Explain Dioptrx and my situation please :)

[Adz]

Hi all,

I was about to buy a 31mm Nagler, but the seller just messaged me this:

'Just realised that the 31 has a 1.5 TeleVue Dioptrix fitted to it. I hope you can use this as I am sending it with the corrector installed.'

As far as I understand it this piece of kit corrects astigmatism which is something that is corrected by glasses. I don't wear glasses, I don't think I need it.

Anyways can I use this thing as the normal eye cup too? Could someone with more knowledge or owning one explain to me?

Many thanks,

[E621Keith]

The Dioptix induce astigmatism that would cancel out your eye's natural astigmatism. It has to be matched to your eye. If you don't have astigmatism to begin with, you will need to remove it. Otherwise you will see the astigmatism induced by the Dioptix.

I'd guess the optical quality and coating quality of the dioptix will be better than the typical plastic spectacles lenses. Also it will be centred on the eyepiece, so you won't need to adjust your spectacle to centre it.

You can sell it the Dioptix, I'm sure there is a market for it. I would have made you an offer, but my eyes are 1.0, so your Dioptix won't work for me.

[Adz]

Thanks Keith. Does this mean it still comes with the rubber eye cup? So I could remove the dioptrx and sell it on?

[haitch]

Having had a quick look around I would say that the Dioptrix has its own shorter cup to give the correct eye relief with it attached. If I were you I would check it still has the original eye cup with it. I wouldn't say don't buy it without (the early Naglers didn't have them anyhow) but you might be able to knock a few quid off.

[Adz]

Thanks Haitch I will do that. If he doesn't have it, does anyone know where you can buy them?

[John]

Getting hold of genuine Tele Vue spares can be difficult and expensive unless you get lucky. A coule of years ago I asked a UK dealer (no longer in business) about getting a 2" TV end cap and was quoted £9 inc delivery plus a 3 week wait

I would not want to use my Nagler 31mm without the rubber eye cup to be honest so it would be worth checking to see if the original cap is included with the eyepiece. If it's not then, having just checked, I can say the the N31 eyecup is the same one they use on the 6mm 8mm and 13mm Ethos so there may be spares around somewhere.

If you get really stuck you can contact TV by phone in the USA (I've done this) and they will sell you spares.

[Damo636]

Not sure if this is the one you are looking at Adam but if not it could save you the hassle of locating an eyecup.

U.K. Astronomy Buy & Sell

I had sent two emails to this seller before deciding to stick with what I have but he hasn't replied to either?

[haitch]

Would any of these fit? Anyone confirm the diamter of the top of the 31 Nag?

SnS Rubber eyecups (3 types)

[Adz]

Thanks for the help guys. Yeah Damo thats the one I have been in touch with him about. Haitch I am not sure about that, one one is in stock and I would prefer the proper televue one but thanks anyway.

[Adz]

Well he doesn't have the original cup so I have asked for a discount and talked to the widescreen centre about ordering a replacement. Heres hoping

[Adz]

So the seller backed out of the sale at the last minute Glad I didn't send him the money first! Back to the drawing board...

[John]

Sorry to hear that Adam but it might be for the best in the long run. Getting a replacement eye cup was a hassle that you could probably do without.

Hope you find another soon.

[Adz]

Cheers John. Maybe its for the best...What is an eyepiece collection if it is considered finished?

[Damo636]

Bad luck Adam, I'm sure another will pop up in the near future.

[Adz]

Cheers Damo, clear skies guys