ED80 .... help

[Arthur Dent]

Hullo,

we finally decided to go for the Skywatcher ED80... It came with a 2'' diagonal, a 10mm Celestron (1.25) and 32mm TS (2") eyepiece. Great fun. Yet, we are a little bit confused what to do with the Barlow... What we mean is, we had a go at the moon with the 10mm Celestron which was fantastic! Yet we wanted to get nearer and opted for the 2x Barlow which (theoretically) should give us an even closer view.

But all we got was not the moon but a very blurry image (at best)...

What did we do wrong? The Barlow is clean...we tried the focusser... It should work, shouldn't it? (excuse this novice question... is the moon too near for such a 5mm magnification?) .

Do we need extra equipment to get this going? Speaking of which which other eyepieces would you recommend with this set-up?

As always, any helping posting would be great!

A.D.

[Naz]

Hi Arthur, when you fitted the barlow, you did refit the ep on the end?

the focus point can change as well from the original point.

No the moon is not to near, and the ep's you have at the moment should be all you need for now.Later when you have become more familiar with the scope and observing, you will be able to decide then.

Good scope you have there, I am sure you will be pleased with it.

nabban

[OXO]

You made a good choice Arthur if you follow what Nabban has said you will be ok

Let us know how you get on please.

James

[Arthur Dent]

Hi Nabban,

thanks for your quick reply. We have just spent a fun 10 minutes unscrewing and reassembling every single piece of both the Barlow and the 10mm, but still cannot figure it out. Running the risk of sounding really dense, I will just describe to you what it looks like: the 2"diagonal is on the scope, with the fitting on the end that makes it 1 1/4 ". into that we can fit the Barlow (which seems to consist of two parts, the actual lens part and a sort of mini-tube). On top of that we can neatly slot the 10mm eyepiece (which as we just found out also has two parts!). This seems to be the only way we can puzzle it together. When we tried to refocus on the moon yesterday (no chance today...) I had the feeling we just couldn't focus...something to do with the length, but I just cannot put my finger on it. And, as you can probably see from this mail, our understanding of basic physics and optics is pretty embryonic!

Apart from that, you are right, it is a great telescope. We enjoy looking at it ...... more so than looking THROUGH it at the moment.

A.D.

[Naz]

Have you tried swopping the ep's?

nabban

[GordonCopestake]

One thing you could try, if and when the weather permits(!), is to bring your focus tube as far out as you can then slowly (very slowly) draw the barlow lens and the eyepiece out of the diagonal, keeping a close eye on the image. If as you draw out the eyepiece you find a distance away that you achieve focus then your ED80 has not got enough back focus and you might need to invest in an extention tube (like your barlow but without the lens bit).

Im not sure if this is the case but it's possible. If your problem is that theres not enough focus travel the other way then im afraid thats more of a problem, you can try the barlow and lens without the diagonal attached, but that makes viewing difficult.

In theory if you work out the focal length of your scope (somewhere around 400-600mm probably) then measure from the front objective lens that distance including the diagonal, thats where your focus point should be. Although theorys are all well and good hehe

Hope this helps a little

[Greg]

Arthur,

Is it a case of not enough inward focus or outward focus??

Greg

[GordonCopestake]

Thats what i thought

[Arthur Dent]

Hi again,

it seems theres is not enough inward-focus... (if that means the further we pull the focusser out the blurrier the picture. On the other side the most inward position is with the moon still unfocussed). So there is no way of getting a clear image from the moon with Barlow and the 10mm.

What to do?

A.D.

[Jamie]

Try sticking the barlow in before the diagonal.

BARLOW - DIAGONAL - EYEPIECE

See if that helps.

[lunator]

Arthur

I had the same issue with my ETX70. The focusser did not have enough travel to bring a barlowed image to focus.

I had to inset in a specific barlow from Meade.

I hope you get it sorted.

Jamies suggestion is a good one.