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Prestep Point the telescope at an object for alignment purposes, as you would in all circumstances. This entails finding a bright, known star in the finder scope and then centering the bright star in the eyepiece. Lock the scope.
1- Remove the "visual back" which is the collective name for the star diagonal and eyepiece, as well as the port where the diagonal slides in. This can be done by unscrewing the ring connected to the tube of the scope.
2- Screw the CCD camera, which is connected to a different visual back, onto the back of the scope. The threads are fine, so the elements must be flush to screw it. Having someone else support the CCD camera while you are attempting to match the threads might be a good idea, since the CCD costs upwards of $3000, equivalent to the price of a freshman meal plan. It's that expensive...
3- Plug the grey parallel cable into the computer's parallel port and run the other end to the white parallel cable attached to the CCD. Plug the camera power cord into the outlet on the deck. If it is on, it will make a low hum from the cooling fan. If you hear no hum, check the power connection to the back of the camera. These connections open a line of communication between the camera and the computer, as well as providing the camera with power.
4- Plug the telescope control cable into serial port 1. This phone-looking cable requires an adapter before it plugs into the computer, while the other end plugs straight into the RS232 port on the telescope. This makes the connection between "The Sky" program and the telescope.
5a- Go "Start"-"Programs"-"The Sky Astronomy Software" to start "The Sky" telescope control program.
5b- Select "Telescope"-"Setup"- and choose "LX200" from the telescope list. Also, unclick the "switch to night vision mode" box if it is not unclicked already.
5c- Select "Telescope" - "Link" - "Establish"
5d-Click on the star upon which you have manually aligned the telescope. This should bring up a menu. Click the "telescope" tab and click "sync" if you are centered on this object. Click "OK". If you have difficulty bringing up the star information by clicking, right click to bring up the "find" menu and select the star from the catalog.
6a- Go "Start"-"Programs-"CCDsoft"-"CCDsoft Version 5" to start up the CCD program.
6b- Within the CCDSOFT program, go to "Camera"-"Setup" and make sure the camera is defined as "SBIG ST-777E/7XE". Also, click on the "temperature" option and make sure that it is on and set to -5 degrees and turned on. Going into the temperature menu should automatically connect the camera to the computer. You can tell that this has happen by the "status" line in the setup window, which will say "connected" if the link was successfully established. If it is not connected, click "Connect" to do so manually.
7a- Focusing is the hardest part. Go to the "Camera"-"Focus Tools" menu in CCDSoft, and set a short exposure time (around .1-.5 seconds depending on the intrinsic brightness of the object). Also, change the "bin" to 3x3 from 1x1. Now, instead of looking at each individual pixel of the CCD chip separately, the program will look at boxes of 9 pixels together. While we lose some resolution, it is effectively 9 times faster, which is important for the focusing step. Start taking images. You should see a faint doughnut on the screen if you're aligned properly.
Bonus Directions! Check to see if the star is centered as you are focusing. If not, you can slew by using "Telescope"- "Motion Control" within The Sky. A reasonable slew rate is 5 minutes, if the star is in the field of view. You can see the results of the slew by looking in CCDSoft's focus window. Trial and error is the best way to gauge which direction you must slew. Remember that "up" and "north" don't neccessarily correlate, due to the optics as well as the position of the star in the sky. You must re-sync within The Sky after centering the star, in a fashion similiar to step 5d.
7b- Back to the focusing, only there's a catch. The Sky controls the focusing, but you want to focus from within CCDSoft. You need to connect the two programs. To do this, go to "Telescope"-"Options"- "Initialize" in The Sky. Click "Focus Steps" and, if you are very unfocused change these values to 1000 for large and 100 for small. When you get closer to being focused, you can reduce the focus step, perhaps to 100 and 10, or 50 and 5. Often times there is a range of ~50-100 focus units where it is very difficult to tell whether your focus is improving. Don't be too legalistic.
7c- Now you get to focus. If you are initially looking at a
large dim doughnut you will need to zoom IN substantially, on the
order of 9,000 focus units. At first, pick a "large" focus
size, which should move you 1000 units at a time. Once you feel like
you are getting close (the dougnuts are going away) you should change
the bin to 2x2 instead of 3x3. This will take longer, but you will be
able to tell when you are making progress. You might also want to use
the "small" focus size, which is only 100 units worth of
focus change. Finally, when you are VERY close, switch down to 1x1
and make the last adjustments. You can zoom in on a specific region
of the image by clicking the "subframe" box to
"on" and drawing a box aroung the region you'd like to
If you go past focus, such that you are now unfocused in the other direction, you must zoom back out. There is a phenomenon called "backlash" which occurs here. Basically, some of the focus units (about 500) go into changing direction from focusing in to focusing out. Because of this, the same amount of focusing will not be appropriate every time.
8a- Once you are focused you can take the image. Go to "Take Image" and set the integration time for something longer than what you are focusing at. You want to get something like 30000 counts at the maximum, so whatever integration time leads to that would be appropriate.
8b- Sometimes you can be focused and still not see the
features that you are looking for. This is because the image has
become saturated, since it is set to show light which is weak with
the same color (white) that it shows light which is strong. To change
this, go to the menu which controls the display properties and go
into the "brightness and contrast" option. Chance the
background and range until the more useful properties of the image
become apparent. A good first guess for the background value is 250,
with 1000 for the range. Trial and error works best for this. This
method might show that more, fine adjustment is needed.
9- In order to move from one object to another, we will use The Sky's "find" command. Right click on the starry background, and choose "find" from the menu. Use the categories on the left to narrow your search to the object for which you are looking. For instance, if you are looking for a planet, click "planet" and then select the one that you are looking for. Once you specify the desired object, you can slew by hitting the green telescope shaped icon on the bottom panel of the find menu.
10- You will not have to focus too much on a new object, since as far as the telescope is concerned, all stars and planets are essentially infinitely far away. So, make some minor adjustments until the second object is as crisp as possible, and repeat step 8 to take the image. You may need to change integration time, depending on the comparative brightness of the two objects.
Having a problem not covered here? Go to the Trouble Shooting Page.
Back to Observatory PageThis page was originally authored by Eric Furst '03 and is now maintained by Ned Ladd and Jack Gallimore.