10 replies to this topic

[BenKolt]

Greetings!

 

Having no shame in admitting my ignorance of many things, particularly regarding NB imaging, I must ask what is likely an obvious thing to many on this forum by now:

 

What are the definitions of SHO and HOO?  Neither showed up in quick searches that I've done, and so I decided just to bite the bullet and ask here.

 

I assume they are palettes for combining Ha, SII and OII.  Are these specific combination weights, or do they represent a "family" of weighting schemes?

 

Thank you for being kind to the ignorant.

 

Best Regards,

Ben

 

 

[anismo]

S - H - O is R G B mapping with Sulphur II, Ha, OIII filter  data. The actual percentage may be different depending on each of the channel and the information you want to emphasize. This is also known as Hubble palette mapping. This typically is blue/green/yellow color.

 

There are quite a few mixes available.  

I use 

R = 0.3Ha + 0.7SII

G = 0.2OIII + 0.6Ha + 0.2SII

B = OIII

 

H - O - O is R G B mapping with Ha, OIII, OIII filter  data. This is the usual bicolor images with reg and blue images you see. 

Edited by anismo, 24 July 2017 - 06:21 PM.

[Alex McConahay]

>>>>>>I assume they are palettes for combining Ha, SII and OII

 

You got it.....Substitute the letters for RGB, and you have the names of different "pallettes" for narrowband.

 

If Red=Sii, Green=Ha, and Blue=Oiii, then you have SHO.

 

And, yes, you can then change the proportion of these somewhat. But, when one says SHO, all three are normally combined at 100 % each. If not, you usually get the actual percentages of combine.

 

Alex

[Goofi]

Ben, 

 

Anis and Alex pretty much answered your question. As a moderator here, I'll encourage you to keep on asking these questions!  Trust me - many others probably have the same question and now they've got the answer too!  

[Alex McConahay]

Yeah, as Goofi says, for every person who asked there are more than a dozen or so who did not know enough to ask. Now, you all know. 

 

Alex

[BenKolt]

Thank you all!

 

I was feigning my trepidation, of course, for humorous effect, but I honestly had never learned what the letters meant, and now it makes complete sense.  It wasn't meant to be an unbreakable code after all!

 

Ben

[dsochaser]

I was just at a star party and before the imaging competition they advised the we should use standard palettes - i.e. NASA or ESO standard.

[Goofi]

I was just at a star party and before the imaging competition they advised the we should use standard palettes - i.e. NASA or ESO standard.

 

Just to expand a little on this for those who aren't sure what the standard palettes are, there are two palette/mixes in narrowband imaging that are more-or-less standards now: Hubble (SHO) that NASA tends to use, and CFHT (HOS) that the Canada, France, Hawaii Telescope team uses (hence it's name).  The SHO palette tends to give (with a little tweaking) a blue-gold mix and the HOS palette gives more pinks-purples.

 

This image shows all six of the regular mixes; you can always blend to give a more natural looking appearance or to emphasize certain colors/features.

[BenKolt]

 

Just to expand a little on this for those who aren't sure what the standard palettes are, there are two palette/mixes in narrowband imaging that are more-or-less standards now: Hubble (SHO) that NASA tends to use, and CFHT (HOS) that the Canada, France, Hawaii Telescope team uses (hence it's name).  The SHO palette tends to give (with a little tweaking) a blue-gold mix and the HOS palette gives more pinks-purples.

 

This image shows all six of the regular mixes; you can always blend to give a more natural looking appearance or to emphasize certain colors/features.

 

Thanks, Goofi.  That's quite a kaleidoscope of colors!  I look forward to trying them out once I've gathered enough data.

 

Ben

[HansD]

Combining SII, Ha and OIII in a way that gives a colorful image is useful scientifically in understanding the composition and make-up of various targets, and useful from a hobby standpoint in that you can make images in a light-polluted environment. But it doesn't really represent anything I would call natural. I only have LRGB filters so I can't do this myself, but I would like to see someone take a picture of a face with a background landscape just to show what these palettes would look like when we know what reality looks like.

 

Hans

[jrcrilly]

Given that the Ha line is red and the OIII line is teal (greenish blue), HOO gives the nearest to true color. SII is also red so unless mapped to a non-true contrasting color it doesn't add anything.