M81 and the Integrated Flux Nebula (IFN)

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Menno555
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Re: M81 and the Integrated Flux Nebula (IFN)

#11

Post by Menno555 »

I did try it with the low(est) gain setting and 500sec a few nights back. The histogram was totally on the left with just a bit of space on the left, so nowhere near the example Brian did post. Busy with the Cat's Eye now but when finished I'm gonna focus on this and gain settings.

On filters: would a IR/UV Cut filter do any good or harm in this case?

Menno
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oopfan
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Re: M81 and the Integrated Flux Nebula (IFN)

#12

Post by oopfan »

Hi Tim,

You wrote: "Maybe the way to approach getting the IFN in the same picture as one that includes M81 is to go for high dynamic range compositions with a wide range of exposure lengths?"

Yes, that is the way to go, although you may only need two exposures as demonstrated in this video I created from data I purchased from Insight Observatory:
https://rumble.com/vcqant-brians-late-n ... d-flu.html

There are two exposures: 300s and 600s. The 300s frames preserved the detail in M81, but barely picked up the IFN. The 600s frames blew out M81, but did a fine job with the IFN. By the way, this was captured at Bortle 2 with a fast 16-inch scope and a camera with a deep well.

Regarding the possibility of picking up the IFN at Bortle 6-7. I agree that light pollution presents an almost insurmountable obstacle, but I still maintain that a high performance camera (very deep well and 16 bits) has a chance of capturing it.

Brian
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oopfan
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Re: M81 and the Integrated Flux Nebula (IFN)

#13

Post by oopfan »

Hi Menno,

You wrote: "On filters: would a IR/UV Cut filter do any good or harm in this case?"
I think if you are using a standard luminance filter, that it automatically cuts off the IR and UV.

Brian
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Menno555
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Re: M81 and the Integrated Flux Nebula (IFN)

#14

Post by Menno555 »

HI Brian

No luminance filters here, I have a color camera :) Hence the question if without IR/UV Cut it would benefit. Stars wil get bigger due to IR then but I don't know what kind of effect it has on the IFN.

Menno
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oopfan
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Re: M81 and the Integrated Flux Nebula (IFN)

#15

Post by oopfan »

Menno,

ZWO's website for the ASI071MC shows a QE graph that includes wavelengths beyond 700nm. That indicates to me that it doesn't have a built-in IR/Cut window. Furthermore it lists a link to a UV/IR Cut filter under Recommended Accessories.

Interstellar dust and gas has a propensity for scattering visible light. Therefore, allowing your camera to capture IR is beneficial with very weak light sources. It seems to me that it could help with the IFN, but it might cause focus problems depending on your optics.

Brian
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turfpit
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Re: M81 and the Integrated Flux Nebula (IFN)

#16

Post by turfpit »

Menno

https://www.astrobin.com/search/?q=UV%2 ... d=top-pick

These are Astrobin Top Picks all using UV/IR Cut filters - some are planetary/lunar, some are deep sky with colour cameras. Might be worth researching these 114 images.

Dave
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