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Is M81 M82 really this hard or is it me?

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#1 psugrue

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Posted 07 May 2021 - 05:57 PM

OK this is not me fishing for compliments. This is NOT false modesty. Let's be honest, this image of M81-M82 sucks. So an ASI 1600 at -15c on a WO 81, CGX and PHD2 running at around 1.3 total. 10x360s R, 10x360s G, 10x360s B, 10x120s Lum Astrodons. 20 darks, 20 flats, 20 dark flats per filter. Over what looked like 2 pretty clear nights. Processed in DSS and GIMP. That's 3 hours 20 min of exposure + 2 hours of darks, not including the 10x360 Lum and 4x360 Ha I didn't even stack coz it was trash. Now I know it's not M42 or Andromeda but is it really that hard? 

 

Regards,

 

Patrick 

Attached Thumbnails

  • rgb-compose small.jpg

Edited by psugrue, 07 May 2021 - 05:59 PM.

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#2 brlasy1

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Posted 07 May 2021 - 06:05 PM

OK this is not me fishing for compliments. This is NOT false modesty. Let's be honest, this image of M81-M82 sucks. So an ASI 1600 at -15c on a WO 81, CGX and PHD2 running at around 1.3 total. 10x360s R, 10x360s G, 10x360s B, 10x120s Lum Astrodons. 20 darks, 20 flats, 20 dark flats per filter. Over what looked like 2 pretty clear nights. Processed in DSS and GIMP. That's 3 hours 20 min of exposure + 2 hours of darks, not including the 10x360 Lum and 4x360 Ha I didn't even stack coz it was trash. Now I know it's not M42 or Andromeda but is it really that hard? 

 

Regards,

 

Patrick 

Maybe one of the imagery Jedi could reprocess your data?


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#3 wizbang396

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Posted 07 May 2021 - 06:08 PM

Or maybe you need a larger scope?  Sometimes (and most of the time) you always get WHAT YOU DON'T EXPECT TO GET.



#4 Number_5

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Posted 07 May 2021 - 06:12 PM

OK this is not me fishing for compliments. This is NOT false modesty. Let's be honest, this image of M81-M82 sucks. So an ASI 1600 at -15c on a WO 81, CGX and PHD2 running at around 1.3 total. 10x360s R, 10x360s G, 10x360s B, 10x120s Lum Astrodons. 20 darks, 20 flats, 20 dark flats per filter. Over what looked like 2 pretty clear nights. Processed in DSS and GIMP. That's 3 hours 20 min of exposure + 2 hours of darks, not including the 10x360 Lum and 4x360 Ha I didn't even stack coz it was trash. Now I know it's not M42 or Andromeda but is it really that hard? 

 

Regards,

 

Patrick 

Something really doesn’t seem right. I don’t have any experience with monochrome cameras, but it certainly seems your image is really dark. The 81 is plenty to get a pleasing image IMO. 


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#5 kathyastro

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Posted 07 May 2021 - 06:15 PM

The data look pretty decent.  What processing did you do on it?  It could do with a bit more stretching and colour balancing.  What exactly do you dislike about it?

 

Can you upload the stacked TIF file to a file server like Dropbox?  That way, we can see what you are dealing with and make more concrete suggestions.


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#6 JamesTX

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Posted 07 May 2021 - 06:22 PM

Hard to say by looking at the picture... I suspect its just processing. 

 

Side note... you don't need separate darks for each filter.  Darks just need to be same temp, gain, offset, and exposure.  So one set of darks at 360s can be used for all your RGB filters.  Wont make any difference in the picture.. just saving you some work on that :)

 

 


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#7 Jeffmar

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Posted 07 May 2021 - 06:26 PM

Untitled1 3

 

There are a bunch of M81/82 photos out there that look better than this one because they spend all night or a bunch of nights on one target. 

 

This is about 8 stacked images. The exposure time on each was about 2 minutes and I didn’t do darks or flats. My camera was a Sony A7RIII, which is a full frame mirrorless. My scope was an Explore Scientific ED127 with no focal reducer. 

 

I tend to spend more time post processing my photos than getting data. I don't use an astronomy camera so I don’t know what the equivalent of ISO would be. Gain, maybe?

 

If you are using a small scope with a focal reducer you are going to get images that may be smaller than you want if you are shooting galaxies. I have found i can push the data i get quite a bit as long as I have enough sub frames to stack. 

 

Longer exposures at higher ISO’s or gain will get more detail to a point. Try experimenting with longer exposures and more post processing. 


Edited by Jeffmar, 07 May 2021 - 06:37 PM.

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#8 Sky King

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Posted 07 May 2021 - 06:32 PM

Here's a few minutes try with Photoshop Elements 2020.... 

 

 

redo1.jpg

 

 

 

 


Edited by Sky King, 07 May 2021 - 10:48 PM.

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#9 f430

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Posted 07 May 2021 - 06:56 PM

Here is yours, just brightened up a bit.

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  • Brightened up a bit.jpg

Edited by f430, 07 May 2021 - 07:47 PM.

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#10 unimatrix0

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Posted 07 May 2021 - 07:01 PM

I would say you got plenty of data to work with , my bet it's a post process issue. 

What I do is when I don't get what should be expected is reprocess without using flats or using bias or darks. 

Try just processing your images without any calibration frame too. You'll soon find the culprit. 


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#11 bobzeq25

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Posted 07 May 2021 - 07:03 PM

Not bad.

 

This is not the easiest of targets.  Small targets and the outer details that make dramatic images are dim.


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#12 Jim Waters

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Posted 07 May 2021 - 07:06 PM

What's your the light pollution like?  Download a trial version of PixInsight and give that a try.  Here's my image of M81/82 taken from a Bortle 8+ site - backyard.  100mm f/5.5 scope.  90 sec x 240 each subs processed with PixInsight.

 

 

50960606071_fea6578bc8_b.jpgM81 82 Area by Jim Waters, on Flickr


Edited by Jim Waters, 07 May 2021 - 07:57 PM.

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#13 Jim Waters

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Posted 07 May 2021 - 07:10 PM

Can you upload the stacked TIF file to a file server like Dropbox?  That way, we can see what you are dealing with and make more concrete suggestions.

+1 waytogo.gif

 

Upload your stacked image so we can process it.


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#14 BQ Octantis

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Posted 07 May 2021 - 07:24 PM

Let me get this straight:

 

  • ASI1600 w/ filter wheel - $2000
  • WO Zenithstar 81 f/7 Apo - $1000
  • Celestron CGX EQ Mount - $2200

 

Followed by

 

  • 1 hour integration
  • Processed in GIMP

 

Not to be judgy, but that's not a recipe for a good outcome.

 

Post your unstretched channel stacks out of DSS (16-bit TIFF preferred), and we can start working on the second part of the recipe. But you're going to need more data. I'd recommend at least 8 hours at f/7 with 3.8µm pixels.

 

BQ


Edited by BQ Octantis, 07 May 2021 - 07:28 PM.

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#15 Mike in Rancho

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Posted 07 May 2021 - 07:48 PM

Hey it looks pretty good.

 

Nah, just kidding (because you said not to do it). wink.gif

 

Something is definitely up.  M81/82 isn't that hard, at least for something reasonable to be satisfied with.  To really get it good of course takes adding up the integration time and will be dependent on your skies and equipment.  But a couple hours ought to show some things - the swirl of M81, and the red stuff in M82.

 

I think three of us from last year's newbie class all did M81/82 for first telescope light (and we didn't call each other either) and got something out of it.  Off the top of my head the scopes ranged from 60 to 100mm, though I forget the focal lengths, and were probably all with DSLR's.  However, I'm also pretty sure two were Pixinsight and one was Startools.

 

We can see if anything is hiding in your stack, though that can depend on what you chose for stacking settings as well.

 

What's wrong with a nice 32-bit FITS from the autosave, BQ? tongue2.gif


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#16 RogeZ

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Posted 07 May 2021 - 08:22 PM

Im with BQ on this one and if you are shooting from LP skies, triple that time to get a decent image.
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#17 Islander13

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Posted 07 May 2021 - 08:46 PM

Let me get this straight:

 

  • ASI1600 w/ filter wheel - $2000
  • WO Zenithstar 81 f/7 Apo - $1000
  • Celestron CGX EQ Mount - $2200

 

Followed by

 

  • 1 hour integration
  • Processed in GIMP

 

Not to be judgy, but that's not a recipe for a good outcome.

 

 

BQ

Idk BQ... I have a way more 'modest' setup and no field flattener yet, and I was pretty satisfied with this image of M81/M82 and I am pretty much a noob.

 

I did get a rock solid PA, and I have a beast of tripod.

 

This is a WO z61, on a skyguider pro to a 12-year old 5d2, with no guiding. I think it was around 90 mins of integration IIRC (default settings in APP). I also have a Bortle 4 backyard though which I'm sure really helps (when we get the rare clear nights).

 

Not trying to say this is better than OP, just trying to help diagnose the problem.  I would love OP setup for now. It does look like the image I shot a couple of days before when I was slightly out of focus on all my subs.

Attached Thumbnails

  • M81-RGB-session_1-mod-St-1-6.JPG

Edited by Islander13, 07 May 2021 - 08:48 PM.

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#18 Professor2112

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Posted 07 May 2021 - 08:56 PM

I agree with the ones saying to upload the raw stack. That will help determine if it’s the data or the post processing that went wrong. 


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#19 psugrue

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Posted 07 May 2021 - 09:04 PM

https://drive.google...gU1?usp=sharing

 

 

You guys are so cool. Thanks for all the help.

 

Kind Regards,

 

Patrick


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#20 Jim Waters

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Posted 07 May 2021 - 09:05 PM

. I also have a Bortle 4 backyard though which I'm sure really helps (when we get the rare clear nights).

Nice image and processing Islander13.  Yes - a Bortle 4 backyard helps significantly.  


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#21 psugrue

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Posted 07 May 2021 - 09:06 PM

Idk BQ... I have a way more 'modest' setup and no field flattener yet, and I was pretty satisfied with this image of M81/M82 and I am pretty much a noob.

 

I did get a rock solid PA, and I have a beast of tripod.

 

This is a WO z61, on a skyguider pro to a 12-year old 5d2, with no guiding. I think it was around 90 mins of integration IIRC (default settings in APP). I also have a Bortle 4 backyard though which I'm sure really helps (when we get the rare clear nights).

 

Not trying to say this is better than OP, just trying to help diagnose the problem.  I would love OP setup for now. It does look like the image I shot a couple of days before when I was slightly out of focus on all my subs.

You don't have to say it's better than the OP because it is.


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#22 psugrue

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Posted 07 May 2021 - 09:11 PM

Or maybe you need a larger scope?  Sometimes (and most of the time) you always get WHAT YOU DON'T EXPECT TO GET.

I have a 9.25 on order. I will get back to you in a year or so.


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#23 psugrue

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Posted 07 May 2021 - 09:20 PM

Hard to say by looking at the picture... I suspect its just processing. 

 

Side note... you don't need separate darks for each filter.  Darks just need to be same temp, gain, offset, and exposure.  So one set of darks at 360s can be used for all your RGB filters.  Wont make any difference in the picture.. just saving you some work on that smile.gif

Yep my post was ambiguous. I did use the same darks, well 2 sets of darks coz the Lum were only 120s but please keep assuming that I am, or anyone else is making those kind of mistakes because at least for me, you will be right 90% of the time.

 

This is not sarcasm, this is my serious face!

 

Respect,

 

Patrick   



#24 psugrue

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Posted 07 May 2021 - 09:34 PM

Let me get this straight:

 

  • ASI1600 w/ filter wheel - $2000
  • WO Zenithstar 81 f/7 Apo - $1000
  • Celestron CGX EQ Mount - $2200

 

Followed by

 

  • 1 hour integration
  • Processed in GIMP

 

Not to be judgy, but that's not a recipe for a good outcome.

 

Post your unstretched channel stacks out of DSS (16-bit TIFF preferred), and we can start working on the second part of the recipe. But you're going to need more data. I'd recommend at least 8 hours at f/7 with 3.8µm pixels.

 

BQ

OK Let's get this straight:

 

First of all it's not a Zenithstar it's a GT (I am not a peasant) so way more expensive! 

Second I have the Astrodon NB filters in the EFW so that's $2 grand right there (I was not using them but they should help right)

Third of all, don't forget the WO guide scope and ASI120, not to mention the laptop $$$$$

And lastly in my defense it was over 3 hours of integration and I had been drinking.

 

Regards,

 

Patrick


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#25 BQ Octantis

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Posted 07 May 2021 - 09:44 PM

OK Let's get this straight:

 

First of all it's not a Zenithstar it's a GT (I am not a peasant) so way more expensive! 

Second I have the Astrodon NB filters in the EFW so that's $2 grand right there (I was not using them but they should help right)

Third of all, don't forget the WO guide scope and ASI120, not to mention the laptop $$$$$

And lastly in my defense it was over 3 hours of integration and I had been drinking.

 

Regards,

 

Patrick

lol.gif

 

Technically, each color channel has an hour of integration—but for the RGB image, this only counts as 1 hour. You can add the luminosity channel to that hour—but that was just an additional 20 minutes. So for luminosity noise, that's just 80 minutes.

 

You should spend at least as much on capture and processing as you did on equipment. You can omit the laptop costs—unless it's a dedicated astroprocessing laptop. For time cost calculations, you should assume peasant wages. The minimum cash wage in the US is $2.13 per hour.


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