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Adding Observations Does Not Add to SNR Total
#1
I'm adding past observations to imaging projects so I can use the projects going forward until I complete my observations.

I added an observation of 17 five minute exposures and it contributed 27 to the SNR.

   
   
I added another observation of 170 five minute exposures, otherwise the same parameters (different date, one day difference) but it is contributing zero to the SNR.
   
   

I have quite a few partially finished projects so it would be convenient to use this to track percent complete.  Maybe I'll try using hours as a goal instead of SNR.

Cheers,
Rowland
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#2
Hi Rowland,

It may simply be a refresh issue. I have had trouble with that. Try closing the project and then reopening it.

Another possibility: are you certain that the new observations meet the "Very Good" criteria, as selected on the dialog? If not, they will be ignored...
Clear skies,
Greg

SkyTools Developer
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#3
Hi Greg,

I closed and reopened the project but no change in SNR.  

I'm not sure what you mean by "are you certain the new observations meet the "Very Good" criteria."  I assumed this is a subjective metric applied by me.  Is ST4 computing whether the new observations are "Very Good" based on the date of the observation and seeing or something else in the dialog used to describe a new observation?

Here's what the "Observations" tab looks like - the SNR of the second observation is shown as zero.   

   

As an aside, in the Track Observing Progress box, it says "2 of 2" in the column "Acceptable Images."   It seems that the count of 2 refers to "Observations," is that correct?  Since I had 170 images taken in one observation and 17 in the other, I think of it as 187 images.  Probably just nomenclature.

Cheers,
Rowland
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#4
Hi Rowland,

Observations are in sets, e.g. 12x300s images is one observation with 12 images in it.

It would help if you would show me the actual observations. Select the Nov 21 observations and the click View/Edit.
Clear skies,
Greg

SkyTools Developer
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#5
Hi Greg,

The observations are in the second screenshot in the original post in this thread.  I'll attach it again here:

   

Thanks,
Rowland
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#6
Hi Rowland,

Sorry about missing the screen shot. You had me reading so many messages when I got home that I lost track! I am concerned that you are being creative again and that is leading to a problem... what does the note "various dates" mean? The SNR calculation is for the exact date and time and conditions. If you kludge it you are going to get garbage... have a look at the start time of the images on the second night. Does it really go for 14 hours?
Clear skies,
Greg

SkyTools Developer
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#7
Hi Greg,

Yes, sorry to bombard you with so many messages.

I was trying to put all my pre-ST4 data into ST4 - meaning things I have imaged over the past few years - so I could use it as my single repository of information about imaging projects past, present and future. (Sounds like Dickens :-) Since most of my past projects were done over many nights, I didn't want to enter hundreds of completed image sets one by one - my goal was just to know things like "I have 4 hours of Ha data on NGC 281 that I took back in November 2017." That Ha data might actually have been taken on four or five different nights in November. I just don't want to enter all those sessions individually. I'll do that for future projects though.

It sounds like I can still enter old data and just ignore the SNR values. It will still be handy to know what I've already imaged and how much data I have for a given imaging system and filter.

Thanks,
Rowland
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