Barlows

[Terry]

This may be a daft question, but can you combine 2 Barlow lenses i.e. a 2X and a 3X. if so what the resultant Barlow be?

Terry

[jgs001]

Terry, you can stack barlows. They multiply up, so a x2 and x3 stacked, becomes x6 (I think).

[aussi skywatcher]

Not sure but I tried it tonight - I was looking at the moon - used a 2.5x and a 2x barlows with a 10mm Ep - it was ok on the moon (nice and bright) resolution was pretty good so I am guessing that the 2 combined was equal to 4.5 x (added together or if you multiply them the you get 5x). So the answer your question could be 5x or 6 x. sorry I cant help you more but I am sure someone will give us both the right answer soon. It was good to experiment with this - its given me a good Idea of what I can do with the gear I have

Cheers Paul (aussi Skywatcher)

[scotastro]

Double stacking barlows is often used by webcam imagers to increase object size. Provided they are of good quality there should be no major problem with the view.

Mike

[The Warthog]

Yes you can, and you multiply the factors.

[Terry]

Thanks everypone for the replies.

Terry

[Viking]

Terry,

I believe there is also a difference if you put the barlow before or after the diagonal.

John

[The Warthog]

Terry,

I believe there is also a difference if you put the barlow before or after the diagonal.

John

Yep, there is. If you put the Barlow in the scope tube, and the diagonal in the Barlow, you will get a higher magnification than stated on the Barlow. Typically, about 3x for a 2x Barlow.

If you unscrew the 2x Barlow lens from the Barlow, and screw it into the filter threads of an ep, it gives about 1.5x. This varies from ep to ep. If you have an empty Barlow tube, you can use that instead of a diagonal (say if you're monkeying about with a Newt) to get more magnification out of the system.

Experiment with this stuff, it's fun.