Magnification using Barlows?

[northcanadian]

Hello:

Using a scope with 2350mm focal length...what would magnification be using a 2X Barlow?

Thank you

[ashenlight]

Hi northcanadian,

Give this a go

Eyepiece Calculator

[jgs001]

That depends on what eyepiece you're using. Magnification is controlled by the eyepiece...

Mag = Scope focal length/EP focal length

The barlow doubles the magnification (by effectively doubling the scope focal).

So as an example, using a 10mm ep will provide 235x, adding a barlow will provide 470x (which sounds rather high..., don't forget it's easy to overpower the scope with a barlow).

[northcanadian]

What if I used 2350mm focal length scope hooked up prime focus to a DBK 21 CCD camera...what would be magnification...then using a 2X Barlow, what would be magnification???

Thanks again for your help:confused::confused:

[jgs001]

I think, the DBK21 has the same chip size as the SPC900, and it's considered to be about the equiv of a 6.5mm ep. Therefore the mag would be about 720x.

[GazOC]

What if I used 2350mm focal length scope hooked up prime focus to a DBK 21 CCD camera...what would be magnification...then using a 2X Barlow, what would be magnification???

Thanks again for your help:confused::confused:

When imaging its more relevant to talk about arc seconds per pixel rather than magnification.

=206*pixel size (micron)/ focal length (mm)

[jgs001]

Gaz, sorry about this.. but where did the 206 come from and why ?