Eta - SII starved

[multiweb (Marc)]

Well, here's the best I could come up with the data I got. Some decent Ha and Oiii but I failed to get enough Sii and the weather being what it is ... well ... frustrating to say the least. Actually after checking Eddie's great repro I realised my Sii exposures weren't long enough. Should have gone for 20min instead of 10min. Live and learn. I've collected so much data on this one though I still processed it but I mixed the Oiii in the red, Ha in green and Sii in blue to bring the details. Massive cheating on the color side of things and processing but hey, the end justifies the means? Until I get more Sii that's the best I can do. Hope you like it.

Full frame is at: http://www.multiweb.com.au/astro/ngc...iGHaBSii_f.jpg
[6MB file]

That was taken with and ED80 at prime focus. There is approx. 5 hours of Ha, 4 hours of Oiii and 4h of Sii. Captured with a QHY8 Bin1x1 Gain:1 Offset:60 in Neb2 and guided with PHD on the C5". NB filters were baader 2" filters.

[gregbradley]

Very sharp shot.

There is room there to boost the red and blue in curves if that's how you want to present it. Narrowband is a bit undefined as far as colour goes although there has been a sort of agreement about how they look.

Did you bin your narrowband 2x2? (I take it your QHY8 is one shot colour?).

Doing 1x1 maybe wasting exposure time as with the Bayer Matrix only every 5th pixel is sensitive to red, every 5th for blue and every 3rd for green (RGGB). The other filtered pixels may be mainly only contributing noise.

Greg.

[multiweb (Marc)]

Originally Posted by gregbradley

Did you bin your narrowband 2x2? (I take it your QHY8 is one shot colour?).

Doing 1x1 maybe wasting exposure time as with the Bayer Matrix only every 5th pixel is sensitive to red, every 5th for blue and every 3rd for green (RGGB). The other filtered pixels may be mainly only contributing noise.

Greg.

I always shot bin1x1. I take the red channel for Ha and Sii and the Blue and green combined for Oiii. I never tried binning 2x2. I'm always afraid of losing resolution.

[BerrieK]

Marc although I'm no astrophotographer I really like the colour. Nice sharp pic.

[multiweb (Marc)]

Originally Posted by BerrieK

Marc although I'm no astrophotographer I really like the colour. Nice sharp pic.

Thank you I think our eyes are more sensitive to greens and yellows so it's easier to bring out more details. The Luminance is Ha which is already sharp. Colors help bringing up the difference in shades too. I'm just missing more red and blues at this stage.

[Hagar (Doug)]

Hi Marc, This is one very nice image. The narrow band has really enlightened the colour and added a huge amount of depth to the colour.

A thing you can try when narrow band imaging with the QHY8 is to image at 1 x 1 and if you have a copy of Nebulosity, select the discard all but the luminosity then go through a full combine process. I found this worked extremely well for Ha. The lum channel contains almost all the light which passes the filters and should allow you to get more detail than you can get by splitting the channels and taking the nearest colour to the band pass colour.

Very nice, It is obvious from the quality of the data that this has been a very long imaging process. Nice work. Keep at it.

[multiweb (Marc)]

Originally Posted by Hagar

A thing you can try when narrow band imaging with the QHY8 is to image at 1 x 1 and if you have a copy of Nebulosity, select the discard all but the luminosity then go through a full combine process. I found this worked extremely well for Ha. The lum channel contains almost all the light which passes the filters and should allow you to get more detail than you can get by splitting the channels and taking the nearest colour to the band pass colour.

Thanks for the encouragement Doug and the great tip Will definitely try it.

[avandonk]

Marc why dont you try combining

HA and SII to Red
O3 green to Green
O3 blue to Blue

The cyan colour of the O3 emission in one shot colour cameras give about the same signal in the green and blue sensor pixel arrays.

If you are using a mono camera you could split the O3 signal between the green and blue.

This gives you a 'natural' looking image.See this thread

http://www.iceinspace.com.au/forum/s...ad.php?t=42309


The reason that the 'normal' NB colours are assigned the way they are is because the human eye is twenty times more sensitive to green than red. This gives a more striking image even though all the colours are false.

Bert

[multiweb (Marc)]

Originally Posted by avandonk

Marc why dont you try combining

HA and SII to Red
O3 green to Green
O3 blue to Blue

The cyan colour of the O3 emission in one shot colour cameras give about the same signal in the green and blue sensor pixel arrays.

If you are using a mono camera you could split the O3 signal between the green and blue.

This gives you a 'natural' looking image.See this thread

http://www.iceinspace.com.au/forum/s...ad.php?t=42309


The reason that the 'normal' NB colours are assigned the way they are is because the human eye is twenty times more sensitive to green than red. This gives a more striking image even though all the colours are false.

Bert

Yeah I remember that thread now. Thanks for reminding me. I'm going to get some more data this week-end from Ilford hopefully then I'll go back and play with the different channels combinations.

[bloodhound31]

Marc, that is just beautiful! I could stare into that for ages.

Your hard work is appreciated very much mate.

Baz.

[RB (Andrew)]

I love it Marc !!

Very nice detail (and colours), almost bordering on artistic !

Well done mate.

[ejcruz (Eddie)]

Wow Marc got to keep an eye on you, great shot, unlimited doors to choose with narrowband, that SII can be a real pain but worth the effort. While waiting to get more SII data you can boost your current SII data by adding/combining ~15% of Ha to the SII then try the hubble palette Sii/Ha/Oiii. BTW you did a better job on the stars then I did.

Looking forward for more from you.

Cheers
Eddie

[rogerg (Roger)]

First impression was Wow! nice shot! ... good detail in the nebulosity. Upon closer inspection it's a shame the stars appear slightly distorted or something, but zoomed out to not see that I like it

[multiweb (Marc)]

Originally Posted by bloodhound31

Marc, that is just beautiful! I could stare into that for ages.

Your hard work is appreciated very much mate.

Baz.

and so are your kind comments mate. thank you very much

Originally Posted by RB

I love it Marc !!

Very nice detail (and colours), almost bordering on artistic !

Well done mate.

Don't you love NB and artistic license? Nobody says too red, not enough blue... bit more green maybe? Not yet anyway Glad you like it and thanks.

Originally Posted by ejcruz

Wow Marc got to keep an eye on you, great shot, unlimited doors to choose with narrowband, that SII can be a real pain but worth the effort. While waiting to get more SII data you can boost your current SII data by adding/combining ~15% of Ha to the SII then try the hubble palette Sii/Ha/Oiii. BTW you did a better job on the stars then I did.

Looking forward for more from you.

Cheers
Eddie

Thanks Eddie. I looked long and hard at your version. Actually had it on my desktop while processing as a reference I tried to mix Sii and Ha yeah. Didn't look too good. My Sii is still very noisy and stars in that channel are still chonky too. I had to do a star mask and decrease saturation to get rid of most the pink hue. I don't know if it's "ethical" but it sort of worked.

Originally Posted by rogerg

First impression was Wow! nice shot! ... good detail in the nebulosity. Upon closer inspection it's a shame the stars appear slightly distorted or something, but zoomed out to not see that I like it

Yep. Guilty as charged. My Sii channel is not the best. If you really look on the edges there is some misalignment/chromatic abberations as well. Next time I'll do a better job at aligning my subsequent imaging sessions more accurately. The cure for this is a TAK (not an ED80) but that's out of the question. In another life maybe.

[bluescope]

That's a WOW image Marc .... well worth the many hours of imaging !



p.s. What Greg said about 2x2 binning is apparently the way to go with one shot colour cameras ... slightly less resolution but quite a gain in sensitivity ... apparently ... haven't done any of this myself so only going on what others say

[multiweb (Marc)]

Originally Posted by bluescope

That's a WOW image Marc .... well worth the many hours of imaging !



p.s. What Greg said about 2x2 binning is apparently the way to go with one shot colour cameras ... slightly less resolution but quite a gain in sensitivity ... apparently ... haven't done any of this myself so only going on what others say

Thanks Steve. Yeah PMd him. Got to ask a few things.

[Tamtarn]

Interesting to see the NB version of eta gives a different feel to it. Lots of detail in there Marc. Good work

[multiweb (Marc)]

Originally Posted by Tamtarn

Interesting to see the NB version of eta gives a different feel to it. Lots of detail in there Marc. Good work

Thanks guys.

[rogerg (Roger)]

Originally Posted by multiweb

... The cure for this is a TAK (not an ED80) but that's out of the question. In another life maybe.

Yeah... I know what you're say'n If only we could all win lotto or be the kind of person to make a wealthy living

[Jen]

Wow beautiful pic Marc