You have to take measurements in the following cases:

- checking the reflectivity of the mirrors

- snowcleaning - before and after

- vapour washing - before and after

IMPORTANT notes (Tibor):

- it turned out (December, 2006) the head could be sensitive to the temperature changes, so it is essential to bring the reflectivitymeter to the place where the measurement of the given mirror will take place and leave there at least 15 minutes before the measurement (in these places the temperature could be considered as stable)

- also because of the same reason, after CO2 cleaning of the mirrors it is necessary wait approx. 15 minutes until the mirror is cooled down, and take the measurements only after this 15 minutes; otherwise it can happen that the reflectivitymeter will show incorrect results (e.g. reflectivity above 100%)

Together with these files a calibration measurement has to be made on the standard mirror in the little Melles Griot case. The reflectivity of the calibration mirror has to be measured just before the measurement of the given mirror to have the same conditions (e.g. temperature) in both measurements. Please use some caution handling this calibration mirror.

1. Connect the laser head with the red module (this is the control unit)
2. Take the protection of the head by pulling it off. Do not screw it is a tight fit and not a screw head
3. Clean the white part of the head wit the optical tissue (try not to get any dust in the hole. Do not use alcoholic liquids to do this)
4. Switch the control unit ON
5. With the up and down arrows ( ­ and ¯ ) get the arrow ( > ) on the display at " > SETUP " and press ¿
6. Then to " > FILE " and ¿
7. Then to " > ADD FILE " and ¿ to make a new file
8. Use the up and down arrows ( ­ and ¯ ) to get the right letter and the left and right arrows ( ¬ and ® ) to go to the next letter. Make the file name as follows:

WHTPBDATE or INTPADATE or CALDATE

WHT = The telescope name (can also be INT or JKT or CAL for calibration)

P = The mirror first letter ( P = primary, S = secondary, N = nasmyth)

B = Before snowcleaning

A = After snowcleaning

DATE = date of the calibration (day/month)

After this press ¿ to save the name

9. Press ESC until you are back in the MAIN MENU
10. Move the arrow to " > MEASURE " to measure the reflectivity
11. Make sure that " > SAVE " is on ALWAYS
12. Put the head on the mirror and press the red button on the measuring head. When it gives the second "beep" then the measurement has been done (you see the results on the screen).
13. Do at least 10 measurements on the mirror (on the WHT at least 10 measurements on each quadrant).
14. Press ESC until you are in the MAIN MENU and OFF to turn the control unit off.

If you want to see a summary of the measurements go to SUMMARY in MAIN MENU and press ¿

Then go to " > FILE " and chose the file you want to see.

When you are done please leave the aluminium case in the OPS room.

To download the files from the control unit use the following instructions. You need to have a computer with any Windows version and one spare serial port to connect the RS232 connection.

1. Connect the charger on the main power supply and the serial port of the computer.
2. Insert the red control unit in the charger
3. Switch on the charger with the switch on the back above the power cable
4. Start the Uscan program on the computer. If this is not on the computer you can install or run it from the diskette which is in the black book in the uscan case.
5. Switch the control unit ON
6. With the up and down arrows ( ­ and ¯ ) get the arrow ( > ) on the display at " > RS232 ACCESS " and press ¿
7. On the computer go to FILE and DOWNLOAD in the main menu
8. The link between the computer and the Uscan is made now
9. Make sure the PATH NAME is set correct so you can find the files back
10. Click the files in the menu which you want to download
11. The files are now on the disk under the path name you entered
12. To make them readable go to FILE and CONVERT to covert them to ASCII file type (.prn)
13. Click the files in the menu which you want to convert
14. The files are now on the disk under the path name you entered previously
15. Exit the menu and the Uscan program by following EXIT

This does not have to be done regular because the memory can contain quite a few measurement files

1. Make the connection between the control unit and the computer using step 1 to 6 of the previous procedure
2. On the computer go to FILE and DELETE
3. Click the files in the menu which you want to delete
4. Make sure you don't delete any files which are not downloaded onto the computer

Please make sure the diskette with the Uscan program is returned in the black book