Why This Page?
The C5, C5+, G5, and NexStar-5/5i, from Celestron, are different mounting
configurations for the same 5” (127-mm) diameter, f/10, Schmidt-Cassegrain
telescope!Whether advertised as a
spotting scope/telephoto lens, portable observatory, or computerized "Go
To" telescope, the optical specifications and general tube mechanics are the same.The convenient size of the telescope makes it a great pick for a variety
of observing needs: from casual observing, to piggy-back photography, to
yielding excellent image-size in prime-focus photos of the Sun and Moon. This highly portable telescope has been used on Space
Shuttle missions and recently did "real" science by imaging Leonid
meteor impacts on the Moon!
Answers to Your Questions
The goal of this
site is to gather information, to increase the usability of the 5” series of
Celestron telescopes.Several main sections here serve to make this information conveniently accessible:
Highlights column to the right contains up-to-the-minute news and information for
Celestron 5" SCT enthusiasts.
Quick Specs section has notes on the optical setup of the
Celestron 5" SCT.
Links are your gateway to reviews and technical material.
new techniques by examining Images
taken through the 5" SCT series.
other great sites
dedicated to the your favorite small SCT.
If you have question or comments, visit
registration required!) Message Board.This is the meeting ground for user-to-user discussions.Post messages with your tips, experiences, and read what others are saying.Ask for advice.
me links to or attachments of images, taken through or guided by your
5" Celestron. Non-astronomy photos welcome -- after all -- these
instruments are 1250-mm telephoto lenses! Include exposure, and manipulation
data so that we can all learn.
an interesting Celestron 5" SCT setup? I'll feature it in the Celestron 5" SCTs Around the
World section of this page.
Mods? Send links or instructions with any illustrations to the e-mail
For formulas: "D" = lens diameter in mm; "L" is wavelength in mm -- 0.00055-mm for green light.
(1) Nexstar5 specs on Celestron.com. Same value derived from Sky & Telescope C5 test Oct. 1993.
(2) My test results for C5+ with included 25-mm eyepiece. For SCTs, focal
length changes with focus!
(3) Using formula: ( 4.5 + 4.4 * Log (D)). North, Gerald. S.,
'Better formula for telescopic limiting magnitudes?', The Journal of the
British Astronomical Association, Volume 107, No.2 (April, 1997), p.82
(4) Using formula: ( 206000*L/D) for arc-seconds.