barlow placement .

[rory]

Browsing through "backyard astronomers guide" I've just read that I can place my barlow lens infront of the diagonal for extra magnification . Effectivly turning a x2 into approx x3 . (Back of the net!)

Well u learn something evey day. Thought I'd pass info incase there are more novices out there who never knew that.

Clear skies...

[Telrad]

Yes,

Barlows are invaluable!

[LukeSkywatcher]

I was not aware. I assume you unscrew the barlow lens from the barrell and then re-screw it to the front of diagonal (i'm thinking out loud).

This i must try.

Thanks for the heads up.

p.s.~you can decrease the magnification of a barlow by screwing the lens directly onto the end of any EP (basically where a filter would go).

[rory]

As I'm reading it there s no dismantling to do. Just remove the diagonal place barlow in,then place diagonal back in.

My only possible issue might be I've a prism diagonal which gives right way up views. And don't know if its possible with that kind of diagonal, I. Shall find out soon enough.

[jgs001]

No need to dismantle.. just move the entire barlow. I'd expect it to work with a prism, although the view might degrade. The same thing is true using tubes between the barlow and ep/camera (although you might have focus issues with the ep and a diagonal...)

[LukeSkywatcher]

Ahhhhhh ok i am with you. I just tried it with an erect prism. It seems to work.

[LukeSkywatcher]

scope>barlow>diagonal/erect prism>ep

[rory]

So it worked with a prism. That's exellent then. My 32mm now also 16 and 11 ish. Thanks luke

[LukeSkywatcher]

John is right. The image gets degraded.

p.s.~~any eyelashes that get in the way become freakishly large and rather scarey. Must be the reflection of them bouncing off the prism mirror. Also any dust particles in the light path become football sized.

[LukeSkywatcher]

Oh ok....................i see the error of my ways. I tested out this method on my little 70mm refractor. Its a widefield scope and does not handle high magnification very well.

Guess i'll have to drag out my 130P and try it again. Next week i'll try on the 8se.

Now where is that "I'm with Stupid" emoticon.

[rory]

gap in clouds give me a chance. focused on jupiter, but my focuser wont go back far enough to bring it fully into focus ,almost but not quite. ah well.

[LukeSkywatcher]

I tried with 70mm, you tried with 90mm.

I think it could work with something over 100mm.

Its something i will keep in mind and try with 130mm and 200mm.