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| Here are some photos
of my "Observatory" in action. The primary telescope is the
Meade 8" LX 200 SCT. I also have an Orion MAK 500 mounted piggy back
on the LX 200 to serve as a "super" finder for imagining at large focal
ratios. I've also imaged through the MAK 500 from time to time when
I want a larger field of view than I can achieve with the LX 200.
Although, I haven't tried a direct comparison, I suspect that the images
I've obtained with the MAK 500 are similar to what you could obtain with
one of the 90 mm GOTO scopes.
I live in a 4-level town house about 20 miles west of Washington DC, USA and usually operate the scope from my second level deck. The light pollution varies from moderate to severe, but I have reasonably good skies as long as the object is 20-30 degrees above the local horizon. I have mounted the Meade Equatorial wedge permanently to my deck and carry the 8" in and out for imaging sessions. The cables run through a nearby window. Total cable length is only about 20 feet. My most significant imaging problems are the fact that the deck is elevated and not vibration proof and that neighboring townhouses often produce strong sources of light that enter the scope unexpectedly. During the winter, the heat from the neighboring townhouses also impedes seeing and reduce the clarity of my planetary images taken at high focal ratios. I've also included some additional pages that show construction detail for the equatorial mount and how I attach the Starlight Express CCD. |
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This
GEOS image shows my location in the Northern Virginia area.
I chose this particular image, because of all of the clouds I've experienced during the spring of 2000. |
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This
photo shows the "Observatory" with the dome closed. What you
are seeing is the equatorial wedge covered with a grill cover and bolted
to its permanent mount.
You
can see the neighboring townhouses in the background and the wife's hanging
plants which occasionally find their way between the scope and what I want
to image.
The
cable tie downs were installed to stiffen the mount and reduce vibrations.
They did help, but I replaced them with 2x4 braces. Click
Here for photos showing more construction details of the mount on the
Home Built Page.
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Here
I am mounting the scope to the wedge. I just carry the scope out
and set it on the wedge. One of the mounting holes is slotted, so
the scope just slides into place.
The single bolt hold the scope in place and you can move it slightly to align the remaining two mounting holes. You then insert two addition bolts to finalize the scope position and firmly hold it in place. You need to be careful when inserting these two bolts. The scope base is made from cast aluminum and the bolts are steel. It is very easy to cross thread the two bolts. The basic rule is "DON'T FORCE THE BOLTS!" |
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After
the scope is mounted to the wedge, position it in the "zero-zero" position
as shown. Zero-zero means zero degrees declination and zero degrees
hour angle.
When the LX 200 powers up, the software assumes the scope is in this position. If you are careful when setting the zero-zero position, if the scope clock is set correctly and if the wedge is aligned, the scope GOTO can find a star, at least in the finder, when you power up without any additional alignment. My power up errors are usually about one degree. |
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This
photo was taken about one year later than the dome closed picture.
It shows some additional modifications to the mount. I replaced the
cable tie downs with 2x4 braces and then moved the cables up to help stop
some minor side to side movement.
These additions helped stiffen the mount considerably, but I still have some flexure in the leveling platform. Fortunately the STAR 2000 is more than up to the task of correcting any remaining alignment errors. The primary affect on the flexure now is to make the GOTO's less accurate. I get around this problem by going first to a bright star near the object I want to image. I can then realign the scope on this star using the finder before going to the deep sky object. |
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This
photo shows the 8" LX 200 mounted on the wedge and ready for work.
The Orion MAK 500 is mounted in the home made holder constructed of oak
hard wood and a PVC pipe fitting.
The MX-5C is attached to a 2X Barlow which is installed in the JMI NGF-S 1-1/4" eyepiece adapter. This makes for a very long optical train and you need to be careful not to hit the CCD on the mount at high declinations. You can also clearly see the Kendrick dew heaters installed on the LX 200, Orion MAK 500 and the Orion eyepiece. The Orion MAK 500 is mounted to
my home made mount made from oak hardwood and a PVC pipe fitting.
Click
Here for photos showing
construction details for the Orion MAK Mount on the Home Built Page.
Click Here for photos showing how the MX-5C and JMI NGF-S work together. Click Here for a front view of the scope. |
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This
photo shows the "Data Link" which is just the cables running inside
though the window. I also have an home Ethernet, which allows
me to access files on the PC and get to the internet via my Linux based
server. I use the internet interface to check for approaching
clouds and to check the STScI
Digitized Sky Survey images.
The
large cable is actually three separate cables tied together with nylon
ties plus the 12 VDC power for the Kendrick dew heaters. The largest
is the interface for the MX-5C. Also in the bundle is the serial
interface to the LX 200 RS 232 port and a simple two wire connection to
the JMI NGF-S moto focus. The STAR 2000 box just lays on the deck
floor. So far I've managed not to step on it.
I
also just use a 25 foot coiled telephone handset cable to attach the Meade
keypad to the LX 200.
With
these connections I can perform all necessary functions from inside the
house setting at the computer desk. This includes: (1)
Moving the scope using either the keypad or STAR 2000 computer interface.
(2) Focus from computer desk. and (3) Take images with
the MX-5C.
The
open window gives me a clear view of the scope so I can make sure things
are going well before a large slew. It's also nice to make sure the
scope isn't pointing at the side of the house before I start to take an
image.
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Here
is the telescope control center about ready to go into operation.
It's a small drop down desk with the Sony VAIO connected to the MX-5C and
LX 200.
I
typically control the LX 200 with the Megastar software package, which
interfaces to the LX 200 through the serial port.
A nice feature of this arrangement
is that I can watch the scope through the window to make certain the CCD
camera is not about to hit the mount and that the scope is in fact pointing
to where I think it is supposed to be pointing.The MX-5C interfaces with the computer
through the Parallel port.
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I
use the key pad to position the object I want to image in the field of
view. To do this I take a trial image and then note which way
I need to move the object.
With the keypad in the guide mode,
I just press the direction buttons for the appropriate number of seconds
to move the object.
After
a little practice you get pretty good at judging how many seconds to slew
the scope and move the object to where you want it.
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The
good thing about this operation, is that the fireplace is directly behind
me for nights when it cold, and I can see the scope from the window.
This lets me make sure the CCD won't
hit the fork and that the object isn't moving behind the townhouse or hanging
plant.
Occasionally,
I have to venture outside to re-sync the scope with the sky, if the pointing
error causes the object to miss the CCD.
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Of
course, this is the best part. The scope is at work collecting photons
for the CCD.
After getting the object positioned on the CCD where I want it, I normally take a 2 min trial exposure. This lets me make certain that the STAR 2000 will guide the scope correctly. Once that trial exposure is a success, I'll go for either 5, 10 or 20 minute exposures. I normally process them "on the fly" to help judge when I have enough exposure time. I use a second computer for this "on the fly" processing. This is easily accomplished because I have the Ethernet local area network in my townhouse. |
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