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Narrowband

M16 Modified Hubble Palette


Rodd

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This might represent the minimum amount of data needed (for me) to render a passable image with the ASI 1600.  It was shot with the TOA 130 and the ASI 1600. Its not a really minimal data image, but the data really is much less than I normally use with the STT-8300--8 hours total.  That's about 1/2 to 1/3  my narrowband exposure times. This would be only 4 30 min subs in the OIII and SII channels.  I don't think any less would work.  Maybe more will not make much difference.  Then again, maybe when I triple my data I will look back and say "what drivel, how could I have even posted that".  My big decision--and it is a big one--is whether I should spend the next coupe of clear nights adding to this image, or if I should consider it done and move on.  Its a big decision, because with only 2-3 clear nights per month, the stakes tend to be inflated.

Ha 49 5min

OIII: 25 5min

SII 25 5min

Fully calibrated (except no flat darks for the SII data).  Each SII flat needed to be 60 sec long to achieve the necessary signal.  There was just not time to collect another hours worth of data.  I don't think it mattered, really.  I had to work fairly hard to eliminate fine scale noise (due to limited data I think).  I probably could have done more--but at least I can say I did not use to much noise control! And the conditions for the SII data were much inferior to the conditions for the Ha and OII.  That can be seen in the FWHM values for the SII subs, which are much higher than the other channels.   That is why several of the stars in the core have mild reddish rings.   As far as saturation--perhaps a bit much--especially blue.  That was a trick.y balance as well

Rodd

 

HaSHO-1e4a.thumb.jpg.3052eee71b95c89d2e4f281950ee4c90.jpg

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6 hours ago, carastro said:

eLovely image Rodd.  Wish i could manage to get only 8 hours on an image, 4 hours is normally the best I can get with my limited opportunities.

Carole 

I think that the better one is at this game, the less data one needs! I guess more importantly here is the number of subs.  It is said that the ASI 1600, being a 12 bit camera, needs allot of subs to generate the dynamics  of a 16 bit camera (like 100+).  I have found (through looking at asi 1600 images and now beginning to process them) that total exposure time for the ASI 1600 is about the same as the KAF 8300 on the same scope.  Maybe its different for narrowband and not as many subs are needed.  Or maybe its the target.  Or, maybe I'll find that if I add 100 subs to each channel I will have a much better image.

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5 hours ago, Demonperformer said:

I'm probably being really dense, but what is a "Modified" Hubbell Palette?

That's where I botch the palette and make it sound like it was intentional!  Only kidding (in part).  I suppose it depends on the definition of "Hubbell Palette".  If that term simply means using the SHO order of combination, then it is merely a Hubbell Palette image.  But if the term "Hubbell Palette" refers to not only the order of combination, but to the overall visual appearance of the image as well (color balance), then I would say the term "modified" is appropriate.  Strictly speaking, most Hubbell palette images published by the Hubbell team have much more green in them.  But I do not like green in my images so I work to remove it.  Also, I add Ha as a luminance--so the image is really an HaSHO image.  That may or may not matter as far as it being "Modified" or not.

Rodd

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1 modification--Looked a bit dark.  I raised the brightness in the outer regions while keeping the core alone.  Also, I reduced the small scale noise a bit--only relevant to zooming (or full resolution).  Lastly--dropped saturation a bit

 

 

 

 

HaSHO-1i-desat.thumb.jpg.c937ba9e3ecb798608a2bd9bfa6dfcae.jpg

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Great images, all 3 of them. On my mobile phone, nr 2 looks best. Or maybe a mix of 2 and 3. Nr 1 is a bit dark around the core.

As for spending more time on , usually AP is like "so many things to do, and so little time to do it in". But the same targets come back year after year. You could let this sit until next year, and look at it with "fresh eyes".

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6 hours ago, wimvb said:

Great images, all 3 of them. On my mobile phone, nr 2 looks best. Or maybe a mix of 2 and 3. Nr 1 is a bit dark around the core.

As for spending more time on , usually AP is like "so many things to do, and so little time to do it in". But the same targets come back year after year. You could let this sit until next year, and look at it with "fresh eyes".

Thanks Wim--I agree about #2--its just that sometimes I look at an image I have processed in the morning and I say--what was I thinking.  But it morphs into decency after a while.  Very strange.  Definitely coming back with fresh eyes is a must.  I still have some weeks left with this one--still debating whether I need more data.  

Rodd

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34 minutes ago, tooth_dr said:

Makes me want a 1600 even more now. 

I do like the camera.  So far no major glitches, and the small pixels are nice with the refractors.  The cooling is pretty good to. I still need to experiment with gain and exposure times--but with teh clear ski I get I tend to want to leave well enough alone and collect as much data as I can.

Rodd

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1 minute ago, StargeezerTim said:

Ouch! thats a gorgeous image...

Thanks Tim.   I am leaning toward calling it done--not sure how much of an improvement more data will bring.  

Rodd

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16 minutes ago, astro mick said:

I dont know why your really worrying, i really dont.

Mick.

Well...not really worried, but enough time and effort goes into this that I like to make it as good as possible.  The worry part I suppose comes in when trying to determine if more data will help.  It means 2 to 3 nights (this target only available for me between 12:00 and 3:30).  After the next couple of nights it probably won't be clear for over a week or more.  So I would like to use the clear sky time I have to the best effect.  

Rodd 

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That's brilliant. The pillars look great even at 100%

You already don't seem to have too much noise so it's difficult to say if more data will make much difference. I think both version have their merits. Perhaps somewhere between the two in terms of contrast would be good, but that's all down to personal preference.

And I'm sorry; I know it's not necessary to, and everyone else has avoided correcting you, but I couldn't keep reading it: it's Hubble ;) Sorry!

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4 hours ago, Shibby said:

That's brilliant. The pillars look great even at 100%

You already don't seem to have too much noise so it's difficult to say if more data will make much difference. I think both version have their merits. Perhaps somewhere between the two in terms of contrast would be good, but that's all down to personal preference.

And I'm sorry; I know it's not necessary to, and everyone else has avoided correcting you, but I couldn't keep reading it: it's Hubble ;) Sorry!

Thanks lewis--Spelling has never been my strength.  I appreciate the correction.

Rodd

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  • Rodd changed the title to M16 Modified Hubble Palette
23 hours ago, Rodd said:

Well...not really worried, but enough time and effort goes into this that I like to make it as good as possible.  The worry part I suppose comes in when trying to determine if more data will help.  It means 2 to 3 nights (this target only available for me between 12:00 and 3:30).  After the next couple of nights it probably won't be clear for over a week or more.  So I would like to use the clear sky time I have to the best effect.  

Rodd 

Ok Rodd.

Your obviously very passionate to produce your best.

Nothing wrong in that though.

By the way a cracking image.

Mick.

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1 minute ago, astro mick said:

Ok Rodd.

Your obviously very passionate to produce your best.

Nothing wrong in that though.

By the way a cracking image.

Mick.

Thanks Mick.  Yeah...I am a bit OC I guess when it comes to my images.  Flaws and deficiencies stand out like flames that burn my retinas.  That, combined with a feeling of awe when an image--or portion of an image--starts to look real, have me ensnared.  There are many worse things to be addicted to I suppose.  

Rodd

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