Orion XT-12 Intelliscope;
In January 2005 we moved from Bristol, TN to Bay Saint Louis, MS. We
were living in an apartment almost on the beach and were building a house in the
neighboring town of Waveland, MS, one block off the beach. Most of our
possessions were stored in Pass Christian, MS. On 29 August 2005,
Hurricane Katrina destroyed all three towns -- Waveland, Bay Saint Louis, and
Pass Christian. We lost almost everything we owned.
Read about our
Katrina experiences here.
My two telescopes were lost in the hurricane. Afterward, we moved to
Knoxville, TN and after we received our insurance settlement, I purchased an
Orion XT-12 Dobsonian reflector telescope to replace the two lost in the
hurricane. This article describes the XT-12 -- it's a BIG scope and I am
very pleased with it.
The XT-12 is a big telescope -- the mirror is 12 inches in diameter and,
fully assembled, the scope and its mount are 6 feet tall -- I am 6'-1" and the
end of the scope tube is at the top of my head. Scope and base weigh 85
pounds -- the Optical Tube Assembly weighs 51 pounds and the base is 34 pounds.
Optical Tube Assembly -- OTA -- is the long tube that holds the mirror,
focuser, finder scope, and other optical parts -- I will use the term "OTA" to
refer to the OTA and I will use the term "scope" to refer to the OTA and base
assembled into a telescope.
Why such a big scope? The larger the scope, the more light it gathers
and the deeper into the sky you can see. The size of a scope refers to the
diameter of the opening through which the scope observes the universe -- the
XT-12 has a 12-inch mirror and its opening is 12 inches, thus, this scope has a
12-inch aperture. Some general rules in amateur astronomy are "aperture
rules" and "you can never have too much aperture." For amateur
astronomers, an 8-inch scope like my XT-8 (destroyed in
Hurricane Katrina) is an excellent scope -- I just wanted more aperture so I
replaced the lost 8-inch with this 12-incher.
Click on this link to go to the Orion Telescopes and Binoculars website
to see more about the XT-12.
This is an XT-12 Intelliscope, meaning that the scope has encoder wheels built into its base that move as the scope moves. These wheels generate
electronic data that is fed to a handheld computer (the Intelliscope
controller); the computer translates that data into positioning information so
the computer knows where the scope is pointed. The computer then refers to
its built-in database of astronomical objects -- stars, planets, nebulae, etc..
If you want to find a certain object, you first align the scope then find the
object in the controller -- the controller then displays arrows telling you to
move the scope right, left, up, down until you get to the object. There
are much more detailed instructions accompanying the scope and on the Orion
website. On 23 December I used the Intelliscope controller for a few
minutes -- I was quite pleased with the way the controller works -- here is an
article describing the Intelliscope controller.
Meanwhile, let's look at the XT-12. I have divided this section into
two pages because of the number of graphics.
If you are interested in the Intelliscope handheld computerized
controller, go to this link.
UPDATE: On 28 January
2006, I took some new photos of the XT-12 that showed modifications I made to
the scope and to the two-wheel handcart that I use to transport the scope.
Click on this link to see the updated photos
Here's what the XT-12 looks like, fully assembled. I use the handcart to
move the scope -- it weighs 85 pounds and is a real load. You can pull off
the OTA (51 pounds) and move the OTA and the base (34 pounds) separately -- the
scope comes apart and goes back together with no difficulty -- takes a few
seconds to disassemble/reassemble. Check
this page for modifications to the handcart.
The OTA is the long, grey-brown metal cylinder -- the mirror is in the
bottom, finder scope and focuser are at the top. The black part is the
base on which the OTA rides -- the base swivels around in a circle, the OTA
pivots on the base for altitude. Note at the top of the base are two white
strips -- these are labels that I put on the tensioning knob -- there are two
knobs, one tension knob, one retaining knob and they are different -- I labeled
each knob and its position to keep me straight.
This is how the scope arrived -- three boxes from FedEx; arrived four days
after I ordered it. I had opened the boxes before this photo was taken.
The OTA and small parts are in the tall box; base is unassembled in the flat box
standing up on left; mirror is in the box in the bottom center. (White
buckets are our recycle buckets -- glass, plastic, aluminum.)
Here's the inside of the OTA box. Small parts are packed in the box
that's wrapped in bubble wrap to the left of the OTA; assembly and use
instruction sheet is on the right of the OTA -- the instructions are EXCELLENT,
detailed, illustrated, very easy to follow.
When you are assembling this scope, do
not let your kids, dogs, cats, ferrets, in-laws, nieces and nephews, or anyone
else come into the room with you -- lock the door -- you don't need the
distraction, you don't need cat footprints on the mirror, and you can do this by
yourself easily. Took me one hour to assemble my scope.
The mirror is packed separately. The OTA has steel
reinforcing rings installed on each end. To install the mirror, you must
remove the steel ring from the bottom of the tube, attach the ring to the
mirror, and re-attach the ring and mirror assembly to the OTA. It takes
longer to describe how to do this than it takes to do it.
Photo of mirror in box.
|Photo of mirror removed from box.
CAREFUL!!! The mirror is a big chunk of glass and it will
tolerate some rough handling -- but -- DON'T HANDLE IT ROUGHLY. Handle the
mirror with a firm grip -- it's heavy and if you don't grasp it tightly and
securely, you can drop it -- and you don't want to drop it. Also -- DO NOT
EVEN THINK ABOUT TOUCHING THE SHINY SIDE OF THE MIRROR -- it has been coated
with highly reflective material. Don't try to clean it, don't try to flick
dust off it -- DO NOT EVEN THINK ABOUT TOUCHING THE SHINY SIDE OF THE MIRROR.
In the left-hand photo above you are looking down into the
mirror packing carton. The mirror is packed SHINY SIDE DOWN.
The right-hand photo above shows the mirror unpacked,
looking at the shiny side. The white spot in the center of the mirror
is the factory-installed center mark -- you need this for collimation.
In the top right corner of the right-hand photo you see the
steel ring removed from the OTA that is to be installed on the mirror.
This ring goes ON THE BACK OF THE MIRROR. I turned the mirror
shiny-side up just so I could photograph it. The mirror is sitting on
a piece of foam packing material -- mirror is wrapped in clear plastic (like
Saran Wrap) -- lay the plastic wrap on top of the shiny side, turn the
mirror over so the shiny side is on the white foam, and follow the
instructions for attaching the steel ring to the mirror cell.
This photo shows the mirror cell attached to the steel ring and
the steel ring re-installed onto the bottom end of the OTA -- turn the OTA
upside-down with the top (open) end on the floor for this operation. The
big silver knobs are used to collimate the scope -- next to each big chrome
adjustment knob is a smaller locking knob.
NOTE: The scope must be
collimated before you use it. Here is an article that describes
how I collimated my 8-inch scope -- the process is
exactly the same. Collimation requires that you adjust the secondary
mirror THEN the primary -- I found that the secondary mirror was in perfect
adjustment from the factory -- the instructions say you should not need to
adjust the secondary and I did not need to -- I adjusted only the primary mirror
and collimation was perfect.
Click on the link below to go to XT-12 Page Two.