I'll bet this is what you thought the whole point of Frosty Drew
Observatory training was about: "How can I make the telescope
run? Hopefully we have disabused you of this before we finally
got around to this section. Actually, running the telescope is fairly
simple unless something breaks. If something breaks, then the technical
staff get to do their stuff. Unless you have managed to become one of
these techophyllic cognoscenti elsewhere and have convinced us that you
really know what you are doing, you won't have to worry about fixing the
LX200 16". All you need to remember is:
If something really horrible is happening
This compendium of wisdom, foresight might better be called fools rush in where angels fear to tread. It is a mixture of hands on experience (some of it quite terrifying), careful readings of the Meade Manuals, help from MAPUG ( Meade Advanced Products User Group ) and various dubious Internet sources. If you think that your all knowing instructor can't be wrong, then you are the biggest darn fool I've ever met. If something doesn't seem to make sense, don't be polite, stop the discussion then and there until we can jointly figure out what really should be done. I'd rather be embarrassed by being told what I said doesn't work than trying it and hearing nasty crunching noises from inside the telescope.
First of all, I'll assume that you have at least looked at our telescope. It is an alt-azimuth mounted Meade LX200 16" Schmidt Cassegrain telescope with many many bells and whistles. Before I am overwhelmed with criticisms about how could we be so foolish as to buy an alt-azimuth mounted scope when any dern fool knows that an equatorial mount is better for photography, I'll simply point out that we are oriented towards viewing. Alt-azimuth mounts minimize eyepiece meander. We compensate for photography by using a de-rotator. Alt-azimuth mounts are all but required in a center pedestal dome unless you want a German mount with a blankety blank big counterweight to swing around in the dark.
This telescope is fully automated. One crucial point is that we can't move the new telescope by hand. While the brakes are engaged* as they always are, moving the scope by hand even the smallest amount will destroy the drive gears and motors. This is a major expense and results in much down time. Movest Thou not thy telescope by thine own hand lest thee be smitten by rod and staff.
I don't expect any of you to remember all of this right now. Just remember that words in this underlined green color have a special meaning in this document when they are applied to the paddle [hand controller]. You can check the meaning b clicking on the word. Some hand paddle operations are so intuitive that they don't have a special word. For example things that require a number are simply the number. So in response to a question if you desire a one or two star alignment you would type 1 or 2.
Always keep in mind:
For now, we'll assume that someone else has
completed the initialization sequences.
In essence, when you turn on the power, this computer waits a moment (its doing some diagnostic checks and figuring out where the planets are) before becoming active. At this time you must complete the FIND HOME sequence before you continue or the telescope will become hopelessly confused and loose its three dimensional orientation. We'll discuss this in more detail in the section called Alignment and Homing the Telescope.
This brings us to the motion controls on the paddle [Keypad Hand Controller]. Lets take a look at a few of its simpler controls. Lets consider the simplest thing we can do - moving the telescope using the paddle. All we need are the buttons labeled [(4) - the direction keys] and [(6) - the speed keys] in the diagram.
The direction keys are labeled [N], [S], [E] and [W].
"Elementary my dear Watson", you proclaim instantly deducing that these
must refer to the cardinal points of the compass. Well they
don't! They would be much better labeled 
or 
Even Hansel, Gretel, Ted and
Alice would make almost as much sense. It is quite possible to
push [N] and have the image in the eyepiece move in an eight
o'clock direction. They are just four orthogonal [that means right
angled- I'm being a show off again] directions in the eyepiece.
The speed keys are labeled [Slew], [Find], [Cntr(center)], and [Guide]. I would have labeled them Fast, Moderate, Slow and Creep. The adjacent small red LED lets you know which speed is active*. Use [Slew] to move the telescope from one area of the sky to a distant area. [Slew] moves at 4° per second which is quite fast. It will move from any object to any other object in no more than 45 seconds, usually a lot less. Use [Find] to generally align the telescope at an object. [Find] moves at 1° per second. Use [Cntr] to find the object in the finder scope. [Cntr] does not move anything towards any type of center. [Cntr] moves at 16 times the sidereal rate. Use [Guide] to exactly inch an object to the center of higher powered eyepieces. [Guide] moves at twice the sidereal rate. Remember make all telescope movements with the hand paddle.
Look at the diagram again. The keys labeled [(10) - Object Keys] are what we want to discuss along with [(1) - Enter] and [(3) - GOTO]. The Meade Corporation slipped up. These keys almost make sense! The object keys specify the thing you want to view. These keys are [M] (Messier), [Star] and [CNGC] (Computerized New General Catalog). Heck, this is taking all the fun out of it.
To find the M31, the Great Galaxy in Andromeda, all I have to do is push the [M] key, the 3 key and the 1 key and the [Enter key in that order. If I want to find the galaxy labeled 7556 in the NGC I simply type [GNGC] 7 5 5 6 [Enter]. This is too easy! Boring! Boo! Hiss!
For common stars you can find them by name. Simply press [Star] [Enter and you will be presented a list of common names for bright stars. Scroll down until you find the correct star and press [Enter] again. The paddle will contain information about Albireo. You can then send the telescope to Albireo by pressing [Goto].
However if the star does not appear in the list, you must look up its number in a catalog at the back of the Meade book. Meade finally made something hard to understand. The [Star] key suddenly is really onscure. Oh joy! Oh rapture! Oh flights of pure passion! Here is a real chance to learn something dark and mysterious! How do I find Albireo, my favorite double star numerically? The Meade Catalog isn't easy to find things. You must known the star's Right Ascension and Declination, before they will give me its code number. This is almost too hard, but I love it! After much rummaging around I discover that the code for Albireo is 223. All I have to do is type [Star] 223 [Enter] [Goto] and away we go to my favorite double star.
Not only is Albireo star number 223, but it is also star number 339 (in the list of ADS double stars). Some stars are listed twice because they are in the ADS list of multiple stars. The full Meade catalog has just under 16000 stars including everything down to the 7th magnitude. Just when I was sure that Meade had out done itself in intricate convolutions, someone sent Joe Hartley some unpublished information about the [Star] function. Simply type [Star][Enter]. An undocumented menu pops up:
Another neat thing about [Star] is that it also means [Planet] and it even means [Moon]. All that stuff I learned about planets and moons being cool objects that reflect light while stars are incandescent balls of gas is apparently not true! I have the telescopes assurance that planets and the Moon are really stars numbered from 901-909. Wow! Is that ever neat! So typing [Star]90# specifies 901-Mercury to 909-Pluto with 903-Moon*.
The [Enter] and [Goto] keys are important in this scenario. Press [Enter] to select an object. This tells the computer you really truly absolutely mean the stuff you just typed in the dark. For example type [M]31[Enter] to say "I really mean the Great Galaxy in Andromeda" or [Star]904[Enter] to say "I really mean Mars". If you want to actually move the telescope to this object finish the sequence with [Goto]. Assuming that the telescope is still properly aligned, it will move towards the desired object. Be careful that you don't mix up the positions of the numeric keys. I have a remote TV control numbered 1 2...9 0. Foolish me, I thought that Meade might use this system as well. No they number things 7 8 9 4 5 6 1 2 3 0. I discovered this looking for M22 in the dark and having the telescope suddenly swing around to M88.
Notice that I haven't mentioned how to get to two huge targets, the
Sun and the Moon. If you look at the Sun, you are either a
complete nincompoop or you have seriously destructive impulses
with possible suicidal tendencies.All joking aside, if the
telescope merely passes across the face of the Sun, it will send a
blast of light and heat into your eye at several thousand
times the energy of you see with your naked eye. That is enough to
totally destroy your eye faster than you can blink. A moment later the
Sun's light and heat will destroy the optical train of the telescope.
NEVER, Never, never slew the telescope when the Sun is above the
horizon without shielding the telescope from its light. Either the
dome can be turned safely away from the Sun or the dust cover can
shield the OTA. You cannot predict the path that the telescope may
take if you specify daytime viewing of say Mercury or Venus. There is
no built in protection in the computer software against slewing across
the Sun's face.
The Moon is another story. It certainly won't cause permanent blindness even though a full Moon can be dazzlingly bright without a polarizer or a #96 dark filter. The Moon's orbit is by far and away the Solar System's most difficult natural orbit to calculate. About two thirds of the gravity that shapes the Moon's orbit is Solar and the remaining third is Terrestrial. This twists the Moon's path into a really weird three dimensional corkscrew shape. The Moon takes almost 25 hours to make a revolution while almost every thing else takes a sidereal day. The Meade engineers came up with a quick and easy solution. They said (in effect) - the Moon is easy to see, it can be easily tracked by hand so we'll use a rough approximation. Type [Star]903[Enter][Goto] and the telescope moves toward the Moon. However it doesn't necessarily point dead center. You need to use the motion controls to see the part of Moon you want.
Over a surprisingly short time period the Moon's image may drift enough to require adjustments. Since the Moon is moving across the sky at a different rate than the stars, it will move out of the field of view even though the telescope thinks it is tracking properly. This period of time can be a few minutes to an hour depending on the eyepiece being used. For many applications a simple touch of the motion controls will work fine. For more precise control, change the speed the telescope from the sidereal rate to the lunar rate. This is described in Part 5 Mode Key Functions in the section covering Mode 4 - Timer and Frequency.
Before we leave this section, lets talk about two more uses of the [Enter] and [Goto] keys. If you press [Goto] and then happen to press the direction keys and speed keys to try to get an object aligned and you do something dumb and lose the target, simply press [Goto] again and the scope will move itself back to the point you last entered. Don't forget the minor emergency stop procedure; you can halt the telescope by pressing [GOTO] while the scope is in motion.
Congratulations! You have just mastered Part 3. Care for some easy ones?
If you refer back to the picture of the hand paddle we have several minor function keys which you use. The [RET] key (labeled 5 in the picture) controls the brightness in the illuminated reticule if you have one installed. The [Prev] and [Next] keys are used after the [RET] key to control the brightness levels. We bought a standalone framing reticule used for CCD imaging which has its own control. Does this make the [RET] control useless? No way! You see the funny black box on the top of the OTA next to the finder scope? It is a Telrad spotting device. We have jury rigged the Telrad so that it responds to the [RET] controls. If you don't know how to use a Telrad, turn the gizmo on using [RET] and sight along the top of the Telrad. See the big red bullseye? That is where we are pointing. By the by, kids love looking through it. The Telrad is great for star hopping.
The [MAP] key (labeled 11 in the picture) used to turn the little LED Map light on and off. OOOPS! Our LED light (labeled 7 in the picture) cracked three weeks after we got the Meade. Since the tiny red light is nearly useless, we haven't bothered to open the hand paddle and wire in a new LED. We have resorted to our old friend the red flashlight to changes eyepieces.
The [Focus] key (labeled 9 in the picture) controls the 1206 motorized eyepiece focuser. Follow the [Focus] key by the [Prev] and [Next] keys to focus near and far. The [Slew]/[Find] keys can be pressed before the [Focus] for rapid focusing. The [Cntr]/[Guide] provides slow focusing. You can ask the person at the eyepiece if the target is getting better or worse as a guideline.
The Focuser has been a bit of a disappointment. We have purchased a JMI digital focuser. We use the Meade focuser or hand knob twisting for bulk adjustments and the JMI for fine adjustments. Focusing the LX200 16" with a full set of additional optical and derotational equipment has proved to be a real pain the butt. The focus knob revolves 45 turns from nearest focus to infinity. The knob can continue past infinity for a number of additional turns to compensate for certain attached instruments. Our equipment is quite thick, meaning it takes many revolutions to focus our telescope. The LX200 16" like many catadioptric systems focuses by moving the main mirror in and out. Using the Electronic Focuser or even doing the job by hand requires endless cranking because the focusing mechanism, even at the highest rate, is very finely graded. There is no very fast focus to avoid a dangerously fast movement of the main mirror in the OTA. It is almost always better to leave the equipment on the telescope. A side effect of this is that this heavy equipment balances the dew shield very nicely resulting in less declination motor strain. Enough of the easy keys, we'll meet a real humdinger in the next section.
The last key on the paddle - [Mode] (labeled 2 in the picture) is the most complex of the keys. Most modes have numerous minor modes. Modes important to FDO are described in detail*.
Since FDO is an alt-azimuth telescope, you will find during slewing in one direction, that both the RA and DEC lines will change at the same time, while the ALT and AZ lines will only change in the direction that the telescope is being slewed. Only the yoke mounted Declination Setting Circle gives a correct reading. The base mounted RA Setting Circle only gives correct readings when the telescope is tilted at the equatorial angle.
To point to a new Right Ascension and Declination, press the [GOTO] key. A double beep will be heard. The blinking cursor that will move to the RA line. Edit the new Right Ascension numbers. To learn about EDITING click here. The blinking cursor will move to the DEC line. Edit the new declination numbers. When the [Enter] key is pressed, the telescope will slew to the new position.
To point to a new altitude and azimuth, press the [GOTO]key. A double beep will be heard. The blinking cursor will move to the ALT line. Edit the desired altitude. To learn about EDITING click here. The blinking cursor will move to the AZ line. Edit the desired azimuth. When the [Enter] key is pressed, the telescope will slew to the new position.
Setting the clock frequency to the Lunar rate keeps the Moon (particularly the crater that interests you) from drifting. If you are interested in an occultation you have a choice. Use the Sidereal rate if you want to keep the star or planet centered. Use Lunar rate if you want to keep the Moon steady. If you change to any nonstandard rate, return the telescope to Sidereal rate when you are through.
Using the clock frequency for long exposure astrophotography is not adequate. Even an exposure as short as 5 minutes can show streaking. If the object has a high relative velocity such as a nearby comet or asteroid, none of the clock frequencies is appropriate. The best tracking can be obtained by using the 201 Autoguider we purchased.
Meade assumes that most smaller LX200 users will need to do a one or two star alignment every time the setup their telescopes on a tripod. An obvious exception to this rule is LX200 16" pier mounted systems. LX200 16" systems can be left aligned from week to week before accumulated errors force a realignment. For permanently mounted systems, Meade supplies a built-in feature called HOME. Once a satisfactory alignment has been achieved, it can be saved using HOME/SET. At shut down, face the telescope south level with the horizon and shut down using HOME/PARK. This records the telescopes position using an internal magnetic sensor. Upon a subsequent start up use HOME/FIND to have the telescope locate the magnetic sensor reestablishing the south and horizon positions.
To initiate these operations, first choose Mode 1 Telescope/Object Library, then select TELESCOPE and then select the HOME menu.
SET: The Setting function should be run when the when the telescope has been realigned. SET is not used in normal start-up, pointing or shutdown operations.
In theory, permanent LX200 16" systems should retain their alignment for many weeks at a time. This might be the case if we always used HOME/FIND and HOME/PARK correctly, and never entered conflicting GOTO commands at the PC planetarium software and hand paddles at the same time. Any of these goofs can cause the alignment to be lost. All of these goofs are easy to make if you are getting a bit sleepy or a thunderstorm is rushing you. We have also discovered that power failures and gear slippages due to extremely hot or cold periods can upset the settings.
Lets assume that somehow the setting is lost. Here is a brief outline of how to reestablish a two star alignment at a specific site.
This completes a two star alignment. Check the alignment by trying some targets. If they don't appear in the finder scope, or they drift after a few minutes, your alignment was done incorrectly. Retry the procedure we just outlined.
PARK:When you are ready to shut down, follow this parking procedure. Make sure that you have the plastic bag over the dew shield first. Bring the telescope to an approximately neutral position (pointing due South at the horizon). From the HOME menu select PARK.
The LX200 16" scope will begin to look for the magnetic markers and will store the angle of the telescope relative to them in long term memory. In the process the telescope may make a variety of large and small motions. Parking causes the LX200 16" to look for electronic markers on RA and declination and stores their angles in nonvolatile memory. During parking, the telescope is lowered to its neutral position (pointing due South at the horizon). Once the telescope says it is complete, you may turn the power off. Remove the eyepiece and diagonals or the CCD. At this time you may place the tarpaulin over the telescope as long as you don't manually move the telescope.
FIND : After powering up and before you do ANYTHING ELSE, follow these instructions: Remove the tarpaulin and the dew shield bag. Insert the diagonal and eypiece or the CCD. From the HOME menu select FIND. The telescope is balanced to expect the weight of the diagonal and the eyepiece. If they are missing, FIND requires extra torque to move the scope which ins't great in the freezing temperatures of winter.
The telescope will begin to move vigorously followed by gentle motions. The movements will occur in the RA (azimuth) directions and followed by the delination (altitude) directions.* The paddle display will say the scope is searching for HOME. When the scope is completed the search for HOME, it will say so in the paddle display. This is a good time to do the other initialization activities like turning on the FAN (Mode 1-A-13) and making sure things like our spaghetti like cables won't get strangulated if you look for an object.
Failure to comply with PARKING and FINDING procedures will result in dreadful penalties including but not limited to ten lashes with a limp noodle.
Once you have told the telescope to GOTO an object or a coordinate, it may not point exactly where you intended. You can have the telescope LEARN from its mistakes by doing the following procedure.
That is all there is to it. The telescope will use this information to adjust its alignment. The next time you try for this or another object the scope will find its target more accurately than before.
For the LX200 to convert between the stellar coordinate system (RA and Declination) and the Alt-azimuth coordinate system (Altitude and Azimuth), it requires the position of Frosty Drew Observatory. Reentry shouldn't be needed, but here's how to do it. You will need to know how to edit items if you do not already know how. To learn about EDITING click here.
The local time (TOD, date and zone) is to determine the sidereal time (star time). The pointing accuracy of the telescope depends on the accuracy of the entered time. Our clock is synchronized by satellite to the official time in Boulder Colorado. You will need to know how to edit items if you do not already know how. To learn about EDITING click here.
Once the date is edited, the paddle will display "Updating planetary data. The position of the planets depends on the date, so anytime the date is changed, the planet positions are recalculated.
We're all aware of the fallacy of rating a telescope in terms of its magnification. Almost any power is possible on any telescope by using a sufficiently small focal length eyepiece. As an absurd example, take our 5 mm Plossl, mate it with a 3 power Barlow, effectively getting a 12/3 mm lens. This yields 2438 diameters on our LX200 (the LX200's 4064mm focal length divided by 12/3 mm). Since no optical system can effectively use powers greater than 50 diameters per aperture inch (800 for our system), we have saturated the image to fuzzy nothingness.
What is startling is that on large telescopes, there is a minimum useful power as well. During the night this is about 4 diameters per inch of aperture or about 64 power on our telescope. In the daytime when our eye's pupils contract, this rises to about 8 diameters or 128 power. Effectively then our range of eyepieces from 5 mm to 56 mm covers just about all possible useful magnifications. The Zoom lens is well designed to handle the sharply bending part of the curve (from 170 to 450 diameters). If the Zoom didn't have a slightly narrowed field of view and some minor loss of light, I think we would use it almost all of the time.
There are two other values which affect seeing through our telescope, the apparent and the actual fields of views of the eyepiece. You can think of the apparent field of view as the angle of the cone from the outer lens of the eyepiece to where light focuses to a point inside the eye. On good quality eyepieces, the apparent field of view is generally marked. The actual field of view is what portion of the sky we see through an eyepiece. The actual field of view is the apparent field of view divided by the magnification.
Meade LX200 16" Powers and Fields of View
Eyepiece Type mm* Apparent Field Power Actual Field of View Plossl 1¼" 5 50° 813 0°03'42" Konig 1¼" 8 60° 508 0°07'05" Nagler IV 2:1¼" 12 82° 339 0°14'32" Konig 1¼" 16 52° 254 0°12'17" Reticule 1¼" 25 50° 163 0°18'27" Super Plossl 1¼" 26 52° 156 0°19'58" Konig 2" 32 60° 127 0°28'21" Super Plossl 2" 40 70° 101 0°41'21" Super Plossl 2" 56 52° 73 0°43'00" Maximum to 8 40° 508 0°04'44" Minimum to to to to Zoom 1¼" 24 55° 169 0°19'29"
Only our 40 and 56 mm Super Plossls are wide enough to hold the entire Moon in a single image. (The Moon is typically about 30-35 arc minutes across). Our 5 mm Plossl forms an image which covers about 10% of the Moon's diameter and 1% of the Moon's area. In effect the 5 mm Plossl brings us within 470 miles of the Moon. The intrinsic magnification of our large telescope creates a tendency towards tunnel vision. You must be pointed nearly dead on, or your object won't appear in the telescope's eyepiece. Good alignment is a necessity.
Before we even consider letting anyone run the new telescope by themselves, they need to know how to handle our slightly cranky and definitely idiosyncratic dome. After a dozen Winters, an occasional hurricane and who knows how many boiling hot days, our Ash Dome doesn't always behave as it did in its salad days. If you can't open the dome, that can be annoying. If you can't close the dome, that can be a disaster! A thunder storm dumping a load of rain and hail on the telescope is my idea of a nightmare.
The dome controls consist of two double throw levers (one has a slider bar), a FireCracker Controller [with real and PC simulated remotes], a variable AC transformer (abbreviated as a variac), an odd 8 prong plug and socket set, and a player to be named later.
The variac
and the shutter lever [the one with the slider bar] must be
plugged into a 120 volt outlet below the variac. When you leave, pull
these plugs as a precaution against line surges during thunderstorms.
The plug which is directly attached to the shutter lever continues on
to an 8 prong plug and socket set. The 8 prong plug is attached to the
motor which raises and lowers the dome. The slider bar prevents
accidental movement of the shutter in the wrong direction while in
motion.
Contrary to popular belief the coil next to the dome controls isn't a lasso used by Black Bart to rustle robo-cows . This 8 prong socket and plug extension cord facilitates raising and lowering the shutter when the dome is turned away from the north. For example, if you see a thunderstorm approaching, use the extension to close the shutter before moving the dome to its standard north position. More prosaically, the extension cord shortens zenith trap openings and closings by avoiding intermediate dome rotations.
The power to the dome rotation follows a bit more circuitous route. Power first reaches the variac. The use of variac is a bit of a black art. In theory, we shouldn't need it because the dome has a 120 volt AC motor. However, sometime in past it was discovered that the dome turns too fast. Nothing really dreadful happen if you power this motor by 120 volts or so I am told. If you give me sufficient warning to leave the dome, you can try it. The variac is set to slow the dome's turning to a safe level. This is about 90 volts. The variac is getting old. In particular, the some settings near 90 volts no longer make contact. If things don't work, twiddle the dial a bit. There is a fuse and a small switch on the top of the variac as well. Any of these can get loose, be set the wrong way or the fuse can burn out. The most common cry of despair is "The @#%*&:$? dome motor won't run! Don't panic, a little gentle tinkering usually is enough.
Power leaves the variac to two variable voltage wall sockets. Depending on the variac setting the wall sockets are usually at about 90 volts. One socket holds the FireCracker Controller; a small white box with a push button and antenna on it. You may turn the FireCracker on/off from a real or a PC simulated hand held remote, or by pushing the small button. Power leaves the FireCracker Controller for a double throw dome direction lever. Left rotates counterclockwise and right rotates clockwise. These directions are intuitive as you would hope.
Joe Hartley has noticed that the FireCracker doesn't seem to work in very cold weather. In this case it is perfectly all right to simply bypass the FireCracker and plug the dome rotation motor into the variable voltage socket. The manual lever will control the dome nicely.
Plug everything in, press the FireCracker remote and away you go - usually. Open the shutter and be sure to disconnect the 8 prong plug/socket before turning the dome!!! Even the most minuscule of minds can foresee dire happenings if you turn the dome prior to disconnection! You also have to reverse the process (turn dome back first and reconnect) when shutting down for the night!
There are also two circuit breaker boxes. The master box is in the Nature Center's in the left rear room's closet; a subordinate box is in the dome on the wall. To reset a circuit breaker, you must push it all the way off before pushing it all the way on. Our circuit breakers frequently trip due to damp ground and lightning.
There is one other emergency dome control - our player to be named later. It consists of a club with wire wrappings at one end which for historical reasons is called the fandango tool [ask an old timer why if you must]. There are regions of the dome track [sections 6 and 19 come to mind] which sometimes don't quite engage the gears. The dome makes a wicked clattery racket that sounds like a:
Reversing the direction sometimes works. If not, try the fandango tool hanging near the motor. You have got to shove the tool under the motor and nudge the gear cage back into the track. This all purpose tool is also useful while chipping ice out of the shutter tracks when they freeze in place. This happens once every two or three Winters. If you are too small [or too wise] to take these responsibilities, leave the dome safely shut, until a larger [less intelligent] staff member arrives who is strong [silly] enough to open the dome.
No, I won't tell you what bifurcated means - you can guess that on our quiz later. The shutter is segmented into two pieces (that's a clue). There are two ways to open the shutter. The upper two thirds is cranked up by an electric motor. If the lower one third is coupled to the upper two thirds, it will stop directly above the scope at the Zenith point. This is fine unless the object you wish to look at is nearly at the Zenith. In this case, lower both sections of the shutter, uncouple the lower one third and raise the remaining two thirds all the way up. This leaves the Zenith open, but at a cost of obscuring the lower third of the sky near the horizon.
There is a chain and a long bolt on the left side of the shutter. If the chain is pushed behind the bolt, clamps at the top of the lower third open. When the dome is raised, the lower third stays below. Now comes the fun part. When you are ready to raise the bottom third again, or when you are closing the dome for the night, pull the chain from in back of the bolt and lower the upper two thirds back. If all goes well, the clamps will automatically catch onto the bar that links the two parts together. Sometime one or the other or both clamps decide to go on the wrong side of the bar. This is where you earn the big bucks the management pays you. You have to jiggle, poke and mumble until you get the clamps free. Redo it but be more cautious this time. Needless to say, don't try this insanity unless a previous inmate shows you how it is done. No amount of verbiage will ever explain this rococo invention and it opportunities for grim discoveries. As with all corollaries of Murphy's Law, the lower shutter will always go wrong at the worst possible moment - say in front of your significant other just as a monsoon arrives.
It was a dark and stormy night when the Lord High Astronomer said to the lowly dome flunky, "Ach, Lowly Dome Flunky tell us a wee tale!" and so the lowly dome flunky began "It was a dark and stormy night when the Lord High Astronomer said..." There is yet another piece of lore from the lesser arcana which you must master - the dreaded drips. Long after the dark and stormy night, the dome has one final trick up it nefarious sleeve. It stores untold watery reservoirs in its shutter tracks. Defying all known laws of physics, this water is held in suspension until the sweet and innocent lowly dome flunky begins to open the dome. Just as the edge of the shutter passes over the telescope, it releases the water bombs with unfailing accuracy. Witness this sad event:
Der Gewoelber Liveebedienter sagst "Mit der sparken und der elektro-gazappen wie das Fernrohr ist ein Unterseeboot bekommen, Meiner Gnadiger Hoher Sternforscher!!" This brief but incomprehensible lapse by the dome flunky from English into a tongue which may be Gerglish or possibly Swabish but is certainly not Hochdeutsch only underscores the flunky's great consternation. Since the Lord High Astronomer thought the dome flunky was shouting in an archaic form of Bulgarian with a weird Scots brogue relatively little information was exchanged leaving the telescope a good deal damper.
However had dome flunky been a bit more subtle and devious he could have escaped this ignominious disaster entirely. Halt the dome shutter just short of passing above the telescope. The shutter becomes too impatient to wait and dumps its water onto the cement steps. This forms quite a beautiful if brief cascade - with water splashing and gurgling joyfully out the door. If perchance thou art duller than a doorknob, this the reason why we drape the infamous blue tarpaulin over as much of the telescope as possible.
I am as much in favor of cleanliness as the next guy, but a word of warning is appropriate. Our dearly beloved optics suffer hideously when a madman with the push broom raises a swirling dust cloud that would be the envy of the cartoon character Taz. Put the dust cover over the dew shield and make sure that the lenses, diagonals and what have you are tightly covered before you wield the broom and dust pan.
One final point, if a thunderstorm is approaching, weather the storm in cars or the Nature Center. While the dome is in theory a Faraday cage, don't trust it to shield you from a bolt. Close the shutter immediately. Try to remember to pull all the plugs before you leave.
SkyChart III[SC3] is one of a series of "planetarium" simulation software which has provided a linkage to a wide variety of GOTO type telescopes. SC3 does not pretend to provide every function that is installed in the LX200's On-Board Computer (OBC) through the Meade hand paddle controller. However for what it set out to do, pointing the telescope, SC3 does an excellent job in a relatively intuitive and straight forward way.
The full SkyChart III program contains all sorts of exotic features from the viewpoint of telescope control. For example, during the Comet Chase Rocket Launch in November of 1999, we used SkyChart III to model Comet Temple-Tuttle and the Leonid Meteor Shower. In some of the models we stood way outside Earth and even pretended that our viewpoint was the leading edge of the comet. None of this exotica is appropriate for directing the telescope, so we will assume that you have used the defaults such as having Frosty Drew Observatory be the viewing location (the "Here default) and the time will be current (the "Now default). We also assume that the LX200 OBC is using the SITE parameter labeled FDO and that the OBC real time clock is set within 5 seconds of the correct local time (Once again these are the defaults).
Do not use SC3 to communicate with the OBC or direct the telescope unless both are using the correct defaults for SC3 and OBC. At the very least you will gum up the alignment on the telescope, requiring a two star realignment to fix things. It has happened!
If two people are running the system, one at the telescope with the OBC hand paddle and the other at the PC using SC3, make sure you coordinate your efforts. If both stations try to direct the telescope at the same time, the two stations break synchronization and the result can cause the telescope to become so confused that it requires a complete two star realignment.
Be cautious about people who think they would like to "play" with the software. More that a few people think they can't do much damage by seeing what the software does, but when it is linked to the telescope this isn't the case. If you must leave the PC for an extended period of time, it probably is a good idea to take the telescope off-line with the Telescope/Disconnect commands. We had one person fooling around with the view of Saturn while the telescope was pointing at the planet. People were looking into the eyepiece when the scope began to move unexpectedly.
When you bring up SC3 you will see a screen something like
the above. You may make any adjustments that suit you such as
changing between ecliptic, equatorial or horizon orientations,
re-sizing the field of view, setting the time, changing the rate to
real time, decide what to see (planets, deep space objects,
constellations etc.) and what have you. When you are ready to link up
to the OBC (which must be running) bring up the telescope
control panel.
The File pull down allows you to select which database will be used to display the screen. If you wish to use the full Hubble Data Base (all 19 million objects) you would start with File. The Edit pull down allows you to select a target which you don't see on the screen. If you want to go to M31, all you have to do is click Edit/Find and type M31. You can also use any of the other names which it is commonly known by. View and Draw are crucial to what is displayed, how large and in what orientation. Computation is required to change the location (it should be Frosty Drew when you direct the LX200) and the time (now of course). Use Animation to set the step time to Real Time.
The first panel to come up will be the Telescope Connection panel.
Because of a bug in SC3, the Telescope Mount box will
always come up as Equatorial. You will have to set it as
Alt-Azimuth each and every time you start a new connection.
Only the Emulate check box will be off. However, while you are
practicing with the software, this feature lets you get used to the
commands without actually doing something to the telescope. We
use COM1 to link to the OBC. We link with a standard
serial interface such as you would with a simple home network.
The interface between the SC3 software and the OBC is relatively simple. For example, if you select Jupiter as the object that you will go to, SC3 simply sends the altitude and azimuth to the telescope. It does not send the command series which invokes the telescope's own ability to find Jupiter. This has both good and potentially less desirable side effects. If both the telescope and software are set up correctly [location, date and time] very few poor side effects occur. However, at least one side effect does not disappear - the scope only knows where it is pointing but not what it is pointing at. The best side effects is that the telescope now can point to about 19 million additional objects.
The SC3 software can be updated to include objects which are either new or which have altered their orbits. We have stored updated table for comets (Temple-Tuttle), asteroids (Eros) and novae (Aql-1999). There is no way to store new objects into the OBC although you can calculate where the object will be and GOTO that location without going to a specific object.
The 
telescope control panel can be hidden but you will probably want to
keep it visible while you are directing the LX200. It is quite
simple but very powerful. Lets go over the fields on this panel. The
top is simple a repeat of the keys on the OBChand paddle. You
can move it in any direction at anyone of the four slewing rates
provided by the telescope. The information in the center describe
where the telescope is pointing and the position of where a selected
target.
It is the bottom four controls which are the real power of the Telescope Control. The GOTO button will move you from where the telescope is currently pointing to the target object. When you or whoever is at the telescope with the hand paddle has made any needed minor corrections to bring the telescope and the SC3 views into perfect synchronization, you inform the SC3 software of the fact with SYNC. STOP is sort of self explanatory. In practice, you would probably STOP the telescope with the hand paddle but either can be used. The CEnter button brings the target object image into the center of the PC screen.
-
Lets see
how it works in practice when we point the telescope at the Moon at 9
PM on 3/19/00. First we select the Moon by bringing its information
panel up. To do this either click on the Moon image if it is present
or use Edit/Find if it is not present. You will see something
like the panel at the right. Most of this information is of only
secondary interest. You may wish to press Center to bring the Moon
image to the center of the PC's screen, but this is not
crucial. What is important is that the Moon was the last body
selected. To begin the process of moving the telescope to the Moon,
simply click GOTO in the Telescope Control panel. At
this point, it does not matter whether you keep this panel on the
screen or remove it. What will happen is that the telescope and the
bulls eye on the screen will begin to move towards the Moon. You will
see something like:
The bulls eye is set up with the outer circle at 4° in radius, the middle circle at 2° radius and the innermost square is 1/2° radius. These values where chosen because they match the Telrad mounted on the telescope. And indeed on 03/19/00 at 9 PM local time, the Moon (almost perfectly full) is in the head of Virgo, neatly blocking out any chance to seem anything in the Virgo Cluster.
We have tried a lash up between the IBM voice recognition program, Via Voice and SkyChart III. Most things work, but unfortunately, the most critical function (selecting an object) results in a nasty message from somewhere and the who shebang terminates. We are hoping that SkyChart III Version?? will have good voice recognition.
Unlike SkyChart II, the Astronomer's Control Panel (ACP) is a strictly Meade LX200 oriented program. It attempts to provide every function available at the OBC hand paddle interface.
What sets this software apart from other software is that it is voice actuated. When it comes up, it greets you in a robotic voice. It will continue to chat with you throughout the session with the telescope. More importantly, you can tell it verbally what you would like it to do. For example, it you wanted to move the telescope onto Mars you would say in clearly enunciated tones "Goto Mars." If everything works and it wasn't distracted by other noises in the dome, it responds "GOTO Mars?" You respond "yes." and away the scope goes.
What sounds wonderful in theory is somewhat less than wonderful in practice. The software is used to Joe Hartley's voice - well sort of. At least he gets far fewer responses of "Huh?" from the program. Les Coleman has had little success and in a noisy dome, the software just does not work. We use it once or twice to wow the audience and then go back to software which responds to the mouse and keyboard.