Beginner stacking

[Andywilliams]

I have just started experimenting with deep sky stacker. I am trying wide field until my barn door tracker is finished. This is my first light with a moded canon 40D......aiming at Sagittarius 

 

 

this is the view from my rural backyard in the Hawke's bay.  

Due to me being a bit of a newbie I have managed to paste two copies of the same pic !

 

Any tips and hints would be most welcomed as I am on a steep learning curve with processing. 

Both images are a stack of 20 lights and 5 darks, stacked in deep sky stacker. 20 second exposures at iso 1600. The Milky Way shot is on my canon 1000D. They have been processed in Gimp. 

[Atreta]

very nice,  i guess  you can stretch it a bit more with levels and curves  to show more of the milky way.  my first stack was also about the same amount of frames and exposure  times,  only iso was 800.  if you want i can post it here so you can see what you can get out of it.  congrats on the image. 

[Andywilliams]

Many thanks Frank. Yes, I managed to get quite a lot more detail in the Milky Way but then the sky looked artificially light?  It seemed like a balancing act between a natural dark sky and details of the dust lanes. I would be very interested to see your stacked image and any tips on stretching. I am doing some stretching but from a position of woeful ignorance at the moment. Cheers, Andy 

[Atreta]

Don't worry, you'll be able to get some great advice from everyone in here, SGL is a great place to start and have lots of information. I'm still a beginner too, so i can't be of much help myself, but sure others will help you.

this is the result just after stacking:

this is the latest processing after i learned quite a bit in here:

Please post your other results here so people can give you tips how to improve it.

[Andywilliams]

Wow! That did make a difference!!

i have kept all of the post stacked tiff files so I can have another go at processing the images when I have learnt a bit more. 

Yours is a great pic Frank, thanks for posting it.

[wimvb]

Very nice images.

As Franks mentioned, you can probably stretch them more. You might also crop the second image, to get rid of the intruding tank (?) and maybe even the trees.

It can be difficult to get a good image with milky way and trees, but if you want to keep them, you can mask off this section when processing. Or blend this part of an unstretched image and a stretched image.

Good luck.

[Andywilliams]

Many thanks Wim,

lots for me to practice here.

thanks for the advice,

Andy

[Stub Mandrel]

Make sure you keep your original stacks - I have gone back to mine over and again seeking marginal improvements!

[cjdawson]

Here's my tips for newbies....

1. Never throw away any image that you have taken, not matter how bad you think it is.  It's only a few MB to store, and hard drives are cheap.

2. Shoot in RAW rather than JPG.   JPG doesn't have all the information from the sensor, RAW does.

3. Take small steps.  Start with the kit that you have, then build from there.

4. Use a cable release, ideally one with a programmable timer - it'll take some of the hassle out of it.

5. Ask questions, giving examples of the image that you have taken.  More questions the merrier, that will help you make the most of what you have.

[Andywilliams]

Many thanks for the tips C.J.

I am very pleased to report that I am already doing no's 2 through 5.

I am keeping all of my stacked images and discarding the many images that made that stacked image. So I am not sure if I am following number 1 or not.

Many thanks though.

cheers,

Andy

[wimvb]

Keep the raw images as well, because sooner or later you'll find you want to redo the stacking. Put them in one folder (named as date and subject), and zip them if you want to save disk space. (Or get an extra hard drive.)

They will take up disk space. One raw image of a dslr can be about 25 MB, depending on camera. If you take 40 of those in one session, you're looking at 1 GB per session, as a rough estimate.

[cjdawson]

8 hours ago, Andywilliams said:

Many thanks for the tips C.J.

I am very pleased to report that I am already doing no's 2 through 5.

I am keeping all of my stacked images and discarding the many images that made that stacked image. So I am not sure if I am following number 1 or not.

Many thanks though.

cheers,

Andy

Nope.  Keep everything.   As one day there might be a new stacking technique that comes out which brings out more data whilst stacking and aligning the images.  What I say keep everything, I mean every last pixel.

Hard drives are relatively cheap, and if you want there's nothing stopping you writing the images to DVD to archive.   Personally, I'd prefer to spend £50 on a drive that will take store seveal years worth of images.  Memory sticks/cards work just as well and are large enough these days.

[Andywilliams]

good point......think I will invest in an external hard drive !

[SilverAstro]

10 hours ago, Andywilliams said:

in an external hard drive !

,,, in TWO external hard drives

If you have just one the law says it will fail at the worst possible time, if you have two mirroring each other then the same law says they will never fail Cheap enough even down the local Tesco !

[cjdawson]

I have two hard drives that I use for my images... hmm actually 3.  One in my desktop that I use for my lightroom library.  That gets backed up to a shared on my NAS Box (which is 3 * 4TB Drives) and that in turn is backed up to a second NAS Box (again another 3 * 4TB drives)

When I'm out imaging, I'll take the set of frames, then copy these to my laptop's SSD.  Using that I'll make a new lightroom library so that I can tag the images properly. (rather than using folders)

I'll make folders and export the images from lightroom.  (At this point they are still the original raw images, just been copied a few times)

Stack them with DSS - using the folders.

Once stacked, I'll import the stacked image back into lightroom.

From there, I'll use the stacked image and process it using a combination of lightroom and photoshop.

This processing could be done on my Laptop... but it could wait until I move to my desktop.

 

To move the files to my desktop what I do is use Lightrooms export function to export the entire library  to drop box.

At this point, I'll switch to my desktop and imprt the library from dropbox into my master library.

Again at this point, could stack and process the image.

 

However as the files are now in lightroom. The images are copied into my lightroom folder.

This library and all the metadata is then backed up on my NAS.

 

After that's done, I can delete the files from my laptop which has limited storage space.

[Andywilliams]

I have been having a little play in gimp to see whether I could improve things by stretching the original water tank image. Still a long way to go but certainly there is more detail now. I seem to be struggling with colours and the sky either takes on too much green or , if I try to adjust it, it goes too red! Anyhow, as usual I look forward to any advice on how to improve it. Slow progress but progress nonetheless ??

[wimvb]

In photoshop and PixInsight there are tools to adjust background colour, called HastaLaVistaGreen and SCNR. In gimp there are no such add ons, as far as I know.

You could try creating a green layer and subtract that from the background.

With the eyedropper tool, measure red blue and green in a part of the background that should be neutral. Create a new layer that has the same green value as the EXCESS green of your background. Then set mode blend subtract for this layer and your image. This method should decrease green in the background, but not so much in brighter parts. I've never tried this myself, but since gimp lacks the proper tools, you'll have to improvise and experiment.

Good luck.

[Andywilliams]

Thanks Wim, yes I am seeing the limitations of gimp I guess....but I can't afford the others right now. Time to use some creativity !