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Contains:  Crescent nebula, NGC 6888
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NGC 6888 - Crescent, 


            Rich Sky
NGC 6888 - Crescent

NGC 6888 - Crescent

Technical card

Resolution: 1355x1075

Dates:Sept. 19, 2019

Frames: 5x300" bin 1x1

Integration: 0.4 hours

Darks: ~33

Flats: ~35

Bias: ~37

Avg. Moon age: 19.61 days

Avg. Moon phase: 75.73%

Bortle Dark-Sky Scale: 8.00

Mean FWHM: 2.40

Temperature: 6.00 job: 2930715

RA center: 302.822 degrees

DEC center: 38.185 degrees

Pixel scale: 4.688 arcsec/pixel

Orientation: 96.333 degrees

Field radius: 1.126 degrees

Locations: Atomic Observatory, Canada, Canada

Data source: Backyard


NGC 6888 image taken on September 19, 2019 using the software Sequence Generator Pro. This image is my first using SGP.

I wanted to use SGP to see if I could improve on Focus. I am not sure if it was the better viewing conditions or the focus, but FWHM were lower to 2.4 for 5 frames until clouds rolled in.

FWHM values of 2.4 are the lowest values, I have ever seen in the past year.

As for my first attempt to use SGP, I had a few issues. For example, I tried to stop the focus routine and crashed all components, PHD2, Focuser, Mount, Camera and guider resulting in wasting 35

minutes. I still don't know, how to stop an element of a sequence. I'll figure it out. As for the focusing sequence, it worked very well, without any issues.

This image is 5 frames of 300 sec or 25 minutes with FWHM=2.4. You can compare it to another of my image with 2h of data with FWHM= 3.5 using a Bahtinov mask.

Which image appears to have a better focus, the 25 minutes, this image or the 2.2 hours Crescent

As part of reducing the unknown, like obtaining the right focus, SGP may be a solution for me, but I am evaluating my options. If I could purchase only the SGP autofocus software module, for sure I would.

Keep looking up,


Polar alignment error:2.0'



Rich Sky
License: None (All rights reserved)

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NGC 6888 - Crescent, 


            Rich Sky