Plossleyepiece design

Conventional wisdom is that the less glass the better for planetary viewing. Plossls and orthoscopics are the standard for that, but it really comes down to personal preference: I don't have any plossls at the moment not because I don't like them, but because you don't get much eye relief, which is more imporant to me.

There aren't really any hard and fast rules about eyepiece types and what you use them for - everyone has their favourites.

Plossleyepiece vs Kellner

So, basically a Plossl eyepiece is a type of eyepiece that enables the viewer to see a wider field of view than would normally be the case, but at the cost of him/her having to physically put his eye very close to the lens of the eyepiece.

Are allPlossleyepieces: the same

An embarrassingly fundamental question I know, but what is the difference between a Plossl eyepiece and a 'normal' eyepiece (if there is such a thing!)

Plossls are fine for general use by most people who are using their scopes for general work. There are however variations in the smoothness of the finish of the glass surfaces and in the coatings, also in the quality of the mechanical construction, these account for (at least some of) the variations in price between different brands.

Plossl eyepiecesreplacement

ArePlossl eyepiecesgood

I think this information is a little out of date. By todays standards the plossl design offers what is usually termed a "standard" field of view - ie: 50-60 degrees (most are 52 degrees). In the shorter focal lenghts the eye relief (how close your eye needs to get to the eye lens to see the full field of view) is tight though.

IMO the most practical weakness of the Plossl design (compared with the orthoscopic) is that the eye facing lens is soft flint glass instead of hard crown glass, therefore the outside surface which is the one which needs cleaning most often tends to degrade with heavy use. For casual users this should not be a serious issue, with reasonable care a Plossl should last for many years.

25mmPlosslEyepiece

Wide angle and ultra-wide angle eyepiece designs (eg: erfle, nagler, etc) tend to have more glass elements in them and tend to be favoured for low to medium power viewing.

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So, basically a Plossl eyepiece is a type of eyepiece that enables the viewer to see a wider field of view than would normally be the case, but at the cost of him/her having to physically put his eye very close to the lens of the eyepiece.

Plossl eyepiecesamazon

Big problem to the plossl market at this time is the inclusion of worse stock eyepieces with most scopes. The Huygens and Ramsdems are pretty bad and when a person upgrades they will often now jump the plossl's. If anyone asks here we tend to say get the BST's, on CN it is very similar where people get told buy the AT-Paradigms (same eyepiece). So very likely the inclusion of these poorer eyepieces mean plossl's are purchased less as an upgrade. If they had half decent plossl's initially many could simply buy a few more plossl's.

I should have mentioned that, as I understand it, becuase it has fewer actual lenses than other types of eyepiece a Plossl is considered superior to them, particularly for viewing the Moon and planets?

The plossl is a fairly simple inexpensive design that is easily produced, and I agree there are a few eyepieces that operate a lot better at not that great a price difference. The catch (if that is correct) is that better ones are "brands" and not "designs". Skywatcher are not going to throw in an Antares W70 as a standard item - they don't make them.

What is a SuperPlossleyepiece

I would call the plossl design a decent general purpose eyepiece. The orthoscopic (another design) has the same number of glass elements in it but grouped differently and is generally considered superior for planetary viewing.

because the Plossl design has a tendency to internal reflections causing "ghost" images of bright objects, which spoils contrast to some extent.

I should have mentioned that, as I understand it, becuase it has fewer actual lenses than other types of eyepiece a Plossl is considered superior to them, particularly for viewing the Moon and planets?

electric polarization, slight relative shift of positive and negative electric charge in opposite directions within an insulator, or dielectric, induced by an external electric field. Polarization occurs when an electric field distorts the negative cloud of electrons around positive atomic nuclei in a direction opposite the field. This slight separation of charge makes one side of the atom somewhat positive and the opposite side somewhat negative. In some materials whose molecules are permanently polarized by chemical forces, such as water molecules, some of the polarization is caused by molecules rotating into the same alignment under the influence of the electric field. One of the measures of polarization is electric dipole moment, which equals the distance between the slightly shifted centres of positive and negative charge multiplied by the amount of one of the charges. Polarization P in its quantitative meaning is the amount of dipole moment p per unit volume V of a polarized material, P = p/V.

It might be argued that the Plossl has had its day. This would be true if you have deep pockets, because it can be roundly outlcassed by the modern exotics both on edge of field sharpness and on field of view. However, the premium TeleVue Plossls are good value and... good, full stop. Whether the Plossl should really have become the default basic EP is another matter, but they are OK as a breed.

Looking back the one that is often still refered to by design and not brand is the planetary, wonder if that was TMB's (person not company) idea. Make the planetary the "standard" eyepiece not the plossl. Certainly the focal length's available to them rivals the plossl's.

There are probably too many plossl's out there now that are poor. Like most things quality is a big factor, and our reluctance to pay is another. Good ones are TV's then something like Vixen and GSO, no doubt others but I simply do not know of them. When someone says why buy a plossl at $80 when you can buy our plossl at $35 people buy the $35 one. I will equally say not all the $80 are better, take the present BST Skyguiders - £47 from StL and the same eyepiece under other names can be £99.