Focal length query and DSLR Camera Question

[Paliadon]

Hi all, I have a 10" Meade LX200 ACF and was wondering what the focal length is. I have searched everywhere and just cannot seem to find it.

Secondly, I have a Nikon D300s and am hoping to do some imaging in the near future. I have Orion's short tube 80 with the StarShoot camera autoguider. Can anyone tell me how I can zoom the image (not post-processed) I mean for DSO. If this can be done it would be great, if not, slap me silly. lol.

Thanks in advance.

[jgs001]

I'm not sure on the focal length of that scope, but if it's an f/10, then it's 2000mm. As to increasing the "zoom", then you need to increase the focal length, but you will increase the exposure time at the same time. A x2 doubles the focal length and I think quadruples the exposure time..

[Cornelius Varley]

I'm not sure on the focal length of that scope, but if it's an f/10, then it's 2000mm. As to increasing the "zoom", then you need to increase the focal length, but you will increase the exposure time at the same time. A x2 doubles the focal length and I think quadruples the exposure time..

If the f number 10 then it has a focal length of 2500mm not 2000mm

www.meade.com

peter

[jgs001]

Thanks Peter... my maths is never good at the best of times... certainly not this early in the morning

[Merlin66]

With the 10" SCT, f10 you can use the Orion for guiding, but to get a better "zoom" factor with the 10" I'd add a x0.63 reducer. This would give a f ratio of 6.3 and a focal length of 1575mm.

Just watch the spacing between the reducer and the CCD chip... the optimum distance is 110mm.

Ken

[ollypenrice]

The focal length is indeed 2500mm native. I think you have to be careful with reducers on the ACF, though. It already has a flat field so the standard SCT reducer-flattener is not what's needed but a pure reducer. I may be wrong about this but I would have a care here.

Olly

[Merlin66]

Whoooops!

Olly,

I overlooked the ACF!!

You're correct the old "standard" reducers don't work with the new design!! I've heard that the Optec NextGen reducers will work (??!)

Ken