Camera setup

[Stagman]

You didn't offend me at all and thanks for posting, really.

I was just showing that I have an understanding of the subject but some of the details I wasn't aware of

I always reasonably assumed that the camera attached to the mount but then people were talking about camera lenses with caused some confusion hence my original question.

Then I assumed that I could take 20x 10 second shots for stacking and the mount would keep the telescope on track - I didn't know that these mounts with their goto features etc wouldn't keep in still enough. So now I know that I need a second scope with a auto guider in order to do those 20 shots.

No probs If the mount is reasonably accurately aligned you should be able to get far more than 10 seconds of exposure!

GOTO only finds the shot and has nothing to do with accuracy of tracking, having said that if your alignment is accurate it will certainly make life easier and autoguiding will help but is not a panacea for a poorly aligned scope.

[RikM]

You should be able to get exposures of a minute or so without an autoguider, but the longer the focal length, the shorter the unguided window will be. I can get 90 sec @ 750mm or 3min @ 300mm unguided, with my baby set up. (150P / EQ3-2 or DSLR+300mm lens / EQ3-2). With an autoguider on the EQ6, I can get +10min at 750mm, never needed more than that with my camera.

[cowasaki]

You should be able to get exposures of a minute or so without an autoguider, but the longer the focal length, the shorter the unguided window will be. I can get 90 sec @ 750mm or 3min @ 300mm unguided, with my baby set up. (150P / EQ3-2 or DSLR+300mm lens / EQ3-2). With an autoguider on the EQ6, I can get +10min at 750mm, never needed more than that with my camera.

Thanks, thats good to know! So I should be able to get some decent images with the kits I am getting at weekend plus the camera attachment...

Unfortunately the advised stuff is not in stock

I am heavily into Nikon kit but my third camera, a D200, is rarely used now and I have been offered a swap for a 40D. I could do with having a Canon camera to test my latest product's compatibility so looks like I will use this for astro photography instead of one of the Nikons. I thought the extended ISO range of the D700 would be a massive advantage but if I just take more shots for a longer time that doesn't matter as much.....

Is the above statement reasonable ?

Doing this means I can modify the Canon and leave it outside etc, things I wouldn't want to do with the expensive Nikon.

[Gina]

Sound reasonable to me Extended ISO is not important - 800 is the highest recommended setting for AP, anything higher just increases the noise. I've bought a Canon DSLR body specifically for AP because of it's ability to be computer controlled and modified for improved IR response, keeping my better quality and much loved Sony for general use.

[cowasaki]

Sound reasonable to me Extended ISO is not important - 800 is the highest recommended setting for AP, anything higher just increases the noise. I've bought a Canon DSLR body specifically for AP because of it's ability to be computer controlled and modified for improved IR response, keeping my better quality and much loved Sony for general use.

I don't need computer control as I have designed my own device for another purpose which will do exactly what is needed here (I'm already thinking of removing it's other purpose, changing the LED display colour, re-programming a bit and offering it to APs )

The D700's high ISO handling is mind numbing! Seriously, if a 450D can take one at 400 ISO the D700 would have less noise at 1600 ISO !! It is a serious bit of kit BUT is it necessary? The D700 is certainly usable up to maybe 3200 if normal cameras manage 800. (but we'll see)

I will probably do a few comparisons later but I think the 40D might be better for this rather than risking the D700. The alternative would be to modify the D200 for a wider range inc IR.

[RikM]

Better signal to noise ratio is extremely desirable for AP.

The main beef with DSLR's is that they are more noisy and less sensitive than cooled astro-CCD's. Most DSLR AP'er don't go above ISO800 simply because they can't because of the thermal noise and reduced dynamic range of the entry level cameras at high ISO.

[cowasaki]

Better signal to noise ratio is extremely desirable for AP.

The main beef with DSLR's is that they are more noisy and less sensitive than cooled astro-CCD's. Most DSLR AP'er don't go above ISO800 simply because they can't because of the thermal noise and reduced dynamic range of the entry level cameras at high ISO.

That's interesting. Maybe a comparison using the D700 might be worthwhile. I have been absolutely gobsmacked at just how well the D700 handles higher ISO. The D3s and new D4 are even better. You can easily take shots at 1600 ISO in a church for a wedding and use it at A3. I know that is not exactly relevant for AP but I wouldn't use a D200 above 400 in the same situation and the D200 is probably as good as Canon's offering at the same time, the 40D.

When I get the setup I might well buy both a Canon and Nikon Mount and do some direct comparisons at different ISOs

[cowasaki]

Here is a comparison of D700 against D3s but unfortunately no comparison with normal cameras is included.

Nikon D700/D3 vs D3s High ISO Noise Comparison

I know it isn't totally transferrable to AP which is mainly black etc but it gives an idea.

[cowasaki]

Here is one that includes the D300 which is still a decent performing pro camera and probably about the same as the equivalent pro Canon ISO wise.

Nikon D3, D700 and D300 ISO 3,200 Comparison

[cowasaki]

The Coma Corrector isn't available at the moment....

Does anyone have any experience of the Skywatcher version.

First Light Optics - Coma Correctors

It is the same price then I just need the adapters at £15 each for Canon and Nikon

So basically the same as the Baader one but available.

UPDATE:

Asked at FLO and was told I can't use the coma-correctors with the Skymax 180 and that I should use the

http://www.firstlightoptics.com/adaptors/flo-2-inch-t-mount-camera-adapter.html

adapter instead with the same adapters.

Then when I later get a 200DPS / 250 DPS or whatever I can get the coma-corrector then.