barlow advice

[terry22]

wonder if somebody could point me in the right direction regarding buying a barlow lens, and also confirm a few queries i have. i've just bought my first scope, a modest 90/1000 refractor which was delivered with 1.25" 10mm and 20mm eyepieces, to which i have recently added a 32mm for lower power magnifications. i want to buy a barlow but a x2 will only in effect add an extra couple of different magnifications to my existing 3, so i'm looking to buy a x1.5 instead. i have spent ages searching around (too long as i'm on dial up !) and have managed to find a couple of suppliers who have an antares dual barlow (x1.5 and x2) or a gso dual (x1.5 and x2). unfortunately one supplier refuses to send to france "because he's had trouble sending there before" !!! and the other is out of stock until further notice ! if anybody happens to know of sellers who are willing to send to france i'd be grateful for any links.

on the same subject i noticed that on both the "dual" barlows i've found to date apparently one piece of the barrel is simply unscrewed, thus the abilty for 2 different magnifications, and somebody i know thought that it might be possible to do the same for some or maybe all x2 barlows. as i don't know, or understand, the mechanics of one perhaps somebody may be able to shed some light on the matter.

also whilst reading up before actually buying the scope i saw that by placing the x2 barlow before the star diagnol a magnification of approx x3 would be achieved, does that mean the increase on all barlows would be incresed by around 50% (ie a x3 would also become a x4.5) ?

[rory]

on the point of placing the barlow infront of the diagonal. it does increase the mag by approx half again., but in my case the focus rack didnt provide enough movement to let it focus properly.(celestron asrtomaster 90mm)

i would personally leave the barlow until you have better e/p's. barlowing the stock 10mm will not be ideal.

[terry22]

thanks for that rory, strangely enough i have the same scope as you ! are you say putting a x2 barlow on a 10mm will not focus properly wherever you put it, or its OK in its normal place. i thought i could cut down costs and increase my range by using a x1.5/x2 dual purpose barlow, plus my understanding is that a barlow will sharpen the image. my aim is to get magnifications of around, say, x30,x50,x75,x100,x120 and x150 as a maximum (believe over that is a bit unrelaistic/optimistic with what i have -celestron astro 90/1000). apparently the orion shorty x2 can also be "converted" to a x1.5, and i'm beginning to wonder if all barlows can have the lens element unscrewed, anybody any ideas ?