Barlows...worthwhile?

[alowen]

Afternoon all, i have recently got my scope (150 dob) and i am thoroughly enjoying it. But i am wondering about getting a 2 x barlow lense.

Are they good, as in do they clearly double the image size? (its mainly planets and the moon i'm interested in)

If so which would you reccomend for my scope with a budget of £50-60 ?

Thanks in advance

Al

[John]

Barlows really do what they say on the tin - they basically double the magnification given by an eyepiece so, say, a 10mm eyepiece that gives 75x, used with a 2x barlow, gives 150x.

Obviously you don't want to overdo the power but with a 150mm scope something around 200x - 250x is very useful for planets, the moon and binary stars.

For you budget the TAL 2x barlow (around £35) is good but you could also look out for a Celestron Ultima 2x / Orion Shorty Plus 2x (same thing) used which go for around £50.

Not everybody likes barlows but they are a good wayt to boost your eyepiece collection.

[brianb]

Barlows really do what they say on the tin - they basically double the magnification given by an eyepiece

And the aberrations of a less than perfect objective. And the "wobbles" caused by less than perfectly rigid mounts. And the distortions caused by turbulence in the air.

And add their own distortions & aberrations.

I do not use a barlow at all for viewing with an eyepiece. I just use an eyepiece with a shorter focal length to get a higher magnification. If you do want to try a barlow, IMO the cheapest that's worth having is the Celestron Ultima.

BTW even if your scope is solidly mounted, the optics are first rate and the atmosphere is perfectly steady, you will not benefit by going over about x180 - x200 with a 150mm aperture scope.

[Bizibilder]

The best thing about a Barlow is that it works as jahmanson says! The added advantage is that it can be used with all your eyepieces (assuming Barlow + eyepieces are all the same size). So you only pay out once instead of buying several eyepieces.

[pvaz]

Go for a good one. Even if 2nd hand.

I had a poor one and it blurred the image.

Now I got 2 quality EPs with the FLs I use the most, and 2 quality barlows that allow me to get another 2 options for each of those EPs. I don't see a noticeable loss in the view quality with this barlows. Only problem is the extended eye relief I get on my Nagler 31T5 which forces me to place the eye in a specific position to avoid blackouts, though the quality is still great it makes it less comfortable to use. On all other EPs the barlows work perfectly.

[stafford_stargazer]

For what its worth,im no expert,but the 2x barlow that came in my revelation eyepiece kit was tried for the first time last night,used it with a 9mm and it was razor sharp.

Honestly there was no noticable loss of quality.Lots of detail too.

Dont know if you can buy them alone but i would imagine so.

G

[crazyjedi]

I do use my 2x barlow regularly for planetary viewing and it does increase image size and on a clear night does bring out some extra detail. however if the seeing is poor it amplifies the problem. It also magnifies the light pollution too making faint DSO's hard to see.

They do have their uses though

TTFN

[brantuk]

Don't forget that when you double the magnification - the object will move quicker accross the ep - unless you have electronic tracking.

[RikM]

BTW even if your scope is solidly mounted, the optics are first rate and the atmosphere is perfectly steady, you will not benefit by going over about x180 - x200 with a 150mm aperture scope.

I agree. I do use a 2x Barlow a fair bit but on planets I get better views with 2x Barlow + 10mm Plossl (x150) than I do with 2x Barlow + 6.4mm Plossl (x234).

The Barlow also increases the eye relief on my cheapo short focal length Plossls, which is great as I wear glasses.

Rik

[crazyjedi]

Rik i use the exact same set up for planetary viewing X2 barlow + 10mm standard Plossl on a 150 newt. I think it's the best budget compromise. anything higher powered just gets blurred and wibbly with a barlow. Using that set up, i got a nice view of Saturn, with a couple of atmospheric bands and (i think) four! moons (had to avert the old vision to pick up the two inner most moons). Not bad considering the light pollution around these parts