getting the nebula colours to show up

[oldpink]

most likely I'm not getting long enough subs to be of any use
but last night I managed to get my PA pretty accurate and alignment pretty good as well
pity the wind was a bit gusty causing problems with shake so I stuck to 30s exposures but got 95 decent ones
from the area around the Pelican nebula / NGC 7000 which I have seen lots of pictures with nice reds showing up in the clouds

anyway I stacked the best 60 subs with 20 darks and 10 bias frames into DSS and ran the process

but playing about with the settings in DSS and upping the luminance etc I can't even get a shade of colour to come out
I just get the stars starting to show a little bit of colour but no cloud

do you bring the colour out in PS or other post stacking software
I have a demo of nebulosity but can't make head nor tail of it (and I thought PS was hard to learn)
or am I just not getting long enough subs to get that amount of detail

though I've seen some images with 60 - 90 sec subs showing quite a lot

I can post up the autosave tiff somewhere if someone wants to play with it
its not great, a lot of coma and slightly shaky stars due to said wind

this is a Jpeg directly from a raw with no processing with sat trail as a bonus

[oldpink]

Ok so I decided to try messing around with Pixinsight last night to see what I could do
I followed a couple of tutorials about removing gradient and background neutralization which went Ok and I could see improvements

on the autosave tif from the other night, then I began playing with the histogram and randomly changing setting all of a sudden I have
not only colour but a lot more "Detail" in the image and a lot more "Stars" though it could just be a lot of noise

so can anyone tell me if this is just that a lot of noise or is this detail in the subs that is hidden until you process the image correctly

the autosave is a 60s sub the other is the result of me messing around with pixinsight

[tingting44]

that is not noise my friend, they are indeed stars id say you done a cracking job to get that from the original i have hardly any experience with PI so will be watching this thread, nice improvement so far tho

[Thalestris24]

Hiya

From what I've read you probably need something like 15-20 x 600s subs - maybe more here in Glasgow! I shall have to attempt a neb myself one of these days and when it gets darker!

I'm sure someone will correct if I've got those numbers wrong...

Louise

[Thalestris24]

Oh, I see someone on the Deep Sky thread got colour with a single sub! That's amazing but I imagine they have darker skies than Glasgow!

[wxsatuser]

A single sub of the NA/Pelican nebs......Canon 60Da....200mm L lens.....120sec ISO 800 f2.8 with Astronomik CLS clip.

RAW channels aligned and converted to TIF in DPP light use of levels/curves in PS CC.

Quite noisey as expected.

[oldpink]

thats really nice for a single sub

[wxsatuser]

thats really nice for a single sub

I just wish that the weather would allow a lot more subs but every night has been useless with varying amounts of cloud and contrails.

This was cheating a bit using f2.8, it does'nt really compare to the average scope where the subs would be much longer for the same effect.

When conditions allow I will most likely use this lens at f4, much better stars across the frame.

[ollypenrice]

There are two major things you need to do straight off with any astrophoto as it comes in from the camera.

1) Balance the colours.

2) Stretch the data. As it comes in it is linear, so almost all you ever see is the odd star. The nebulosity may be in there but without a stretch it won't be seen.

RobH's is a good tutorial. http://www.middlehillobservatory.co.uk/articles-primers/Levels%20and%20curves.htm

Olly

[Thalestris24]

Hmm.. makes me wonder how best to deal with lp - I get a big lump in the middle of the histogram (well, most of it!) so never much room to stretch

[oldpink]

I'm finding that somewhere around 60s is optimal under the LP I suffer from
I can push up to 90 Sec's if the target is high up in the sky
but when I run 2 - 3 minutes I get too much LP (no filter) to deal with reasonably

hopefully I'll get to order my Astonomik CLS filter in the next week or so and see if that helps out with exposure time

[Thalestris24]

I've been doing mostly 480s subs - sometimes 600s tho that's really  pushing it!

[andrewluck]

I'd add one step to Ollie's; Remove the light pollution gradients.

I use Pixinsight's routines for this and they're really effective. http://blog.andrewluck.me.uk/?p=799 has a before and after image of Orion. Of course, it's no substitute for a dark sky but it helps.

Andrew

[Thalestris24]

I use the 'wipe' function in StarTools - works quite well usually but Glasgow skies will always be limiting unfortunately

[andrewluck]

Yes, the sky will always limit the faintest object that you can reproduce. Have you considered narrow band imaging?

Andrew

[Thalestris24]

Yes, the sky will always limit the faintest object that you can reproduce. Have you considered narrow band imaging?

Andrew

Hi

I have indeed but I have a colour ccd and can't really afford all the other parts I'd need anyway. I could maybe get an H-alpha filter but I have a limited view of the sky so can't see many nebulae. I'll soldier on for now!

Cheers

Louise

[Giray Gencaslan]

There are two major things you need to do straight off with any astrophoto as it comes in from the camera.

1) Balance the colours.

2) Stretch the data. As it comes in it is linear, so almost all you ever see is the odd star. The nebulosity may be in there but without a stretch it won't be seen.

RobH's is a good tutorial. http://www.middlehillobservatory.co.uk/articles-primers/Levels%20and%20curves.htm

Olly

How can i balance the colors?

This is 10 x 10s lights and 10 x 10s darks Cygnus photo.

Normally there is North America Nebula and other colorful stars. But there is no color in my photo.

[oldpink]

my best outcome yet
not even sure how I got to this stage as I tried a multitude of thngs
and undid most of them had trouble saving the image I had on screen in Pixinsight, it always saved the file without the STF info
finally managed to get it to save close to what I wanted and tweaked it in PS
and I'm finally getting to grips with the PS histogram and how to stretch the graphs better

anyway I think the red channel is still wrong but star colour is looking good on most of them
 

[ollypenrice]

How can i balance the colors?

This is 10 x 10s lights and 10 x 10s darks Cygnus photo.

Normally there is North America Nebula and other colorful stars. But there is no color in my photo.

Go to Levels in Ps and choose the  All Channel View. The top left of the histo peak in each channel should be aligned. Move the black point (bottom left slider) to the right to clip back a channel with a peak way over to the right.

You may accidentally have saved the image in mono. Is this DSS? I don't use it and can't remember what the mistake is but I've seen it discussed a few times.

Olly

[Giray Gencaslan]

Go to Levels in Ps and choose the All Channel View. The top left of the histo peak in each channel should be aligned. Move the black point (bottom left slider) to the right to clip back a channel with a peak way over to the right.

You may accidentally have saved the image in mono. Is this DSS? I don't use it and can't remember what the mistake is but I've seen it discussed a few times.

Olly

Thanks. Which program you use instead of DSS?

[ollypenrice]

I use AstroArt 5 for stacking. Controllable, logical, incredibly fast.

Olly