Nebulosity 2 + ICNR

[rogerg (Roger)]

OK, next dumb question..

Has anyone been using Nebulosity 2 + In Camera Noise Reduction (ICNR) ?

I'm trying this with my canon 350D and it seems Nebulosity isn't waiting sufficient time for the ICNR before downloading the file. It seems to go like the following for a 300s:

1) start 300s exposure
2) finish 300s exposure
3) wait for download for about 90 seconds
4) creates a file with correct name, and what appears correct content
5) waits for 5 second delay/time-lapse
6) attempts to start second exposure, camera does not respond - still doing ICNR
7) after 300s of ICNR camera immediately starts next exposure, no download occurs.
8) Camera and Nebulosity are now "out of sync"

I can't find any search results for Nebulosity + ICNR to determine if ICNR is just not supported?

Thanks,
Roger.

[netwolf]

Roger, I had this discussion with Craig Stark the author some time back before v2 was released. Craig was basically of the view that ICNR was not the best approach, as such Nebulosity did not support this feature. I am not sure if his position has changed on this, but you maybe better of asking him direct or via trhe yahoo support group. I found Craig to be very friendly and easy to approach, with quick response to such enquires.

Craig did put forward that he did not belive that ICNR was the best method. His opinion back then was that it is better to take the dakrs seperately than to waste the time on dakrs which could be spent capturing light frames. Also I think it has to do with the fact that if you caputure 50 light frames you dont necessaryly need 50 dark frames. You can probably do with 10. So if you used ICNR then you would waste time on 40 extra dark frames. Also if your imaging train was not changing and temprature drop was not very substantial during your run you would be ok to reuse 10 dark frames as a master set for all your light frames witht he same exposure time as the dark frames.

I have V2 but have not really used it so am not sure if the ICNR support is now included or not.

Here is the link to the yahoo user group.
http://tech.groups.yahoo.com/group/s...nomy-software/


Regards
Fahim

[peter_4059 (Peter)]

It's interesting that another one of his products (DSLR shutter) does support ICNR by having a delay before and after frame setting. I use this and set the delay after frame to be equal to the exposure time plus some time to download the image.

[rogerg (Roger)]

Originally Posted by peter_4059

It's interesting that another one of his products (DSLR shutter) does support ICNR by having a delay before and after frame setting. I use this and set the delay after frame to be equal to the exposure time plus some time to download the image.

I was thinking about that. The longest exposure I've done with DSLR Shutter was 60 seconds, and that would have fitted within the timeout period Nebulosity 2 waits for the download, so would have worked with ICNR. Do you use it with exposure times longer than two minutes?

Originally Posted by netwolf

Roger, I had this discussion with Craig Stark the author some time back before v2 was released. Craig was basically of the view that ICNR was not the best approach....

Thanks... I wasn't aware of that yahoo group, that might be very useful! I'm still struggling with it saving files as FITS so I might ask some questions there about that. (Deep Sky Stacker seems to open the FITS OK but photoshop interprets them as greyscale, and I can't get Nebulosity to save the RGB FITS as separate files).

Anyway.. as for the ICNR issue... I have emailed Craig and just received his reply. Very much as you said, he believes it's best to not use ICNR. Oh well, while I disagree in some circumstances, I am happy to reside myself to being limited to not using INCR and instead a batch of dark frames. It just makes processing out the amp glow a lot harder.

Thanks,
Roger.

[peter_4059 (Peter)]

I have done 2 min exposures (+2min ICNR) with it but can't see any reasone why it wouldn't work with longer ones.

[leon]

I understand where you are coming from, however ICNR, although doubling your exposure run, is the best way to go, but I suppose it is personal preferences, I do prefer it that way.

Leon