Stacking??

[Lance]

Hello all.
I am hoping to shoot a star trails, I have heard of stacking images but haven't got a clue how or what this is, con anybody explain to me how this process works..
Many thanks Lance..

 

[JulesP]

its when you take a series of shots at 30 second exposures (for example) one after the other for whatever time length you want (I've done 2 hours worth - about 240 images!) and use a programme called startrails.exe (google it - its free) to lay them one on top of the other to complete your startrails shot (dont forget the tripod to keep all the images the same and a cable release / intervalometer is handy)
It saves having your shutter open for an hour or two at a time and getting loads of amp noise in the picture - especially if your camera has a CCD sensor - CMOS are not so bad apparently. I've done it with long exposure noise reduction turned off as well with no problems on my old D80, not tried the D90 yet - not had a clear night since I got it.
Also, if a car goes by, it wont ruin hours of work with headlights as you can just drop that single 30 second frame.
Have a look at the startrails group on flickr as well
Hope that all makes some kind of sense!

BTW - that looks like a pickled alien in your plasma lamp shot on flickr!

 

[Lance]

That makes perfect sense, thanks for taking the time to explain, I do really appriecate it...
The Lamp does look like a alien don't it

 

[Escy]

Have a look here Deep Sky Stacker it gives loads of info how to stack images and also the free software to do it

 

[Lance]

Thank you Escy for the link...