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NGC7822 Bi-colour

swag72

By swag72
in Imaging - Deep Sky

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swag72

swag72

Posted
Posted

Here's the thing - The refractor has gone back on the mount and I am LOVING it!!! If anyone says that they want to image at 2m plus in focal length and f10, I will tell them they are mad!!! :grin: I spend many a post saying that short refractors are easier in imaging ....... Blimey, are they ever!!

The purpose of this post really is to gain some idea about likes and dislikes with this bi colour image. I see people producing these and they look fine and delicate, almost dreamy and subtle...... Cue my effort!! About as subtle as a house brick and almost the same colour too!!! Try as I might I can not get the subtle look, and I have really tried as well.

What are you thoughts on this as a bi colour? I don't see many that are as 'stand up and grab you by the throat' and I'm not sure whether this works. I suppose I am saying that so long away from this type of imaging I wonder if I've got this one right?

Details

M: Avalon LInear Fast reverse

T: Takahashi FSQ85 0.73x

C: QSI690-wsg with 3nm Ha and OIII filters.

13x1800s Ha

13x1800s OIII flats and bias used in both.

post-5681-0-95805200-1406273307_thumb.jp

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Stargazer33

Stargazer33

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Speaking as a mad 2032mm f10+ imager (well, trying to be an imager - can't seem to find my backside with both hands tied behind my back at the moment!) I think that is a very nice bi-colour image. It shows lovely depth and an almost 3D effect.

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Martin-Devon

Martin-Devon

Posted
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Sara, there almost equal amounts of SII and OIII in NGC7822, so I guess the SII is needed to give the range of colours that are seen with other images posted on the web of NGC7822. I tried this target last autumn, attempting a huge mosaic, but my eyes were bigger than my ability and I never finished it!

Looking back at my data though I did get a hubble image out of one of the panels which has similar framing to yours, and with full HA, OIII and SII you'll see in my image in the attached JPG, that it's possible to get the dark blue and orange hues typical of a hubble palette. 

You do have tremendous detail in your image, the lighter area in the centre, and contrast there is excellent. At the moment the colour range does look a bit limited, but as I mention above, that may be transformed if SII data was added. 

Martin

post-7944-0-77334300-1406305926_thumb.jp

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Chris-A

Chris-A

Posted
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I find Matts Sporre's website excellent for ideas for narrowband colourings because for each target he tends to do 6 versions - 3 variants of Hubble and 3 "artificial RGB" versions, with an explanation of each. Here is his go at NGC 7822, you can see each version by hovering over the thumbnails on the left. I must say my favourite is definitely his "ARGB bluer" version.

http://istarion.net/Picturepages/Nebulas/NGC7822.shtml

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PhotoGav

PhotoGav

Posted
Posted

That is a return to the Swag norm! Very sharp, wonderful contrast. As for colour, it is rather like a sepia toned b/w image. How have you mapped the Ha and OIII channels? As you well know, I'm very new to this narrowband stuff, so can't offer much in the way of advice, but have you tried creating a synthetic green channel after mapping Ha to R and OIII to B. You could try Noel's Action to do it. Might give that area of difference that could lift the image that bit extra?

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swag72

swag72

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Thank AG, Mark and Gav.

@Gav - This image was mapped using a synthetic green. I've had another play since and it's better, I think I just got a little lost with this one, being the first one in ages!!!

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ollypenrice

ollypenrice

Posted
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I love your image, Sara. It doesn't shout but it is of excellent quality, sharp and with superb control of the illumination. The dark patches don't look clipped and the central glow is lovely.

It does lack colour range, but any bicolour image lacks colour range to my eye. How can it not? The colour is built from two sources of information, not three. The only way I can think of to approach a third would be to do a different stretch of the Ha (say) for adding as a repeat channel and this would just be invention by the imager.

Matt Sporre's image is a virtuoso performance in three band imaging. As good as it gets, I'd say. Thanks to Chris for the link.

I never enjoy processing anything so much as refractor images. This isn't very rational but i's the truth.

Olly

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johnrt

johnrt

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I tried a bi-colour image of a section of this very nebula last year and could not for the life of me drag anything out of the OIII signal to get a contrasting hue of colour, it came out very much like yours.

An interesting note from the link above to Matt Sporre's website is that he bins his OIII and SII 3x3, perhaps there lies the answer?

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adamphillips

adamphillips

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I am a 2800mm f/10 imager just with a DSLR at the time being. but I have gotten some pretty nice results surprisingly, especially from jumping in and starting with that set up.

but I cant wait to buy a new Atik 383L to finally start on my intimidating RGB adventures. and eventually ill get myself a refractor. ive been looking at the skywatcher pro 127. I could save a lot of money with the pro 100 but the focal lengths are the same which means more aperture and faster f ratios with the big guy, its too mouthwatering.

I cant wait to see the difference of refractor vs SCT in images. everybody swears by the imaging capabilities of refractors.

and by the way, that new hubble palette image you just posted is pretty incredible, I wouldn't be surprised to see that thing pop up on my astronomy picture of the day app.

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swag72

swag72

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Cheers Adan, Gav and Paul :smiley: This is more like I had in Mind, shame the bicolour was such a let down.

@Adam - I had only used refractors for about 3 years. 7 months ago got an SCT  Loved the focal length. Now the refractor is back on ............ it's like chalk and cheeses. Life is easier with a refractor on all counts :grin:

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adamphillips

adamphillips

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hey sara thanks for replying.

I am looking forward to wide field nebula images with a reractor, but I am still glad ill always have my SCTs for the focal length because my real passion is galaxies.

right now I have an 8" and 11". so my focal length choices are 2800, 2032, or 1280 with the FR on my 8"

its nice to have options for different FOVs I think.

the refractor will give me 900 and 765 with FR. im sure one day ill want a nice expensive one with 500-600 FL

isn't it such a great hobby/money pit?

that's ust a joke though, I think it is well worth every penny

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