Information for Visiting Observers

The information on this page is intended exclusively for users of the F. L. Whipple Observatory who are conducting professional astronomical research.

Here are some of the MOST IMPORTANT items regarding your observing run.   Many of these are intended for first-time observers, but it is advisable to review them from time to time, as we update the features periodically.   If you find errors or if you have suggestions, please let us  know (see below for  contact information).

Phone system:

FLWO switched to a VoIP phone system in November 2011. There are more numbers now and many more capabilities such as caller ID and voicemail.
A directory with current numbers is available here (pdf, accessible only from FLWO and CfA).

From any FLWO phone, you need only dial the last 4 digits of another FLWO number.


Make dorm reservations, preferably two weeks in advance of your arrival, for the Summit or Ridge dormitory. As of December 2018, the cost of a room for non-SAO observers is $50 per night. Reserve your room by submitting this form.
Please contact Mara Lopez-Becerra ( or Murdock Hart ( for help with dorm reservations and for the combinations to the doors and gates.

Transportation to the Observatory:

Flights: Make your travel arrangements through your respective institution's Travel Department or agency.
Taxi Service or Car Rental at the Airport: Out-of-town visitors may consider renting a car if scheduled on the mountain for 3 days or less. The rental car cost is generally less than the round-trip taxi of $130, plus tip. For observers scheduled on the mountain more than 3 days, you will want to read the following regarding the taxi service to the Administrative Complex (Basecamp).

The physical address for FLWO is:    

F. L. Whipple Observatory
670 Mt. Hopkins Rd.
Amado, AZ 85645

For deliveries of packages by UPS or FedEx, use the physical address.
For postal deliveries, the address is:

F. L. Whipple Observatory
P.O. Box 6369
Amado, AZ 85645

Taxi Service:

This is a small business that will pick you up at the airport, stop at a grocery store in Green Valley and drive you to the Administrative Complex for a total trip time of two hours. The taxi service does NOT drive you to the telescopes on the mountain.

At least two days prior to the requested service, call April Van der Pohl at April's Transportation Services, (520) 596-9743. If necessary, leave a message for with your name, phone number, airline, flight number and arrival/departure times.

It is your responsibility to make a reservation with the taxi service. Call regarding any changes to your trip schedule or to cancel out. Taxi reservations that are not cancelled will be billed to you.

Driving Between the Administrative Complex and Mt. Hopkins:

Your decision about driving your rental car or an observatory vehicle (known as FLWO shuttles) should be based on weather and road conditions, your compliance with the vehicle policy and your confidence with driving on a narrow, unpaved, winding mountain road.  To check road conditions, call 520-879-4422 for a recorded message.The message is updated only when there is a change in road conditions.

Observatory visitors (including rental car users) are required to read the Vehicle Operator's Guide. Prior to your visit, you must comply with the Vehicle Policy. You may download these documents here. NOTE THAT INCLEMENT WEATHER (WINTER SNOW OR SUMMER MONSOON RAIN) MAY MAKE DRIVING TREACHEROUS ON MT. HOPKINS ROAD so you may need to use a 4-wheel drive vehicle from the FLWO fleet. Visitors must review the policy; sign the statement and, prior to their visit, email it to the staff listed above.


FLWO has an all-digital radio system.
Please read the User Manual (PDF) if you have any questions.  Here is a summary for handheld units:
Rental or Personal Vehicle Users:

Ensure you know the gate combination (see below) and pick up a hand-held VHF radio from the Administrative Complex. Radio chargers are located in the Central office area on the upper level. Radios should be set to channel 1 (or "normal" on some radios).


If you do not have a driver's license or you are not confident about driving on a narrow mountain road, you should arrange in advance with your project, FLWO, or MMT staff for transportation round-trip between the Administrative complex and one of the dorms.

Driving directions and maps:

For directions from the University of Arizona, see the Tucson Map.
For driving directions from Tucson visit this link, which includes a map of the vicinity of Mt Hopkins.
Layout of FLWO on Mt. Hopkins.

Gate and Building Keypad Combinations:

Be certain that you know the current lock combination for the gate on Mt. Hopkins Road at km 13 and for the Administrative Complex gate, as well as for the doors to the buildings. One combination applies to all building locations, but not for the gates. Please call the staff listed above for the current numbers. Shuttles are equipped with remote openers mounted on the driver's visor. They operate just like a garage opener: press the button as you approach the gates from the outside (at km 13 and at the Administrative Complex).

NOTE: ALL keypad combinations were changed  on 01/11/14
NOTE: ALL gate (not building) combinations were changed  on 12/12/16

Protecting all Telescopes from Vehicle Headlights  is crucial!

On the mountain:

It is imperative to keep the outside of the dorms as dark as possible. Any outside lights must be turned off whenever possible. In individual rooms and in common areas, curtains must be closed at night. Lights in rooms or in common areas must also be turned off when visitors are not in the dorms.

If you need to drive to a telescope after dark, you should warn observers either by radio, or by telephone from the Ridge dorm or the Common building at the bowl. It is about a 10-minute walk from each dorm to its corresponding telescope (although the summit road is steeper and more challenging than the Ridge road).

At the basecamp:

The VERITAS collaboration operates four 12-meter telescopes at the Basecamp.   Their hours of operation are posted daily on a whiteboard in the Basecamp Ready Room; typically they operate every dark moonless night.  A set of road-level LED lights will be blinking, approximately one-half mile above and below the Basecamp on the side of Mt. Hopins Road whenever VERITAS is operating.  Because the telescopes are extremely sensitive, they could be damaged by passing headlights, day-time running lights and even reversing lights.

When VERITAS is operating, outside lights at the Basecamp must be turned off, or kept to a minimum.  VERITAS observers monitor the FLWO radio system and can be contacted by phone at the VERITAS control room, 520-879-4435.  If you plan to enter or pass by the Basecamp while VERITAS is in operation please make sure to notify the observers in advance.

Other important information:

Food:   The Observatory has no food service so you must buy groceries on your way to the Administrative Complex in the Sahuarita/Green Valley area.  The Observatory maintains fully equipped kitchens with a variety of staples such as coffee, flour, margarine, and condiments.  Outdoor grills are available. Kitchen users are responsible for timely dishwashing and kitchen clean up.

If you are using the taxi service, your driver will stop at a supermarket and either wait for you or pick you up at an agreed time.   If you are driving yourself from the airport, the following list of supermarkets and their business hours are:

- Fry's on Sahuarita Road - Exit 75, East (6AM to 11PM)

- Safeway on Duval Mine Road - Exit 69, West (Hours: 5AM to 11PM)
- Wal-Mart on Duval Mine Road - Exit 69, East (Hours: 24 hours)
- Safeway on Continental Road - Exit 63, West (Hours: 5AM to 11PM)

Personal Supplies : Bring warm clothes and winter shoes/boots as it snows in southern Arizona winters, especially above 4000 ft.  You may want to have lip balm and hand lotion along on your trip as it is very dry on the mountain.  First-aid kits are available in all buildings but non-prescription medicines (e.g., anti-histamines, antacids and aspirin) are not supplied by the Observatory.

Staffing Hours: The Ridge telescopes (1.5m and 1.2m) have daytime staff who work Monday through Friday, unless emergency repairs are necessary, approximately 9:15am to 4:30pm.   Basic telescope instructions are provided mainly during these working hours, or by arrangement. Observers arriving on Saturdays or Sundays to use the 1.5 or 1.2m telescopes will most likely have no one to instruct them. Please consult the MMT Observing Policies link for MMT information.

Computers: The telescope computers usually accessible to observers are all connected to the internet via the mountain network. At the Ridge, FLWO provides (as is, without support) internet connections for portable computers, as follows.  In the telescope control rooms, you will find cables with RJ45 connectors to plug a laptop to the network via dhcp. At the telescope buildings and at both dorms, you will find wireless (G) access points.  Your connectivity and its quality will vary significantly as a function of your coordinates.

Filters: The 1.2m telescope has a BVRI Harris filter complement (the default), a set of SDSS and some narrow-band filters in residence, mounted on an 8-slot filter wheel. If you need filters other than the default set to be mounted, make sure you email or call in to the staff a request, well in advance of your trip to FLWO. For MMT instruments, please consult the MMT observing page.

NOTE: only 1.5/1.2m staff members are allowed to change 1.2m filters.

Training: Night-time instruction is required for observers new to the telescopes. Such observers should contact the staff and the observer that precedes them to arrive and arrange for training at least the night before the beginning of their own run. It is very effective to accompany an experienced observer for a first run.

Observing: At times, the person who actually observes is not the PI on the proposal that was awarded time. In that case, it is the responsibility of the PI to advise FLWO staff of who will be observing, in advance of the run. The PI should also ensure that the observer communicates with FLWO staff regarding any special needs, such as filters, and that the observer will have prepared by studying the appropriate online manuals. Observers who have not used the facilities for more than a year should also reacquaint themselves with all relevant online manuals.

Local fauna: Mount Hopkins is within the Coronado National Forest and is home to a large number of animals. Some of these, such as bears or snakes, may be dangerous. Please avoid approaching them. Never attempt to feed any wildlife.  Here are some examples of recent sightings.

Steve Johnson, an experienced Tucson climber, was climbing near the FLWO site over the weekend of 05/04/13 and was found dead on 05/07/13, possibly due to
multiple bee stings (see news article). Please be aware that bees are here and if agitated may become aggressive! If you wish to read about avoidance measures
this article should be informative.

If you have any questions or comments, please do not hesitate to contact Murdock, Mara, or Tom.
If you see a swarm of bees report it to your supervisor, Murdock, Mara, or Tom at once and inform everyone in the area.

User's Guide to Safety and Training Information: The safety and security of all users are of the utmost concern to FLWO. All visitors, especially those who have never visited or not visited in a while, should take the following two steps. First, take the time to read our User's guide before traveling to Mt. Hopkins; please download the PDF file here . Second, fill out, sign and date the form in the last page of the guide and have your supervisor do likewise. Please email the completed and signed form to and

Updated 12/20/2023 by AC