2.5x Barlow

[Altomar718]

Hi All - I bought a 3x barlow from Joy's Optics on Ebay (picture attached) and when I tried it with a Skywatcher 150, it would not focus.

I am not sure if it is because the actual Barlow was too long in design or 3x was too much for the scope.

Does anyone know if a 3x would work with the Skywatcher 150 if it was a different design (not so long!!) or if not, would a 2.5x work as a 2x seems to be fine but would like as large as possible for using a webcam with it.

Thanks

Chris

[Freddie]

Is it the case that as you were trying to focus, you ran out of focus travel or that you just couldn't get a sharp image?

[Altomar718]

Hi Freddie - ran outof focus travel - in and out !!!

[Freddie]

I'd have a look again as you would expect to be moving in one direction getting a sharper and sharper image but before you get it to focus, you run out of focus travel. From what you are describing you may find that the focus point is somewhere within the focus travel but conditions were not good enough to take the high magnification.

[JamesF]

What focal length eyepiece were you using it with?

James

[Altomar718]

Hi James - I tried 10mm 25mm and 6.3mm and it was the same with all of them - turned the focus wheel from one end to the the other and it was blurred all the way through

[JamesF]

Hmmm. It's possible that you've run out of focuser travel, but it could just be that the conditions weren't good enough to support the level of magnification that you were trying to achieve. I'd try during the day on a distant landmark I think, to see if that would work.

Which 150mm Skywatcher is it? There must be at least five different ones.

James

[Altomar718]

Its it the 150P and that is what I did, used it during th eday ona mast 12 miles away - I centered it with smaller (mm) eyepieces and ten put in the 2x barlow and then used the 3x which was all out of focus and no turning the focuser wheel did not bring it in to focus. I don't understand focal lengths etc. but it seems as though the image was 'out of range' to fcus on the eyepiece if you know what I mean ! - Thats why I said in the forst post I wondered if it was the design as the 3x was quite a long tube

[dmahon]

When you use your 2x Barlow, do you need to focus more in or more out [than without it]? You probably need to go even further in the same direction with the 3x - if it's outwards, try holding the eyepiece further away and buy a spacing tube if that works.

My focal reducer results in

More inward focus, so I presume the Barlow will need more outward travel.

[Stargazer_00]

You can just hold the Barlow and eyepiece in the air by hand in line with the focuser to see if it needs back focus you don't have.

[JamesF]

My Tele Vue 3x barlow is also very long but I have no trouble reaching focus with it. I've not tried it in a newt though and as a rule they do have far less focuser travel so it's plausible as a reason for not being able to reach focus.

James

[andyo]

HI

yes it is more magnification ie barlow more outward travel required to achieve focus a reducer would be more inward travel as dmahon stated.So I would try the extension tube as someone already mentioned.