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gnomus

NGC 281 - Pacman Nebula Bicolour

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This is the Pacman Nebula - 5 hours of Ha and 5 hours of OIII captured over 5 nights with my Esprit 120, QSI 690 and Astrodon filters.  Some of the OIII nights were a little indifferent and a couple of OIII frames were discarded but most were kept.  Combination was: Red - Ha; Green - 40% Ha plus 60% OIII; Blue - OIII.  Processing in Pi and PS. 

E_PS_Tweaksx1800px.jpg

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Excellent Pacman Steve, like the pastel pink colour, my version is so red it looks embarrassed :grin:

Dave

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Just now, Davey-T said:

Excellent Pacman Steve, like the pastel pink colour, my version is so red it looks embarrassed :grin:

Dave

Very good, Dave.  When I put it together as HOO it was VERY red.  Then I stumbled upon the idea of using a blend of Ha and OIII as the green channel, and that seemed to tame things considerably - especially in the central area.  The blend is not my idea - I haven't had an original thought since around 1986 - I stole it from one of Kayron's (Light Vortex) tutorials.

Steve

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Good one. The 'earwig,' as I call it, often comes out too black (as in my woeful attempt, for instance) but here it has plenty of dynamic range. I might work up the local contrasts on the large Ha areas, though.

The scope looks like a keeper.

Olly

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Oooo, I like that Steve! It has a beautiful soft and gentle look to it and that muted red is very calming.

Is the Esprit 120 a new toy then? I hadn't really considered that range of scopes, but this image is a great advert for them. What is the focuser like on it? Is it good and heavy duty? Do you have a motor focuser attached to it? Also, do you use the flattener?

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3 minutes ago, PhotoGav said:

Oooo, I like that Steve! It has a beautiful soft and gentle look to it and that muted red is very calming.

Is the Esprit 120 a new toy then? I hadn't really considered that range of scopes, but this image is a great advert for them. What is the focuser like on it? Is it good and heavy duty? Do you have a motor focuser attached to it? Also, do you use the flattener?

Gav - the scope is relatively new.  I upgraded the stock focuser to a Feathertouch, and then (**gulp**) bought the Feathertouch motor focus unit.  Ludicrous price, but it was very easy to fit and worked straight away without fuss.  I am very happy with what I am getting out of my 120.

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1 minute ago, gnomus said:

Gav - the scope is relatively new.  I upgraded the stock focuser to a Feathertouch, and then (**gulp**) bought the Feathertouch motor focus unit.  Ludicrous price, but it was very easy to fit and worked straight away without fuss.  I am very happy with what I am getting out of my 120.

Never a penny spent in vain when it comes to things astro!! Thank goodness it all works well though. This has certainly got me thinking.

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23 minutes ago, ollypenrice said:

Good one. The 'earwig,' as I call it, often comes out too black (as in my woeful attempt, for instance) but here it has plenty of dynamic range. I might work up the local contrasts on the large Ha areas, though.

The scope looks like a keeper.

Olly

Thanks Olly - I used LCE in PS, but then kept dialling it back.  Is that what you had in mind or were you suggesting doing something with Ha as luminosity?

I am maybe overcompensating for being a 'pedal-to-the-metal' kind of guy in my astro-photographic youth ...... a few weeks back!

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1 minute ago, PhotoGav said:

Never a penny spent in vain when it comes to things astro!! Thank goodness it all works well though. This has certainly got me thinking.

I'm even thinking of getting a matching Esprit 80.....

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Just now, gnomus said:

I'm even thinking of getting a matching Esprit 80.....

Very nice, now why not?! I'm looking at the 100.

Do you use the dedicated flattener with the 120?

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Just now, PhotoGav said:

Very nice, now why not?! I'm looking at the 100.

Do you use the dedicated flattener with the 120?

Yes

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55 minutes ago, ollypenrice said:

Good one. The 'earwig,' as I call it, often comes out too black (as in my woeful attempt, for instance) but here it has plenty of dynamic range. I might work up the local contrasts on the large Ha areas, though.

The scope looks like a keeper.

Olly

A more contrasty version as per Olly's suggestion (I think).  Do folks prefer 1st or second?

G_Blend.jpg

 

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It be nice to see them side by side I keep going up and down the page its hard to say Steve. still like the look of this image you geting to good at this game.

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At the risk of being slow roasted, like Cardinal Bruno, by the PI Inquisitors I would always use LCE (an excellent tool) to modify a copy which I'd then take into Ps as a layer. I like the greater modelling in the open expanses of gas in the second version but some of the dark patches are going over into visible sharpening. I would just run the eraser over these in V2, allowing V1 to come through. A month or two's experimention with masks might eneble you to make one which just hid the bits in question prior to LCE but I know which I think is easier...

Olly

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I took a copy of your image and worked on just the 'central plain' to increase the contrast and this worked very well, producing an increased contrast not dissimilar to your second version. However, I used PS3 to paste a sharpened version of your image into a 'hide all' layer mask and I then gently and selectively brushed in the more contrasty version in the central area.

I'm really pleased to see that the Esprit 120 is working so well for you, If I didn't already have my FLT98, I'd be sorely tempted myself but the 120 is just too close in focal length to make it worthwhile. The obvious choice for me would be the 150 but my sampling rate would be just 1.06"/pixel which concerns me somewhat. BUT, I note that your sampling appears to be 0.9"/pixel so maybe my concerns are unfounded?

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Thanks Steve and Olly.  I will produce a V3, but need a break for a few minutes.  I too was worried about that 0.9"/pixel.  However, I fairly routinely get around 0.2-0.3" total RMS reported in PHD2 from the Mesu and things seem to have been OK.  When guiding deteriorates to around 0.6"' (as has happened frequently over the last few nights when I have had bands of cloud floating over, the subs still seems to be OK to my eyes.  So far, I haven't had to discard any subs because of guiding. 

A 150 would be nice.  I wonder what it would be like to look through the 120 (or your soon to be acquired 150) - but, since everything seems to be working, I'm not going to touch anything.

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1 hour ago, steppenwolf said:

I took a copy of your image and worked on just the 'central plain' to increase the contrast and this worked very well, producing an increased contrast not dissimilar to your second version. However, I used PS3 to paste a sharpened version of your image into a 'hide all' layer mask and I then gently and selectively brushed in the more contrasty version in the central area.

I'm really pleased to see that the Esprit 120 is working so well for you, If I didn't already have my FLT98, I'd be sorely tempted myself but the 120 is just too close in focal length to make it worthwhile. The obvious choice for me would be the 150 but my sampling rate would be just 1.06"/pixel which concerns me somewhat. BUT, I note that your sampling appears to be 0.9"/pixel so maybe my concerns are unfounded?

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H_1800px.jpg

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That is incredibly similar to my version :icon_biggrin: - the only difference is that the stars in the centre section of my version are a fraction brighter than yours as I only had your single layer to work with. I do think that the contrast increase was worthwhile as it gives an already excellent image a little boost. But, more importantly, which of your versions do you prefer?

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Although my method is a little different from Steve R's (and notably lazier!) it's essentially aiming to do the same thing. If you over sharpen small features in an image I think it somehow gives the processing game way. Your last version still looks slightly under processed which I think is a great place to end up. (As Mrs Gladstone said to her husband when he complained of a tendency towards constipation, 'Such a tendency is, after all, a tendency on the right side.')

Olly

Edited by ollypenrice
Typo
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Thanks for your suggestions.  I think I prefer the final image a little more than version 1.  I've been trying not do overdo things - these nebulae are not solid objects after all.

I'm going to get 5 hours of SII for it next, to try a Hubble Palette.   I will no doubt be calling for assistance soon afterwards.  

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Especially liking the 3rd version Steve - I think that often the Pacman can appear to be a little on the flat side and so some work on the contrast in the middle will really pay off, as you've shown. Very nice :) 

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41 minutes ago, swag72 said:

Especially liking the 3rd version Steve - I think that often the Pacman can appear to be a little on the flat side and so some work on the contrast in the middle will really pay off, as you've shown. Very nice :) 

Thanks Sara.  Encouraging words (as ever).

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