I've completed my sensor analysis (ZWO ASI294 Pro) without issues. When I try to run the smart histogram, it seems to be taking a long time. I have the max exposure time set to 3m, but the exposure times the tool is running keeps doubling without stopping. I finally stopped it when it tried to run a 16m exposure. I wouldn't expect it to run beyond what the max exposure time is, but I am very new to this. Do I just need to let it run until it completes, and if so, how long can I expect it to take?
TIA for any advice!
How long should Smart Histogram take?
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admin
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Re: How long should Smart Histogram take?
Hi,
during the measurement stage, SharpCap is trying to see how bright the background sky is, and it will keep increasing the exposure until it gets a strong enough signal to be confident that it has a real measurement rather than just noise near the black level of the camera. Certain things can make this need very long exposures:
* Narrow band filters
* Small Pixels (if your 294 is the mono one and you are using it in 47 megapixel mode then that might be influencing it)
* High f/ratio
* very dark skies
* vignetting near the corners/edges of the frame.
Make sure you are using the latest SharpCap 4.0, as there have been some improvements in SC4 to try to reduce the frequency of very long exposures being needed. There is also an option to tick to exclude the edges/corners of the frame if you suffer from vignetting.
Another option is to calculate the approximate value - you can do this if you know how dark your skies are (for instance bortle scale or NELM) - this web site will help do the calculation for you : http://tools.sharpcap.co.uk/
cheers,
Robin
during the measurement stage, SharpCap is trying to see how bright the background sky is, and it will keep increasing the exposure until it gets a strong enough signal to be confident that it has a real measurement rather than just noise near the black level of the camera. Certain things can make this need very long exposures:
* Narrow band filters
* Small Pixels (if your 294 is the mono one and you are using it in 47 megapixel mode then that might be influencing it)
* High f/ratio
* very dark skies
* vignetting near the corners/edges of the frame.
Make sure you are using the latest SharpCap 4.0, as there have been some improvements in SC4 to try to reduce the frequency of very long exposures being needed. There is also an option to tick to exclude the edges/corners of the frame if you suffer from vignetting.
Another option is to calculate the approximate value - you can do this if you know how dark your skies are (for instance bortle scale or NELM) - this web site will help do the calculation for you : http://tools.sharpcap.co.uk/
cheers,
Robin
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TexasAstroNewb
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Re: How long should Smart Histogram take?
Thanks for the quick reply! I think the narrow band filter I have on may be the issue. If I'm going to be shooting with that filter, should I leave it on while smart histogram runs, or should I take it off? I don't mind waiting if I need to, just want to make sure I'm doing the right thing.
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admin
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Re: How long should Smart Histogram take?
Hi,
you should leave the narrow band filter on, since it reduces the light levels reaching the sensor, which is what the 'brain' is trying to measure. If it is taking an excessive amount of time then use the estimation tool instead (or measure *without* the filter then divide the value by {bandwidth without filter}/{bandpass of filter} - bandwidth without can be taken as 300nm for mono cameras and 100nm for colour)
cheers,
Robin
you should leave the narrow band filter on, since it reduces the light levels reaching the sensor, which is what the 'brain' is trying to measure. If it is taking an excessive amount of time then use the estimation tool instead (or measure *without* the filter then divide the value by {bandwidth without filter}/{bandpass of filter} - bandwidth without can be taken as 300nm for mono cameras and 100nm for colour)
cheers,
Robin