Help with M42 core blowout

[Seanelly]

How do I prevent core blowout of my M42 image?

I have 8x5minute quality light frames plus 12ds, 12fs, and 12bs. When I stack them (DSS) the core is obviously already blown, and removal without any DSS processing (I believe the recommended procedure) straight to Gimp is no help, the core is blown no matter what I do.

I'm using the APO equipment listed in signature, with the modded Canon T6i (750D) and D1 LP filter.

Is it just a matter of filters (Ha, etc.) which I don't have yet ($!!!) or is there something I can do during imaging or before stacking to prevent or at least minimize core blowout?

[Sunshine]

Ok for what my opinion is worth, i did see an episode of Astro Backyard where Trevor imaged M42. I did notice he used photoshop I believe to adjust the core, I’m guessing it’s hard to image M42 without blowing the core. I hope this link helps. Coming from a guy with no AP experience, if I embarrassed myself just point it out and laugh haha I’m cool with that.

heres the link.

 

[Adreneline]

49 minutes ago, Seanelly said:

I have 8x5minute quality light frames

Sean, with my f2 Samyang 135mm and Atik428ex combination I can blow out the core with 20s LRGB exposures let alone 5 minutes.

I have found it a very difficult target to image successfully without recourse to layers in Photoshop to get an acceptable result.

I've tried a huge range of exposure timings from 5s LRGB up to 5 mins Ha/OIII/SII and most things in between.

M42 is a real challenge; however, it does provide you with plenty of processing experimentation on cloudy nights!

Adrian

 

[Seanelly]

50 minutes ago, Sunshine said:

Ok for what my opinion is worth, i did see an episode of Astro Backyard where Trevor imaged M42. I did notice he used photoshop I believe to adjust the core, I’m guessing it’s hard to image M42 without blowing the core. I hope this link helps. Coming from a guy with no AP experience, if I embarrassed myself just point it out and laugh haha I’m cool with that.

heres the link.

 

Hello, again, thanks for the link. I checked out the video, but he does not explain how he manages to achieve the spectacular final image with such core detail shown at the end, other than a couple of hints, being 'hundreds' of ten-second images combined with many three-minute images for a total of several hours of data. He does not mention any special changes to the camera settings during imaging, which leads me to believe that he is somehow using the ten-second images for the core and the long-exposure images for the outer structure, though in what way is not mentioned. 

P.S. I just found his U-tube video on processing all (3h, 8m) of the Orion data in AdobeCC, and he mentions using just the default parameters in DSS and removing the final stacked image straight to Adobe without any alterations, so that tells me that his final image is achieved stricly through Adobe processing.

I willl now watch that video in it's entirety, but I will not be able to use the help for a while, because I do not yet have Adobe Photoshop. I just shelled out for a dedicated laptop for running the scope and processing the data and have used up my financial 'allowance' for a while.

All this info is great to have, however, as at some point this year I will have the software and hopefully the data and more experience to achieve better results.

[Seanelly]

42 minutes ago, Adreneline said:

Sean, with my f2 Samyang 135mm and Atik428ex combination I can blow out the core with 20s LRGB exposures let alone 5 minutes.

I have found it a very difficult target to image successfully without recourse to layers in Photoshop to get an acceptable result.

I've tried a huge range of exposure timings from 5s LRGB up to 5 mins Ha/OIII/SII and most things in between.

M42 is a real challenge; however, it does provide you with plenty of processing experimentation on cloudy nights!

Adrian

 

Hi, thanks for responding. I'm beginning to realize that processing the data is pretty much everything when it comes to Orion, and that surely must be the case with all other data as well, which makes sense. I just got a dedicated laptop for the scope and data processing, as my old one was running 32-bit Windows and Gimp imaging led to crashes, so I should be good to go with Gimp, but AdobeCC ($!) will have to wait a while, yet.

So much to learn, and such weather to learn in. I got 40 minutes of Orion data last night (8x5m between two trees!) but set-up was in -18C and tear-down was -20C (Ottawa, Ontario), and my limited experience and the continuous crappy weather not giving me a chance to practice, set-up was long and brutal even with hand and toe warmers! Tear-down was as fast as humanly possible, all the stiff cables and ice-cold paraphernalia quickly placed in the covered plastic container I use to keep the laptop and camera remote warm (I have a lightbulb on inside), and the whole mess then laid out in the den to warm up and dry off before repacking.

My wife is beyond thinking I've lost my mind, given the fact that I've been out with the Dob so often in cold weather that she's given up trying to analyze what makes a man do such a thing voluntarily time after time. And now this.

We have an unspoken agreement, I think: I don't question the strange stuff she does and vice-versa!

[Adreneline]

16 minutes ago, Seanelly said:

but AdobeCC ($!) will have to wait a while, yet

Several years ago I was very, very fortunate to purchase PS-CS6 Extended Version for Mac only on an Education Licence and saved myself literally hundreds of pounds. I don't have PS on a PC but I have been experimenting with Affinity Photo - very much cheaper and very capable compared with PS. I am still having trouble understanding how to work with colour channels but layers is very much like PS. Might be worth a look

HTH

P.S. It's been cold here but nothing compared with the temperatures you folks are experiencing. I remember being in Pittsburgh 25 years ago when the Monongahela River froze over - that was pretty cold!

[Seanelly]

I have Affinity on my list of potential software. Now that I have a 64-bit operating system I will look into it. What I like about it thus far is that you can buy it, rather than continuous monthly subscription, and it has good reviews as an alternative.

[Sunshine]

1 hour ago, Seanelly said:

P.S. I just found his U-tube video on processing all (3h, 8m) of the Orion data in AdobeCC

Actually. I just realized that I intended on sending you the second video, which you found, rather than the first in which processing is not mentioned. Sorry about that, I watched the one you found just a week ago but when I sent you the link I didn’t realize there was a capture only video also.

[AstroPhil]

I had exactly the same question! It's something I have been working on for a while; I'm trying to avoid going down the multiple layers/exposures route and so far have been playing about with the HDR multiscale transform function in PixInsight - but it's a real challenge to keep the image from going 'flat' and retaining some detail. Attached is a before and after, using 7 layers, 2 iterations, and overdrive of 0.3 - 5mins of data (11 x5). Any thoughts welcome!

P.

[noah4x4]

I use Hyperstar (hence f/2) and live stacking and I can blow out the core of M42 using my powerful camera with merely 1 second exposures and it hence needs a fair amount of aggressive histogram adjustment. M42 is a remarkably bright object.

You will similarly need very short (single) exposures with a DSLR, but at (say) f/6.3 inevitably somewhat longer than mine at f/2  So start very short and built from there. It's been a while since I used my DSLR, but I recall it didn't take many seconds before I had captured a decent image of M42. It was not minutes. But other DSOs require vastly longer.

Edited February 6, 2019 by noah4x4

[ollypenrice]

My technique on M42 simply follows Jerry Lodigruss' tutorial. I love this method because of the smoothness of the blend if you're careful but the website is not being found by my saved link. You could try Googling Jerry Lodigruss Compositing different exposure lengths in Photoshop yourself to see if you can get to it. I don't know how GIMP compares.

The basic principle is to align and fully process the short and the long exposures separately. Paste the short on top of the long, create a layer mask and paste the long onto the mask. Blur the mask and adjust it in curves while looking in real time at the output image. This is the method I show our guests.

Olly

 

[JemC]

@ollypenrice

Is this the site you mean ?

http://www.astropix.com/html/j_digit/laymask.html

 

Edited February 6, 2019 by JemC
add info

[ollypenrice]

1 hour ago, JemC said:

@ollypenrice

Is this the site you mean ?

http://www.astropix.com/html/j_digit/laymask.html

 

Yes. Thanks. Our internet has been dodgy this afternoon. My result using this method is below.

Olly

Edited February 6, 2019 by ollypenrice

[AstroPhil]

Thanks for the advice and weblink, @ollypenrice, @JemC, I'll have a go! I've taken 5minute and 1 minute subs so far - if the skies clear I'll try replacing the 1m subs with something shorter. I'm not using a cooled camera (SX Ultrastar), so short is good.

[Seanelly]

On 06/02/2019 at 15:51, ollypenrice said:

Yes. Thanks. Our internet has been dodgy this afternoon. My result using this method is below.

Olly

Thanks, I'll check out the link. (What a great image, here!)

[carastro]

Quote

Is this the site you mean ?

http://www.astropix.com/html/j_digit/laymask.html

Brilliant,

I've been having the same problem as Olly, my old link not finding this tutorial. 

I was planning to do M42 in the near future as I've not done it for a number of years and was wondering how I was going to combine the short and long exposures without this tutorial, nothing I have tried works as well.

So finally have a link to it again.

Carole 

 

[AstroPhil]

Well, here's my attempt: before and after. This is an overlay of 30s and 1 minute subs on a background of 5min subs.