By Heidi Schweiker
Edited By Hillary Mathis


Latest updates
PDF version of the February 2011 manual (2.5Mb)

Telescope Operations

   Location of the 0.9m Telescope
   Safety Walk-through
   Safety Interlocks
   Filling the Dewar
   The Dome Cameras
   The Exhaust Fan
   The Wind Screen
   The Dry Air System
   Dome Vent Operation
   Startup Checklist
   Shutdown Checklist
   Overview of the TCS
   Starting Up the TCS
   Telescope Park Positions
   Importing Coordinate Catalogs
   Aquiring an Object
   Small Telescope Motions
   Moving the Dome
   TCS/Instrument Communication
   Checking the Weather
   Data Acquisition Computers
   Checking and Zeroing Pointing
   Changing Filters with S2KB
   Dome Flats
   Guiding with Mosaic
   Guiding with S2KB
   Automated CCD Log
   S2KB Information
   WIYN 0.9m/S2KB FAQs
   The MOSAIC Manual

Troubleshooting Tips
Startup Checklist
Shutdown Checklist
End of Run Checklist


   Lightning Shutdown Procedures
   Extended Horizon Map
   Additional S2KB Information
   The KPFILT script
   More on the Mosaic Guider
   A Unix Cheatsheet
   An IRAF Cheatsheet
   An SFTP Cheatsheet
   An EMACS CheatSheet
   An Vi CheatSheet
   A Guide to Taking Sky Flats
   Dewar Filling Tips and Tricks
   Taking a Seeing Measurement

Other Useful References

   0.9m User's Manual
   ICE Observing Manual
   Direct Imaging Manual
   The MOSAIC Manual



The 0.9-m telescope is located on the southern ridge of Kitt Peak in the Quinlan Mountains, about 50 miles southwest of Tucson.


Prior to starting up the systems or moving the telescope the safety walk-through needs to be done to ensure that systems are at nominal operating conditions and that one can safely move the telescope.

Observing level
Make sure the crane is fully stowed.
Check to make sure the ladder is stowed to the north of the telescope, along the railing.
The platform should be at its lower limit.
Check the area around the telescope for obstructions.
Check cabling on/around the telescope for snagged, strained, or pulled out cables.



Turn off the white light at the entrance.
Make sure the bathroom door is closed.
Make sure the door to the loading dock is open.
Check liquid Nitrogen level: It should be > 1/4 full
If it is monsoon season and you have been doing lightning shutdowns, check the N2 tank pressure: it should be > 500psi
Make sure the preload power supply, in the computer room, is reading voltages
Check in the computer room that the dry air system is running
Turn on the fan above the dry Nitrogen bottles.
Turn off the light in the loading dock area.
Make sure the door to the control room is closed.


Check cables around telescope - make sure none are strained, pulled out.
Check the area around the telescope for obstructions.
Make sure the crane is stowed.
Make sure the handpaddle is properly stowed.
Fill the dewar (if using S2KB) and sign the log sheet.


Bring up the control system on Olive if not already up (Select "ACE" from the desktop)
  - Login and password are on the whiteboard (ACE TCS Olive).
Home the dome
Slew the telescope to the mirror cover park position.


Use the ladder to remove the mirror cover. Be careful not to bump the flat field lamps.
Stow the mirror cover in the blue holder on the south side of the platform.

Move the telescope to the Dome Flat Park position (via the ACE TCS computer). The dome will also move to the correct position.

Open the dome shutter via the control panel on the platform.
Turn on the dome fans.
Open the dome vents - Be sure to turn off the circuit breaker when done.
Plug in the exhaust fan (if humidity is below 70%)
Turn off the dome lights.


Slew the telescope to zenith (Remember to Reset the slew interlock)
Move the telescope to a bright star near zenith and check the pointing or simply turn on the telescope tracking if taking sky flats.
Turn AutoDome on.
Go to your first object and check focus.



Stop your exposure and guiding. Quit the guider software on Moss. If using S2KB be sure to Disconnect the guide camera before quitting the software.
If using Mosaic, turn off the guide cameras and put shutter in "dark" position.
Turn off AutoDome and send the dome to the home position. Under the Dome Menu => Home.
Move the telescope to the mirror cover park position.


Use the ladder to replace the mirror cover.
Close the dome shutter via the control panel on the platform.
Turn off dome fans.
Unplug the exhaust fan.
Close the dome vents - remember to switch off the circuit breaker.
From the control room, bring the telescope to zenith. Fill the dewar (S2KB only) and sign the log sheet.


Log out of and exit the TCS control system on Olive (Select User => Logoff from the top toolbar).
Stow the radio in the charger if you have removed it.
Turn off the heater or A/C and the coffee pot.
Fill out the nitelog form at
Fill out the Observing Run Evaluation if it's your last night.
If there were problems during the night not reported in the night log send an email to the Site Manager at


Turn off the fan in the loading dock.
Check the liquid Nitrogen level: Liquid should be > 1/4 full.
Check that the dry air system is still running.
Check the N2 if you have done lighting shutdowns: The pressure should be >500psi

When leaving the building please make sure the outside door closes fully behind you.

If this is the last night of your run see the End of Run Checklist for additional shutdown items.


For safety reasons, there are a couple of interlocks in the dome that will disallow slewing of the telescope when people are in the dome or the platform is raised. The telescope will also stop slewing if an interlock is tripped during a slew. This only affects a slew - all other functions (telescope tracking, guiding, dome tracking, etc.) will still function normally when an interlock has been tripped.

  1. Motion sensor
    A motion sensor is located below the upper stairwell in the dome. Someone walking on the platform will trip this sensor.
  2. Platform interlock
    When the platform is raised it will trip the interlock. The platform must be stowed at it's lower limit in order to slew the telescope.

When an interlock has been tripped a small window will appear on the TCS.
Safety Interlock Window

The platform interlock is automatically reset when it has been fully lowered. To reset the interlock caused by the motion sensor, click the Reset button in the small window. Keep in mind that you will need to reset this each time you walk onto the platform.


In order to keep the CCD cold the dewar needs to be filled on a regular basis with liquid Nitrogen. The observer is responsible for filling the dewar when S2KB is in use, but the WIYN OA will fill the dewar when Mosaic is on the telescope. The telescope does need to be at the zenith park position in order for the liquid nitrogen fill line to reach the instrument so be sure to park it there at the end of each night. The Site Manager will review proper liquid nitrogen handling procedures with you if appropriate.

S2KB holds approximately 8 hours, meaning it will be necessary to fill the dewar every 8 hours. If the dewar is allowed to warm up it may take quite a while for it to cool down again and could cause the vacuum to go soft, resulting in even shorter hold times. So please be diligent about filling it. However, Mosaic will hold for 12+ hours so you shouldn't need to interrupt observations to have it filled.

To check the temperature of the S2KB dewar and camera type "ccdinfo" in the Data Acquisition window. The last two lines displayed indicate the dewar and camera temperatures. Nominal temperatures are: CCD= -98 Dewar= -191. If the dewar begins to warm up you should stop your observations and fill it with liquid nitrogen, even if it has been less than 8 hours since the last fill.

If the dewar has warmed up, check the troubleshooting section Dewar Warmupsfor recovery procedures.

Mosaic's temperatures are constantly displayed on the Mosaic GUI. If the dewar begins to warm up mountain personnel will be notified by email and will come to fill the dewar shortly.

The dewar is usually filled at the beginning and end of each night with liquid nitrogen (you may have to interrupt observations during the night to make sure S2KB is filled every 8 hours). There is a fill line and valve mounted on the side of the telescope pier that runs down to the 230L dewar in the loading area where the liquid nitrogen is stored. The fill line should be precooled before attaching it to the instrument - simply open the valve on the observing floor and point the fill line away from you. Close the valve when liquid starts to spew out of the line and attach the line to the instrument. Liquid will spill out (of the overflow holes between the dewar and the nut attaching the line to the instrument) when the dewar is full. Close the valve when it is full and replace the cap on the dewar.

For more help on filling a dewar, see the href="">Dewar Filling Tips and Tricks section in the Appendix.


There are two small video cameras fixed in the dome - one located on the south wall and the other just below the stairs above the motion sensor. The cameras allow you to view the telescope and platform area when there is light in the dome. (Nothing will be visible on the cameras during the night or when the lights are off.)

You can view the video on Olive. On the Desktop there is an icon called Video Cam. Double clicking will open the camera viewer. A small window with 4 quadrants will pop up. The quadrants are labeled CH1, CH2, CH3, CH4. We have the capability to view up to four cameras, but only channels 1 and 2 have input. At the moment the camera on CH2 has a lot of noise.


To help improve the seeing at the 0.9m an exhaust fan has been installed along the polar axle. This will draw air across the primary mirror, alleviating pooling of hot air on the mirror.

If the outside humidity is greater than 70% this exhaust fan should not be used. For more on how to check your humidity see the weather section.

Currently, operation of the fan is done manually. (Weather permitting) the fan should be turned on when opening the dome for the evening, and turned off when closing in the morning. The fan is located on the observing level behind the telescope pier. You will need to plug in the electrical into the socket on the wall to turn it on and uplug it to turn it off.

In order to determine the effects this fan is having on seeing we request that observers closely monitor seeing throughout the night, noting the seeing in the nightly observing report. In addition, we request that observers check the seeing near the end of the night on a very short, unguided exposure (e.g. on a standard star field) on a field that is at less than 2 airmasses. This seeing measurement should be noted in the comments section of the nightly observing report


In cases where the wind has not reached the closing limit of 45mph, but the telescope shake is affecting science, a wind screen is available for use. The controls are located to the left of the dome slit. In order to reach the controls the dome must be rotated to face the slit west. Make sure to turn the power on for the controls before use and turn it off after moving the screen into place.


The WIYN 0.9m observatory uses a dry air system in order to keep the dewar window from frosting up. Normally, this system is active 24 hours a day and does not require the attention of the observer outside a quick visual check at the beginning and end of a night to make sure it is running. The compressor for this system is located in a small exterior room on the very south side of the observatory.

Operation of this system should be checked at the beginning and end of each night as part of the start-up/shutdown procedure. To check its operation, go to the computer room and find the moderately sized blue box mounted on the wall near the black air compressor. The power button should be in the "On" position, the green light should be illuminated on the panel, and ONE of the two pressure gauges should read just short of 40psi. This system alternates between two internal pressure tanks, so only one of the two pressure gauges should read any pressure at a time.

See the Troubleshooting section of this manual for problems related to the dry air system.


The 0.9-m at sunset with 7 of the 11 ventilation louvers visible.

In August 1994, dome vents were added to the 0.9-m dome to provide much improved flow-through ventilation as part of an image quality improvement project. The 11 individually controllable vents are located opposite the dome slit to allow the dome air to flush several times per minute under typical wind conditions. Rapid flushing helps eliminate warm air pockets from forming in the dome, which in turn, reduces convection that would otherwise compromise image quality (that is, "seeing").

Normally, some complement of vents will be opened at the beginning of the night, around sunset, and closed when the telescope is closed. If the dome is iced up, the vents may need to be broken free.

Based on limited testing, the dome flushes adequately with about half the vents open during mild wind conditions. You may wish to open every other vent.

Under the following conditions the observer should restrict the air flow by closing some or all of the vents.

  • High gusting winds that cause the telescope to bounce.
  • The dome shutter is opened during the day and the outside temperature is higher than inside.
Selective operation of the vents is done by setting the switches on the control panel located near vent #7, opposite the dome shutter, as described in the "detailed operation" section below.

If the air is very calm, less than about 5 mph, you may wish to open additional vents.

Detailed Manual Operation of the Vents

In this mode, one can open or close any or all of the 11 vents individually. The vent control panel consists of four types of switches as described below. The term "ensemble of vents" refers to those vents whose "Together-Off-Separate" switches are set to "Together".

  • Auto-Off-Manual - this is the main control switch at the top of the control box.
    • Auto - Enables automatic open/close of the ensemble of vents when the dome shutter is opened/closed. This disables manual open/close operations from the "Open-Close" main switch (see next major bullet).
    • Off - Disables both automatic and manual open/close operation of the ensemble of vents.
    • Manual - Disables automatic open/close of the ensemble of vents when the dome shutter is opened/closed. Enables manual open/close of the ensemble of vents with the "Open-Close" main switch.
  • Open-Close - This switch operates on the ensemble of vents. It is a "momentary" switch which must be held while the vents continue to open or close.
  • Together-Off-Separate - This is a row of 11 switches, each having 3 positions, to control the detailed operation of an individual vent.
    • Together - Include this vent as part of the ensemble.
    • Off - Remove this vent from the ensemble and disable it from manual open/close operations.
    • Separate - Remove this vent from the ensemble and enable it to be opened/closed manually by its individual open/close manual switch (see next major bullet).
  • Open-Close (row of 11) - If the individual vents "Together-Off-Separate" switch is set to Separate, then it can be opened/closed by its individual open/close switch from this row (towards the bottom of the control panel).

Last updated 03/05/09 hlm