Photoshop Question

[MikeK02048]

I'm totally new to astrophotography processing. I stacked my 150 images of Andromeda Galaxy with darks and bias. I imported them into Photoshop, but when I went to stretch them all the data was way on the left, even though I can plainly see the galaxy in each of the light frames. And since it was all against the left, I couldn't use the sliders to stretch the image. Very frustrating. Any suggestions?

[tooth_dr]

5 minutes ago, MikeK02048 said:

I'm totally new to astrophotography processing. I stacked my 150 images of Andromeda Galaxy with darks and bias. I imported them into Photoshop, but when I went to stretch them all the data was way on the left, even though I can plainly see the galaxy in each of the light frames. And since it was all against the left, I couldn't use the sliders to stretch the image. Very frustrating. Any suggestions?

Hi

Can you attached the stacked image here to have a look at it?

 

Thanks

[Alien 13]

What software did you use to stack the frames? if it was DSS then contrary to popular belief (have found that using DSS processing is far far better than anything else) use the sliders in that to get a decent image and a final tweek in PS.

Alan

[Freddie]

That’s what you would expect!!!   The data is mostly dark so the histo is to the left. You then use levels and curves to stretch the histo to fill across to the right leaving a small gap on the left to avoid clipping the data.

[MikeK02048]

Here's the stacked image tooth_dr.  It's the first I've ever tried.  And it was done with a Nikon D850 and a 80-200 f2.8 zoom (at 200mm), just on a tripod.  2 sec exposures at f3.6 and ISO 1000.

Andromeda stacked copy.TIF

[MikeK02048]

1 hour ago, Alien 13 said:

What software did you use to stack the frames? if it was DSS then contrary to popular belief (have found that using DSS processing is far far better than anything else) use the sliders in that to get a decent image and a final tweek in PS.

Alan

Alan - yes, I used DSS

[MikeK02048]

1 hour ago, Freddie said:

That’s what you would expect!!!   The data is mostly dark so the histo is to the left. You then use levels and curves to stretch the histo to fill across to the right leaving a small gap on the left to avoid clipping the data.

Yes, I've watched countless YouTube vidoes from Astrobackyard, Dylan O'Donnell and others and seen them do it.  But always they have a little room to the left of the data so they can grab the slide to the left and move it right.  I have no room to the left of my data.  All my data is firewalled to the left side of the histogram.

[Davey-T]

Just keep moving the levels middle slider to the left to grow the histogram, lots of vignetting doesn't look like flats have worked.

Dave

[michael8554]

I'm afraid there's so little data in your stacked image that stretching it like Davey did is not going to give you anything meaningful.

Can you tell us what your equipment is, and details of your exposures ?

Could be due to Flats robbing all the data in the subs like Davey says.

But I think you're going to have to increase your individual exposure time significantly, as there's a limit to what you can get with hundreds of very short exposures, and this looks like it.

Michael

[Tenor Viol]

I have that lens (70-200 f/2.8) and this is a single exposure with a Z6 at 200mm... but its 140 seconds (tracked) 

[MikeK02048]

45 minutes ago, michael8554 said:

I'm afraid there's so little data in your stacked image that stretching it like Davey did is not going to give you anything meaningful.

Can you tell us what your equipment is, and details of your exposures ?

Could be due to Flats robbing all the data in the subs like Davey says.

But I think you're going to have to increase your individual exposure time significantly, as there's a limit to what you can get with hundreds of very short exposures, and this looks like it.

Michael

Until I get something to track the sky, I can't uncrease my exposure length.  Right now, it's just a camera/lens on a tripod.

[MikeK02048]

24 minutes ago, Tenor Viol said:

I have that lens (70-200 f/2.8) and this is a single exposure with a Z6 at 200mm... but its 140 seconds (tracked) 

Beautiful image Tenor.  Looks like I have to get a tracking mount to make these type of images.

[MikeK02048]

I know this isn't a big deal for most, and my image is pretty rough.  But I can't tell you how excited I am at my very first astrophotography result!  Thanks for your suggestions.  I just basically played around with Photoshop until I got this result.  I think it may be the best I can get out of my data.

[wxsatuser]

Cannot expect to much from 2seconds but the first image is a big deal as your no doubt hooked now. 😀
Bump up the ISO, 3200 will not hurt and go for f/2.8.

BTW
You can see individual images because they have a tone curve applied, back of camera and software will do this.
The RAW image will be very dark and lack colour, histogram hard left.

[Tenor Viol]

11 hours ago, MikeK02048 said:

Beautiful image Tenor.  Looks like I have to get a tracking mount to make these type of images.

That was taken with the camera on an HEQ5 - it was only my second night of using it (weather doesn't help). Tracking mount makes a huge difference. I've now got a Sky Guider Pro as well.

And well done on the M31 pic - it's a good result.

Edited August 24, 2020 by Tenor Viol

[Davey-T]

11 hours ago, MikeK02048 said:

I know this isn't a big deal for most, and my image is pretty rough.  But I can't tell you how excited I am at my very first astrophotography result!  Thanks for your suggestions.  I just basically played around with Photoshop until I got this result.  I think it may be the best I can get out of my data.

Nothing like your first astro' image, try higher ISO and longer exposure and take some flats.

There is a tutorial by Bob German on Y'Tube for removing gradients in P'Shop.

Keep up the good work, good luck

Dave

[MartinB]

On 24/08/2020 at 01:12, MikeK02048 said:

I know this isn't a big deal for most, and my image is pretty rough.  But I can't tell you how excited I am at my very first astrophotography result!  Thanks for your suggestions.  I just basically played around with Photoshop until I got this result.  I think it may be the best I can get out of my data.

You're on your way MIke!