Image By Request

[Bert Candusio]

Ive posted one of my images (Jupiter), taken earlier on this year at the request IceinSpace members and readers of Australian Sky and Telescope.
Image taken with a 205mm F5 Newtonian with EPP at an effective F/32.
Enjoy.

[asimov]

Nice image.

[matt]

Bert

Great pic. I'm new to imaging. Can you explain how you achieve F/32?

I keep seeing people refering to the effective f number of their scope for a pic, but don't know how they achieve it or calculate it?

I'm keen to hear from you since I'm working with exactly the same aperture and f ratio.

Thanks mate.

[davidpretorius]

welcome bert.

nice intro, you are more than welcome here. That is really great imaging!!!

Come on Saturn!!!

[davidpretorius]

hi matt,

you have a 200mm aperture (8") f5, so i would calculate your focal length to be 1000mm ie 200 x 5

if you start using a 2x barlow, that now is 2000mm or the ratio that was f5 (1000/200) is now (2000/200) = f10

a 5x powermate would give you 5000mm focal length of ratio of f25.

hope this helps

[matt]

cheers Dave...

The learning never ends. I love it!!!!

Matt

[rumples riot]

Matt, if you have an f8 scope and put a 2x barlow in you will have and effective ratio of f16, or with a 5x f40. The Barlow does the multiplying to your scopes focal length.

Bert nice shot, and welcome to the Mad house.

[acropolite]

Welcome Bert, nice shot...:D

[matt]

Thanks rumples.

So how did Bert achieve f32 out of an f5 scope, which is the same as mine??

[davidpretorius]

it could be a combo of barlows,ie 2 x and 2.4x etc.

i am not sure where the 50mm of a say a camera at prime focus comes into the calcs.

also coma correctors like the televue parracor, have aprox 1.16 x adjustment as well.

so they may be a few ways to end up at f32 mathematically.

[ving]

32 divied by 5 will give the barlow you require matt.

great shot of joop there! :D