HELP my eyepiece has fallen apart!

[kerrylewis]

I feel so stupid. I decided to give my eyepieces a light clean. I removed the 1.25" barrel from my TV 19mm Panoptic and the whole thing fell apart! I did not realise that you couldn't remove the barrel as it seems OK to do this with other eyepieces. I know- the instructions probably warn against it.

I have emailed Telescope House but they are closed for the hols.

I am hoping that they can reassemble. There is no way that I can see the right order for the various lenses and other bits.

Any advice other than don't be such an idiot next time!?

Kerry

[nightfisher]

Good luck with it, i found this page that might help put it back together    https://www.google.co.uk/search?q=Televue+panoptic+diagram&espv=210&es_sm=93&tbm=isch&source=iu&imgil=n74GRxJ_-v9weM%253A%253Bhttps%253A%252F%252Fencrypted-tbn2.gstatic.com%252Fimages%253Fq%253Dtbn%253AANd9GcS83z2DVWThzYQJfsrFxXkid2TI4TmB-FCn2gTgAqv0o8w3FKJc%253B250%253B200%253B4SDvIJYLEuSL7M%253Bhttp%25253A%25252F%25252Fwww.handprint.com%25252FASTRO%25252Fae5.html&sa=X&ei=tWLBUsyfLc2u7AaVqYHwCg&ved=0CEYQ9QEwBg&biw=1366&bih=666#facrc=_&imgdii=_&imgrc=n74GRxJ_-v9weM%3A%3B4SDvIJYLEuSL7M%3Bhttp%253A%252F%252Fwww.handprint.com%252FASTRO%252FIMG%252Fpanoptic.gif%3Bhttp%253A%252F%252Fwww.handprint.com%252FASTRO%252Fae5.html%3B250%3B200

[John]

The diagram that Jules links to was the one that I came up with too. It corresponds with the Panoptic design of 6 elements in 4 groups. I believe the eye lens would be on the right hand side of the diagram.

There will be spacer rings to go between the lenses so that thy are not actually touching one another.

[kerrylewis]

Thanks Jules and John

I could try it but I'm not sure there is quite enough info in the diagram because apart form the lenses there are some spacers etc

[nightfisher]

Many years ago i did this with a plossl, then did not know what way round they go, so had to strip another plossl (carefully) to get the correct order

[John]

It's possible that Telescope House won't know either - it's quite possible that they have not seen inside one !

Tele Vue are contactable by phone in the USA and they are very helpful. Their phone number is on their website - www.televue.com

[kerrylewis]

Telescope House have actually responded and you are right John they can only refer to Televue for a cost. I may try phoning TV

Not my day! I really liked that eyepiece

[John]

If you have to sent it to TV in the USA and have them re-assemble and send it back the costs could be high. TV's time won't be costly but the carriage will be I fear.

Hopefully TV will explain the order of lenses and spacers. I'm sure you are not the first person to do this.

[Moonshane]

as long as you have not damaged the lenses I am sure you'll be able to put it back together. I am sure that almost everyone will have done something similar.

[kerrylewis]

Thanks for the advice so far. The lenses don't seem to be damaged, it just resembles some sort of puzzle that you might get in a Christmas cracker - just a matter of solving it! There will be one correct order.

[nightfisher]

Kerry, just take your time, ease it back together in the order you think it should be, then try it, might take a couple of goes

[Pig]

Kerry,

My brothers eyepiece fell apart last month I managed to put it together despite the number of components, As John said a spacer goes in between each lens, it looks more daunting than it actually is.

Edited December 30, 2013 by Pig

[Alien 13]

Most things have a logical way of fitting together if you can do a rough assemble and hold the bits in your hand then look through at some fine print it will be obvious if you have got it right.

Good luck.

[bombassa]

Perhaps you'll end up with an ethos 

Good luck!

[itmo]

You know how anytime you disassemble and then assemble something, one part is left over and everything still seems to be ok? After a while you have two eyepieces  

[demessieres]

I just had the same problem with our observatory's TV 19mm Panoptic, and I spoke to Al Nagler at TeleVue who was very helpful and clear.

You should have four lenses: two singlets (with a convex and flat surface), and two doublets (one concave and one convex surface).  You also need spacing rings to go between them.  None of the lenses should touch each other.

On the telescope end, the concave face of that doublet should face the telescope.

Then the two singlets should be in the middle, with their convex surfaces facing each other.

On the eye end, the concave face of that doublet should face the eye.

Clear skies!

[kerrylewis]

Good luck! it is not as easy as it sounds. I'm afraid  mine was a write off. Personally I think it is a poor design that has loose lenses inside and yet allows the barrel to be easily unscrewed  - but I put it down to experience. 

[Macavity]

Happened to me - Albeit with a £60 eyepiece. I knew the ordering,

but sadly one of the lenses got STUCK on reinsertion. My tip, for

what it's worth: Don't just "gently drop" the elements back in?

Perhaps you can use something - A piece of clean doweling or plastic

to push up on the lower side of the first element inserted - Basically to

allow the components to be lowered slowly into the body of the e.p.? 

On the larger scale, I found a CLEAN plastic cup helped with lowering

a 100mm achromat back into a tight lens cell. Just "Jiggle it about a bit"

(Granville?) occasionally to ensure nothing is sticking as you go? 

Edited August 21, 2014 by Macavity

[cs1cjc]

There are only a limited number of ways an eyepiece will go back together and only one way will be truly sharp.  You have to be methodical in trialing different arrangements.  An artificial star is the best way to test sharpness and has the advantage of allowing assembly and test in the light. 

If you do not have an artificial star, a pinhole in foil with a bright light behind will do.  This needs to be far enough away for your telescope to come to focus (test with an eyepiece that is still intact!).

Good luck

[D4N]

Well with 6 elements even if you know the correct order there are 64 different combinations just depending which way each is facing. If you don't know the correct order then there are 46080 combinations!

And that's assuming the spacers are all the same, if they aren't your looking at 5529600 combinations.

If you test a combination every five minutes for 12 hours a day every day it would take over 105 years to try them all.

I think I'd rather send it back to the manufacturer

TSED70Q, iOptron Smart EQ pro, ASI-120MM, Finepix S5 pro.

[Charic]

Good luck! it is not as easy as it sounds. I'm afraid  mine was a write off. Personally I think it is a poor design that has loose lenses inside and yet allows the barrel to be easily unscrewed  - but I put it down to experience. 

Don't give up, unless you have damaged something? There has to be a way to replace everything in the right order!  

If you  have truly have given up, or feel its too expensive to have TeleVue re-assemble the lens, send me the lens. It would be a challenge to re-assemble the optics, and the option to try out the one of the TeleVue  branded EP's to really see if a lens can make a difference, not that there is anything wrong with  BST's on my f6 telescope? If I manage to get it up and running, I`ll return the lens. If I'm unsuccessful, someone else could try.

I changed some capacitors on a 42" TV last week, and succesfully restored the power function to the TV. Cost of capacitors £2 for the pair. I also managed to photograph each stage of de-construction ready for re-construction. Maybe an option for anyone considering an eyepiece overhaul. Despite this particular eyepiece "....the whole thing fell apart..." there is still good reason  to photograph in-case of any mis-hap. Now where's my horse!

[timwetherell]

I wouldn't feel too bad, many of us have done stuff like this - it's human nature. Worth contacting TV - most of these top notch manufacturers are really nice and helpful. Just make sure to fill in the right customs form if you have to send it back (marked returned for repair) so you don't slugged with VAT when it comes back in the country

all the best

Tim

[cs1cjc]

Well with 6 elements even if you know the correct order there are 64 different combinations just depending which way each is facing. If you don't know the correct order then there are 46080 combinations!

And that's assuming the spacers are all the same, if they aren't your looking at 5529600 combinations.

If you test a combination every five minutes for 12 hours a day every day it would take over 105 years to try them all.

I think I'd rather send it back to the manufacturer

TSED70Q, iOptron Smart EQ pro, ASI-120MM, Finepix S5 pro.

Although the panoptic has 6 lenses, there are only 4 separate pieces of glass (6 elements, 4 groups).  See:

http://www.televue.com/engine/TV3b_page.asp?id=214&plain=TRUE#.U_hGzrtx0xA

This gives only 48 arrangements (ignoring spacers), not all of which will be possible because of lens curvature.   There is a diagram of the lens arrangement here which should be a useful guide:

http://www.handprint.com/ASTRO/ae5.html#panoptic

The problem is, from my own experience, solvable. 

You do have to be very very careful with the lenses which will get stuck and can be chipped if they go into the barrel at an angle.  I have found it a help to support each lens in turn on a post of smaller diameter and to lower the partially assembled lens down, over the top.  You need not worry about the lens getting dirty in trial assembly indeed it can be a help to mark the surfaces for identification purposes.  Thorough cleaning for final assembly is vital and you may need more than one go to completely eliminate annoying dust.  Of course return to base is a good option for Televue eyepieces but not for most other makes.

[Alien 13]

As above i have done similar with camera lenses usually using the eyepiece on a bit of newsprint will tell you if its worth testing in a scope.

Alan

[Moonshane]

this sounds daft but it may be worth buying a another used one, checking the order by careful removal (aligning each of your own lenses as you take one out of the other one) and then once all back together, sell one of them. assuming there's no damage and you are happy it works fine I'd knock off a bit (20%?) from the normal used price and explain the circumstances. I am sure it would be snapped up.