barlow trouble

[algol]

my barlow that came with my 130pm seems to be having a mad one.

i got decent focus with the 25mm ep but when i put the barlow in with it i couldn't focus, this at 52x. however when i used my 10mm ep at 65x i got focus, anyone know why the barlow was acting weird?

and i was focusing on stars not planets etc.

[The Warthog]

With most Barlows you have to refocus. If your 25mm ep is close to one end or t'other of the focus travel, you may just have run out of focus. If you are at the outer end of focus travel. try slipping the Barlow and ep a little farther out. You could put a parfocalising ring on it if this is a solution.

[The Warthog]

If it's at the other end of the focus travel, just live with it for now. 10mm and 12.5mm are pretty close.

[Astro_Baby]

No idea why your Barlow would do that. My 130PM and its supplied Barlow and EPs would all come to focus fine. Possible solution would be as said above - pull the Barlow out from the focus tube slightly and see what happens.

Also - unlikley - at the end of the Barlow there is a threaded bit which hold the lens - has the thread slipped down a bit ?

[algol]

cheers for the replies guys and gal, i'll try it out and get back to you