Re: Raw Beginner Questions

Posted by BPVietje on Apr 19, 2020; 2:43pm
URL: http://astroimagej.170.s1.nabble.com/Raw-Beginner-Questions-tp1306p1322.html

I Hope its OK to slide a question into this thread?

I'm wondering why the aim is 50%-75% of the maximum linearity limit?

Since there are accurate timing questions of interest, would a minimum SNR threshold be even more useful?  Say for example, the data can only be used if the SNR is above 100 for the entire transit.  I would think that the minimal exposure that reaches an SNR of 200 would be a reasonable target, allowing a lot of latitude for a deep transit SNR to never fall below 100.

Perhaps I'm way off the mark on the threshold, but would an SNR exposure guideline be useful, or have I failed to understand something fundamental here?

The CCD camera I use is linear to roughly 60,000 ADU, so 50%-70% would be 30-45K, which is easy enough with the brighter TESS targets, but could result in longer exposures that might miss temporal details on dimmer targets.

Woudl love to learn additional details on this.

Clear skies,

Brad Vietje
Newbury, VT
www.nkaf.org