Need help trying to take photos of space!

[asteele3]

This may seem a stupid question but thought I'd try it!

My camera (Olympus SP-800 UZ) only has 6 seconds, on night mode, for the shutter to stay open!

Say I took an image of the Orion Nebula and then took another 10 images, then stacked them in registax, would that be enough to bring enough detail?

I'm only enquiring as I have heard other people say they take 10x 30 second exposures and I wonder if they mean a 300 second exposure or a 30 second one and then another click of the shutter button and then same again?

Anyway, I need something to do until I get my new telescope and new camera at the weekend so please give me something to do!

Thanks,

Andrew.

[Digz]

Hi there.

You might get something. The easiest thing is to give it a whirl and see. Also it might be better to stack in DSS (deep sky stacker) rather than registax.

If you just using you camera though and no scope you might not have enough zoom to pick up the object.

[asteele3]

Thanks.

My camera has 150x zoom so I don't think that's a problem! haha. Yea, just need to wait for a clear night and I'll give it a go!

[ollypenrice]

I wouldn't use any zoom. You don't want to kill the F ratio. Deep sky imaging is almost invariably done at prime focus, ie the focal length of the telescope alone. I guess you can't remove the lens from this camera? This is why people use DSLRs. The scope alone becomes the lens.

Olly

Olly's Favourites. - ollypenrice's Photos

[sgazer]

hi, your camera lens is the equivalent of 28-840mm (then 5x digital zoom which you definitely don't want to use, just crop the final image later), f2.6-f5.6. For Orion on a tripod, I recommend about 200mm, approx 7x zoom, (to keep the focal ratio down and reduce star streaking) and set to iso 800 or 1600 (depending on how bad the noise is) at 6 secs (if that's the max). Take up to 100 shots (which will drop the noise by 10x or square root of 100), then stack in DSS (not registaxs). If possible, also do 20 or so dark frames with the lens cap on with exactly the same settings at the same temperature. This will reduce noise further in dss. You should get something pretty good.

[dph1nm]

If possible, also do 20 or so dark frames with the lens cap on with exactly the same settings at the same temperature

I see this Olympus has automatic built in noise-reduction for long exposure shots - this might mean it does an internal dark.

NigelM

[pete_l]

This may seem a stupid question but thought I'd try it!

My camera (Olympus SP-800 UZ) only has 6 seconds, on night mode, for the shutter to stay open!

Say I took an image of the Orion Nebula and then took another 10 images, then stacked them in registax, would that be enough to bring enough detail?

You'd get something, but there are factors to take into account.

The wider the zoom, the longer you can expose before star-trails appear. However, by taking widefield images you won't get much detail of the nebula.

If you do zoom in to get detail, then the speed of the stars moving across the frame will limit the time of each exposure. If you expose too long the trails spoil the image. The complication is that the shorter the time you expose for, the more images you'll need to stack.

To give an idea of what's possible, here's a 33% size image of some foolin' around I did with a small PnS camera earlier in the year.

As you can see, the total exposure time was 35 * 15 seconds, or 8¾ minutes and there wasn't much in the way of "deep sky" once I'd processed out the light pollution.

But you can see the sorts of results you could get.

[asteele3]

Thanks for all the advice!

This is what I get when I just take one picture in night mode, so I would be very pleased to see the results you've achieved!

Just waiting for a clear night now, been raining all day and it doesn't look like it'll clear until mid next week!