not sure what to do next

[rightguard]

hi all,

Ive taken about 25 pics liek the one attached - iso800, 25s exposure.

I'm not sure what to do with dss etc to get the best out of them, if it's even possible.

any help greatly appreciated.

thanks,

tom

[zakkhogan]

have you run them in dss at all yet?

[rightguard]

no, still not entirely sure what im doing with it. ive got a black frame too add in, but no idea what an offset or bias is. so do i just load the black frame, then all the pics, and stack?

[Digz]

Just stack the subs you have at the moment. Don't worry about darks, bias and flats they can come later. Get use to DSS, stacking and editing I.e. stretching curves, levels etc. Once you are comfortable you can then add darks, once comfortable again you can think about flats

baby steps its quite a steep curve you've embarked on.

[rightguard]

just doing it now. 25 pics stacking, using recommended settings, no darks or anything else. will post a post-stack image

[Digz]

just doing it now. 25 pics stacking, using recommended settings, no darks or anything else. will post a post-stack image

Good work. That's the best way IMO, just dive straight in, mix it all up and see what comes out.

[rightguard]

theres a horrible gradient still which i have no idea how to remove. anything i try with the histogram exagerates this and makes it look worse! argggggh!!!

[zakkhogan]

post a pic of the stacked image before you stretch it

[rightguard]

looks the same as a single frame to me??

[zakkhogan]

is that the stacked file?

when you processed all 25 frames what did it say was the total exposure time? did it say around 12 minutes ?

[rightguard]

yes thats the stacked file, was around 10 minutes. think i had 20 pictures not 25. in dss it was a very bright pinky colour. when i saved it it came out like that as a tiff - i saved as png in PS then downsized and saved as jpeg in paint to upload here.

[zakkhogan]

hmmmmm.... in im experience dss normally produces a desaturated image (mono) and then you re-introduce the colour later...

feel free to e-mail me the raw file and ill have a look if you like

MOD EDIT - I've removed the email address to prevent any unscrupulous behaviour taking advantage of this offer for help.

[rightguard]

thanks very much. I've got version 3.3.2 and im just restacking the raws(starting again). il send you the output file if thats ok?

[zakkhogan]

hey tom, Ive not really been able to add to the image although you have captured a fair amount of star light.

The Gradient is caused by light pollution, probably from a near by town, light pollution can be really tricky to deal with.

At one of my location that seem pretty dark, down by a reservoir, the sky is just full of stars and the nearest town is 10miles away, but it still works its way into my shots

any ways, wheres my attempt

[Dave]

Hi Tom,

A good start.

It really needs a lot more data, and its always best to work on raw images.

But a quick dabble got this out of your jpg.

Dave

[rightguard]

thanks to you both for your help

dave - is it possible to give me a quick run down of what you did? im so lost

[Digz]

Certainly potential there. I always find the finished stacks in DSS are grey and flat. I mess about with the sliders but read somewhere it is better to process in something like Photoshop rather than DSS. That way you can stretch the curves with better control.

[Dave]

Make a duplicate layer.

Use noise filter to get rid of all the stars in the new layer.

Make it 50% transparent.

Invert the colour of the new layer.

Merge the two layers.

Use levels to adjust the black point of the resulting image just to the left of the peak, which will now be near the middle of the histogram.

That should produce something reasonably acceptable.

It's a bit of a harsh method of removing gradients, but its good for starting you off.

Hope that helps.

You'll get mush better results if you do it all from a raw image, or better still a stacked TIF.

If you want to adjust the brightness levels, curves is always the best method giving you far more flexibility.

Dave