x2 Barlow

[Postie]

Omni 2x Barlow

Is this barlow any good? Reason I ask is that using it last night I could not get a sharp focus with it. I was using a 5mm & 10mm Ep, the EP's on their own were fine - pin sharp, great views of Saturn.

Thanks

[russ]

I wouldn't be too worried about it not working with the 5mm, 400x is a big ask. The scope and skies will need to be at their optimum to produce anything half decent at that maginifcation.

But the 10mm and barlow should work well, especially if the 5mm alone was producing a sharp image as they are both operating at the same magnification. Is the 10mm the standard Skywatcher 10mm that came bundled with the scope?

Try barlowing the 12.5mm with the Omni and see how it performs.

[michael.h.f.wilkinson]

Will it not come to focus at all, or is the image not sharp at focus? Sometimes the travel of a Newt's focuser is too small to allow focus with some barlows. If you can try it with a different scope, you can see if this is the case.

I agree with Russ that 400x is usually too much. I rarely if ever go beyond 250x (288x max!)

[Postie]

I was trying the Barlow to just to see how it performs. I will give it a go at 12.5. It seemed that each movement of the focuser was just too much either way.

As for the 10mm, I think it is the Skywatcher, not too sure as the scope was second hand.

[Orion]

Bit too much mag' really, more mag means harder to achieve exact focus as well, esp' with a single speed focuser.

[russ]

The Omni did well in the Sky at Night test, so it should be a good barlow. If the barlow is sharp with the 12.5mm, then that can rule out a faulty barlow. And could point to the 10mm as being the culprit. The 10mm is not a great eyepiece, i used one myself last year to get myself going again and it couldn't be pushed at all. But saying that, it could be the barlow that has the problem. You'll know once you try it with the 12.5.

Does your 200P have the older rack & pinion focuser? They are a pain in the bottom and make focusing a little frustrating. I have just bought a secondhand 250P and it was quite a shock using that focuser again. It can be tuned up to perform better by re-greasing and playing with the tension. I haven't decided whether to do this or just buy a secondhand crayford. Fitting the Skywatcher Autofocus to the rack & pinion also does wonders.

Russ

[Postie]

Yup, the scope has the rack & pinion type focuser, I'm thinking of maybe replacing it for the new type, they are supposed to be a lot better, wish I could afford the dual speed one but I'm done for spending for a while....or so I told my wife

I don't think the barlow is a faulty one, I think maybe I was asking for too much....