Used Delos 6mm

[Bundin]

Hi folks,

I recently bought a used Delos 6mm from Ebay. This is my first precision eyepiece (I’ve only used the ones that came with my scope). My question, not able to find any talk about this on the ole’ internets, is why the 1.25” plug/base is loose. It spins and can be pushed up and down/in and out of the eyepiece. It doesn’t twist tighter. I’m not talking about the upper rings that extend the ER. Is this a defect in the EP? Is it bad that it can spin and rattle around in there—elements rubbing and grinding on each other and whatnot? Can this be fixed or is it meaningless?

The views are pretty great despite the loose base and a few dust specs that seem to be under the first elelemt. Only a miniscule hint of distortion at the very edge in my f/4.7 dob. Maybe the person I got it from tried to take it apart to clean it and didn't put it back to gether very well.

[Paul73]

That doesn't sound right. Mine are all rock solid.

I'm guessing that we are talking about the silver 1 3/4 inch barrel that is clamped onto by the focuser screws. This should just tighten up. I would go very carefully though if getting scrunching sounds...

Good luck.

Paul

[John]

This does not sound right. The chrome barrel should not rotate and nor should any of the lenses or retainers contained in it. If you are in the USA why not give Tele Vue a ring and ask their advice ?. They are very helpful and you may end up speaking to David or Al Nagler

Their contact phone number is on their website:

http://www.televue.com/engine/TV3b_page.asp?id=27

[Reeny]

My second hand 6mm Delos loosened all by itself after a few days of my ownership.

The steel sleeve at the base started to unscrew. 

It was simple enough to hand tightened it back into housing - firmly.

I'm glad I caught mine early.

I never had any trouble since.

Your previous owner should have tightened it up securely as soon as it tried to fall to bits.

I thought I was unlucky - but maybe there is a theme with the 6mm Delos

i.e. they don't like being rattled about in the postal system.

[alan potts]

Not only does it not sound right it is not right. These sleeves on pretty much all of my TV collection have come loose from time to time and you just nip them back up agian but not too tight. This sound to me as if it has become so loose that one of the lens elemnts has got stuck on an inturnal spacer or something else, I say this as I have never taken one apart and would suggest you don't either.

I would be inclined to try and somehow get it tightened again or return it, don't try to over do it. If you can send it back I would do so, personally I would never buy this type of equipment from E-bay there are always astronomers selling these eyepieces on A B&S and this site, but sometimes you have to wait a little.

I am really sorry your first TV eyepiece has not been a 100% success and I hope you get sorted out.

[Bundin]

Thanks all,

I had tried tightening it, but it was so squeaky that I thought I was doing harm to the elements. Hearing from some of you that this barrel does screw in tighter (and shouldn’t be loose), I just went for it. It did tighten up so that it’s all solid now, but it was pretty noisy. Hopefully, this was just the barrel squeaking in the threads and not glass (or a jammed element)! When I first bought this EP, I had no idea about all that goes into an effective eyepiece (and therefore what can go wrong with them). So, a half-price Delos on Ebay seemed like a no-brainer. Too good to be true usually is. In comparison to my 40-something* FOV kellner EPs, it's been a pretty fun spacewalk. Probably worth the 2 benjies I paid for it (at least, that's what I'm telling myself ). New moon in a couple of days. I’ll take it out to my dark site to see if I can detect any damage. Thanks again everybody.

[John]

Tele Vue products typically command around 70% of their new price on the used market if in excellent condition. This is quite consistent with their newer lines so if your Delos was priced at 50% of the new price I think I might have been asking a few questions before committing. The optical design that Tele Vue uses is not known in detail for the Delos but my guess is that there are 6-7 glass elements in there, some in the upper part of the eyepiece and some in the chrome barrel. If you look through the eyepiece (no scope) at a light background you sould see a perfect illuminated circle of light (the apparent field of view) with a sharp black edge. If it looks like this and there are no fuzzy edges or obvious debris showing then things are probably OK. Using it at night with brighter objects such as Jupiter will also show up any optical defects.

[Bundin]

Here's a looksee of the eyepiece.

You can see the dust specs with the bright circle in the center. It seems like a fairly hard black edge.

[alan potts]

Mine looks rather like that but I feel John meant that you get a sharp black edge when you look through it close up at a light source which would be very difficult to take a shot of. I feel that things sound as if they are OK now but I have tried all of mine by un-screwing the sleeve and none are tigh or squeeky. Maybe your just needs a bit of tender loving care which I am sure it will get. Dam good 6mm eyepiece that is not really possible to better in my books.

Alan.