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Questions about imaging California Nebula

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#1 Seanem44

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Posted 18 February 2020 - 10:43 PM

My time is short. Twins coming Monday. I’ve got 8 hours of Ha. I got 5 hours of Oiii. The Oiii seems hardly noticeable. With two nights of clear skies forecasted, should I spend remaining time on Sii as it seems to be an Sii heavy target? Or do I gather more Oiii? Thanks all,

#2 Astrola72

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Posted 18 February 2020 - 11:27 PM

"Twins coming"?



#3 bobzeq25

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Posted 18 February 2020 - 11:38 PM

It might be difficult to capture and more O(III) light than you have.  Or S(II).

 

Different nebulae have different proportions of H, O, and S.  The California, a classic diffuse nebula, is more dominated by H than most.

 

But H is almost always (planetaries or supernova fragments can be exceptions) dominant to some degree.  Multicolored images usually have O and S amplified, often to a large degree.  The iconic Pillars of Creation image would be straight red, if O and S had not been amplified, and mapped to other colors.  This is that nebula, in LRGB.

 

https://www.reddit.c...creation_shown/

 

For my image of the California, I just used HaRGB.

 

https://www.astrobin.com/285813/B/

 

Just curious.  Why do you think the California has a lot of S?  Where would it come from?  The California (because of its shape) seems to me to be mostly just ancient hydrogen from the formation of the Universe.


Edited by bobzeq25, 19 February 2020 - 01:24 AM.


#4 lucam

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Posted 19 February 2020 - 08:34 AM

The California Nebula is one of the few objects for which a straight SHO palette produces a pleasing image. Similar to the elephant trunk and M1, it's easy to balance the signal from the three narrowband channels and create a beautiful rainbow of colors. 

 

Of course the signal is dominated by Ha but there is plenty of OIII and SII with distinct spatial distributions. 

 

See this image by Masahiro Takahashi on AB for example:

 

get.jpg?insecure

 

With the data you already collected, I would get one night of SII (you will have about 5-6 hours per night on this target this time of year) and one night split between OIII and SII. That should give you plenty of signal to make a nice image out of it. 


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#5 Seanem44

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Posted 19 February 2020 - 08:26 PM

The California Nebula is one of the few objects for which a straight SHO palette produces a pleasing image. Similar to the elephant trunk and M1, it's easy to balance the signal from the three narrowband channels and create a beautiful rainbow of colors.

Of course the signal is dominated by Ha but there is plenty of OIII and SII with distinct spatial distributions.

See this image by Masahiro Takahashi on AB for example:

get.jpg?insecure

With the data you already collected, I would get one night of SII (you will have about 5-6 hours per night on this target this time of year) and one night split between OIII and SII. That should give you plenty of signal to make a nice image out of it.

Awesome. That’s the info I was looking for. Working on Sii tonight and there is ton. I’m sure the Oiii I captured is there, it’s just not s as obvious as in other targets.

Edited by Seanem44, 19 February 2020 - 08:27 PM.



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