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Mandel-Wilson 2 (aka the Angel Nebula) in Ursa Major


gorann

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This faint nebula is made up of Integrated Flux Nebula (IFN), which according to Steve Mandel-Wilson is dust lit up by by the energy from the integrated flux of all the stars in the Milky Way.

For being IFN, I get the impression that this nebula is relatively bright, but it certainly took quite a bit of stretching to bring out. Numerous galaxies can be seen hiding behind the dust.

Captured 4th and 5th of March with the RASA 8 and ASI2600MC (gain 100) without filter. 85 x 4 min, so 5.7 hours.

Thank's @wimvb for suggesting this cool target!

EDIT: Added the annotated image provided by Wim.

 

 

 

 

 

 

20210204-5 Angel Neb RASA PS33smallSign.jpg

Skärmavbild 2021-03-06 kl. 16.18.51.png

angelneb_gn_Annotated1.jpg

Edited by gorann
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3 hours ago, gorann said:

For being IFN, I get the impression that this nebula is relatively bright, but it certainly took quite a bit of stretching to bring out. Numerous galaxies can be seen hiding behind the dust.

Skärmavbild 2021-03-06 kl. 16.18.51.png

Quite a few more according to the HyperLeda catalogue ;)

angelneb_gn_Annotated1.thumb.jpg.9ea1ebc89df0ae2943947dc252158316.jpg

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29 minutes ago, The Admiral said:

And it's in Technicolor too! 👍

Out of interest, how do you judge the level of exposure needed?

Ian

Thanks Ian! No deep thoughts about the level of exposure really. In this case I thought 4 min was appropriate since there were no very bright objects in the field that would have been blown out. I do not think it matters too much with this camera since it has virtually no read noise. Longer exposures means less to store and stack but shorter exposures means you lose less if you have occational clouds around. So, 4 min seemed as a good middleground. I expect anything between 2 and 10 min would have given the same end result.

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3 minutes ago, PeterW said:

Very nice shot, there are lots of other IFN up there, Mel Bartels has a long list, though few seem to be imaged. Wonder how many more you could pick up?

Peter

Thanks Peter! I am on to it if I get enough clear skies. Great targets for the RASA since the Milky Way is now largely below the horizon.

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1 hour ago, gorann said:

Thanks Ian! No deep thoughts about the level of exposure really. In this case I thought 4 min was appropriate since there were no very bright objects in the field that would have been blown out. I do not think it matters too much with this camera since it has virtually no read noise. Longer exposures means less to store and stack but shorter exposures means you lose less if you have occational clouds around. So, 4 min seemed as a good middleground. I expect anything between 2 and 10 min would have given the same end result.

Thanks for that Gorann, but what I would really like to know is how you judge what the total exposure time should be, particularly for these feint objects?

Ian

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10 minutes ago, The Admiral said:

Thanks for that Gorann, but what I would really like to know is how you judge what the total exposure time should be, particularly for these feint objects?

Ian

Depends on your scope and camera. My gut feeling is that for an object like this with a RASA 8 at f/2 and the very sensitive ASI2600MC then 4 min will be quite enough to capture everything there is for it to capture. With an f/5 scope with a CCD then maybe 30 min would be needed.

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2 minutes ago, gorann said:

Depends on your scope and camera. My gut feeling is that for an object like this with a RASA 8 at f/2 and the very sensitive ASI2600MC then 4 min will be quite enough to capture everything there is for it to capture. With an f/5 scope with a CCD then maybe 30 min would be needed.

Sorry to persist Gorann, but what I meant was how did you arrive at 85 subs for the total exposure i.e. nearly 6 hours? Did you calculate it, or did you see what sort of total exposure time other imagers had used and adjusted it for your scope/camera combination?

Thanks, Ian

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1 hour ago, The Admiral said:

Sorry to persist Gorann, but what I meant was how did you arrive at 85 subs for the total exposure i.e. nearly 6 hours? Did you calculate it, or did you see what sort of total exposure time other imagers had used and adjusted it for your scope/camera combination?

Thanks, Ian

Oh, that is simply what I got. First night I got 4.4 hours before clouds moved in and I processed what I had and it looked rather ok but I thought it could look even better with a bit less noise so I gave it another night. Then clouds moved in last night even earlier so I only got an extra 19 subs but decided it was enough for my attempt on this target. Simply it looked good enough by my humble standards.

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