Brief Review of Celestron ED80

After a week-long trip from Cal-if-orn-i-a, including a train
derailment, a relatively unscathed package arrived from OPT containing
a shiny new Celestron ED80. Having found very little information about
this new offering, my curiosity got the best of me and I decided to
take the plunge. Hopefully, I will be able to quench the general
thirst for information and squelch some confusion in the process.

Unpacking the OTA and accessories revealed a few surprises. First
of all, this thing is BEEFY! Looking at it, the dew shield and focuser
housing look like black plastic; however, they are in fact a thick
walled, sturdy metal, with what seems to be a very thick powder-coat
type covering. Starting at the business end, the dew shield extends a
hair over 3 inches in front of the lens cell, which is metal, but
unfortunately, non-collimatable. The Dew shield screws smoothly and
firmly onto the lens cell, which in turn is screwed onto the OTA body.
This configuration will allow easy access to the inside surface of the
rear lens element, should ocasional cleaning be needed. Also, the OTA
length listed in Celestron's literature is 22". I measured and found
it to be precisely 21 1/2": The dew shield can be unscrewed and a
cover for the lens cell rigged, resulting in an overall length of 19
1/2", not at all bad for travel. Shining a bright flashlight at a 45
degree angle, the lens almost seemed to disappear.... nice coatings.
Peering down the optical tube itself, I was very pleased with the
baffling and blackening of internals. The only "shiny" surfaces
revealed were a couple of @ 1/8" arcs along the circumference of the
focuser drawtube. The exterior of the tube itself has a smooth,
semi-gloss appearance. The focuser housing has the typical dovetail
mount and bracket for finder, as well as a lock-screw for supporting
heavy loads and photography. The knobs are very nice! Tapered aluminum
with rubber grip rings around the circumference. Included is a 2" -1
1/4" adapter, threaded for T-Rings. The adapter is NOT threaded to
accept 2" filters. Motion of the focuser, while smooth, is very stiff.
No lubricant coats the drawtube, but the threads of the pinion gear
are layered in the notorious "Syntaglue".

I was a bit apprehensive after discovering that the scope was
lacking any real adjustment for collimation, but sliding an Orion
lasermate into the drawtube placed a red dot square in the center of
the objective, a very good sign(and a big relief!). I have read in a
post elsewhere that the mount ring/dovetail plate (a one-piece design)
would not fit onto an lxd-55 mount, but I had no problem securing in
on my Skyview Pro EQ head. I headed out under steady but slightly hazy
skies to see what this this is capable of.

First target was the first quarter moon at 57x with a Pentax 10.5
XL. WOW! In-focus image revealed a sharply defined lunar limb without
a trace of C.A. and inky black shadows at the terminator. A trace of
lime green was visible just out of focus on one side, a difficult to
pin down reddish hue on the other side of focus, but in focus?
Wonderfully abberation free. Still, 57x is not exactly pushing the
envelope. In goes a 5mm University Ortho. More detail really starts to
kick in at 120X, and still, no color at all noted in focus..... I am
really digging it. Enter the Celestron Ultima barlow. Now we are
cruising at 240x, the max my eyepiece collection allows with 600mm to
work with. At 77x per inch, the image has not broken down, and I still
have a clean, color free lunar limb. Testing verdict on Luna? Passed
with flying (lack of ) colors!

I swing over to lyra, and center up D-D. Duplicity of the components
is suspected with the 10.5 pentax.... with the 5 mm ortho, both
components are cleanly split with black space in between. On the next
clear night I have a chance, I will grab a list of test doubles, and
see what the best split I can obtain is. So far, so good.

Lastly, I swung over to Polaris (I didn't have the drive running and
wanted a steady target). With the Ultima and 5mm back in for 240, I
carefully examined the diffraction rings in and out of focus, and the
airy disc in focus. The out of focus fresnel rings showed a very
clean, identical pattern on both sides. Not a hint of astigmatism was
noted. Unlike a nice triplet, from say, AP or TMB, the rings were not
white, but showed a green hue on one side of focus and a ruddy hue on
the other. The airy disc was a nice, tiny ball of light with the first
diffration ring noticable but the second only suspected.

I do not have access to an Orion ED-80 for direct comparison, but
based on rewiews I have read, The Celestron seems to be at least its
equal, if not better. Throw in the mount cradle, correct image
terrestrial prism, decent quality 25mm plossl, and finderscope, and at
a price point up to $90 less, the Celestron is quite simply an
unbelievable deal! I highly recommend anyone considering a small, high
quality scope to give this little jewel some thought. I have NEVER
been more satisfied with a new scope purchase.... Period.

Jason Martin
------------
NexStar 8i
Burgess Optical 1278 w/ Chromacorr
Orion ST-80
Coronado PST
Celestron ED80

Nice review.

What is the diameter of the tube?

It is already a little shorter than the ED80--if the tube is
significantly less than 4", overall it could be more compact, making
it the better buy if the QA is high.