Does "Flip" Matter for Dark Frames?

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poolemarkw
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Does "Flip" Matter for Dark Frames?

Post by poolemarkw » Tue Mar 12, 2019 2:47 pm

When creating a Dark Frame library, do you need to generate a set for each "Flip" camera setting that you intend to use for the camera? If doing a capture sequence that involves a Meridian flip, you have to flip the camera view as part of that. Can the same Dark Master that was used prior to the flip be used after the flip, or do you need a different one that was taken in the new flip view?

I created a Dark Library but have no idea how my "Flip" was set at that time, and am wondering if they will work in all Flip setting options or do I need to create a whole new library for each flip setting I'll use.

Thanks,

Mark

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admin
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Re: Does "Flip" Matter for Dark Frames?

Post by admin » Tue Mar 12, 2019 10:03 pm

Hi,

If you use the flip options in the camera controls then you have to ensure that the dark and flat frames that you use have matching flip settings to the image frames being captured. You don't need to worry about orientation if all you are doing is performing a meridian flip as long as you don't touch the camera flip controls at the same time. Obviously images that you take after the flip will be inverted compared to images before the flip, but that can be fixed in post processing later. I wouldn't recommend running a live stack over a meridian flip!

Hope this helps, Robin

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turfpit
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Re: Does "Flip" Matter for Dark Frames?

Post by turfpit » Tue Mar 12, 2019 10:29 pm

wouldn't recommend running a live stack over a meridian flip
I agree with that also for conventional imaging. I learned the hard with my Celestron C8. A meridian flip meant mirror shift, which then needed a re-focus, which then meant another set of flats - many wasted sessions working this all out and all because of poor planning. Things are better these days with some organisation and planning. ;)

Dave

poolemarkw
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Re: Does "Flip" Matter for Dark Frames?

Post by poolemarkw » Wed Mar 13, 2019 1:09 pm

Thanks Robin and Dave. I tried to do a meridian flip while live stacking a few nights ago and failed but for a different reason. I did a "Save as 16 bit stack" and then paused the live stacking, moved the mount to the other side, and then changed the gain to maximum and shortened the exposure to about 3 seconds so I could recenter my subject. In the Live Stack panel I changed the view to "View Individual Frames". I wasn't seeing anything refresh on the screen and then noticed that the frame count up/count down timers in the lower right corner weren't working correctly and the green progress bar was stuck all the way to the right. The count-up time just kept getting larger and the count-down timer was negative and growing negatively. Is this a known bug?

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Re: Does "Flip" Matter for Dark Frames?

Post by admin » Wed Mar 13, 2019 8:51 pm

Hi,

The symptoms you describe sounds very much like your camera stopping responding and SharpCap sitting there waiting for a frame to be delivered that never arrives. Sometimes changing the exposure can help fix that problem, sometimes using the reconnect camera option from the menu. Other times you have to either close the camera and reopen it or sometimes unplug and re-plug the camera. It really depends on whether the problem was a temporary glitch or whether the camera's internal computer or the Windows driver for the camera has managed to end up in a hung state.

Hope this helps, Robin

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Re: Does "Flip" Matter for Dark Frames?

Post by poolemarkw » Wed Mar 13, 2019 9:14 pm

Ok, thanks!

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