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horsehead nebula barely visible

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#1 dave2space

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Posted 02 March 2021 - 06:38 AM

Dear,

I tried to make a picture of horsehead nebula, but it's barely visible. I used 90x60" shots with skywatcher 100ED with 0x85 reducer, with a resulting 7.65 focal ratio.

I used a full frame panasonic S1 for the shots.

I can stretch the image, but still the horsehead is barely visible

what could be the problem?

light pollution?

the camera cuts the reds?

the exposure is not sufficient?

 

original (stacked and cropped image)

501k3v.jpg

 

extremely stretched to see the nebulas but everything becomes light blue

501k5k.jpg


Edited by dave2space, 02 March 2021 - 07:16 AM.


#2 Tapio

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Posted 02 March 2021 - 06:56 AM

It's both camera not seeing red and processing.
If you share stacked image I'm sure someone can show pretty nice end result.

#3 F.Meiresonne

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Posted 02 March 2021 - 07:05 AM

When did you take this shot?



#4 dave2space

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Posted 02 March 2021 - 07:10 AM

It's both camera not seeing red and processing.
If you share stacked image I'm sure someone can show pretty nice end result.

yes I can process it more heavily, but I was trying to understand if there was some underlying issue I could fix to improve the signal.



#5 dave2space

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Posted 02 March 2021 - 07:12 AM

When did you take this shot?

yesterday night



#6 Tapio

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Posted 02 March 2021 - 07:20 AM

Then the moon has a role too in image quality.

#7 Supernova74

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Posted 02 March 2021 - 07:25 AM

Well I’m no imager as I’m visual only,however I cannot stress enough it’s not so much the aperture of your scope it’s your weakest link it’s the sky conditions,especially the type defuse nebula the horse head is,it just demands the best of clear very dark sky’s unless you are useing image intensifiers which are very expensive to ease out the horse heads hidden detail.some amateurs visually can never achieve even a glimpse of the horse head as it’s one of the hardest deep sky targets up there

for a fighting chance I would introduce an H-alpha filter if you already don,t own one,darker sky’s, if your able to do that.and then unfortunately increase the aperture of your scope itself.


Edited by Supernova74, 02 March 2021 - 07:27 AM.


#8 dave2space

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Posted 02 March 2021 - 07:25 AM

Then the moon has a role too in image quality.

oh I see, it was low, but I guess it does not help



#9 WoodlandsAstronomer

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Posted 02 March 2021 - 07:33 AM

Use calibration frames if you are not already doing so.

Increase total integration time.

Unless you are shooting with h-alpha or duo/tri band filter, shoot faint nebula on moonless nights.

If you are new to post processing watch a few tutorials but start with adjusting levels and sliding left slider over to data and then adjusting curves to show detail and repeat. Try minor improvements each repetition. Eventually you will add gradient removal, color balancing, and the like, but if it’s new to you just learn how to adjust levels/curves in the beginning to reveal detail.

PS you can probably do a simple black point set on that image to see the horsey a little better.

Hope that helps.

Edited by WoodlandsAstronomer, 02 March 2021 - 07:35 AM.


#10 charlieb123

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Posted 02 March 2021 - 09:20 AM

Editing the ultra compressed jpg shows there is something there worth working with.

 

hhr.jpg


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#11 jonnybravo0311

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Posted 02 March 2021 - 09:54 AM

Dear,

I tried to make a picture of horsehead nebula, but it's barely visible. I used 90x60" shots with skywatcher 100ED with 0x85 reducer, with a resulting 7.65 focal ratio.

I used a full frame panasonic S1 for the shots.

I can stretch the image, but still the horsehead is barely visible

what could be the problem?

light pollution?

the camera cuts the reds?

the exposure is not sufficient?

Problems:

  • While a fantastic camera for daytime photography, the S1 is not that great for astrophotography of hydrogen-rich targets like you shot because the camera is not sensitive to the Hydrogen-alpha wavelengths of light.
  • 1.5 hours is just barely getting started on data collection :)
  • Light pollution plays a significant role. The more light polluted, the more total integration time you need to combat it. For emission nebulae, filters like the Optolong L-Pro can help.

The above list is just a high-level overview of some of the issues in actually collecting the data. The other side - processing it - needs to be looked at as well. As charlieb123 showed, the images you provided actually have considerably more detail than you got out of them.


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#12 Phil Sherman

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Posted 02 March 2021 - 11:09 AM

If your camera has a "raw" format you should be using that for all astro i aging. JPEG imaves are compressed and my experience is that the compression routines discard a significant portion of the dim data the camera captures. Nebula imaging is primarily looking at the dim stuff that's recorded.

 

You should also be using software that's designed for processig astro images. An often overlooked program is Mike Unsold's "ImagesPlus", now a free download from his web site. You can download the software and written documentation for the program. There's also videos showing actual use of many of the program's features.

 

ImagesPlus can do all of your pre and post processing. If it doesn't have a conversion model that will handle your camera's raw format, you can use other software to convert the raw frames to fits or tiff which ImagesPlus can process.



#13 F.Meiresonne

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Posted 02 March 2021 - 11:11 AM

yesterday night

Without any filter then, the moon kills it



#14 dave2space

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Posted 02 March 2021 - 11:39 AM

Editing the ultra compressed jpg shows there is something there worth working with.

 

attachicon.gifhhr.jpg

wow, what is the main steps you do? I stretch it with the curves (at least that's how is called in GIMP) but the background becomes all blue / light blue.

thanks!!



#15 charlieb123

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Posted 02 March 2021 - 12:28 PM

Levels.

 

Taking your blue image and applying an Auto Level in Photoshop results with this.

 

hhra.jpg

 

 

Making careful level adjustments with your high res tif will result in a decent image.
With that said integration is everything.. well not everything but I think you get it.


Edited by charlieb123, 02 March 2021 - 12:31 PM.


#16 F.Meiresonne

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Posted 02 March 2021 - 12:28 PM

GIMP is not really what you want to use...i found this out only after experimenti ng a big year and after getting better suited software.

 

There a many, PI, APP, Startools, PS to mention a few...

 

I use Startools.



#17 dave2space

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Posted 02 March 2021 - 05:38 PM

thanks all, I got the issue, stretching every channel at the same time is not the best way, indeed just the auto white balance (even in GIMP) gives a lot of colors:

504mzv.jpg


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#18 jonnybravo0311

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Posted 02 March 2021 - 05:46 PM

Now that's a much better looking edit. Well done :). Next step: go out and collect a whole lot more of those light frames. Also, check your histogram to ensure it's about 1/4 - 1/3 from the LEFT side (i.e. what would be considered a few stops underexposed). That's not a hard and fast rule, but rather a general rule of thumb for shooting with a DSLR (or MILC like the S1).



#19 dave2space

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Posted 02 March 2021 - 06:03 PM

does anyone knows why in this case I get an RGB histogram like this? (peaks so misaligned).

This without white balance (with standard values for white balance). Obviosly the white balance helps to align this

is it normal?

thanks!

504qhv.jpg


Edited by dave2space, 02 March 2021 - 06:05 PM.


#20 *skyguy*

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Posted 02 March 2021 - 06:42 PM

Maxed out the nebulosity to showcase the Horsehead using Photoshop. Overcooked? Yes, but the Horsehead does look pretty good!

 

Horsehead.jpg



#21 belliott4488

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Posted 02 March 2021 - 06:49 PM

does anyone knows why in this case I get an RGB histogram like this? (peaks so misaligned).

This without white balance (with standard values for white balance). Obviosly the white balance helps to align this

is it normal?

thanks!

504qhv.jpg

That's pretty similar to what I got shooting M42 a little over a week ago when the Moon was very high.

 

My first step in GIMP is to adjust the levels for the blue channel to bring it in line with red and green. In your case I'd also bring the red up. I did this before applying any level adjustments to the overall value levels.


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#22 dave2space

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Posted 02 March 2021 - 07:23 PM

Maxed out the nebulosity to showcase the Horsehead using Photoshop. Overcooked? Yes, but the Horsehead does look pretty good!

 

attachicon.gifHorsehead.jpg

nice! I got that the main problem was the white balance, I didn't know it was so important. I guess when you have to stretch a lot it matters a lot.



#23 *skyguy*

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Posted 02 March 2021 - 07:46 PM

Went back in a adjusted the white balance to pretty up the stars and and make the background more natural.

 

Horsehead.jpg


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#24 Eclipsed

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Posted 03 March 2021 - 08:15 AM

extremely stretched to see the nebulas but everything becomes light blue

501k5k.jpg

I copied your stretched light blue picture and used a simple freeware photo editing program called "Irfanview" on it.  Only basic adjustments like color balance, saturation, contrast etc....  Spent 5 minutes on it.

Attached Thumbnails

  • 501k5k R2.jpg



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