BST Explorer EP's actual sizes

[ChrisThePuma]

Hi

I want to get a few and keep them in a foam lined case. Does anyone know if the different focal lengths change the actual size of the eyepiece? (i.e is the 5mm one a shorter lump of EP than the 24mm?)

( i want them all lined up neatly in the case - sad i know but that's my OCD for you)

[tbird]

There's a picture of my BST's on here : Members Equipment - North Lincs Astro

The 5mm is the largest on left with the 8mm and 18mm very similar in the middle and a 25mm, slightly larger on right.

[johninderby]

They do vary a bit. Here's a photo of the Omegon version of these eyepieces that'll give you an idea of the variation in size.

John

[callisto]

This is from spaceboys thread

http://stargazerslounge.com/members-equipment-gallery/167482-finally-bst-firm.html

[bigbox]

Hi Chris,

There's Noting wrong with keeping your EP's in a case. Thats where mine are kept 24/7 these days with the weather we have had lately lol...

Congrats on reaching the 100+ post too...

[ChrisThePuma]

Ohh - very helpful - thanks all

[ChrisThePuma]

Interestingly the 5mm is the longest, where as the basic Skywatcher ones i have the 10mm is much smaller than the 25mm.

[John]

Interestingly the 5mm is the longest, where as the basic Skywatcher ones i have the 10mm is much smaller than the 25mm.

It's the same with many eyepiece designs that use an additional lens set in the eyepiece barrel to attain the desired focal length. I assume that the spacing between these extra lenses and the ones in the main body of the eyepiece needs to get longer to produce a shorter focal length.

Simple eyepiece designs like kellners, modified achromats, plossls and orthoscopics don't use these additional lenses.

[todd8137]

odd indeed

[ecosse]

You should still be able to get them in a case. Here's my 3 in my case with spaces left for the 5, 15 and 25mm.

The 5mm is the largest in size being slightly larger than the 12. My eyepieces are in a maplin small flight case.