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Replacement 2” EP caps


Stardaze

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2" is not better than 1.25", just like size 9 shoes aren't better than size 8. For eyepieces it has to do with the size of the field stop. This has to to fit in the barrel.

The focal length and apparent field determine the size of the field stop. Combinations above the blue line in the graph won't fit in a 1.25" barrel.  Fore instance, a 50mm 50° eyepiece will not fit in a 1.25" barrel.

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37 minutes ago, Ruud said:

post-38669-0-54120600-1452021037.png

2" is not better than 1.25", just like size 9 shoes aren't better than size 8. For eyepieces it has to do with the size of the field stop. This has to to fit in the barrel.

The focal length and apparent field determine the size of the field stop. Combinations above the blue line in the graph won't fit in a 1.25" barrel.  Fore instance, a 50mm 50° eyepiece will not fit in a 1.25" barrel.

I think you’ve got the wrong end of what I’m after here, I just need a cap as a secondhand 2” EP I bought has one that is very loose. They don’t seem so plentiful for sale?

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Oh I missed the word cap. I found end caps 2" in a box with used stuff at a local store. They also had new ones made of bright yellow very pliable plastic. Much like these:

https://eyepiececaps.com/caps-for-eyepieces-5-or-10-packs/

I didn't get the yellow ones. The originally black used ones were grey with age but still looked better.

Edited by Ruud
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Make the caps hard plastic so that pushing the eyepiece down into the case does not push the eyepiece cap into contact with the lens and leave a smudge.

Those soft vinyl eyepiece caps will only work when the lenses on each end are a good distance in from the ends of the eyepiece.

Explore Scientific learned this the hard way, and had to provide caps to consumers for a lot of eyepieces.

APM and Stellarvue have this issue with the 20mm 100° eyepieces.  I change all the caps and clean the lenses before shipping, but I'd bet most dealers don't.

 

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1 minute ago, Don Pensack said:

Make the caps hard plastic so that pushing the eyepiece down into the case does not push the eyepiece cap into contact with the lens and leave a smudge.

Those soft vinyl eyepiece caps will only work when the lenses on each end are a good distance in from the ends of the eyepiece.

Explore Scientific learned this the hard way, and had to provide caps to consumers for a lot of eyepieces.

APM and Stellarvue have this issue with the 20mm 100° eyepieces.  I change all the caps and clean the lenses before shipping, but I'd bet most dealers don't.

 

Thanks Don, the APM 20 is my next purchase, so I had the replacement in mind having noted you mentioning it previously. People lose caps, and so I’m quite surprised how scarce they seem to be over here in the UK? Still haven’t found the right version? Ironically, the cap I want to replace is on an ES 24.

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for the barrel or the eye end? barrel caps are quite easy to find on ebay- i used these ones- they’re a tight fit- maybe annoyingly tight so i cut them down to half height

https://www.ebay.co.uk/itm/5Pcs-50mm-Inner-Dia-PE-Plastic-End-Cap-Bolt-Thread-Protector-Tube-Cover-/382422567251?_trksid=p2349624.m46890.l49292

Edited by markse68
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30 minutes ago, markse68 said:

for the barrel or the eye end? barrel caps are quite easy to find on ebay- i used these ones- they’re a tight fit- maybe annoyingly tight so i cut them down to half height

https://www.ebay.co.uk/itm/5Pcs-50mm-Inner-Dia-PE-Plastic-End-Cap-Bolt-Thread-Protector-Tube-Cover-/382422567251?_trksid=p2349624.m46890.l49292

Perfect, that’s what I’m after Mark. Maybe the metric search would have found them?

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14 minutes ago, Stardaze said:

Perfect, that’s what I’m after Mark. Maybe the metric search would have found them?

yes maybe- the PE is soft enough to give a bit and fit the 50.8 barrel but in the field it’s too tight for comfort but cutting them down makes them more usable.

Of course there are 1.25” versions too which actually fit pretty perfect- tight but not too tight 👍 and cheap 😉

https://www.ebay.co.uk/itm/10Pcs-32mm-Inner-Dia-PE-Plastic-End-Cap-Bolt-Thread-Protector-Tube-Cover-/183145595884?_trksid=p2349624.m46890.l49292

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Sorry to jump in on this, but as the Op got the answer, I might be able to get one too. I'm afer something to plug a baader clicklock 2", so I can leave it attached to my visual back without a gaping hole open into the back of my sct, can anyone advise?

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16 hours ago, Don Pensack said:

Cheers, just didnt know what to call them. Don't offer them in the UK the shipping is close to £12!!

Edited by DeathWarpedUp
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11 minutes ago, DeathWarpedUp said:

Cheers, just didnt know what to call them. Don't offer them in the UK the shipping is close to £12!!

I think Opticron in the UK stock some lens caps, not sure what sizes are available.

John

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