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Should I add 'all frame' types ?  

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(@autonm)
Brown Dwarf Customer
Joined: 2 months ago
Posts: 9
October 13, 2020 22:21  

So I feel there are 101 posts on forums about frames - I'm specifically talking - flat, fark, darkflat, bias.

If I have all types of those frames available - should I add them all to APP "1) Load" ?  or should I only add a certain combination. 

I'm trying to understand if all are load does APP use all of them? or does it not use one of the frame types because there is a combination of other frame types loaded?

 

Also, do all my frames have to be of the same rotation? My current flat frames when viewed individually are rotated portrait, whereas everything else is rotated landscape. Should I retake them, or does APP calculate any rotation?

 

I appreciate there are 'master' versions of each.. but for this question, I'm ignoring those.

*I am using a Canon DSLR.

Thanks

This topic was modified 1 month ago 3 times by Michael Auton

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(@vincent-mod)
Universe Admin
Joined: 3 years ago
Posts: 2653
October 15, 2020 11:25  

So you take these frames for various reasons;

- Bias - this is to correct for readout-noise
- Darks - this is to correct for hot pixels and amp-glow
- Flats - this is to correct for vignetting and dust

Instead of Bias, many also take darkflats, which basically are bias frames but then taken with a little longer exposure (the same as the flats to be exact).

For each of these you take a good amount. For Bias and Darks, usually at least 40 (ideally about 100, but 40 is a also fine). Flats, about 10-20. These you can all load in together with your lights if you want, APP will then calibrate the calibration frames correctly and create Masters. These Masters are then used to calibrate the lights.


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(@autonm)
Brown Dwarf Customer
Joined: 2 months ago
Posts: 9
October 15, 2020 12:16  

@vincent-mod

Thankyou. I understand the frame types, I am trying to understand more of how APP handles them based on the following:

 

1) should I add them all to APP "1) Load" ?  or should I only add a certain combination. What happens if I loaded ALL TYPES i.e. Bias and Darkflats does APP calculate which ones to use i.e. Bias over Dark Flats, or will it just process the all.

2) do all my frames have to be of the same rotation? My current flat frames when viewed individually are rotated portrait, whereas everything else is rotated landscape. Should I retake them, or does APP calculate any rotation?

 


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(@vincent-mod)
Universe Admin
Joined: 3 years ago
Posts: 2653
October 15, 2020 12:23  

Ah ok, just wanted to make that clear first. 😉

1) If you assign them correctly and load all in, APP will process them in the right order.
2) Flats rotation, good question, I think that's going to be an issue yes. APP is expecting the same dimensions (never tried to use rotated flats so, not sure).


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(@autonm)
Brown Dwarf Customer
Joined: 2 months ago
Posts: 9
October 15, 2020 12:30  

Great thankyou.. will redo my flats. The camera must have been slightly orientated in a way, it thought it was being held as a portrait.

 

Is there anything wrong with using Bias and Dark Flats together ?  From what I understand Bias frames are at the shortest exposure the camera can perform at while the Dark Flats are at the same exposure as the Flats. Comparing both Bias and Dark Flats could be at different exposure lengths and therefor hold different 'noise'. 


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(@vincent-mod)
Universe Admin
Joined: 3 years ago
Posts: 2653
October 15, 2020 12:37  

You can try to use the "batch rotate" tool in tab 9. I've never used it for this specific case though, but you may want to try that first before retaking the data.

Bias and darkflats can be used together, when properly assigned APP will use the darkflats for the flats and bias for the lights. However, be aware that some sensors (mainly the new CMOS type) have issues with bias, darkflats seem to be fine as well to use as bias for many sensor types. At least in my Canon 6D, bias works fine.


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(@autonm)
Brown Dwarf Customer
Joined: 2 months ago
Posts: 9
October 15, 2020 23:56  

many thanks !


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