The "No EQ" DSO Challenge!

[Filroden]

2 minutes ago, Nigel G said:

The surrounding area of the cone nebula

Haven't you finished this yet  You still have a long way to go to link up to the Pacman!

Yep, I think it never ends. I guess it's just take a frame and see if it looks good.

[The Admiral]

2 minutes ago, Nigel G said:

The surrounding area of the cone nebula  

Okay, okay . But seriously Nige, I do like that mosaic very much.

Ian

[The Admiral]

7 minutes ago, Nigel G said:

The mount did do well last night. I got 90x60s on the Pacman and a further 45x60s on the Horsehead.

A slight small problem was the focus had shifted slightly during the Pacman shoot. Not much but enough to blur the image a little.

I have processed it a couple of times with much better result than the last time. Just wish I had checked the focus during the shoot.

Cheers

Nige.

First process of 90x60s

Second process of 90x60s

Very nice Nige, the extra data certainly helps.

Ian

[Nigel G]

Ian.

Your Cone nebula is great, fine details, well done.

It's another on my list too.

Do you fancy swapping scopes  

Nige.

[The Admiral]

7 minutes ago, Nigel G said:

Ian.

Your Cone nebula is great, fine details, well done.

It's another on my list too.

Do you fancy swapping scopes  

Nige.

Thank you Nige. What, a reflector! Not a chance. But with your larger aperture I guess you might see a bit more resolution, unless you're looking through cloud, in which case it doesn't make a whole lot of difference .

Whatever happened to you using your 200P? Or was that someone else?

Ian

Edited January 21, 2017 by The Admiral

[Nigel G]

Just now, The Admiral said:

Thank you Nige. What, a reflector! Not a chance. But with your larger aperture I guess you might see a bit more resolution, unless you're looking through cloud, in which case it doesn't make a whole lot of difference .

Whatever happened to you using your 200P?

Ian

 The 200p was way to heavy for my mount, Sold it a few months back.

Nige.

[happy-kat]

I'm being chicken it is too cold for me at the moment so my revised mount attachment is so far untested

[Filroden]

1 hour ago, The Admiral said:

Yes, you can see the green crescents in the stars that I was referring to.

It wasn't these that I thought gave it the green tint. Rather, there are small patches of green in the background. I've circled them here. I think the green appears over the stars in those areas too, making these starts a little off-yellow. When zoomed to normal size, I was seeing this as a green cast to the image but it's not. It's just small pockets of green.

Because they are so patchy, I wonder if they've appeared when the image has been converted to jpg for uploading to this site?

[The Admiral]

45 minutes ago, Filroden said:

It wasn't these that I thought gave it the green tint. Rather, there are small patches of green in the background. I've circled them here. I think the green appears over the stars in those areas too, making these starts a little off-yellow. When zoomed to normal size, I was seeing this as a green cast to the image but it's not. It's just small pockets of green.

Because they are so patchy, I wonder if they've appeared when the image has been converted to jpg for uploading to this site?

No, they're in the original TIFs. When I re-process I'll keep an eye out. The target was drifting a bit so I had to re-align a couple of times, so I wonder if some slight optical distortion is putting the stars in slightly different positions relative to each as they drift, so that they don't align perfectly. Anyway, we'll see.

Ian

[Filroden]

3 minutes ago, The Admiral said:

I wonder if some slight optical distortion is putting the stars in slightly different positions relative to each as they drift

That might be it. Given sensors have twice as much green response as they do blue or red then this might be why I've seen the green.

[The Admiral]

1 hour ago, Nigel G said:

Second process of 90x60s

Having another look at this I noticed a very straight edge to the nebula about half way down on the LHS, and I was beginning to think it was an artefact that I'd encountered using the deconvolution tool. BUT, having just Googled some images it appears to be the case! Quite remarkable that the nebula edge should appear so straight, naturally.

Ian

[The Admiral]

2 minutes ago, Filroden said:

Given sensors have twice as much green response as they do blue or red.

An even greater proportion in the Fuji X-Trans!

Ian

[Nigel G]

8 minutes ago, The Admiral said:

Having another look at this I noticed a very straight edge to the nebula about half way down on the LHS, and I was beginning to think it was an artefact that I'd encountered using the deconvolution tool. BUT, having just Googled some images it appears to be the case! Quite remarkable that the nebula edge should appear so straight, naturally.

Ian

I noticed that too while processing, it looks out of place, a perfect right angle sticking out. very odd.

Nige.

[Stub Mandrel]

2 hours ago, Nigel G said:

The surrounding area of the cone nebula

It would be a cool and possibly achievable project to expand that into a meandering mosaic that takes in the whole sky more or less on the ecliptic visiting all teh interesting patches. The leo galaxies aren't far away for you (Orion is just about in the best place for me ATM).

[The Admiral]

Well, here's another go at processing the Christmas Tree/Cone nebulae. Over processed as usual in an effort to squeeze out as much from this fairly feint object as I can, so much so that it's looking rather messy. You guys with modified cameras should be able to do a lot better. This time I binned 25% rather than 35%. Not sure if that was the cause of the 'greenish' stars, but whatever, I don't think it is so evident this time. I think I'll leave it at that now

I rather like this picture of it: https://apod.nasa.gov/apod/ap130806.html

Ian

[Filroden]

49 minutes ago, The Admiral said:

Well, here's another go at processing the Christmas Tree/Cone nebulae

Not a hint of green  And when you really look close there's an amazing amount of stuff going on inside the area. You can see what looks to be so many shock waves within the nebula. Something really cataclysmic must be happening in this region! 

50 minutes ago, The Admiral said:

I rather like this picture of it: https://apod.nasa.gov/apod/ap130806.html

The diffraction spikes make the Christmas Tree Cluster stand out! I've never thought it obvious until that image.

[SteveNickolls]

You've really captured a lot of colour and detail in your Christmas Tree Nebula/Cone Nebula image Ian, your camera is sensitive in the red.

Nige, I do admire your mosaic - do keep it growing!

Cheers,
Steve

[The Admiral]

46 minutes ago, Filroden said:

Not a hint of green  And when you really look close there's an amazing amount of stuff going on inside the area. You can see what looks to be so many shock waves within the nebula. Something really cataclysmic must be happening in this region! 

The diffraction spikes make the Christmas Tree Cluster stand out! I've never thought it obvious until that image.

Thanks Ken, and it's worth a diversion on that link too to look at the information on the Subaru telescope. Quite an outstanding engineering marvel.

Ian

[rotatux]

8 hours ago, The Admiral said:

I software binned 33%, which isn't a nice round figure, so I might try a different binning.

 

9 hours ago, Filroden said:

On closer zoom, it seems there are small areas with a green cast and the rest of the image unaffected.

Here's a screenshot from my iPad:

Its almost like a noise pattern with green? It may even be an effect of jpeg compression rather than in the original image?

Very strange because I've got some near-looking problem : I've been working on a failed Flame+Horsehead of late december, I tried to bin it at 50% in the hope to gain some SNR, which about worked, but as a side effect I've got colored arcs around stars. It seems it would be linked to binning, but there must be something else or other  people would have noticed.

Look at this:

(Capture: 82 good of 96 lights x 15s x 2500iso, usual equipment, 50% binning then X2 scaling)

[Nigel G]

That's strange, almost like a shadow on the stars.

Not see it like that before.

Will be interesting to find the cause.

Nige.

[The Admiral]

13 hours ago, rotatux said:

 

Very strange because I've got some near-looking problem : I've been working on a failed Flame+Horsehead of late december, I tried to bin it at 50% in the hope to gain some SNR, which about worked, but as a side effect I've got coloured arcs around stars. It seems it would be linked to binning, but there must be something else or other  people would have noticed.

Look at this:

(Capture: 82 good of 96 lights x 15s x 2500iso, usual equipment, 50% binning then X2 scaling)

It's a bit more than just a crescent though, isn't it? It looks like chromatic aberration because there is blue on one side of the stars and red on the opposite sides. This was similar to my case, except that it was green and yellow (just!). And I did use the ST colour module so the colours could well have changed. I suppose it could be an atmospheric diffraction effect we're seeing, as the targets never get that high in the sky, and there could be ice crystals in the upper thin haze of cloud. On the other hand, I do wonder what aberrations a Bayer matrix might give (though my Fuji has a non-Bayer filter array, though presumably just as susceptible but with a different result). This is all waffle of course as I don't really have an answer! I would need to go through the ST log files to see what differences there were in processing, though I do know that in the final one I used a 50% bin rather than a 35% one, and the effect isn't visible. I can't remember now what software you use to process Fabien.

Ian

[The Admiral]

Here's my result for the Rosette nebula which I imaged on 4th January and 19th January (exactly one year after my first attempt at imaging this object). I collected a total of 360 x 30s subs, from which I managed to stack 213 in AstroArt. I used 60 flats and a generic bias from 200 frames. Processing was performed in StarTools and final polishing in Lightroom. I didn't use the ST colour module for this as it seemed to produce gregarious colours; I generally find I don't use it for targets which give me a decent signal, but for weaker objects I find it brings colour to an otherwise fairly monochrome image.

The FoV of my 'scope only just covers the Rosette, so I needed to avoid having to crop too much from the frame, especially as this turned out to be long imaging session where field rotation was going to be an issue. I stumbled on a ST workflow where I would do an initial wide crop of the frame, trying to avoid the stacking artefacts, do a 'wipe' with 'temporary develop' switched on, and then if I was getting poor results I'd cancel the 'wipe', crop off a little more, then repeat the exercise as many times as needed to get a decent 'wipe' result. Why I hadn't thought of doing this before goodness knows

The usual equipment:  Fuji X-T1 through an Altair 102mm f/7 Super ED with a TS Photoline 2" 0.79x reducer/flattener. Mounted on a Nexstar 6/8SE Alt-Az mount.

Hope you like it. Ian

 

Edited January 22, 2017 by The Admiral
Reduced sharpening

[rotatux]

9 minutes ago, The Admiral said:

I collected a total of 360 x 30s subs

That's quite a job for an alt-azer I hope you are automated somehow. Nice image with plenty of details, maybe too globally red for me but the subject is probably like this. Nice color shades (of pinks on my monitor).

5 hours ago, The Admiral said:

It looks like chromatic aberration because there is blue on one side of the stars and red on the opposite sides. This was similar to my case, except that it was green and yellow (just!).

Usually my CA is only with vintage lenses, and normal processing (without binning) does not have these, so I'm pretty sure it's a processing "feature".

5 hours ago, The Admiral said:

I can't remember now what software you use to process Fabien.

DCRaw for deraw (driven by Regim) and 50% bin,  and Regim for registering and stacking. The fact that you got something similar let me think it's linked to binning.

Anyway I will continue trying processing options...

Last evening was clear so I had another try at Flame & Horsehead, and a first at Rosette. Didn't look at them yet, just made a stock of subs to process for the coming (bad weather) days. So not sure about it but I may have managed 30s subs this time, maybe because I made the scope back-heavy this time (will report when confirmed).

BTW I would never find the Rosette by naked eye and in polluted sky; Thanks to Mr Goto I asked it for NGC2244 and bang! there it was

[Nigel G]

Very nice Ian.

Great detail, maybe a little pink for me  

It's a biggie, I end up cropping quite a bit of it too.

Cheers

Nige.

[The Admiral]

Thanks Nige. Colour is such a personal thing I find. With images in conventional photography it's generally very apparent when colours are a bit 'off', as we're all used to seeing them for real. Not so with astro though, particularly when there is so many images using narrow band and false colour. Looking on t'internet reveals such a variety, and more often than not the fact that H-alpha was part of the blend is only in the small print. For what it's worth, I didn't use the colour module in ST or make any colour temperature changes or hue shifts in LR, so I guess it's as native as it can be, barring any default colour balancing that ST does I suppose. Interesting that both you and Fabien have commented about it though.

Ian

Edit. I could do this with it!

Not sure which I prefer, or is the more valid.

Edited January 23, 2017 by The Admiral