A Night of Observing at the KPNO 0.9m Telescope:

Opened in March 1960, the National Science Foundation's 0.9-meter telescope was the first major telescope at Kitt Peak National Observatory. After 41 years of service to NOAO, operations of the 0.9m were transfered to the WIYN consortium in February 2001. Despite its relatively small aperture, the 0.9m is a popular instrument because of its large field of view. This website recalls the history of the 0.9m, with a virtual tour, a pictoral description of a typical night at the telescope, a gallery of images taken with the 0.9m, and anecdotes from some of the many astronomers who have observed with this remarkable instrument. You may click on any image to see an enlarged version.

A Night at the 0.9m:

This page recalls the night of January 11th, 2001, in many ways a typical night of observing at the 0.9m. NOAO astronomer Travis Rector recalls that evening, on which he used the 0.9m to take images of M31 and M33, in an ongoing RBSE project to search for novae in Local Group galaxies.


0.9m Telescope

Its a 12 mile drive from the base of Kitt Peak to the summit.


Driving to Kitt Peak:
Kitt Peak is 56 miles west of Tucson. It takes about 75 minutes to drive to the summit from NOAO headquarters, which is located on the University of Arizona campus. The mountain is open to the public daily from 9 a.m. to 3:45 p.m. After that time it is closed so that astronomers can prepare for the night's observing.


0.9m Telescope

The door on the left is the entrance to the 0.9m telescope.


Arriving at the Telescope:
I arrived at the summit of Kitt Peak around 2pm. It was my first scheduled night so I wanted enough time to make sure the telescope and Mosaic, a powerful electronic camera attached to the telescope, were working properly. Technical assistant Bill Binkert erased the data on the computers from the previous observers and made sure the correct filters are in place in Mosaic.


0.9m Telescope

Removing the cover to the telescope.


Removing the Telescope Cover:
Once the computer is initialized the next step is to calibrate the telescope, which requires uncovering the telescope. On most professional telescopes the primary mirror cover is opened and closed via a motor. However, to remove the cover to the 0.9m, the telescope must be tilted over and the platform must be raised. The astronomer must stand on a step ladder to reach up and remove the cover.
      speakerListen to the platform as it moves up to the telescope.


0.9m Telescope

The white spot is the white circle inside the black square.


Calibrating Mosaic:
The rest of the afternoon was spent calibrating the instrument. This is done in part by pointing the telescope at the "great white spot" on the side of the dome and taking exposures. The spot is uniformly illuminated with halogen lamps on the end of the telescope. Images of the white spot are used to calibrate the sensitivity of the electronic camera.


0.9m Telescope

The cafeteria serves meals for lunch and dinner.


Off to Dinner:
While the calibrations are underway I head down to the cafeteria for dinner. Casey Muse and the rest of the kitchen staff keep the mountain well fed. Usually we also eat a "night lunch" in the middle of the night. Plenty of food is available in the cooler. I like to stock up on food because it helps keep me awake late at night. After dinner I put on warm clothes and head back up to the telescope for the night.


0.9m Telescope

The 2.1m telescope is visible at the bottom of the dome slit.


Opening the Shutter:
The domes may not be opened if the weather is considered to be potentially dangerous to the telescope. Weather permitting, the dome shutter is opened just prior to sunset to get ready for observing. Observing can begin about 45 minutes after sunset, leaving little time after sunset to set up the telescope.


0.9m Telescope

The Mayall 4m telescope as seen through the open louvres.



Ventilating the Dome:
The louvres are also opened at this time to let air flow through the dome and bring the telescope to the ambient temperature. Fans in the dome and in the basement are turned on to flush out pockets of warm air.


0.9m Telescope

Clouds billow from Mosaic as it is being filled with liquid Nitrogen.


Keep it Cool:
After the dome is opened, liquid nitrogen is pumped into Mosaic to keep it cold. The camera is most sensitive when kept at -100 degrees Celsius. The silver cylinder in the center of the instrument is a dewar that holds enough liquid nitrogen to keep it cold for about 16 hours.
      speakerListen to the dewar as it is being filled with liquid nitrogen.


0.9m Telescope

Weather on Kitt Peak usually moves in from the southwest.


Checking the Weather:
Unless a bright moon is up, its difficult to see clouds once the sun has set. Thus its a good idea to go outside before sunset and check the weather. More often than not the weather on Kitt Peak is clear, windy and cold. On this night it was partly cloudy, but we were able to observe.


0.9m Telescope

Sunset over the southwest ridge of Kitt Peak.


Time to Work:
Tradition dictates watching sunset before every night of observing. I've never missed a sunset. Not only is it beautiful, but its a good way to mentally prepare for staying up all night. After sunset, every minute of the night is used. Telescope time isn't easy to get, so a minute isn't wasted.


0.9m Telescope

Twilight flats are taken shortly after sunset.


Imaging the Deep Blue Sky:
Just after sunset (around 5:45pm) I turn on the telescope and start to take calibration images of the sky during twilight. These images are used in much the same way as the images of the white spot in the dome. While harder to get, images of twilight usually provide a better calibration. The dome is synchronized to move such that the telescope is always looking out the open shutter.
      speakerListen to the awful racket the dome makes each time it moves.


0.9m Telescope

The pointing and focus can be checked during twilight.


Initializing the Telescope:
As twilight starts to fade the sky becomes dark enough to check the "pointing" of the telescope. Like most other research-grade telescopes, movement of the 0.9m is controlled by computer. To check the pointing and focus, the telescope is commanded to move to a bright star. If the pointing is good, the bright star will fall at the center of the field of view. Stars within the field are used to focus the telescope. When properly focused, the stars will look like sharp points.


0.9m Telescope

The telescope and dome move to track the object.


Moving to the First Target:
Once twilight is over (around 6:30pm) I pointed the telescope towards the first scientific target to be observed that night. My first target was M31, the Andromeda Galaxy. It is a nearby galaxy that we are studying in a search for novae. Once centered on the galaxy, the autoguider is started. The autoguider is another electronic camera that is designed to help the telescope accurately track the night sky.


0.9m Telescope

An image of M31 taken with Mosaic and the Hydrogen alpha filter.


Taking Images with Mosaic:
I commanded Mosaic to move the Hydrogen Alpha filter into place and start the first exposure. The Hydrogen Alpha filter only allows a certain color of red light to pass through that is produced by hot Hydrogen gas, thereby making it easier to detect this gas. Mosaic consists of eight CCD cameras which are combined to make a single image consisting of over 64 million pixels. Each processed image taken by Mosaic is over 300 megabytes in size!


0.9m Telescope

Life of glamor? Most of the night is spent in front of a computer.


The Nightly Grind:
I finished observing M31 around 9pm and moved onto the next target, the nearby galaxy M33. Once underway, a night of observing is fairly dull. Time on Kitt Peak telescopes is valuable and hard to get, so each minute of darkness is used, observing from dusk until dawn. During the winter this can be as long as 15 hours. As long as there are no problems with weather or the telescope, the hardest part of observing is simply staying awake.


0.9m Telescope

The summit of Kitt Peak in moonlight.


But it's Wonderful!
To stay awake, I like to go outside to walk around and get some fresh air. A clear night on Kitt Peak is a thing of wonder, and something you never forget. On this night the moon was nearly full, and was brightly illuminating the landscape. While the telescope was busy collecting data, I was outside watching the stars myself.


0.9m Telescope

Mosaic needs to be refilled after a night of observing.


Closing Time:
I observed until morning twilight began (around 6am). The long night is mercifully over and its time to shut down the telescope and close up the dome. It can be tricky to remember everything you need to do at 6am when you've been up all night! The last step is refilling Mosaic with liquid nitrogen to keep the camera cold during the day.


0.9m Telescope

I was able to observe all night despite incoming clouds at dawn.


Closing Time:
After closing down the telescope the goal is to get in bed before sunrise. I find it hard to sleep after seeing the sun. The dorm rooms have light tight shutters so you can sleep during the day. I usually wake up around noon and spend the afternoon checking on the data from the previous night. You may visit the 0.9m Image Gallery to see some of the images that have been taken with the 0.9m over the years. Additional images are also available in the NOAO Image Gallery.




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