- Price: $479 (USD)
- Type: Newtonian Reflector
- Mount: Dobsonian
- Aperture: 203mm (8”),
f-ratio: 5.9, focal length: 1200mm
- Weight: 42 lbs. (Base 23 lbs.
Tube 19 lbs.)
- Included: Collimation cap, eyepiece
rack, 6x30 finder scope, 10mm Plossel eyepiece, 25mm Plossel eyepiece, 'Where
the Stars Are' astronomy software on CD-ROM
- Dealer: Starizona in Tucson,
Being a relative newcomer to astronomy,
I decided to begin my foray into this new hobby slowly. I started my viewing
with a pair of 7x35 binoculars. I was amazed by what I was able to see with
them. Of course, this instilled the desire to obtain a telescope.
Having a modest budget for this
new hobby, I decided that the best course of action would be to conduct intensive
research before making a purchase decision. Over the next few months, while
continuing to gaze through the binoculars, I embarked on an information seeking
campaign. I read such books as: 'Turn Left at Orion', 'NightWatch', 'The Practical
Astronomer' and 'StarWare'. I read Sky & Telescope and Astronomy magazines.
I scoured the internet. I joined a local astronomy club.
Most of what I read recommended
that I define what I wanted to view prior to making any decisions on equipment.
I knew I wanted to view the planets. I also knew that deep sky objects held
special appeal. Astrophotography also interests me, but that will have to wait
- a visual experience is the immediate desire. I knew that modest aperture would
be necessary. After a long, detailed, exhaustive investigation I decided on
the Orion SkyQuest XT8 Dobsonian. What follows is my review of this telescope.
While I could have purchased this
telescope directly from Orion, I chose to support a local dealer. Orion is highly
regarded in the industry for outstanding customer service, but I like the idea
of working with a local dealer. I chose Starizona in Tucson - about 100 miles
from home. While there is a closer Orion dealer, the price from Starizona was
better (identical to purchasing directly from Orion)
I called Dean at Starizona to see
if they had an XT8 in stock, and by the time I arrived he had it fully assembled
and collimated. I also purchased a Celestron Ultima Barlow and a Telrad (which
Dean also installed). Dean also helped me with a slight mechanical problem with
my Jeep - but that's a story for another time! Gotta love dealer support!
My normal observing location is
my backyard; a slightly light-polluted suburban place southeast of Phoenix.
The skies to the south and southeast are usually dark.
The telescope is easy to operate:
movements in altitude and azimuth are smooth (azimuth movements are slightly
stiff near zenith). With Orion's Correct-Tension (springs) on the altitude bearings,
the scope always stays where it is pointed. I have experienced no problems with
unwanted movements, even with the finder scope, Telrad, and a Barlowed eyepiece
in place. Moving the scope to the observing location is relatively easy, given
that a large handle is mounted on the back of the rocker box. However, the placement
of the handle is below the center of gravity. The tube wants to swing upwards
when you try to pick it up. I solved this problem by positioning a web belt
around the base and tube while it is 'in transit'. I have also installed a retrofit
for smoother azimuth movements. This modification consists of the addition of
six 'milk jug washers' on the central bolt between the upper and lower baseplates.
This fix was outlined in Sky & Telescope magazine. The washers provide a
slight amount of lift to the rocker box, alleviating some pressure on the Teflon
pads. I also loosened the tension on the central nut, and keep a 9/16"
wrench in my accessory case for in-field adjustments.
The tube is constructed of rolled
metal with a black enamel finish. It is painted flat black on the inside. The
end caps are cast aluminum, making for a very nice looking product. The tube
has what Orion calls a navigation knob at the top. It is quite convenient for
positioning the scope, especially when tracking a planet. The dust cap (included)
fits snugly atop the tube. A shower cap keeps dust (and spiders) out as well.
The rocker box is constructed from
black melamine over particle board. It is quite sturdy, even if it is hard to
see in the dark. An eyepiece rack is mounted to the side of the rocker box,
which will hold four eyepieces (three 1.25" and one 2").
The primary mirror is mounted on
an aluminum cell that allows for some movement of air. It is usually acclimated
after a hour of cool-down time. Of course, this is wintertime in the desert.
The primary is factory center-spotted and has three spring-loaded thumbscrews
to facilitate collimation.
The secondary mirror uses a four-vane
spider assembly. The vanes are quite thin so as to introduce a minimum of obstruction
while providing firm support.
The cast aluminum focuser is a rack-and-pinion
design. It is 2" with an included adapter for 1.25" eyepieces. In
fact, all of my eyepieces are 1.25". Someday I would like to get a low-power
2" eyepiece. The focuser movements were somewhat smooth, however the grease
that Synta uses is quite sticky. I cleaned all of the grease off of the rack
and pinion gear and replaced it with a silicon grease obtained from a SCUBA
shop. Now racking the focuser in and out is very smooth. The focuser has two
very small setscrews to adjust the position of the draw tube, relative to the
assembly. Practically all play can be eliminated with minor adjustments. The
focuser also has a thumbscrew to lock the position. The standard-issue focuser
knobs are small, black plastic. A big improvement in focusing action and feel
is achieved with the addition of aluminum knobs from focusknobs.com.
This telescope is quite easy to
collimate using the tool available from Orion. While collimation hasn't yet
been necessary - even after the drive back from Tucson on the back seat in my
Cherokee (seat-belted, of course) - I had to try it anyway. I read the instructions
that accompanied the collimation eyepiece and checked collimation. Everything
looked good. So, I purposely misadjusted things and quickly brought everything
back into proper alignment. The star test appears as it does in the online and
magazine descriptions, concentric and identical on both sides of focus.
The views provided by this telescope
have been incredible. I have looked through other scopes, and it is my opinion
that the XT8 has good optics. While I don't have years of observing experience,
I can honestly say that my expectations have been exceeded. My eyepiece collection
includes 7mm, 10mm, 15mm, 25mm, and a 32mm (all Plossls except the 7mm orthoscopic).
The details available of the moon, Saturn and Jupiter are only exceeded by the
deep sky objects I have located. I am really looking forward to taking the scope
to a dark sky site… which I am planning to do in a couple of weeks!
All in all I am quite pleased with
this telescope. It is well designed and nicely balanced. It delivers good optical
performance. It is quite easy to move, considering its size. On a scale of one
to ten, I would rate this scope a ten. It represents an outstanding value and
an excellent first telescope.