Expanding Universe Guided Tour—Ends Nov 14


120 minutes
*Approx 1 mile of walking on hills.


Daily except Tues.

Now thru Oct 17: 6:30pm, 7:15pm, 8pm
Starting Oct 18: 5:45pm, 6:30pm, 7:15pm


$64 adults (13+)

$30 children (6-12)

The Expanding Universe Guided Tour lasts 120 minutes and is designed for astronomy enthusiasts who don’t want to miss a thing. This Guided Tour is led by an observatory educator and includes stops at the historic 24” Clark Refractor and the Pluto Discovery Telescope. It also includes evening viewing at all six telescopes of the Giovale Open Deck Observatory and a laser-guided constellation tour.
In the event that weather makes viewing difficult, the Expanding Universe Guided Tour will replace telescope viewing with a tour of the Giovale Open Deck Observatory and constellation tours will be replaced with a tour of the Putnam Collection Center. This tour includes steep grades and 1 mile of walking.

Note: Stargazing may not be available due to sunset times.

After checking in at the Steele Visitor Center, you’ll see the 124-year-old, 32-foot-long Clark Refractor, which was custom made for the observatory by Alvan Clark & Sons. This 24” diameter telescope was used by Percival Lowell to study Mars and other planets, by Vesto Slipher to find the first evidence that our universe is expanding, and by scientists in the 1960’s to create detailed maps of the Moon in preparation for the Apollo Moon landings. Doors and dome shutters are kept open at the Clark Dome in fair weather to facilitate fresh airflow while guests are inside.

Next, the tour takes you to 1930, when amateur astronomer Clyde Tombaugh discovered the dwarf planet Pluto. You’ll pass by the building that housed Tombaugh’s office and living quarters as you head up the Pluto Walk toward the Pluto Dome, which houses the 13” Lawrence Lowell Astrograph, which was used to image Pluto. Because of the small size of the Pluto Dome, guests will tour the interior in groups of five.

Next, the tour heads to the six advanced telescopes of the Giovale Open Deck Observatory, which just opened in October 2019. One by one, you’ll get to observe a variety of celestial objects at the four visual telescopes, including the 5.5” TEC wide-field refractor, the 8” Moonraker Victorian-inspired refractor, the 32” Starstructure reflector and the 16” Meade ACF catadioptric (using both a lens and mirror) telescope. Telescope eyepieces will be sanitized between each guest. Masks are optional when you are outdoors, but they are required whenever you are indoors. In the event of cloudy weather, your educator will give you a tour of the facility and its six telescopes, but observing will not be possible.

The tour continues at the two PlaneWave CDK catadioptric telescopes, both of which are connected to monitors instead of eyepieces. The 14” PlaneWave is equipped with a MallinCam color video camera that shows detail in celestial objects that are too faint for human eyes. The 17” PlaneWave is equipped with the Slipher Spectrograph, which shows the spectra that astronomers use to learn about an object’s chemical makeup and whether it is moving toward or away from us. In the event of cloudy weather, your educator will use previously captured images and spectra instead of live ones.

Your Expanding Universe Tour will conclude outside the observing plaza at the Giovale Open Deck Observatory. Here, you’ll become acquainted with the constellations that are visible in Flagstaff’s famously dark skies during your visit. Using a high-powered laser, your educator will point out prominent stars and constellations and tell their stories. In the case of cloudy skies, your educator will lead you on a tour of the Putnam Collection Center, a rare treat that is not typically open to the public.

At the conclusion of the Expanding Universe Tour, you can browse the Starry Skies Shop for gifts to commemorate your observatory experience.

To avoid overcrowding, please do not arrive more than 15 minutes in advance of your scheduled start time.

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