EP question: can a wider FOV affect mag?

[furio]

Hi guys,

Just wondering while slowly starting to look at futures EPs, can a wider FOV affect the magnification?

What I mean is, for two different 10 mm EP, one with a FOV of 45^o and the second with something like 67^o, will the narrow one provide more effective magnification?

If not, what's the goal to go with narrow views?

This all started when I took a serious look at TAL EPs, the Super Plossls ones that are inexpensives but supposed to deliver really sharp images, even when compared to much pricier EPs. They have a theorical narrow FOV of 45, though in review they were effectively sized at 52.

http://www.talteleoptics.com/eyepieces.html

Thanks!

[emadmoussa]

A decent wide field EP will be as sharp on high mag, but will give you more room as well.

[Stephen]

No, a wider FOV will not change the magnification. That is determined by the EP and scope focal lengths alone

As FOV goes up, cost goes up (typically.)

The "goal" as you put it is not what do you gain from using narrower FOV EP's, it's what do you gain from using wider FOV EP's ... to which the simple answer is more sky in the eyepiece

[Naemeth]

As others' have said, a wider AFOV will not affect magnification, however a smaller FOV may increase apparent magnification. For example, Jupiter will look bigger in the FOV (relative to the size of the FOV that is) in a 20 degree eyepiece that gives 200x than a 100 degree eyepiece that gives 200x.

HTH .

[emadmoussa]

Yes, like Jonathan says, there's the illusion that Jupiter looks bigger for instance in a Plossl rather than a wide FOV EP.

[AlexB67]

The other thing that may occur to lesser or greater degree  is that there can be angular magnification distortion where mag is not constant across the FOV. In a wide FOV there is more  room/scope for that to happen, depending how much you pay and the design.

For a short ramble on the topic and its implications see here.

http://www.televue.com/engine/TV3b_page.asp?return=Advice&id=113#.UvJCRGfiuUk

In the end  with most things in life, there are some compromises to be had and can't get the best of everything in every area, though you can get closer and closer if you are prepared to split you wallet in half :0)