20mm plossl celestrone eye peice

[shyam]

hi

just dismantled the eyepeice 20 mm apart from lenses it also has a prism kind of optics below. what is this for, as a 10mm or a 4mm dont have this .

thanks

shyam menon

[Cornelius Varley]

The 20mm is designed for terrestrial viewing, the prism inside the eyepiece flips the image so that it is the right way up. Astronomical eyepieces don't have the erecting prism because there is no up or down in space.

[shyam]

ok.. but does this prism help in collecting light ?

[Cornelius Varley]

6 minutes ago, shyam said:

ok.. but does this prism help in collecting light ?

No, it just flips the image. 

[shyam]

hi 

can i use a OMNI 1.25" 2X BARLOW LENS on a  astromaster celestrone 114eq on a 10 mm eyepeice for magnification. How much does it justifies .

thanks

shyam menon

[MarsG76]

yes, that will deliver a magnification of 200X... which is about the max power you can practically use with a 114mm objective scope.

 

[MarsG76]

1 hour ago, shyam said:

hi

just dismantled the eyepeice 20 mm apart from lenses it also has a prism kind of optics below. what is this for, as a 10mm or a 4mm dont have this .

thanks

shyam menon

Why dismantle it? 

[shyam]

2 hours ago, MarsG76 said:

Why dismantle it? 

hi 

can i use a OMNI 1.25" 2X BARLOW LENS on a  astromaster celestrone 114eq on a 10 mm eyepeice for magnification. How much does it justifies .

thanks

shyam menon

[shyam]

curiosity ... ?

[MarsG76]

4 hours ago, shyam said:

curiosity ... ?

Curiosity is always good... but if you have or will even get an eyepiece like a Televue Ethos type, this about dismantling it. Apparently the lenses within it are collimated and vacuum spaced, put back together wrong will render it much worse quality than out of the factory. So study optics before allowing your curiosity to have the better of you or you could damage a expensive toy.

[Louis D]

13 hours ago, shyam said:

curiosity ... ?

If you end up with Pentax XLs or XWs, you won't be able to dismantle them because they're weather sealed having started out as spotting scope eyepieces.  The threads are all glued solid.