stacking dslr?????

[punchy]

Hi all I have not got a scope yet but have a background in photography, this however doesn't cover photo stacking techniques I and would like to know exactly what stacking can do?

Also can I stack image from a DSLR (nikon D80) If attached to a scope will this help bring out detail reduce noise? Is stacking usually done with a webcam?

completely new to this be patient I have been researching on the net quite a lot:icon_confused:

[Ags]

Welcome to the forum. Stacking can be done with any digital image. The idea is that the signal appears in each image so it adds up, while the noise changes in each image so it can be subtracted.

[punchy]

So in theory I would keep the scope fixed on one subject and not track it but take multiple shots?

[Psychobilly]

So in theory I would keep the scope fixed on one subject and not track it but take multiple shots?

Ideally you want to track the object and take multiple shots... effectively the sky rotates around the Celestial pole at roughly 15 degree per hour...

Peter...

[rfdesigner]

As others have said, you stack images to give longer effective exposures.. instead of taking one 10 hour shot you take 60x10 minute shots, then add them together.

Clearly even a 10 minute shot needs guiding. (note: image resultion gets down to around 1 arc second at highest magnification, and the stars are moving at up to 15 arc secononds per second)

Recently there's been one poster here who's been taking 10 second images on a fixed tripod with a normal camera lense (low magnification) then stacking those images with substantial success.

Unfortunetly I do have some slightly bad news for you.

Nikon made an error and have a mode in their DSLRs that make them less suitable for astrophotography. (they meddle with the RAW files)

see: NIKON D3 / D300 ET ASTRONOMIE

Most people here who use DSLR use Canon, partly because technically they're very good, partly because they don't need a lense to functiony and partly because you get a really truely raw image, not one that's been modified with by 'helpful' software. If you want to stack lots of images so that you can average away the noise, then anything that mucks about with that noise will reduce that ability.

That shouldn't stop you trying, indeed, on the next night there's a clear sky, do pop a 50mm lense on your DSLR and take a series of 10 second images of the sky, then use one of the freebee software packages to stack them... you should still get conciderable success.

(also try using the lense stopped down 1 or 1.5 stops, not just wide open)

Clear Skys!

Derek

[punchy]

Yes nikon rather helpfully saves files as NEF I tried a while back to see if I could update firmware to get around this no luck.

I will give it a go with the Dslr I don't fancy getting the film cameras out although noise is dramatically lower in film.

[rfdesigner]

Yes nikon rather helpfully saves files as NEF I tried a while back to see if I could update firmware to get around this no luck.

I will give it a go with the Dslr I don't fancy getting the film cameras out although noise is dramatically lower in film.

Excellent.. do post up your results when you get that far.

Derek

[x6gas]

Yes nikon rather helpfully saves files as NEF I tried a while back to see if I could update firmware to get around this no luck.

I will give it a go with the Dslr I don't fancy getting the film cameras out although noise is dramatically lower in film.

Just make sure that you have the noise reduction on your camera turned off (otherwise the camera will automatically take and subtract a 'dark' for you). I believe there maybe some firmware processing by the camera (possibly the application of a median filter) but plenty of people use Nikon DSLRs for astrophotography and get excellent results.

[rfdesigner]

Just make sure that you have the noise reduction on your camera turned off (otherwise the camera will automatically take and subtract a 'dark' for you). I believe there maybe some firmware processing by the camera (possibly the application of a median filter) but plenty of people use Nikon DSLRs for astrophotography and get excellent results.

From what I can gather on the D70 and D80, that isn't an option.... unless you can point the OP in that direction, which would be a help.