Maxvision 24mm Nightmare - HELP

[NoSiriusly]

I've done a very silly thing. I twisted out the eyecup of my 24mm Maxvision eyepiece and I noticed there was another thread also unscrewing.

"Ooh what's that?" I thought. "Let's carry on unscrewing to see what happens".

Next thing I know I've got lens elements all over the desk and no clue how to put them back

I've ended up with this mess. Finger prints all over the place (hopefully I can clean it all up) .

Has anyone seen a drawing or sketch to show the order in which to put these back in? Has anyone else ever done something as silly as this?

I've tried several different orders but I can't seem to get it right. I'm beginning to look at my bank account and wonder if it's time for an emergency upgrade!!!

Hope you can help.

[Daniel-K]

There's a lovely 22mm T4 on ABS

Hope you get it sorted

[YKSE]

Just had a look at my 24mm 68deg MV, My guess is that it's similar design as Panoptic, which you can see the lens arrangement here(almost the end):

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

The two singlets should be in the middle with the most convex side facing each other, a few combinations for you to try out. Good luck.

[Mark at Beaufort]

The first thing that I would do is clean all the lenses. I have looked at my 24mm Maxvision and its difficult to work out which lens goes in which position. However, I believe the lens on the left goes in first, then insert one of the lenses (centre of your picture) - at this stage I don't know which way round they go (experiment). Add a spacer, then another lens, then a spacer then finally the one on the right with the 1.25" adapter.

Take your time over this but don't tighten too much at this stage. I don't think you have completely broken the lens just experiment. Use a tissue to place the lenses and have the eyepiece upside down when doing the task.

When complete put it in the scope and find a TV aerial and focus. If you can't focus turn the two central lenses around until you get it right.

Wait a little before starting just in case someone on the forum has done this task for real.

Hope it works for you.

PS - I have just looked at YKSE's post and I think the Panoptic is a good place to start because its shows the correct position of the two central lenses.

[bingevader]

I have the 82° so can't offer to undo mine to check! 

However, with all the talk when they initially came out of them being re-badged Meade 5000 SWAs, have you tried searching for a diagram for the 24mm Meade?

Sorry I can't be of any more assistance. 

[bingevader]

Ooh, this maybe!?

The 6 element SWA is the middle pic, does that look about right?

[Ruud]

This may help: http://www.patentbuddy.com/Patent/4525035

Note how L3 and L4 have their strongest curved sides facing each other and how the lenses are arranged from smaller to bigger.

Good luck

[NoSiriusly]

Wow thanks so much for the responses from you all.

The panoptic design seemed to make sense so I went with that. I seems to have done the trick.

First the nose piece with lens

Then the large spacer

Then the small spacer

First singlet lens

Second singlet lens

Lens Spacer

Eye lens

Then about 20 minutes of fiddling with trying to get it all back in with as little contact as possible. Straight into the grab'n'go scope and away we go. I think its all going to need another thorough clean as I can still see finger prints but I'm pretty happy.

I'll test it properly on my SW 200p and see how it goes. Thanks so much for your help. I really freaked out earlier and it's amazing to see how quickly the SGL gang pulled together.

[John]

Thanks for posting the pics - might help someone else who has done the same thing

Also good to see blackened lens edges, spacers and decent baffling used in the construction of the eyepiece - all contribute to good performance.

[NoSiriusly]

Thanks John.

When I first closed the eyepiece up there was movement inside. I cranked it up tight to bring it together and that took the play out of it. A bit scary doing that to an eyepiece but worth knowing if someone else follows the pics and notices a rattle.

[phoobar]

This happened to me Sunday night on my 16mm, fortunately I realised after half a turn and it didnt end up in bits like this .

I am concerned as this happens every 1 in 5 or so times I extend the eyecup now, are these threads normally glued or have a nylon lock? Not the end of the world but could do without it.

My 24mm looks ok at the moment but the eyecup is quite stiff to move.

I did read yesterday somewhere that these eyecups can be removed permanently so I might try that.

Anyway  hope you get it sorted and would be interested to know how you get on please NoSiriusly.

[NoSiriusly]

It seems OK now Phoobar.

There didn't seem to be any thread locking compound on it but when I was trying to put the eyepiece back together it was quite difficult to open it back up again. On the last time I put it together I put a fair amount of pressure into it and it doesn't move at all now.

It must have loosened over time. In future I'll give it a check tighten before use so it doesn't happen again.

I don't think you can get the eyecup off easily. Certainly not without removing the internals first. That said, I was focussing more on putting it back together as opposed to taking more bits of it so I may be wrong.

Just tried it outside but there is a freezing fog so it's difficult to see anything clearly (there's one of those weird icy rings around the moon, which will no doubt spark some kind of "debate" on Facetube or Youbook). I looked across the valley and the house/street lights seemed crisp so all seems well.

[Peter Drew]

I'm a bit concerned about the "second singlet" photo. It looks to me as though the two components are going to touch glass to glass which would result in scuffing if this were so. I would have expected a spacer to avoid this. Maybe it's just the photo angle? 

[Ruud]

Me too, I think it should be like "lens group - spacer - lens - spacer - lens - spacer - lens group" 

 

You have two spacers on top of each other,  and you have two lenses that might touch each other (cranked up tight as well). I think one of the spacers might need to go higher in the stack.

 

As far as I know, the lens spacing of a panoptic is equal between all groups and no group should touch another.

[NoSiriusly]

That's what I thought at first but when you read the panoptic description that YKSE put above it says that the two lenses actually touch. Seems a bit strange, I know, but the eyepiece seems to be working and each other order I put them in resulted in the stack being too short or too long. Also, moving a spacer up the stack resulted in the first singlet touching the nose piece lens.

I imagine the light path is being directed around the outer edges of the singlets by the first nose piece lens hence it not mattering about the singlets touching.

I hope It didn't sound like I know what I'm talking about because I'm not sure I do!

[phoobar]

Sounds like a right nightmare  Maybe leave it alone now and email ES for advice

[wupdigoj]

I have found this thread looking for help with a similar problem with a 16 mm maxvision. After several iterations, and with the help of the pictures, I think I know (more or less) the correct order. In my case, the two single lenses have a slightly different curvature, and  the two spacers are also different. I am sorry I didn't take photos, but I am not brave enough to disassembly it again to show the process!. I will refer to the pictures taken by the original poster.

1.- First the nose lens, just as shown in the picture.

2.- Next the thin spacer, but not as in the picture above: the borderer side must be downwards (I am pretty sure of this one)

3.- Next,  one plano-convex lens, with the plane side downwards.

4.- The other (thicker) spacer, again the side with the small border downwards (perhaps the opposite, not sure)

5.- The other plano-convex lens, with the plane side upwards.

6.- Finally the last lens spacer and the eye lens, as in the pictures.

Try to keep the lens tower in equilibrium and carefully insert the eyepiece body and screw the nose (do not over tight, just enough to prevent the "rattle").  In the telescope, pointing to a distant building  it showed a little field curvature (centre sharp and the border not so sharp). I just disassembled it again and swapped the positions of the plano-convex lenses (not the spacers!) and the field is sharp again from border to border. I am not 100% sure or this procedure, but the eyepiece seems to perform as before the disaster. I hope this can help someone.

 Javier

 

[trynda1701]

Having just "decloaked" my own 16mm Maxvision as shown in this thread...

 

https://stargazerslounge.com/topic/288310-repair-help-on-es-maxvision-16mm-plossl-needed/

 

...I'm getting worried about using my Maxvision eyepieces! Are @NoSiriusly, @wupdigoj and I using the twist up eyecup incorrectly to cause these faults? I think I caused my problem by trying to only twist the upper rubber cap, as in my BST Explorers, instead of the main body. What are we doing wrong?

 

Mark

[bingevader]

My goodness, this is a blast from the past!

I have the 24mm, so not sure if I can help much, but I can't twist the rubber cup on its own, I have to twist it and the body of the EP as one, whilst holding the bottom (the piece that inserts into the focuser, the nose piece?), the same as the Meade 5000 UWA design.

Cheers

[Louis D]

2 hours ago, trynda1701 said:

Having just "decloaked" my own 16mm Maxvision as shown in this thread...

 

https://stargazerslounge.com/topic/288310-repair-help-on-es-maxvision-16mm-plossl-needed/

 

...I'm getting worried about using my Maxvision eyepieces! Are @NoSiriusly, @wupdigoj and I using the twist up eyecup incorrectly to cause these faults? I think I caused my problem by trying to only twist the upper rubber cap, as in my BST Explorers, instead of the main body. What are we doing wrong?

 

Mark

The rubber part AND the metal part below it must be twisted together.  Thus, the only place to grab is the 1.25" barrel.  As the shiny metal/rubber combination goes upward, a greased black eyepiece body should become visible below it.  Be careful not to touch it or you'll get the grease on your fingers.  It should look like this when extended.

[trynda1701]

I'll just have to get used to using them, and remember the difference between them and the BSTs. I haven't used them much since I picked them up due to all the lousy weather.

 

Or not adjust them back to the lowest setting when putting them back in their boxes!

 

Mark

[Ricochet]

I've got a 24mm in Meade colours and I only adjust the height with the eyepiece secured in the focuser. The nose piece is stiffer to unscrew than the adjustable eyecup so only the eyecup moves when twisted but a nose piece unscrewing could happen to most eyepieces and is something you should be aware of. Sealed/waterproof eyepieces might be the exception and have extra screws to prevent the seal being broken. Unscrewing of the nose piece can also be caused by holding onto an eyepiece too tightly when securing them in a focuser with a twist lock adaptor. The adaptor will start to "grab" the eyepiece just before it is fully secured and the clockwise tightening of the twist lock is an anti clockwise unscrewing action from the perspective of the eyepiece barrel. As such it is better to loosely hold the eyepiece so that it can rotate for those last couple of degrees of tightening if required. 

[wupdigoj]

I have decloaked the 3 maxvisions I own (16 and 20 68º and 24 82º) so my problem was not related to the twisting of the rubber eyecap. While using it, the nose piece of my 16 mm somehow unscrewed itself a little, so the lenses rattled. I tried to screw on the piece, but something inside went wrong so it was not possible. In fact one of the plano-convex lenses skewed and got stuck inside the eyepiece body, so it was impossible to square or extract it. I tried to heat the eyepiece body and finally could extract the lens, but with it, all the other lenses and spacers came out as well in a row. I was only sure about the position of the first (from the nose) lens and spacer.

I have double checked now my other eyepieces, and the "noses"  seem firmly attached. To prevent further accidents I have fixed the 16 mm  thread with a drop of glue (DO NOT use cyanoacrilate glue for this, you risk to hopelessly fog your lens!)

javier