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Sensor Analysis and then Optimal Settings... Is that reall all there is to it?
Posted: Mon May 07, 2018 2:41 pm
by eseavey
I ran the sensor analysis carefully and plan to use the results for future imaging sessions. For my QHY224C camera I though I'd use the "Optimize for Dynamic Rage" and " Noise less than 1%"option next time I image. Is that really all there is to it to get the best exposures for a given imaging period? Is it recommended to increase/decrease exposure times for fainter/brighter objects as I see fit?
Thanks
Re: Sensor Analysis and then Optimal Settings... Is that reall all there is to it?
Posted: Tue May 08, 2018 5:57 am
by admin
If you have used the 'brain' to calculate the exposure and gain for 1% noise contribution then making the exposures longer will not gain you anything (even for faint targets). Well... not very much anyway - by setting a 1% threshold then you can only improve the noise in the image by a further 1% even if you make the exposure 10x or 100x or 1000x as long as the recommendation, so not worth going longer.
You *may* want to go for shorter exposures under some circumstances:
* If the sub frames are over exposed - stars too blown out for instance - then just reduce the exposure
* If the sub frame time is too long for your guiding/tracking then re-run the brain and set an upper limit on the exposure length
Also, remember that the values you see depend on your sky brightness, so you need to re-run the brain and re-measure the sky brightness if
* The sky brightness changes significantly - for instance new moon to full moon or transparency changes a lot
* You change equipment - ie different scope or add/remove barlow or reducer.
Hope this helps,
Robin
Re: Sensor Analysis and then Optimal Settings... Is that reall all there is to it?
Posted: Wed May 09, 2018 8:44 pm
by eseavey
Thanks Robin. I will try it out this weekend at my dark location.