Plossl...?

[gobes]

Can anybody explain to me what a Plossl ep is, and does?

I'm looking into gettign a new eyepiece, and seen a lot of people recommending Plossl's.

Any recommendations for a Skymax 127 mak scope?

Thanks.

[Doc]

A quick run down of what eyepiece designs are around....

Eyepieces come in a variety of designs. Choosing the right one depends on what you plan to observe, how finicky you are about image quality and field of view, and how much you're

willing to spend.

Kellner

The 3-element Kellner gives sharp, bright images at low to medium powers. Best used on small to medium-size telescopes,

Kellners have apparent fields around 40° and good eye relief, though short at higher powers. Good, low-cost performer, far superior to simpler Ramsden and Huygenian designs.

Orthoscopic

The 4-element "ortho" was once considered the best all-around eyepiece, but has lost some of its luster because of its narrower field compared to newer designs. Excellent sharpness, color correction, and contrast. Longer eye relief than Kellners. Especially good for planetary and lunar observing.

Plossl

Today's most popular design, the 4-element Plossl provides excellent image quality, good eye relief, and an apparent field of view around 50°. High-quality Plossls exhibit high contrast and pinpoint sharpness out to the edge. Ideal for all observing targets.

Erfle

The 5 or 6-element Erfle is optimized for a wide apparent field of 60° to 70°. At low powers, its big "picture window" viewing area

provides impressive deep-sky views. At high powers, image sharpness suffers at the edges.

Ultrawide Types

Various improved designs incorporating 6 to 8 lens elements boast apparent fields up to 85° - so wide you have to move your eye around to take in the whole panorama.

Light transmission is slightly diminished, but otherwise the image quality in these eyepieces is very high. So too is their price.

[AWR]

Gobes,

A Plossl is a design of eyepiece. Other designs include Kellners, Orthoscopics and various wide angle arrangements. The design relates to the number and arrangement of lenses which make up the eyepiece.

Various manufacturers will make eyepieces in different designs.

From the Astropedia here on this site:

There are a number of different optical designs which have particular properties. Some fancy modern eyepieces are a combination of these classic designs or a even a design unique to that eyepiece. Here are the basic types:

Orthoscopics are excellent for high power as they are cheap, bright and with excellent contrast. They have small AFOVs, but you do not usually need a large AFOV for high power work.

Plössls are good for general medium power.

Wide angle eyepieces (65°+) can be used to good effect for any power range, but generally they are more of a luxury and hence cost more.

Plossls were recommended to me as a good all round eyepiece design - reasonable quality but not too expensive.

For my 127 Mak, I bought a 15mm Plossl (from Vixen) which gives 100x and a 0.5 degree field of view and a 2x Barlow lens as my first additions.

HTH,

Andrew

[The Warthog]

Plossl is sort of the Chevy sedan of eps. Reliable and not particularly sexy, but gets you there.

Here is a site that will tell you more than you need to know about ep designs, with diagrams: Eyepieces