Skywatcher ED Deluxe 2x two-inch Barlow Lens

[Gina]

Thinking one of these should nicely compliment my Evostar 80 ED DS Pro scope for both observing and imaging. Anyone have experience of one of these? Any comments please? http://www.firstlightoptics.com/skywatcher-eyepieces/skywatcher-ed-deluxe-2x-two-inch-barlow-lens.html

[rwilkey]

Hi Gina, the 2" ED Barlow is a cracking piece of kit, will compliment your telescope nicely as long as it has the 2" fitting, it is a quality product and gives good clear views, a little on the heavy side but that's irrelevent when you compare with the great views, I have used it in combination with my Baader Hyperions at 2" and the 8mm gave a cracking view of Saturn when it was available, also great for Lunar studies, you'll love it.

[Gina]

Thanks for your reply Yes I have a 2" Crayford dual speed focuser and 28mm SW EP which is why I'm looking for a 2" Barlow. I'm delighted with my scope, the little bit I've used it so far

[rwilkey]

That's a lovely scope you have there, also I would add that the 28mm LET EP is good for a bundled ep I have found, though slated in other places by those who, I suspect, have not tried them, I should imagine it would work well in your scope, esp. for DSO's.

[Gina]

I certainly get lovely sharp views The mountains and edges of craters on the moon just leap out at you And the moons of Jupiter were very sharp points.

[rwilkey]

Hey Gina, that's great, that's what astronomy is all about, I love quality views like that, the only thing with barlowing the 28mm is that the exit pupil may be too large, what is the focal length of your scope and I will try the math online?

[Gina]

600mm FL. I expect to get another (or 2) shorter FL EP of similar quality later. I want the Barlow for DSLR imaging too (plus webcam for planets). I thought a 2" Barlow with the SW adapter would avoid vignetting on the DSLR too.

[rwilkey]

As you will be using it for imaging, then the math would be irrelvent, however, I did the math on a 28mm barlowed and it gave an answer of 'infinity' so I guess the exit pupil would not be useful for visual, I assumed the AFOV of the ep was 60 degrees, if you find it useful here is the link: N.A.A. Telescope Math Calculator It can be really useful sometimes esp. when considering longer f/length ep's where the exit pupil is critical. Av max for visual astronomy is about 7.5mm, for an older person like me about 5mm is comfortable, otherwise light loss occurs and the visual image will be dimmer.

[Gina]

I'm getting one My OH is buying me one for Christmas

[John]

I believe they are good barlows. It's worth checking that you can fully insert the long barrel that these barlows have into your focuser drawtube. I know that some folks with Skywatcher newtonians with the standard Skywatcher crayford focusers have found that a raised ridge inside the drawtubes prevents full insertion. It may not be a problem with the refractors of course but it's worth a quick look down your drawtube just in case

[Gina]

I believe they are good barlows. It's worth checking that you can fully insert the long barrel that these barlows have into your focuser drawtube. I know that some folks with Skywatcher newtonians with the standard Skywatcher crayford focusers have found that a raised ridge inside the drawtubes prevents full insertion. It may not be a problem with the refractors of course but it's worth a quick look down your drawtube just in case

I'll just have to see when it comes - there is a small step in the draw tube. I would have thought that the SW ED Barlow should match the SW ED 80 DS Pro scope. Otherwise which of their scopes would it be designed for? (Rhetorical question)

[rwilkey]

Hi John, I read that thread with interest, as I have the 200P R&P, and it is OK, hopefully Gina will be OK with her focuser, but it is an unusual problem I agree. However, the Barlow is a cracker IMO

[John]

I would have thought that the SW ED Barlow should match the SW ED 80 DS Pro scope. Otherwise which of their scopes would it be designed for? (Rhetorical question)

You would have thought so but it does not always work that way unfortunately

[Aoraki]

Hi Gina, you could always ask FLO if it all fits together, I hope so as I want one of them!

[Gina]

I rang FLO but got a recorded message to email them as they were very busy, so I've done that - asking then to confirm that the Barlow is compatible with the scope.

[Gina]

Had a nice quick reply from Martin at FLO :-

Yes, it should be OK, this was a problem with an earlier batch of barlows. I haven't heard of a problem lately.

Of course if there was a problem you are welcome to return it, but it should work fine for you.

Looking good Fingers crossed

[rwilkey]

That's good Gina

[Gina]

I've just received the Barlow and tried it in my scope. It is alright PHEW!!!

At first I thought it wasn't but it was me. I tried putting it in the focuser draw tube and it only went half way in, being stopped by the ledge in the draw tube. So I came indoors all set to email FLO and post on here. My email app crashed (Thunderbird - very unusual) so started writing here first instead. In the process I had a thought... You don't put the Barlow between draw tube and diagonal, you put it between diagonal and eyepiece. Was thinking Newt where the diagonal is inside rather than outside. With the diagonal in the draw tube as usual and the Barlow between diagonal and EP as was fine. I was able to focus on buildings and trees on the far hill and got a superbly clear and sharp view - I could have seen individual leaves had there been any

Unfortunately it now has to go away until Christmas

[John]

Surely that long barrel won't fit fully into the diagonal drawtube though will it ?.

Do check that it will come to focus with astro objects as well - apologies for being over-cautious

[Gina]

It goes to the bottom inside the diagonal - less than an inch and a half. The barrel of the Barlow is something like 3" long. It's obviously designed like that. As for focus, there is about a quarter inch of draw tube to spare, but I will check it with an astro object as soon as we get clear skies, whenever that is

[John]

Well I hope it works for you Gina

My experience of Skywatcher refractors is that there is not much inwards focuser travel left when you have added a 2" diagonal. If the projecting barlow is using some of that then you could find that eyepieces will struggle to come to focus when viewing astro objects. Terrestrial objects (being much nearer) require quite a lot more outward focuser movement to be in focus so can be misleading.

[Gina]

The lens on this Barlow (like others) is right at the inner end so all the length is to bring the EP further out. But I'll be checking on celestial objects as soon as any are visible when I can get out to the obsy.

[Gina]

I thought it might have been clear tonight - it was until teatime. NOPE!!! It's raining

[Gina]

Actually, the rain stopped, the clouds parted and I had a clear spell for nearly an hour before it clouded up again. I was able to test the Barlow on Jupiter. No problem with focussing at all. Yes, the draw tube was only 1/4 inch out but focus was fine. In fact the image was really sharp and clear - I could even see the coloured bands on Jupiter, the moons were sharp pinpoints of light and I could see dozens of stars. That was until the EP misted up

I'm very impressed with this Barlow Didn't get to try it with the webcam as this stopped working - think there's a bad connection or something in the box (yesyes style LX modified). So it's indoors for examination.

[John]

I'm so glad it's worked out well Gina