcsec/pixel

Orientation: 0.556 degrees

Field radius: 0.132 degrees

Resolution: 4059x2685

Locations: KG Observatory, Julian, CA, United States

Data source: Backyard


My first image with the FLI PL16803 swapped out with a ZWO ASI6200MM Pro.

My goal here was to see what's possible with this new CMOS camera while imaging a DSO.

Stephan's Quintet is always a challenge. Since it's now positioned well for most of the night, it was my 1st choice.

Selecting a proper CMOS exposure length and gain is new for me. So I tried a few experiments.

Long story short...

1. 900s exposures with Gain = 0 seemed to yield very similar SNR as 60s exposures with gain = 100, given the same overall stacked exposure time.

2. Given #1, I decided to use 60s exposures at gain = 100 for Luminance to help collect more subs with low FWHM.

3. For color, I selected 300s at gain = 100. FWHM is not as important for color, so I didn't want to mess with too many subs.

4. I collected all data at bin 1:1 (9567 x 6388). Since the target was much smaller, I used a ROI in PI to speed post processing.

Seeing was good for Luminance. I collected about 300 subs (5 hours) and only kept the best 121 (2 hours) with FWHM between 1" and 1.5". Stacked data was a bit noisy and not as deep as the 16803. But it was sharp. (-:

Seeing during color was relatively poor. Red was between 1.59" and 3.03", Green 1.75" and 2.09" and Blue 1.49" to 3.07". This caused some red halos around the brighter stars that I needed to soften.

In summary...

1. The CMOS camera lets me try things that would not be possible with CCD, especially for extracting detail.

2. The 16803 ***may*** allow me to go deeper and it has a bigger frame size. So it's still a keeper.

3. I look forward to adding 2x magnification to the CMOS setup to try very hi-resolution imaging of smaller targets.


Added more data on 8/23/20 and 8/24/20...

L: 267 x 60s (FWHM < 1.56" && Eccentricity < 0.55)
R: 27 x 300s (1.17" < FWHM < 2.05")
G: 24 x 300s (1.24" < FWHM < 2.09")
B: 28 x 300s (1.33" < FWHM < 2.25")

Camera gain = 100 for all.





    Stephan's Quintet with Lucky Imaging, 


  • Final
    Stephan's Quintet with Lucky Imaging, 




Description: Added more data. See main Description for details.

Sky plot

Sky plot


Stephan's Quintet with Lucky Imaging, 



In these public groups

ASI 6200 MM Pro