Telescope Guide

Despite the apparent length of the following directions, our telescopes are rather easy to set-up and to use. There are a few caveats though, one of which is that the Dec/Alt axes of the Meade telescopes have a simple nylon gear, and this can be easily damaged if the telescope is dropped, or someone physically yanks the telescope down. Be gentle. Note that the 8″ telescopes take much more time to set-up, so start early (and practice before you need to use it!). Troubleshooting hints are listed at the end of this document.

Note, unless you have used them recently, start setting up these scopes 20 to 30 minutes before the start time of your event. You cannot just show up five minutes ahead of time and expect to get them working in time!

Opening the Domes

North Dome

1) Open the dome and power the rotation box: Remove the bolt and pull open the dome slit. Plug the dome rotation power supply cord into the wall.

2) Telescope Power: Plug in the telescope. Power on the telescope using the small toggle switch on the telescope “Power Panel” (if you can’t find this switch, see the Celestron manual, Figure 2, for the switch location labelled E). Note that the telescope should execute some small motions (you can hear the motors whirring), and that the red LED should light. If not, see troubleshooting power problems, below.

3) Remove the Covers: Remove the plastic dust sheet from the telescope. Using the hand paddle, slew the telescope eastward until you can reach the metal cover that covers the corrector plate at the top end of the telescope. Remove this cover slowly (it sticks partially due to vacuum pressure), and place it out of the way of foot traffic. Remove the lens and eyepiece covers from the finderscope.

See the “Observing” section below for alignment procedures.

South Dome

1) Power on the dome rotation box, and the shutter control box. The dome rotation box is by the eastern doorway. It has the “dome right”, “dome left” buttons on it. The power is the rocker switch on the south side of the box. The central, red LED should light. The slit control box is located near the base of the dome opposite the slit. The power switch is located just as the rotation box (that “power on-off” button on the front face of the box with “stop” written above it is the emergency stop, and has nothing to do with the power!). It also has an LED to signal the presence of power.

2) Open the shutter: Press the open shutter button. This will only open the shutter, not the windscreen flap. If the object you’re observing is low in the sky, hit the open windscreen button to also lower the windscreen flap. If for some reason you hit the emergency stop button (resist this urge), you must cycle the power on the shutter control box to reset this box, and allow further motions.

3) Telescope Power: Plug in the telescope. Power on the telescope using the small toggle switch on the telescope “Power Panel” (if you can’t find this switch, see the Celestron manual, Figure 2, for the switch location labelled E). Note that the telescope should execute some small motions (you can hear the motors whirring), and that the red LED should light. If not, see troubleshooting power problems, below.

4) Remove the Covers: Remove the plastic dust sheet from the telescope. Using the hand paddle, slew the telescope eastward until you can reach the metal cover that covers the corrector plate at the top end of the telescope. Rotate the cover to remove it (it may stick partially due to vacuum pressure), and place it out of the way of foot traffic. Remove the lens and eyepiece covers from the finderscope.

See the “Observing” section below for alignment procedures.

Observing with the Celestron 11″ CPC Telescopes

We recently installed a new 11″ Celestron in the North dome, which means both domes now contain the same model of telescope. The Celestron is fairly significantly wedded to its GPS. It will not let you do much of anything until you perform “an alignment.” Here is the manual. The older South Dome instructions may also be useful.

1) After power-up, it will ask you to begin the alignment process by hitting “enter”. There are numerous options for this procedure, but the one you MUST select is “EQ North Align” (see page 17 in the manual). Do this by scrolling down using the “Down”/Key#6 button (“Up” is #9). It then starts listening for the GPS, but also asks if the current displayed time, dates and daylight savings time, etc.—change them to the correct values and hit Enter.

Note: Make sure you do not select TwoStar or OneStar align on the very first screen- you need to choose “EQ North“. Once you have selected EQ North and completed the time/date updates, then you can choose TwoStar or OneStar align.

2) After this there are additional selections. For the highest precision pointing you should select “two star”, but “one star” should be sufficient. It will give you some random star to center-up for alignment (like Deneb), but note that you can scroll up/down to find a star that YOU DO LIKE! You do not have to use the first one that pops up (that’s what the up/down arrows on the screen, next to the star name, are trying to tell you!). Some basic knowledge of bright stars in the night sky is very helpful for this.

3) Manually slew to this star. Push Rate, and then a number between 1 (slow) and 9 (fast) to change the slewing rates. Follow the handpaddle directions, and hopefully you end-up with an “Alignment Successful” message. Note that if you did not get this message the telescope will not slew, point, or track. If you have issues here, it might be due to bad time/date, or it lost the local Long & Lat. I have left the manual out in the dome for any troubleshooting you might need to attempt. Note that times and dates are essential for accurate solar system pointing (as well as defining the local horizons).

Hints: For the various object menus hit the “LIST” button. There you will find named stars, and everything else it knows about. You can slew to and sync on any of these things. It should also be possible to “align” on the Sun to search for daytime planets, but this requires skill to keep from destroying the optics and your eyesight—novices (i.e., anyone reading this) should not attempt this.

Notes: Once I finished the two star alignment, I was able to blindly slew to any object I wanted and it was in the eyepiece’s field-of-view–I even went under the pole to get NGC188 (very hard for most scopes). You can update the pointing throughout the night by hitting the Align button, and choosing the correct star (it will ask about replacing the earlier one, just agree) and centering it and then hit “sync” (follow the handpaddle directions, see page 18). For some far southern objects (M41, NGC3115) the handpaddle flashed “exceeds slew limits”, but I knew they didn’t, so I hit enter to have it go to them—if you get this message AND KNOW that the object is high enough in the sky to observe, just hit “Enter” to slew there.

The handpaddle menu guide is on page 26 of the manual.

Note: If you just want to manually move the telescope to a bright planet, or the Moon, you do not need to do a precise sync on a bright star to get the telescope to track. Just pick a star from the menu that you know is above the horizon, roughly point the telescope in its general direction, and “sync” it. Now the scope will turn on tracking, and you can stare at the Moon for the rest of the night. Sometimes with clouds, bright Moon, or stadium lights, you cannot find many stars for a proper synching. But you must sync on SOMETHING, even a random spot in the sky, or the telescope will not track!

Observing with the Meade 8″ GPS Telescopes in Alt-Az Mode

Using these telescopes (one in the North dome, one in AY 118) requires you to become familiar with the operation of the handpaddle, see page 9 of the manual. Note that these telescopes will not point and track without a full alignment, thus even looking at the Moon requires a full alignment to be done–this takes time, so start early (at least 30 minutes before you need it!).

1) Place the tripod at a location that is flat, and stable (and from which you can see the objects of interest). Adjust it to the appropriate height. Mount the telescope onto the tripod by screwing-in the large bolt, insuring the “tripod spreader” aligns with the legs of the tripod—this is required for stability. The “control panel” should be on the south side of the mount. Use the bubble level and adjust the legs to get the telescope as level as possible. Do not power anything on!

2) Now, unlock the axes so that you can manually point to some distant light/pole/tree and center this in the eyepiece. Now adjust the screws on the finderscope to make sure it is aligned with the telescope. This is essential for getting a proper alignment!

3) Manually point the telescope (roughly) north, keeping it horizontal. Lock both axes! Plug it in, and power it on.

4) The telescope will whir a bit, and then the handpaddle will display “Automatic/Alignment”, you should press “Enter” to select this mode (this entire process is described in the manual, starting on page 18). The telescope will now go through about 10 minutes of alignment–getting a GPS fix, finding north, and performing a software leveling exercise. It will then slew to a very bright star (e.g., Arcturus). It will not come very close though–you must now center this star in the eyepiece and then hit “Enter”.

Note that the slew operation resets the motion control speed down to “guide”, so press the “Speed” button followed by a number (5 is good), to allow you to center the star.

5) Now the hard part—star #2. After completing step 4, the telescope now picks a star located well away from the first. Unfortunately, this is probably not a first magnitude star, but some obscure 3rd magnitude object (e.g., Alderamin). Assume that the brightest star in the finder is the correct star (it usually is!). Center it, and press Enter.

Note that if you cannot identify this star, there is a way to skip it and go to another object, see the manual for details.

6) As long as no one kicks the tripod, the telescope is now aligned, and will point fairly well to any object above the horizon. You can select various menus using the handpaddle. For example, the “SS” button brings-up the solar system menu which you can scroll through to select a planet. While the “M” button allows you to choose a Messier object (hit M and then type in a number, then “Enter”, and then “Goto”). There are also other “hot keys” that allow catalog access, such as the Caldwell, NGC, and IC catalogs, named stars, etc.

Using the (New) 8″ Celestron in AY 118

We purchased a new 8″ Celestron for public events to replace the 8″ Meades that are getting a bit cranky in their old age. The Celestron is much, much lighter than the Meades, and thus will be much easier to deal with. It is currently sitting in the back of AY 118 (small brown box, and the assembled tripod), next to the Meade. Unlike the Meade’s, the Celestron is not a GPS. You need to enter the time and date, and then perform an alignment. Like the Meades, it is helpful, but not necessary to know star names. I left the manual and quick start guide in the box. It runs on 8 AA batteries, or a regular 12V power supply.

1) Like the Meades, get the finderscope aligned first! There is an extra battery for the cheapo finder in the box.

The set-up of this telescope is slightly more complex than the 8″ Meades. It does not have any of the gizmos of the Meade, so it needs at least three stars to figure out how flat it is, and where North is, etc. to get good pointing. This is the “Sky Align” method. See page 12 of the manual. You must first start with a level tripod, an accurate time and the correct date. See page 12 of the manual.

2) Turn the telescope on, chose Sky Align. After entering in the time and date and site info, slew the telescope at ANY bright object in the sky (a planet, the Moon, a star), center it in the finderscope hit “enter,” then in the eyepiece and hit “align.” YOU DO NOT HAVE TO KNOW THE NAME OF THIS OBJECT! Just pick a bright thing that is isolated in the sky from other things (i.e., don’t use stars in Orion!).

3) Slew to another bright object as far away as possible from the first object, center it in the finder, and hit “enter.” Center in eyepiece, hit “align.”

4) Repeat this for a third object. The third object should form some sort of wide triangle with the other two objects. If all three are in a line, the process might fail. If everything goes as planned, the display should say “Match Confirmed”. Hitting the “UNDO” button lists the three objects. This might be a good check to make sure it found everything correctly–as long as you know what you pointed to! If everything is kosher, hit “ENTER” and you should be good to go. See page 13 of the manual for hints if things didn’t work.

Notes: Like the 11″ Celestrons in the domes, there are one and two star alignment methods, see page 13 of the manual. Note, due to backlash, you should try to approach all three stars from the same direction, e.g., “up” and “right”. Center the object in the eyepiece, move the telescope away from the star using the down and left buttons and then move the star back into the eyepiece using “up” and “right” for all three stars. This is just to try to get rid of backlash in the gears. I was able to get good deep sky pointing on this telescope, but it takes practice. Again, you don’t need a perfect alignment if you are just going to use it to look at the Moon or a bright planet. If you got a “Match Confirmed”, it will track ok, and you can adjust the pointing when the object starts sliding out of the eyepiece (you can also sync on this object to update the pointing model).

Equatorial Mounted Telescopes

We have a number of equatorially mounted telescopes. Some old 8″ Celestrons, an 8″ Orion in the middle dome, and a 6″ Newtonian next to it. These do not have computer controls, so you need to know the sky to use them for deep sky observing. But for a quick setup to look at the Moon or a bright planet, they are trivial! The 8″ Meade only requires a 9V battery to track, and the Celestrons use a special power cord to plug them into any 120V outlet. Align the forks of these 8″ telescopes to roughly point North, and you are good to go. A precise alignment can be made, but for public events, this is all you should need. The 6″ Newtonian needs to point at the North star (with Dec=90, HA=0.0).


As noted earlier, the gearing inside these telescopes is not especially durable–while the nylon gearing keeps the damage minimal when the telescope suffers a severe shock, it does mean the telescope will need to go back to Meade for repair (about $400, no matter the issue!). So treat these telescopes with respect, and watch the students/parents/children (and faculty, especially the faculty!) closely so as to attempt to avoid damage (and injury).

1) Focus issues. All Meade telescopes have a coarse focus knob, and a focus lock. The focus lock is very nice, acting to keep the mirror from “flopping” around inside the tube. But trying to manually focus the telescope while the focus is locked causes damage. So be careful. Usually, you can manually set the focus close to what is needed, and then use the electronic focuser to fine-tune the focus. Note that the total travel of the electronic focuser is about 3/8″, so run it to the middle of the range before attempting a coarse focus. Then lock the focus and use the electronic focuser. I recommend that you press the “Focus” button on the paddle to allow individuals to focus the telescope for their eyes. This also insures that no one moves the telescope without hitting the correct key sequence.

2) Finder scope issues. There is no way to keep these perfectly aligned–they will eventually get bumped and need to be re-aligned. This can be a daunting task for the scopes in the domes since we cannot see below the walls. If the moon, or a bright planet is visible, point the telescope at that object. I find that you can pull out the eyepiece, and can usually see an image of the moon/planet in the wider field of view–if so, sort-of center it up (the secondary mirror obscures the very center of the field of view), and replace the eyepice (use the lowest power eyepiece–i.e., the one with the longest focal length,). You can usually sight along the tube to try to get it close–do this from two sides of the tube to make your error symmetric. There is a spiral search feature that can be invoked from the software if this does not work. The TELRAD finders often need to have their batteries replaced since they are left “on” all of the time. They take two AA batteries. You remove the whole thing from the scope by loosening the two thumb screws. Slide the top off the plastic case, replace the batteries. Be careful, as the bullseye target is plastic and can break easily. You will need to do a re-alignment of the TELRAD after re-installation. The three screws on the back are what you use—super fast and easy.

3) The “Mode” (Undo) button is your friend! Whenever you get stuck in some odd menu on the handpaddle–and some of those areas are very dangerous(!), repeatedly press the Mode button until the display returns to the “Select Item: Object” mode. Especially dangerous are the “Align” menus, and the “Site” menus. You can get the telescope stuck in a very funny mode of operation from which you cannot recover without additional guidance, so be careful (someone in our department seems to frequently change our permanently mounted telescopes from Equatorial mounted to Alt-Az mode–not a very good thing to do, and surprisingly hard to de-bug!).

4) Dome issues. The middle dome works fairly well, both boxes have to have power supplied to them to get it to work. The one on the wall by the light switch controls power to the rotation motor. The red LED lights-up to confirm power is present. The box on the dome drives the slit motors. It is run by a 12V car battery. We’ve had issues lately with the dome slit not closing at the end of an observing night. So far I’ve been able to close the dome by waiting 5-10 minutes then trying again. This is an intermittent problem and surprisingly hard to debug. If you do run in to this issue, send Jon Rees an email. Sometimes it can blow a fuse. There are three of these, located on the side of the grey box. Spares are in the desk drawer–NOTE THAT THEY HAVE DIFFERENT AMP RATINGS! Choose the right one. The only other failure is that the 12V car battery that runs this needs replacing every 4 or 5 years. Be careful as the solar panel provides power when the Sun is shining to recharge this battery, so there is voltage up there (don’t short the battery cables!).

Once upon a time, we had trouble inside the gray dome rotation box. The AMC people were quite helpful in giving me simple tests to do on various circuits inside the box. We eventually had to replace one of the cards, as a chip on it had died. So, if this happens again, you might have to remove the box and send it back to AMC to get them to check it out and fix it (unless you have some confidence in your voltmeter abilities, and replace the card yourself). Let’s hope they stay in business, and this thing doesn’t become too ancient to repair.

The North dome is old and clunky. It is driven by a rubber wheel. In cold weather this wheel can become hard, and not have sufficient tackiness to rotate the dome. Take the broom out of the closet, and while one of you pushes on the dome with the broomstick, someone else pushes the rotation button. I have “belt dressing” that can be sprayed on the rubber part of the wheel to increase its tackiness. I also have to spray the pulleys with WD40 every once in a while, as they get rusty, and make the slit hard to open (and very squeaky). Note that I have done this for the wheels that support the dome rotation. The dome used to get stuck at a certain azimuth—a low spot—and I actually leveled the dome using some shims and the big bolts around its base. Not sure this will ever happen again, but someday this dome will need to be replaced, as the whole rotation mechanism is slowly decaying. The motor also draws a lot of current. Do not slew the dome while the telescope is slewing or the telescope might not end up in the right place.

Weird Tracking. This is almost certainly because you have the polar aligned telescope in Alt/Az mode (or vice/versa for the 8″ GPS). Go to the menu to reset the alignment to “polar” (Meade), or EQ-North (Celestron). But motors die, controllers fail, so report this to Jon Rees, as it might be something more serious (we have had one of the “rubber bands” that drives the Dec axis fail, and a card inside the base had an electrical fault–that one was hard to find). Such things will require factory repair. I have shipped telescopes back to Meade four or five times. It takes a few months, and often they don’t actually repair anything. One of the reasons for the Celestron purchase (we have not yet tested their servicing).

5) Cabling Issues. Due to moisture and dust, the (rj-11) phone cord-like (NOTE: they are not phone cords!) cable jacks can lead to poor contact, and erratic behavior. This is also true for the Celestron power supply jack. Unfortunately, Meade and Celestron like to have “priority” designed cables and you usually just can’t buy some random cable off of Amazon and use it. This site is incredibly helpful with all such Meade issues. Pencil erasers are especially good at cleaning the connectors. Blow the dust out of the recessed connectors. Note we have had internal connector issues in the past that required similar “servicing.”

6) Restoring the Operating Systems. Note that there are procedures to reload the operating system for both the Meades and Celestrons. This needs to be done at least once per year due to static electricity or mechanical shocks (yes dropping and banging the handpaddle causes issues!). It is trivial for the north dome, you turn on the pc just start up the Autostar program (but first read directions from here). Note that you will be updating the software version to the same software version. The Autostar suite should identify which system is loaded, and you pick that one to reload from the menu (if there happens to be more than one). The reason we have those old clunky PCs in the dome is for this procedure. Both have a recent-enough operating system on disk to get the telescopes running correctly. The north dome sometimes has wireless internet access from the baseball stadium, so updated versions can be downloaded–but don’t do this unless you know what you are doing! The passwords are the same on both pcs, the usual one. Currently, the portable 8″ Meade in the dome is not responding to this upload process, so it needs to be sent back to Meade.

Updating the Celestron follows a similar path, except a special cable needs to be used, and you have to connect to the serial port on the PC, and into the handpaddle on the telescope. This requires some zip ties, and a properly configured cable (I have one special for this—but note that Meade and Celestron use the same size cable, but switch which wires are used, so I manually rewire the connector each time I do a different scope (I need the Meade configuration for the solar telescope mounts). The directions for updating the Celestron are here.

Note that this process can take two hours!
You can often find help on the web if you take a look. This site has much information on the Celestron CPC series. And this site has lots of info on Meade GPS telescopes. Try them first.