Re: Anyone tried the Zoom EPs from eBay or Khanscope?

From: Jon Isaacs (jonisaacs_at_aol.com)
Date: 06/28/04 

Date: 28 Jun 2004 03:40:45 GMT

First: The specs on these eyepieces you have given as 7x-24x, that should be
7mm-24mm, the actual magnification being a function of the focal length of the
eyepiece and the telescope. (Mag=FLscope/FLeyepiece)

Now on with my reply:

 I have seen several vendors offering similar eyepieces for about $50 including
Orion and Apogee Inc. Orion sells (or used to sell) two zoom eyepieces, the
$50 explorer 2 zoom and the premium zoom costing around $200 which is Japanese
and essentially the same as the TV and Celestron units. These seem to be the
decent quality zooms.

I have never used one of the $50 Zooms but they do have a rather limited FOV,
the Ebay specs the FOV from 29 degees-40 degrees.

Assuming that the narrowest FOV occurs at the 21mm focal length, then with a
1000mm scope this eypiece will have maximum FOV of 0.604 degrees. In the same
scope, the $39 9mm Synta 66 degree Widefield would have a FOV of 0.594
degress, essentially the same.

Not gaining a great deal over that 66 degree eyepiece by zooming out at a
constant FOV..

jon

Jon

Relevant Pages

  • Re: Accessories Suggestion ?
    ... I think a decent zoom is a good investment - good for getting magnification /background darkness optimal, saves buying lots of eyepieces, and great fun on the moon. ... A lot of scopes will come with a finder, e.g. 6x30, which is pretty essential if you are non-GOTO. ... Any of these will be a big help in making sure that you are pointing at roughly the right area of sky before you start looking through the scope or finderscope. ...
    (uk.sci.astronomy)
  • how to plan an observation?
    ... some eyepieces and now i want to plan an observation but don't really know ... For example, the dubble cluster between ... casseopeia and perseus isn't vissible unless you zoom in. ...
    (sci.astro.amateur)
  • Re: Binoviewers and zoom eyepieces
    ... I've heard the power switch is the way to go.. ... get another one vice another zoom. ... reduce the need to have a whole box of duplicate eyepieces. ... >> binoviewers I can see that one is in my future. ...
    (sci.astro.amateur)
  • Re: Leupold spotting scope?
    ... view at the same maginfication. ... Do you like to zoom better? ... I'm going to guess, though, that the Swarovski eyepieces, zoom and fixed, ... by, say, Vortex or Audubon, may show more striking differences. ...
    (rec.birds)
  • Re: 9.25 lives up to its Rep
    ... at just over perhaps 1 degree FOV. ... The focal reducer allows this to be reached with shorter focal length eyepieces, but does not make the SCT into a 'widefield' instrument. ... The 24mm Panoptic for example, at F6.3 corrected for field curvature, provides a larger flatter field of view than the 35mm Panoptic sans corrector. ...
    (sci.astro.amateur)
Quantcast