I think I have a Binning Issue - Forums

Topic starter

Mar 16, 2023

Hello!

Last night I created 60 lights using Bin 2 in ASIAIR Plus. I did this because I wanted to get the best resolution in arc seconds per pixel for my camera (ASI2600MC) and telescope (Edge HD 8 with reducer) combination.

But this morning when I tried to calibrate my lights with my master dark and master flat, which are Bin 1, I get the Pixinsight error saying incompatible image geometry.

Does this mean I must resample my lights from Bin 2 to Bin 1?

If so, can someone explain how to do that? I hope I didn't waste 3 hours of imaging time!

Thanks!
Jerry

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Jonny Bravo

Mar 16, 2023

You can't calibrate binned images with un-binned ones. Best solution is to take new darks/flats that are binned to match your lights.

I suppose you could try using integer resample in PI to bin your flats/darks to match your lights… not sure how well that'll work, though. Are the flats/darks at the same gain/offset/temp as your lights? What about bias (or flat darks)… you don't mention those. Did you take them as well? They are necessary to properly calibrate the flat.

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Jerry Gerber

Topic starter

Mar 16, 2023

Jonny Bravo:
You can't calibrate binned images with un-binned ones. Best solution is to take new darks/flats that are binned to match your lights.

I suppose you could try using integer resample in PI to bin your flats/darks to match your lights... not sure how well that'll work, though. Are the flats/darks at the same gain/offset/temp as your lights? What about bias (or flat darks)... you don't mention those. Did you take them as well? They are necessary to properly calibrate the flat.

Is it possible to resample the lights to match the binning of the master dark and master flat? That would be the simplest solution otherwise I would have to reshoot the flats, which means I would have to set up again and reshoot the lights as well.

The flats are the same gain, temperature and image train as the lights, the darks are the same gain, temperature and exposure time as the lights.

andrea tasselli

Frequent contributor

Mar 16, 2023 · Edited: Mar 16, 2023

Jerry Gerber:
Is it possible to resample the lights to match the binning of the master dark and master flat? That would be the simplest solution otherwise I would have to reshoot the flats, which means I would have to set up again and reshoot the lights as well.

The flats are the same gain, temperature and image train as the lights, the darks are the same gain, temperature and exposure time as the lights.

Yor best bet is still to re-take the flats with the correct binning. And whatever else needs be, be it dark-flats and darks. And no, you can't rescale the lights nor can you down-scale the calibration masters. You have an OSC camera, after all.

Don't get too concerned about the right position of the camera/image train, a ballpark approx will do. BTW, why are you taking down the image train at all???

P.S.: Once I found myself in a similar situation and I binned the master flats in PI but it was a very convolute affair...

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Jerry Gerber

Topic starter

Mar 16, 2023

andrea tasselli:
Jerry Gerber:
Is it possible to resample the lights to match the binning of the master dark and master flat? That would be the simplest solution otherwise I would have to reshoot the flats, which means I would have to set up again and reshoot the lights as well.

The flats are the same gain, temperature and image train as the lights, the darks are the same gain, temperature and exposure time as the lights.

Yor best bet is still to re-take the flats with the correct binning. And whatever else needs be, be it dark-flats and darks. And no, you can't rescale the lights nor can you down-scale the calibration masters. You have an OSC camera, after all.

Don't get too concerned about the right position of the camera/image train, a ballpark approx will do. BTW, why are you taking down the image train at all???

P.S.: Once I found myself in a similar situation and I binned the master flats in PI but it was a very convolute affair...

Lesson learned, I am going to reshoot everything next opportunity I get. I brought the equipment inside as I didn't want to leave it unattended all night in case it rained or got real windy. We've been having huge amounts of rainfall in California and last night was the first night in a month I was able to get out...live and learn.

andrea tasselli

Frequent contributor

Mar 16, 2023

Jerry Gerber:
Lesson learned, I am going to reshoot everything next opportunity I get. I brought the equipment inside as I didn't want to leave it unattended all night in case it rained or got real windy. We've been having huge amounts of rainfall in California and last night was the first night in a month I was able to get out...live and learn.

I get it but you could have left the image train attached to the scope, couldn't you? Mine always are when moved inside and out. Easier to get started and easier to have everything rotated in the right position for any subsequent session on the same subject, isn' it?

dkamen

Mar 16, 2023

If the camera is still attached to the scope and the focuser hasn't moved much and there aren't any pathological dust motes moving around on the sensor, you can just take the flats and they will probably be just fine. Goes without saying that you can take the darks and dark flats whenever you want.

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Jerry Gerber

Topic starter

Mar 16, 2023

If the camera is still attached to the scope and the focuser hasn't moved much and there aren't any pathological dust motes moving around on the sensor, you can just take the flats and they will probably be just fine. Goes without saying that you can take the darks and dark flats whenever you want.

Yeah, the flats I took last night are fine I don't have to re-shoot those since they're BIN 1. It's the lights I have to re-do. And I might have the chance tonight to do so, I hope.

dkamen

Mar 16, 2023

I don't understand.

Why redo the lights and not redo the flats?

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Jerry Gerber

Topic starter

Mar 16, 2023 · Edited: Mar 16, 2023

I don't understand.

Why redo the lights and not redo the flats?

Because the flats were shot at BIN 1. The lights were imaged at BIN 2. It's simpler to redo the lights. People I've been talking with on the PixInsight forum agree. I tried debayering the master flat and resampling it at Bin 2 but it didn't work. The flats were taken with the same image train, gain, temperature and focus as the lights will be tonight, only this time I shoot the lights at BIN 1. That seems like the best way to resolve it.

I put the equipment away last night in the house, so everything came apart, it's a portable setup that I didn't want to leave out all night unattended as a wind gust or rain might have made me sorry that I did...

Jonny Bravo

Mar 16, 2023

Jerry Gerber:
it's a portable setup

Probably the first person ever to describe a rig with an EdgeHD as "a portable setup"

Of course, I carry my entire rig, fully assembled, from my garage to the end of my driveway, so I guess it's "portable", too.

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Jerry Gerber

Topic starter

Mar 17, 2023

Jonny Bravo:
Jerry Gerber:
it's a portable setup

Probably the first person ever to describe a rig with an EdgeHD as "a portable setup"

Of course, I carry my entire rig, fully assembled, from my garage to the end of my driveway, so I guess it's "portable", too.

Believe it or not, the Edge HD 8" weights 2 lbs LESS than my Esprit 100ED refractor, the Edge weighs 14 lbs, the Esprit weighs 16 lbs.
Where I really save my back is with the AM5 mount---I'm too old to get a mount that weighs 38 lbs, the AM5 weighs around 11.5 lbs.

Last night, while autoguiding the Edge with the ASIAIR and the Celestron OAG, my guiding numbers were between .27" and .5". Not bad for 1422mm focal length!

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dkamen

Mar 17, 2023

Jerry Gerber:
I don't understand.

Why redo the lights and not redo the flats?

Because the flats were shot at BIN 1. The lights were imaged at BIN 2. It's simpler to redo the lights. People I've been talking with on the PixInsight forum agree. I tried debayering the master flat and resampling it at Bin 2 but it didn't work. The flats were taken with the same image train, gain, temperature and focus as the lights will be tonight, only this time I shoot the lights at BIN 1. That seems like the best way to resolve it.

I put the equipment away last night in the house, so everything came apart, it's a portable setup that I didn't want to leave out all night unattended as a wind gust or rain might have made me sorry that I did...

Flats do not need to match any of that. They correct uneven field illumination. As long as (any) dust motes on the sensor are in the same place and as long as (any) vignetting is centered and doesn't change by rotating the camera, they should work.

Believe it or not, many people take their flats later, inside the house, using some type of monitor or flat panel as the light source. Because this tends to work much better.

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Jonny Bravo

Mar 17, 2023

Jerry Gerber:
I don't understand.

Why redo the lights and not redo the flats?

Because the flats were shot at BIN 1. The lights were imaged at BIN 2. It's simpler to redo the lights. People I've been talking with on the PixInsight forum agree. I tried debayering the master flat and resampling it at Bin 2 but it didn't work. The flats were taken with the same image train, gain, temperature and focus as the lights will be tonight, only this time I shoot the lights at BIN 1. That seems like the best way to resolve it.

I put the equipment away last night in the house, so everything came apart, it's a portable setup that I didn't want to leave out all night unattended as a wind gust or rain might have made me sorry that I did...

Flats do not need to match any of that. They correct uneven field illumination. As long as (any) dust motes on the sensor are in the same place and as long as (any) vignetting is centered and doesn't change by rotating the camera, they should work.

Believe it or not, many people take their flats later, inside the house, using some type of monitor or flat panel as the light source. Because this tends to work much better.

There's a fairly long, well-detailed thread on CN about this: https://www.cloudynights.com/topic/860572-should-flat-frames-be-gain-matched-with-their-light-frames/

I think the primary takeaway is "it depends"