m42 m43 processing

[alacant]

Hi everyone

We're gonna have a go at the lower layering frames to get the white bits coloured. There doesn't seem to be any rules to calculate which exposure these should be. Can remember guessing this some time but wasted a lot of time on it. Visitor leaves tomorrow so must get the frames -in between the cloud it seems- tonight...

These are 3 and 4 minute frames as we stupidly thought the shorter time would sort us, DUH.

Any guidelines most gratefully received.

As an anecdote: apart from advising on the colour scheme, our better halves got involved in competing for the most animal heads they could find in the image. Eat your heart out ngc2174.

Cheers and clear skies.

[Skipper Billy]

I used 10 second subs for the trapezium but it depends on your scope/camera.

It is VERY bright!

 

[alacant]

3 minutes ago, Skipper Billy said:

scope/camera

130mm skywatcher eos700d. 10s?

Cheers.

[Skipper Billy]

Maybe 20 secs - take one and have a look and see what you think.

[almcl]

Here's an unstretched 10 second sub I took a while ago with my 700d to get the centre:

 

After processing this was layered with a few 30 second subs to give this result:

 

About 12 minutes capture time in all.  I have improved a bit since then...

Edited February 1, 2020 by almcl

[alacant]

Yes. I think I understand.

JTOL: I suppose the long and short exposures should be registered as the same sequence  before separating them and stacking each separately?

Cheers. Getting there...

 

[alacant]

@almcl, is that ISO800?

Thanks.

[almcl]

ISO 1600  and possibly before I started using a CLS CCD Filter (it might even have been pre-guiding!).

It was with the 200P, as well.

[geordie85]

How does the stacked, unprocessed image look? If the core isn't blown out on the stack, you can always use that for the trapezium/ core. 

[alacant]

22 minutes ago, geordie85 said:

How does the stacked, unprocessed image look?

Hi. Yeah, unfortunately it's all white too:( But a good idea for maybe a third, mild stretch layer for the core surroundings This may indeed come from the 3 minute frame stack.

Cheers.

Almost astro dark here...

[happy-kat]

I'll have a dig I thought I've seen an Ivo post or video on how to reveal the core with what you have

sorry could not find it

Edited February 1, 2020 by happy-kat

[alacant]

1 hour ago, happy-kat said:

how to reveal the core

Hi. Yeah, I was looking for a free lunch too! I tried StarTools' HDR (I think that's what Ivo would use?) but unfortunately you can't mask in the HDR module, so you end up with a full frame HDR when what you want is just the core. Maybe worth asking over on st. 

Thanks

**We've just bagged the 10s frames, so my participation is over,  but they too look dangerously blown in EKOS' fitsviewer. Here's hoping the auto-stretch has overdone it.

[happy-kat]

I create a mask just on the core area and then used HDR reveal DSO core and it seemed to limit the spread of HDR applied, either that or it was the Reveal DSO core that limited the area of use.

[alacant]

When I try, it seems to ignore and mask. The nearest I could get was Layers in Darken mode but it just makes the core grey instead of white.

[happy-kat]

this was a deconvolution cook ( rather over cooked it) but I didn't like the overall changes but I had probably not done a very good mask.

HDR cook

Edited February 1, 2020 by happy-kat

[alacant]

10 hours ago, happy-kat said:

a deconvolution cook

Much better than we managed. That looks more like we're trying to acheive. It's also the colour we'd like to add. Ivo mentioned something about it being green.

[Starflyer]

I found that I needed something in between the very short and long exposures. It's a few years back, I think I went for 8s, 30s and 720s at ISO 800, to get this;

 

[alacant]

10s and 240s. maybe the 10s is stretched too far but getting there. I think the mask mode isn't the best. Too many choices! Got a bit of green though;)

Any ideas? Too much, not enough...

Cheers and thanks for your patience.

 

Edited February 2, 2020 by alacant

[teoria_del_big_bang]

I tried something similar a week or two ago for first time but just as a training exercise for myself to see how to combine frames of different exposures so maybe a lot simpler than what you are trying to do.  

I used two methods both taken from a website by Jerry Lodriguss, not sure if you have looked at these or not, oe whether there is anything useful to you or not regarding the colour.

Compositing 2 Different Exposures with Layer Masks

Compositing 2 Different Exposures with Selection Masks

Steve

[alacant]

46 minutes ago, teoria_del_big_bang said:

anything useful

Thanks, yeah. So far we've been punching through the layer mask, blurring the edges and hoping for the best. The method of the colour mask looks doable too.

Edited February 2, 2020 by alacant

[bottletopburly]

14 hours ago, alacant said:

Hi. Yeah, I was looking for a free lunch too! I tried StarTools' HDR (I think that's what Ivo would use?) but unfortunately you can't mask in the HDR module, so you end up with a full frame HDR when what you want is just the core. Maybe worth asking over on st. 

Thanks

**We've just bagged the 10s frames, so my participation is over,  but they too look dangerously blown in EKOS' fitsviewer. Here's hoping the auto-stretch has overdone it.

I’m sure you need to use the layer mode I’m sure @jager945 will happily set you on the correct path in startools 

[willcastle]

23 hours ago, alacant said:

Hi everyone

We're gonna have a go at the lower layering frames to get the white bits coloured. There doesn't seem to be any rules to calculate which exposure these should be. Can remember guessing this some time but wasted a lot of time on it. Visitor leaves tomorrow so must get the frames -in between the cloud it seems- tonight...

These are 3 and 4 minute frames as we stupidly thought the shorter time would sort us, DUH.

Any guidelines most gratefully received.

As an anecdote: apart from advising on the colour scheme, our better halves got involved in competing for the most animal heads they could find in the image. Eat your heart out ngc2174.

Cheers and clear skies.

blimey it's not a very good image is it. i can hardly see the nebula at all :') :') 

[ollypenrice]

Because the signal is so strong you need only a few subs so shooting a wide range of exposure times doesn't take long at all. I'd just experiment.

Olly

[jager945]

On 02/02/2020 at 08:35, alacant said:

Hi. Yeah, I was looking for a free lunch too! I tried StarTools' HDR (I think that's what Ivo would use?) but unfortunately you can't mask in the HDR module, so you end up with a full frame HDR when what you want is just the core. Maybe worth asking over on st. 

Thanks

**We've just bagged the 10s frames, so my participation is over,  but they too look dangerously blown in EKOS' fitsviewer. Here's hoping the auto-stretch has overdone it.

You may indeed be able to rescue some details from the highlights, but if an area is overexposed (very easy to on M42), the detail and/or colour information is just not there and you will have change tack;

In that case, you will want to take a shorter exposure stack, make sure it is aligned with the longer exposure stack, process it to taste (preferably fairly similar to the other stack) and then use the Layer module to create a High Dynamic Range composite. To do this, put the one of the two finished images in the foreground and the other in the background. Then choose the 'Minimum Distance to 1/2 Unity' Filter. This filter creates a composite that switches between the background and foreground image, depending on which pixel is closes to gray (1/2/ unity). To make the switching less apparent/abrupt, bump up the Filter Kernel Radius. This will make the transitions nice and smooth.

[alacant]

This is by the old GIMP layers method. Ivo's method to follow:)

Not sure. There's stuff and haze everywhere...

Thanks for looking anyway. Not given up yet.