Stacking Sunday 1: Stacking M57 in Siril. Celestron EdgeHD 8 inch versus EdgeHD 9.25 inch

[@kajouman]

mooi,siril word ook steeds beter,en gratis he!!! 2 dagen helder straks Martin,eindelijk.

[@KopLamp]

Siril is inderdaad steeds beter aan het worden. Twee dagen helder! Eindelijk! Alleen jammer dat net 1 van mijn ASIAIRs is overleden (gisteravond) 😢

[@kajouman]

@@KopLamp gewoon laptop ,ff met apt astro etc . hierna regent t weer lang.

[@KopLamp]

@kajouman en in de kou zitten? Nee. Ik ga wel alleen met de Edge aan het werk 😅

[@kajouman]

@@KopLamp ow..haha ik zit gewoon binnen,netwerkkabel gaat goed. tip,ik heb goedkope zotac nano boxjes,op marktplaats zijn die wel voor 100 euro. voor de telescoop werkt goed genoeg.

[@KJRitch]

I'm liking this series of Stacking Sunday. I'm using a C8 (non HD) with a Celestron OAG and Celestron 6.3 focal reducer and just beginning astrophotography. I just received an ASI071MC Pro to use. I was trying my Nikon D5100. I'm just starting learning Siril so I'm looking for any Siril stacking content. I've started using Deep Space Astro tutorials but I noticed here you used different options. I've decided to learn manually how to stack in Siril vs the OSC Preprocessing script. I'd be happy with either of those results. Maybe you can on the next one slow down a little and explain some of the choices you make when stacking. When I finished calibration on M33 from my D5100 my image was not green but blue. I'm hoping using the ASI071 may get better results. Thanks.

[@KopLamp]

I really need to make more Siril content indeed. Thanks for the suggestion! That a stacked image has a very strong color cast (blue or green) is normal. I am not completely confident into why, but it must have to do with the Bayer matrix in the color camera.

[@KJRitch]

Can you explain how you figured out synthetic bias. I would like to try that option with my ASI071MC. What would the expression I would need to use for calibrating with flats? Is the expression “64*$OFFSET” used for any camera?

[@KopLamp]

@@KJRitch If you go to the website of Siril, in the tutorial section you'll find a page devoted on synthetic biases and how to get to the value to use.

[@KJRitch]

I read that tutorial but once they refer to the spreadsheet data they loose me. How do they get 64 out of that example data?

[@KopLamp]

They plot the trendline through the measured ADU values for every offset increase. The goal is to find the factor of increase in ADU for every offset increase. For a 294MC pro sensor this indeed is a linear increase. The graph shows that every increase in gain, the ADU value will increase by 64 times more. So that is how they deduce the synthetic bias to be "64*$OFFSET".

[@Robert_Nik]

The mouse cursor is not visible. This is a huge disadvantage for demonstrating your actions.

[@KopLamp]

I corrected that mistake in subsequent videos. Apologies. I hope the video is still understandable

[@Robert_Nik]

@@KopLamp alright

[@CDigata]

clearly not worth the extra money (debatable)

[@KopLamp]

I am not sure if that is possible to conclude yet indeed. In my case it was a good deal that got me a 9.25”.