Last December, when I
was lusting for a serious telescope, I really wanted the RCX, but that was
too much money. The Domestic Authority would never approve. The LX200R was
nice, but a thousand more than the GPS - On Clearance.
The LX200GPS came home
A couple weeks ago, an
LX200R OTA came up for grabs and I was the lucky guy. I thought why not swap
out the tubes? Can't be that hard.
So, here is how I did
If, you decide to follow
in my footsteps and you make a mess of eveything, well, Good Luck!
A Word To The Wise
If, you do not know your
way around tools and/or just taking things apart, think twice before you rip
into this project.
What To Expect
Our goal is to remove
the exisiting OTA and replace it with the new one.
In order to accomplish
this, I decided to completely remove the left fork arm. That one being easier
than the right. The wiring inside must be carefully gotten out of the way.
A special duty nut must be removed from the shaft. We must use tape and mark
the arm/base so we can orient the pieces correctly again. We must physically
position the unit in such a way when things start coming apart, we do not
dent/mutilate the tube itself.
Here We Go
The LX200GPS still in
one piece. The "R" OTA ready to go.
Here are the three spots
we really want to get at. As you borrow deeper into this project, and you
see the actual size of these three screws, be mindful of all the weight you
hang on your scope and these three, little, screws must support it all.
Here, we take the screws
from the bottom panel under the left fork arm, and thread them into the holes
in the plate. Snuggle them up against the two mounting screws. This is done
so later, we can return the new OTA to the same spot as the old one. These
base castings are CNC machined, so I would wager, these things are pretty
much the same, tube to tube.
After we snug the four
screws up, two per plate ...
We back each off one half
turn. That is so we do not mess up any threads when we remove the screws in
the side plate. We will turn them a half turn back in again later.
We carefully, and I mean
carefully, remove the white plug from the receptacle. Be --very-- careful
with these connectors. the wires pop loose really easy.
Here, the wires are threaded
down the left fork arm.
And thru to the base of
We --carefully-- thread
the connector and wires thru the left arm, down thru the elbow and into the
center casting that holds both forkarms in place. We need to get this wiring
out of the way so we do not damage it.
The leveling gizmo and
circuit board. We need to remove this.
We need to remove this
special purpose "nut" on the shaft.
I inserted two drill bits
that fit pretty snug. (A Poor Mans's way of doing this.)
A good sized Crescent
wrench and it popped right loose. Off it comes.
Now, we need to disconnect
the black connector.
And we carefully, with
our finners, lift this plate and assembly off the shaft.
Here it is and we set
it out of harm's way.
I laid the tube and base
on its side for easier access. Note, I taped the wires out of the way.
Peterson Grips sure come
in handy. Pete did not agree that I needed both sides, but, I knew they would
come in handy.
Note carefully. I placed
two strips of tape - one on the fork arm -the other on the base. But, I made
a Big Mistake. Both pieces are on the fork arm. Make certain your tape is
one on the base, one on the arm. Also note the little Tick Marks I placed
on the tape. Both sides, and the top.
After you place the tape
in the right spot, take a MarksAlot and mark it up with lines so when it goes
back together, you can re-align everything alot better than I did.
The tube is propped up
Now that is done, we pay
attention to these four screws.
We start cracking the
four bolts loose for the left arm.
Place a piece of tape
on this hole. Prevents washers from rolling where they do not belong.
Here, the left arm is
removed. And we proceed to take off the plate on the topside of the tube.
Plate is gone and we are
now at where we need to be. At those three holes.
Here is the side plate
just removed. Note, those three tiny screws. I marvel they do their job with
OTA's clobbered full of stuff.
Note, there is a washer
that goes on this shaft, and stuck to the bearing on the inside of the fork
arm. A photo later on shows it. Do not lose this little guy. You will be sorry.
Now, we need some assistance
so when we crack the tube completely loose, the base and remaining arm do
not tumble to the floor.
And, we remove the three
screws from the right side plate working between the tube and the countertop..
When the last screw is loose, be very careful as, the OTA can go where it
There it is. Pay Dirt!
We will now carefully
place the new OTA on top of where the old one was, and thread the two socket
head bolts in place. All the while, between the tube and the countertop. Do
not tighten the screws, just snug them up.
Then we fasten the top
side plate on. We snug up the two cap screws, and tighten the screws that
half turn from so long ago.
This is where the two
cap screws should snuggle up to.
Things should be snug,
yet allow us to slide the plate with our finners. We push it towards the front
of the OTA.
Tighten this screw first
and then the other two.
We will get the bolts
on the right hand side plate in a bit.
Oh. Here is that washer
on the back side of the left arm ...
And we place it on the
shaft so we know we got it in the right spot.
As I fouled up and taped
the wrong area, we need to kinda get the fork arm back to the same spot it
came off from.
Sometimes, when two parts
are really bolted together tightly and the surfaces are painted, the paint
will have a different sheen. Here, the light reflected off the paint and this
marks where the fork arm was bolted tight.
My goal is to get it back
to that spot again (some how?).
Before I placed the fork
arm on the base casting, I placed tape on each side to indicate the bottom
edge of those shiny marks on the paint. we need to line up the spot on the
fork arm that made these shiny spot.
Here we are, adjusting
things to line them up.
Note, the fork arm has
slotted holes for the four cap screws. And that range should be at least an
eighth of an inch. But, I found, I could barely move it back and forth less
than a 1/16". The above image shows the arm pulled left.
This one shows the arm
shoved right. Note, there is barely any travel in the slots.
This leads me to believe,
the orthagahexanalinity will be close enough. As, there just is not that much
adjustment to be had.
And, it still is a "Kinda
Gets There" scope so all will be fine.
And we wrench the four
bolts down tight.
Now that the left arm
is on and the scope needs a break, I do too. Aaah, Janice Joplin's favorite
Time to get The Beast vertical again.
Here is the right side
and we tighten these two screws one half turn as well.
One half turn for both.
Just as on the left side,
by tilting the tube more vertical, the weight of the tube will force things
down and we can snug up this screw.
Tip it a bit further and
snug up the other screws and then, in position like this, we can thread in
the third one and tighten it up as well.
The remainder is simply
putting everything back together in some reasonable fashion and sequence as
we took things apart. I will not bore you with those details.
About 1:00am, I got outside
with The Beast, set it up, and to my surprise, the collimation was pretty
good. The OTA came with the Meade screws and I replaced them with Bob's Knobs.
But, later, I did do a fairly patient collimation.
The Bottom Line
Well, was the effort worth
all the aggrevation and fuss? And expense?
Altho the skies were really
good, I have looked thru the GPS long enough to kinda know what I have been
The R -does- show me more
faint stars. You can see them "pop'' when you approach focus. After I
sell the GPS OTAand balance the books, I should be about $2-400 for this upgrade.
And, the R really comes
thru on the advertising. In my 41mm Panoptic, the stars are tack sharp right
to the edge of the eyepiece. And all my other TeleVues as well.
Let us all remember to
enjoy our toys and, the beauty above and within, each of us ...
Big Dog's Asylum
LX200KGT 12" KindaGetsThere