ED 2x Barlow focus problem

[k16charger]

I got my barlow and zoom eyepiece this week in the mail but when using the 2x ed barlow with any eye piece I just can't get any focus. Scope is a 10" dob any idea what to do next ?

[Shiraz (Ray)]

Originally Posted by k16charger

I got my barlow and zoom eyepiece this week in the mail but when using the 2x ed barlow with any eye piece I just can't get any focus. Scope is a 10" dob any idea what to do next ?

do you mean that you can find a best focus point (image gets worse as you move the focuser either side of the best point) but the best focus is poor - or do you run out of movement in the focuser before it gets to a sharp image?

if you can reach focus, but the image is no good, what exactly do you see? eg does it have colour fringes, elongation in one direction etc?

[Wookie (Ryan)]

Narrow it down to which direction has the smallest circle when looking at a star. That will tell you if you have too much in or out focus for it.
What brand is it? Any modifications to your scope (i.e have you changed anything to enable you to get focus with a DSLR camera?)

[loki78 (Jon)]

Probably going to be the not enough inward focus travel issue that has seen ppl move primary mirrors and/or fit a shallower profile focusser.

Don't be put off, there are ways around just about every problem, just narrow it down like the guys have suggested and get back to us!

[Asteri (Labros)]

I have an 2 X celestron Ultima barlow with my baader hyperion zoom and it works great. you have to be careful with some barlows, especially cheap ones. i purchased a 5x gso barlow today and am so disappointed. my celestron ultima 2x is brilliant.. this new junk i bought today taught my a valuable lesson, " don't expect quality when spending 30 dollars ".
my next barlow will be a televue 4x or 5 x ! Not sure what kind or brand you bought today, but i highly recommend the Ultima in the 2 x !

[k16charger]

http://www.ebay.com.au/itm/380435262...84.m1497.l2649

This is the one I have also got the zoom from them. I fitted it then used either the zoom or my 25mm piece and pointed at a star all i see is just a massive blur spot as you adjust the focuser it does nothing..

Same when viewing the moon just a big blur

Happy with the zoom piece .

[Shiraz (Ray)]

Is the Barlow seated right down in the focuser tube? I think I read in the forums a while ago that some 2 inch accessories do not fit all the way into the Skywatcher focuser - could possibly be the problem?

Otherwise, does the Barlow actually have glass in it?

Something is major league wrong if you cannot see anything on the moon and it's more than just poor quality optics.

[NorthernLight (Max)]

sometimes it helps if you do not fully insert the barlow into the focuser. the same can be done with the eyepiece not being fully inserted into the barlow. I have a GSO Dobson and found that certain barlow- eypiece combinations require the eyepiece to be a little out. the two screws will still hold it firmly in place. give it a shot. if that doesn´t work either, then send the barlow back and get a powermate. they are pricy but you get what you pay for and won´t look back.

[Suzy]

Originally Posted by Shiraz

Is the Barlow seated right down in the focuser tube? I think I read in the forums a while ago that some 2 inch accessories do not fit all the way into the Skywatcher focuser - could possibly be the problem?

I was one of those that had the same problem mentioned above. Though my scope is a Saxon- but all the same I'm led to believe which come from the Synta factory.

I had a Skywatcher 2 inch 2x barlow which worked beautifully on my 6" Saxon dob. But not on my 10" Saxon dob. It just wouldn't focus. It wouldn't go all the way into the focusser, i.e. part of the silver barrel which should go all the way in was partly sticking out. Turned out that the stopper was at a shorter distance than on my 6".

Fortunately, a friend of mine gave me a spare 2inch 2 x barlow he had which worked a treat for me, so I didn't have to resort to (what I call) drastic measures in cutting down the short stop to allow longer travel for the barrel (I'm sure there's a couple of words that would explain that better ).

How about going to a club viewing night and trying other peoples barlows to see if it does the same thing.
Hope all works well for you- frustrating isn't it?!

[Larryp (Laurie)]

I bought a 2" GSO ED barlow and it would not go all the way into my 2" diagonal-took it back and bought a Televue 2"-no more problems!