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Sh2-129 and Ou4 - doable with an ASI294 MC Pro and dual band filter?

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#1 wesnikon

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Posted 18 April 2019 - 05:27 AM

As the moon is almost full and I just got the STC Duo Narrowband Filter the other day I thought I'd turn my attention to nebulae. Looking for potential targets I stumbled upon Sh2-129 and Ou4 (flying bat/squid) which is supposed to be very dim but it should be a perfect target for this filter (Ha and OIII) and the 294 is rather sensitive, so it's at the top of my list for this weekend now. I was thinking 2-3min subs, and lots of them.

 

Hopeless case or perfectly doable? 


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#2 dcornelis

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Posted 18 April 2019 - 07:26 AM

Hopeless until you prove me wrong :) 

I own the old camera with which some of the OU objects were discovered, a microline 6303e without coverglass to make it catch a few percent more light.


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#3 2ghouls

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Posted 18 April 2019 - 07:35 AM

With my ASI1600mm and a 3nm OIII filter shooting at f2.8, I found 5 minute subs with moonlight from the suburbs were not really working for OU4. I captured a few hours and it was still way too buried in the noise. I tried again with 10 minute subs from very dark sites (West VA, Cherry Springs, etc) I visited on a road trip and it was at least presentable after 6 hours.

Sh2-129 will be no problem, but I suspect you will have difficulty capturing OU4 well with that setup, especially under moonlight. That said, if you like tough challenges like me, you can still go for it, but be prepared for a very long integration!!

Here’s my interpretation of the amazing pair:
https://www.nebulaph...rpless/sh2-129/
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#4 wesnikon

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Posted 18 April 2019 - 07:46 AM

Hopeless until you prove me wrong smile.gif

I own the old camera with which some of the OU objects were discovered, a microline 6303e without coverglass to make it catch a few percent more light.

Sounds like a challenge :-) I actually think this can be done, just takes a lot of patience. 

 

This image here was taken with a Canon 450D and a 200mm lens.

 

http://www.astronome...php?c=159&p=525

 

Sh2-129-200-450D-HaOIIIRGB-Final.jpg


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#5 wesnikon

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Posted 18 April 2019 - 07:54 AM

With my ASI1600mm and a 3nm OIII filter shooting at f2.8, I found 5 minute subs with moonlight from the suburbs were not really working for OU4. I captured a few hours and it was still way too buried in the noise. I tried again with 10 minute subs from very dark sites (West VA, Cherry Springs, etc) I visited on a road trip and it was at least presentable after 6 hours.

Sh2-129 will be no problem, but I suspect you will have difficulty capturing OU4 well with that setup, especially under moonlight. That said, if you like tough challenges like me, you can still go for it, but be prepared for a very long integration!!

Here’s my interpretation of the amazing pair:
https://www.nebulaph...rpless/sh2-129/

Absolutely gorgeous, great image! Yeah, I figured Ou4 might be a problem, will probably have to get an OIII filter to just capture Ou4 and enhance the image with that data in post.


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#6 scopenitout

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Posted 18 April 2019 - 01:39 PM

While I know nothing much about the camera or filter you mention, I can tell you from experience Ou4 is a very shy emitter of OIII. A dark site, 3nm filter, long exposures and plenty of integration is what you'll likely require.
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#7 dcornelis

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Posted 19 April 2019 - 12:06 PM

60+ hours, respect Wesnikon!



#8 Jon Rista

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Posted 19 April 2019 - 04:59 PM

As the moon is almost full and I just got the STC Duo Narrowband Filter the other day I thought I'd turn my attention to nebulae. Looking for potential targets I stumbled upon Sh2-129 and Ou4 (flying bat/squid) which is supposed to be very dim but it should be a perfect target for this filter (Ha and OIII) and the 294 is rather sensitive, so it's at the top of my list for this weekend now. I was thinking 2-3min subs, and lots of them.

 

Hopeless case or perfectly doable? 

It might depend on the bandpasses of the filters, and how much LP you have. I used 3nm filters with an ASI1600, 3 minute exposures @ Gain 200 (~1.33e- read noise, 1980e- FWC), with just a little over 11 hours of integration...under ~18.2mag/sq" skies:

 

DujiGSw.jpg

 

There is no noise reduction here...this is the raw integration with just a simple stretch.


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#9 Jon Rista

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Posted 19 April 2019 - 05:03 PM

In my HOO blend, I tried to keep the relative intensities of Bat and Squid as natural and realistic as possible. Squid is extremely faint in relative terms:

 

FJbeciq.jpg

 

I think there are only around 4-6 hours of Ha here. So about 15 hours total imaging time with 3nm filters. I don't know what the multi-band filters have in terms of actual bandpass for each band, but if they are narrow enough, you should be able to get a good enough result with an IMX294. Now, since the camera is acquiring both bands simultaneously, instead of 15 hours, you might be able to do just 10. The IMX294 will also probably have some overlap at the OIII line between blue and green...depending on just how high the Q.E. is in both bands at the emission line, that might help improve SNR in a given exposure time.


Edited by Jon Rista, 19 April 2019 - 05:05 PM.

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#10 Jon Rista

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Posted 19 April 2019 - 05:04 PM

A different blend of the same data:

 

jOYCPLn.jpg


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