Site Description

Winer Observatory Aerial Photo The observatory site provided by Winer to its customers is located at latitude N 31° 39' 56.08" and longitude W 110°36' 06.42" at an elevation of 1515.7 meters (4973 feet) as measured by GPS (WGS 84 Datum). This site is approximately 27 km (17 miles) east and 2.7 km (1.7 miles) south of the MMT Observatory on Mt. Hopkins, and is 5 km (3 miles) east of the town of Sonoita, Arizona (population approximately 1200).

The altitude is a compromise between good sky transparency and good weather. Although higher elevations can provide better transparency, they also are subject to lower temperatures, more freezing precipitation, higher winds, and more frequent lightning strikes. These mountaintop conditions can exact a heavy toll on observatory, telescope, and instrument systems which makes operation of a fully automatic observatory and telescope more difficult and expensive. Such expenses must, inevitably, be passed along to those whose telescopes are located at the site. Our view is that mountain tops are financially viable for large telescopes with large operating budgets, but not for smaller telescopes with proportionally smaller operating budgets.

The site enjoys good weather - roughly 60% of the total hours without lunar interference are usable, with half of these being of all-sky photometric quality. Most cloudy nights occur in July and August during the summer rainy ("monsoon") season. Operation of the site includes keeping accurate logs of the weather, and we plan to install a seeing monitor during the coming year.

Customers should be aware that with a roll-off roof, telescopes are more subject to wind and dust than if they were mounted in a dome. Consequently, critical parts (drives and encoders in particular) should be enclosed, and optics should be protected by motorized covers when not in use. Truss assemblies for secondary mirror support are favored over tubes for reduced wind loading, which places greater demands on proper optical baffling.

Our land is zoned General Rural, which permits cattle grazing, sheep ranching, agriculture, and residential structures. The zoning does not permit a high level of vehicular traffic. Consequently, we cannot permit observers to visit their telescopes to observe on a regular basis. Our facility is designed for remote, robotic observing using the Internet to transfer command and data files.

The location in southern Arizona, famed for its clear skies and dry air, coupled with the experience of the staff in astronomy and electronics, gives you the best combination of site and service to meet your research and education needs.

Climate Summary from the Western Regional Climate Center

The data in the table below were taken over the period January 1, 1910 through March 31, 2003 at the Canelo 1 NW station (station number 021231).

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Average Max. Temperature (F) 57.9 61.4 66.2 73.7 81.7 90.4 88.2 85.5 83.7 76.5 65.9 58.1 74.1
Average Min. Temperature (F) 26.1 28.2 31.7 36.7 43.4 52.4 59.8 58.4 52.6 41.9 31.8 26.7 40.8
Average Total Precipitation (in.) 1.22 1.19 0.92 0.45 0.20 0.73 4.41 4.04 1.69 1.04 0.84 1.40 18.13
Average Total Snowfall (in.) 1.6 1.3 0.9 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.2 1.25.4
Average Snow Depth (in.) 0 0 0 0 0 00000000

Information

Percent of possible observations for the entire recording period:

Max. Temp.: 78.7%, Min. Temp.: 79%, Precipitation: 97.3%, Snowfall: 96.4%, Snow Depth: 95.9%

Table of Open Nights by Month

The data in the table below show the number of nights each month of each year listed the roof was open for more than half the night. In 2004, the roof was operated manually, while in 2005 through 2007, it was operated automatically by computer, but was not closed by weather sensors. During these years, when the roof was open, it was open the entire night. Also during these years, the roof was closed throughout most of July and August and at least half of September to avoid the annual summer monsoon season. The "Closed" column includes those nights outside the Monsoon season when the Observatory was closed due to weather (the usual cause), equipment failures, or vacation by the Winer staff in 2004 through 2006. In 2007, we began keeping separate records of vacation days outside the monsoon season (vacation taken during the monsoon season does not count, as we are shut down during that time).

Year J F M A M J J A S O N D Open Monsoon Closed Vacation
2004 10 18 20 20 29 23 0 0 8 25 17 19 193 83 89 n/a
2005 18 7 20 28 18 21 3 0 11 23 25 26 200 73 92 n/a
2006 26 21 18 24 25 13 0 0 15 22 26 23 213 78 74 n/a
2007 17 19 27 23 24 26 3 0 10 28 21 24 222 76 58 9
2008 19 21 25 29 24 19 0 0 14 24 24 20 219 85 42 10
2009 24 22 22 24 24 15 0 0 15 27 22 26 221 82 49 13
2010 22 16 26 26 29 25 0 0 10 22 29 23 228 81 54 2
2011 28 22 30 23 27 28 0 0 11 28 18 15 230 80 55 9
2012 27 22 27 23 26 20 0 0 14 30 23 22 234 85 41 6
2013 24 18 27 26 24 13 0 0 14 28 19 24 217 93 48 7
2014 28 22 26 23 13 30 1 0 6 25 28 21 223 83 38 21
2015 19 22 20 25 25 15 0 0 8 10 24 21 189 93 76 7
2016 22 25 26 24 30 17 0 0 10 25 24 14 217 93 76 7

Page last updated on: January 20, 2017