20mm eye peice

[shyam]

Hi

I have a Celestron 114 eq  Newtonian telescope, I am totally new to this area. While installing accidently oppend 20 mm eye peice now can any one please guide me the how is the lenses fixed originally.

[ronin]

At a guess it is a Huygens eyepiece - any markings on the body like "H20" ??? Last I was aware they are supplying basic Huygens as the supplied eyepiece.

If so then by rights you should simply have 2 single lens and the eyepiece body, a spacer ring and a threaded retaining ring. (??)

CLEAN the bigger lens and drop it into the eyepiece body with the curved face pointing to the scope end, drop in the spacer, CLEAN the smaller lens and drop that in again with the curved face towards the scope end, then screw in the retaining ring and tighten.

Piccy:

 

Now the problem is I have guessed at a Huygens and you have not stated the lens, assume 2 and so far assumed both are singlets.. Need to know ANY lettering on the eyepiece.

Possible alternatives are:

RAMSDENS

 

KELLNERS

As can be seen Huygens and Ramsdens use similar lens but differently orientated. Kellners seem to use a doublet as the eye lens. So if H20 the Ramsden, if R20 then Ramsdens, if a doublet then likely Kellner.

Clean the lens and try to get noting on them when reassembling.

[shyam]

Ronin , Thanks for the reply so fast. Again bothering you. How will i know what make is the lens. Please guide me. Also thanking you with the best of the best  reply with illustration.

[michael.h.f.wilkinson]

Another frequently used type is the Plossl, which is like the Kellner, but with two doublets, the smaller the eye lens, and again with both most convex sides facing each other. The Huygens is different from the other also in that the field stop lies in between the two lenses

[michael.h.f.wilkinson]

I just looked up some images of the 10 and 20mm eyepieces of the Astromaster 114EQ on the Celestron website. The 20 mm seems to have 20mm Erect... written on it (an erecting EP). These have an extra lens incorporated to create an upright, non-mirrored image

I googled "erecting eyepiece 20mm", and it seems you are not alone

Celestron have a page describing reassembly:

http://www.celestron.com/support/knowledgebase/articles/i-“accidentally”-took-apart-my-celestron-20-mm-erect-image-eyepiece-how-do-i-put-it-back-together

 

[michael.h.f.wilkinson]

BTW, I think there is a lens fixed at the bottom of the main barrel (the erecting lens), and the other two work more-or less as a reverse Kellner (doublet field lens, singlet eye lens).

[shyam]

@Neutron Star  ...... Thanks for the Info.

[Cornelius Varley]

3 hours ago, shyam said:

Hi

I have a Celestron 114 eq  Newtonian telescope, I am totally new to this area. While installing accidently oppend 20 mm eye peice now can any one please guide me the how is the lenses fixed originally.

Was the telescope supplied with a 20mm erect image eyepiece ? If this is the case then this should help you I accidentaly took my 20mm erect image eyepiece apart.