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Narrowband

Elephant Hubble Palette Help Please


gnomus

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I've been having a go at putting together a 'Hubble palette' image using the standard Baader NB set.  I have found it a little challenging.  I gathered 6 hours 40 of Ha and 4 hours each of OIII and SII.  I found the Ha data relatively easy to process and was quite happy with the resulting image.  The other two sets of data though were nowhere near the Ha in terms of ease of processing and result.  I should point out that all of these were taken with a moon at 50% plus (over several nights).  Here is what I ended up with:

post-39248-0-93456800-1448305256_thumb.j

Here are some 100% crops to show the noise issue - the cleaner one is Ha, the other one is OIII:

post-39248-0-45730600-1448305419_thumb.j

post-39248-0-74267800-1448305421_thumb.j

Is this the sort of data that one would expect when doing narrowband imaging?  Do I need even more SII and OIII, or was the problem the moon?  I am not sure if I have over-processed the OIII and SII.  Should they be even darker - that is have I stretched them too much?  (I think I was probably trying to get some 'detail' out of them.)   I wasn't entirely sure what I was doing in Photoshop either - an awful lot of layers, many of them with 'Selective Colour' against their name.  Am I supposed to re-use the Ha layer as a luminosity layer?

Anyhow, here is the finished effort (I'm not sure I could call it Hubble palette - but it started off bright green):

post-39248-0-57367400-1448315994_thumb.j

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That is a striking image, I'm afraid I can't help with the processing other than to say Ha won't help as luminance as that would kill off any SII and OIII in areas where there is no Ha.

/Dan

Sent from my iPad using Tapatalk

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Thank you.  I went back to PI and reprocessed.  This time I used SCNR to take out some of the green - then back into PS.  Still a lot of processing.  I counted 16 different layers by the time I was done.  This version seems to have fewer artefacts.

post-39248-0-01186600-1448362943_thumb.j

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Have you looked at this guide Steve? It really is the basis for any Hubble palette in my experience. 

Your OIII and SII will always be full of noise when compared to the Ha - I tend to merge them into a colour image before doing any processing on them if I can. I find that works best for me.

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Have you looked at this guide Steve? It really is the basis for any Hubble palette in my experience. 

Your OIII and SII will always be full of noise when compared to the Ha - I tend to merge them into a colour image before doing any processing on them if I can. I find that works best for me.

Thanks Sarah. Thanks for the reassurance about noise levels. And thanks for the advice to combine early. I did try DBE and NR on the separate channels before combining. I can have another go. I did follow that guide you linked to, but I didn't get the same result as in the tutorial. I think my Ha was so 'strong' that the image was almost monochrome - green and black. The SCNR in PI seemed to help with that but I don't know if that is the kosher approach.

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I am new to this too and used Light Vortex Astronomy's guide

In Pixmath I used his percentages to try and get a more natural outcome.

It's a personal thing though.

http://www.lightvortexastronomy.com/2013/02/tutorial-nebulae-pixinsight-workflow.html

I had SII data similar to yours and re-took the SII data when the seeing was better and it made a big improvement.

Great looking image nonetheless.

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That's just such a cracking image! In all its variations. This thread is excellent, as I'm thinking about getting OIII and SII filters.

How on earrth did you manage to get 40 hours?! I've been lucky to get one night's imaging lately.

Alexxx

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Alex

I remember when I first started getting into this Astrophotography malarkey you were one of the people who offered considerable support and advice, so your kind comments today are very gratifying - thank you.

I think I was probably not clear enough in my description. I did not manage 40 hours. I got 6 hours and 40 minutes of Ha 4 hours each of SII and OIII. That is a total of 14 hours and 40 minutes. It still took me several nights though ... Please don't get me started on our recent weather or I will end up ranting and foaming at the mouth....

Steve

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Awww, thanks Steve, and it's a pleasure!

My dyslexia strikes again! How do you manage to correctly frame the object each imaging session? I've tried but it's hard.

1). I didn't take the camera off of the telescope, so no rotation.

2). I use a program called Sequence Generator Pro which has a great plate solve, slew and centre feature that generally puts you within a dozen or so pixels of the image you give it to solve (the image you give it is, of course, one of the ones you took the previous night).

By the way, I often use the SGP plate solve feature to centre on targets that I have chosen from pictures on the internet - from memory I think I used one of Barry Wilson's images on Astrobin to initially centre on the Elephant...... It saves a lot of time.

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