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Hi Greg

Quick Issue.  When using the exposure calculator, the tab for selecting the gain seems not to work.  In all the other top line radio button, when I click on them, a drop down window opens.  But with the gain, it seems to be stuck at a value of 2.3, which isn't one of the options I have entered for my ASI294 camera.

Any suggestions ?

Another point, the read noise you have entered for the ASI294 appears to be for an uncooled camera (it is the 10 C value).  For cooled cameras it is much lower - typically below the smallest value you can accept of 0.01.

BTW, I am having fun getting accustomed to this new  tool.  Thank god it is cloudy out.  How often have I said that ?

john
Hi John,

I don't have an explanation for why the gain would work any differently on the Exposure Calculator than on the other tools. Please ensure that the correct camera is selected on the dialog. If so, please try changing the camera and then changing it back. If that resolves the problem please let me know.

"Another point, the read noise you have entered for the ASI294 appears to be for an uncooled camera (it is the 10 C value). For cooled cameras it is much lower - typically below the smallest value you can accept of 0.01."

I don;t know what you expect me to do about that. I think this may be the best example I have yet seen for why I don't like to input the camera data. It's not nearly as straight forward as people might think. Ultimately each observer must take responsibility for their own equipment. The available data should merely be a starting point. BTW for standard CCD cameras the gain also varies from one camera to another even of the same model... there is no simple turnkey solution.

Thanks,
Greg
(2018-09-21, 08:31 PM)theskyhound Wrote: [ -> ]Hi John,

I don't have an explanation for why the gain would work any differently on the Exposure Calculator than on the other tools. Please ensure that the correct camera is selected on the dialog. If so, please try changing the camera and then changing it back. If that resolves the problem please let me know.

"Another point, the read noise you have entered for the ASI294 appears to be for an uncooled camera (it is the 10 C value).  For cooled cameras it is much lower - typically below the smallest value you can accept of 0.01."

I don;t know what you expect me to do about that. I think this may be the best example I have yet seen for why I don't like to input the camera data. It's not nearly as straight forward as people might think. Ultimately each observer must take responsibility for their own equipment. The available data should merely be a starting point. BTW for standard CCD cameras the gain also varies from one camera to another even of the same model... there is no simple turnkey solution.

Thanks,
Greg

I tried changing the camera type in setup>imaging systems, and then changing back to no avail.  I admit that I'm only 2 hours into this, so I may have easily missed something.  The only other place I have yet found to deal with variable gain is in the camera setup dialog under imaging system setup.

I'll keep pecking away.  

I can understand the problems of an infinite number of variables.  

Thanks for the product !

john
(2018-09-21, 09:00 PM)galljj Wrote: [ -> ]I tried changing the camera type in setup>imaging systems, and then changing back to no avail.  I admit that I'm only 2 hours into this, so I may have easily missed something.  The only other place I have yet found to deal with variable gain is in the camera setup dialog under imaging system setup.
Hi,

I see now that I mis-typed camera for imaging system. I just wanted you to switch another imaging system and back. Anyhow, It was my understanding that the camera gains showed up elsewhere, such as the Target Selection tool and Scheduler. If the gains are only showing up on the camera dialog, you should go back to the camera dialog and ensure that you actually entered more than one gain for your camera.
Greg:

Thanks for getting back. I've tried switching imaging systems, to no avail.

I've got 4 different gain levels associated with my camera, so that doesn't appear to be an issue.

I created the camera by importing the saved ASI294 version you uploaded, and modified the gain settings to the ones i typically use. I've also tried the base ones you provided.

I must have done something wrong, as the gain setting radio button only shows up in the exposure calculator. There appears to be no way to modify the gain in target selection - while I can use the setup button for the imaging system to drill down to the gain setup dialog, that doesn't seem to do anything

Regardless of what I do (including changing the imaging system to one of your stock ones), the exposure calculator always comes up with the same gain value of 2.3 - even though the gain of the system i selected was only 0.6

Also, when I pull up the scheduler, there does not appear to be a way to modify the gain settings in that tab.

I take it that if you attempt to use the ASI294 camera in one of imaing systems, your application is fully functional ? Maybe I need to do a reinstall !

john
Hi,

My apologies. I forgot that I removed the gain selection from the Target Selection, and the Scheduler never had one (shakes head). There are a lot of types of imaging systems to keep track of. Ok, so just now I selected an imaging system with a ZWO camera and tried it, and sure enough it is clearly broken. I know it was working at one time, because we tested it extensively. I never considered that it really could be broken!

Thank you for your patience. I will have it fixed soon, as I am just about to release the first update.
Great ! Looking forward to using it. I think it would be a useful addition to the Target Selection screen at some time in the future.

Best

john
(2018-09-22, 06:18 PM)galljj Wrote: [ -> ]Great !  Looking forward to using it.  I think it would be a useful addition to the Target Selection screen at some time in the future.

Best

john

Actually, it was meaningless, which is why I removed it. You haven't had the chance to yet experiment with changing the gain on the exposure calculator (my bad). I think you will find experimenting to be insightful.

The thing to remember is that the Target Selection tool and the Scheduler both work primarily off of SNR, and gain has no real effect on SNR, or blooming for that matter. A lot of people think gain changes the sensitivity of the camera, but it only affects how the signal is converted into ADU.

Under most circumstances you want to use the ZWO Base Gain Setting (0) in order to keep large signals from clipping (or overflowing). For example, a 12-bit camera has a maximum ADU value of only 4095, compared to 65535 for a 16-bit camera. Values above 4095 will be clipped, so we do not normally want to boost the ADU numbers by increasing the ZWO Gain. But when exposing for very faint objects, and particularly with short exposures, the ZWO Gain can and should be increased. This is because for very faint signals you risk losing information when converting from e to ADU.

To see how, lets look at an example. A faint nebula might result in e = 12. For the base Gain (lowest ZWO value), the ADU is computed as 12.0/4.75 = 3 ADU. But e = 15 will also result in 3 ADU. The difference between the two e values is lost at this Gain setting. By increasing the ZWO Setting to the unity Gain, 12e becomes 12 ADU, and 15e becomes 15 ADU, and no information is lost.  But this comes at a cost. For the base Gain, sources as bright as 19,451e can be represented in ADU without clipping. But for the unity Gain setting, all signals brighter than 4095e will be represented as 4095 ADU, and if there is detail above 4095e, it will be lost.

So the game you need to play is to look at the tradeoffs. If the target object is fairly bright or you are using long exposure times, you need to take care that the signal won't clip. But for very faint objects or short exposures you want to boost the signal as much as possible.

Regardless, the most suitable target objects for your imaging system and the best time to image a given target don't depend on the gain, and that is what the Target Selection tool and Scheduler are all about.
reg:

Thanks, understood.

Do you know when the update might be available ?

j

One last question - if I create a fake ZWO camera with a static gain, but leave the ZWO box unchecked, will I lose any functionality (except for being able to modify the gain with the radio button in the exposure calculator) ?

j
(2018-09-23, 01:26 PM)galljj Wrote: [ -> ]reg:

Thanks, understood.

Do you know when the update might be available ?

j

One last question -   if I create a fake ZWO camera with a static gain, but leave the ZWO box unchecked, will I lose any functionality (except for being able to modify the gain with the radio button in the exposure calculator) ?

j

I released the update yesterday. You should be prompted when you start SkyTools. You can force the update via the Updated, Registration & Feedback selection of the top level Setup menu.

It should be fixed now.