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Old 11-09-2018, 05:19 PM
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Lognic04 (Logan)
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What to do with Ha Data?

Hi all,
With my new mono cam i know i am definitely going to be collecting a lot of HA, especially since my backyard is light polluted! So, the question is, what do i do with the data?
Obviously i dont live in a dark sky area, so there is only so much dark sky time a year (1 24hrs at most, across seasons) so i cant collect that much LRGB. Is it even worth collecting LRGB in LP? I havent actually done RGB in LP just yet because i don't know if it is worth it.
Also, i dont have O3/s2 to go with it, im not a fan of tri/bicolour anyway!
Thanks!
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Old 11-09-2018, 05:49 PM
kens (Ken)
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You can use Ha as your luminance channel or just use it in greyscale. There are plenty of people imaging in LRGB and RGB under light pollution. It is possible - just a bit harder.
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Old 11-09-2018, 06:28 PM
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ZeroID (Brent)
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Ha is only one component in an image. If you collect just Ha you will only have a grey image that lacks a lot of detail. Ha can be bright but lacks definition. RGB + Ha is a normal process with Ha added to the Red Channel or used as a luminance in Lab Colour mode. There are probably other options but I haven't found them yet. Some RGB filter sets have frequency notches in their coverage which does reduce some LP effects.

Ha also works with OIII and SII for a Hubble palette image. In that case RGB is not used. That combination gets around most light pollution problems but does make for longer exposure times because you are capturing such a small part of the spectrum. Ha normally gets assigned to the Red channel, OIII to Green and SII to Blue in that case.

I normally try to capture in all 5 channels, LRGB and Ha unless I am specifically looking for particular Ha targets where L can be a waste of time. It may only be a couple of captures, as much to test focus and get a full picture of my target in grey of course. It is often not used in processing later.
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Old 11-09-2018, 07:49 PM
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Sorry, the "you can't do RGB in LP" carp sandwich needs to end. It is just absolutely not true!

It's not the best image on earth, but here is my Corona Australis, shot 300 metres from Canberra International airport, which is surrounded by 24/7 lighting, including the RAAF Fairbairn base, and all the Defence buildings around, plus a Bunnings Light House the other side of the runway, plus a shopping centre...and a highway with exit ramp lights....and so many LED and Sodium street lamps around... and this is just 8hrs with an 85mm refractor AND an OSC CCD.

https://www.astrobin.com/full/343506/G/

...plus an ultra-faint PN done with the same rig, same location:

https://www.astrobin.com/full/339252/D/

So, whilst these are not brilliant, it also shows the LP vs RGB nonsense is precisely that - NONSENSE.

As Nike says - JUST DO IT!
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Old 11-09-2018, 07:54 PM
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Thats actually pretty good Lewis!!! now if only there was a bloody target this time of year!!! aargh!
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Old 11-09-2018, 08:07 PM
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And BTW, I do NOT use LP filters either.

All the magic happens in...PIXINSIGHT - the saviour of my sanity
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Old 11-09-2018, 08:23 PM
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Lognic04 (Logan)
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Will give it a go, whenever the melbourne weather cooperates!
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Old 12-09-2018, 07:54 AM
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The real question is, can I get IFN from home???
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Old 12-09-2018, 07:58 AM
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multiweb (Marc)
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Quote:
Originally Posted by LewisM View Post
Sorry, the "you can't do RGB in LP" carp sandwich needs to end. It is just absolutely not true!

So, whilst these are not brilliant, it also shows the LP vs RGB nonsense is precisely that - NONSENSE.

As Nike says - JUST DO IT!
You're like an astro-moses... you need to come to my place and stand next to my scope when I image. I need the sky color to turn from bright orange to a deep inky black.
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Old 12-09-2018, 10:19 AM
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Octane (Humayun)
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Logan,

Do something different and create black and white masterpieces using just your hydrogen alpha data -- collect loads of data and make mosaics.

H
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Old 12-09-2018, 11:32 AM
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mosaics?!

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Old 12-09-2018, 11:56 AM
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Octane (Humayun)
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The ultimate imaging challenge.

H
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Old 12-09-2018, 01:53 PM
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Quote:
Originally Posted by multiweb View Post
You're like an astro-moses... you need to come to my place and stand next to my scope when I image. I need the sky color to turn from bright orange to a deep inky black.
I've got RED skies...I wonder if the Red Sea...Moses...never mind...
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