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Eyepiece weight

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#1 clearwaterdave

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Posted 19 June 2019 - 07:27 AM

One of the things I want to know when I consider buying an eyepiece is the weight of said ep.,Agena Astro usually has good specs listed but other distributors do not.,

  I wanted to know the weight of the ES 9MM 62* ep.,Agena has xn listed??? All the other ep's on the page have their weight listed.,So I went to the ES website.,again no weight listed.??Same with Highpoint.,

  I also noticed that some sites have the ep pages really mixed up.,no order what so ever.,5mm plossl next to 12mm82* next to 20mm100*??? all different makes as well., Whoever put these pages together should be fired.,lol.,

  So can anyone tell me what this eyepiece weighs?? Thanks.,



#2 havasman

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Posted 19 June 2019 - 07:49 AM

Dave,

EyepiecesEtc.com has it at 115gm. That sounds about right but the eye relief seems short at 12.6mm. I've not seen one but that's shorter than I'd expected.

Best regards!


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#3 Mike W

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Posted 19 June 2019 - 08:44 AM

Buy a Televue, all weights are listed on their website including discontinued models.


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#4 GOLGO13

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Posted 19 June 2019 - 09:33 AM

I can tell you I've had great experiences with eyepiecesetc.com. Don is great to work with and has good knowledge on eyepieces. He even allowed me to send my eyepiece back to him to confirm if there was a problem with it (the Nagler 3-6 zoom). Turned out it was my eye floaters that were the issue and not the eyepiece. Don sent it back free of charge after performing inspection of it.

 

It's a small company but I like to give him my business when I can.

 

Eyepiece weight is always a consideration for me. I prefer lighter weight eyepieces. My heaviest is the Meade 34mm decloaked (take off the big dew shield). I use a Televue equalizer (think that's what it is called) to help balance between the 34mm and my smaller eyepieces like Brandons.

 

This setup is especially helpful with my FTX mount which is all about balance. But I find it's nice with all my mounts/scopes.


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#5 Starman1

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Posted 19 June 2019 - 03:49 PM

Dave,

EyepiecesEtc.com has it at 115gm. That sounds about right but the eye relief seems short at 12.6mm. I've not seen one but that's shorter than I'd expected.

Best regards!

12.6mm eye relief (ES' claim is 12.55mm) is 1.4x the focal length, which is hard to do on a small eyepiece.

The eye relief on a 9mm Plössl would be 1/2 as great.

I just measured the eye lens of the 9mm ES.  It is consistent with a 13.5mm eye relief at 62° IF the entire eye lens is used for the exit pupil

(and I don't know whether or not it is).

So, the eye relief cannot be longer than 13.5mm, but might be slightly longer than 12.55mm.

And if the real apparent field is slightly less than 62°, the eye relief could be a tad longer.

If the eyepiece were really 58°, for example, the eye relief could be 14.66mm.


Edited by Starman1, 19 June 2019 - 03:53 PM.

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#6 havasman

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Posted 19 June 2019 - 04:19 PM

To be clear, I did not doubt your posted data. It has proven reliable in the past and was obviously where I went to find this answer. It was only when measured against my uninformed  preconceived notion that it was unexpected. 



#7 Starman1

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Posted 19 June 2019 - 04:58 PM

No worries.  It is necessary to point out, though, the eyepiece does NOT have enough eye relief for glasses.


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