stupid barlow question

[dave364634]

If I have a telescope with theoretical 260x magnification, but only get 130x magnification with a 10mm lense and a 2x barlow, what do I buy to get it to 260x magnification?

I'm guessing either;

1 - A 4x barlow

2 - Amother 2x barlow.

Ta.

[phw26]

Hi Dave,

What is the focal length of your scope?

Mag = Focal Length/Eyepiece mm

[Carbon Brush]

A 5mm eyepeice + barlow will do it.

Now whether the sky, scope and mount are up to good images at 260x is another matter.

David.

[John]

It's best not to worry about getting a scope to it's theoretical maximum magnification as the reality is that 99% of the time the practical maximum is quite a lot less. This is because of the seeing conditions. I'm guessing you have a 130mm aperture scope in which case you will find 180x - 200x the maximum that is useful for the vast majority of the time. Obviously high power like this is for the moon, planets and double stars. Deep sky objects are best viewed at much less magnification, eg: 30x - 70x

[dave364634]

The scope would have a focal length of 650mm (f/5). It is 130mm primary mirror.