Observatories make great locales for nightscape photography. This October 9, 2019, field trip to the Very Large Array in New Mexico illustrates how to plan an observatory astrophotography adventure. Thanks to the Astronomy in Chile Educator Ambassadors Program for making this trip possible.
The National Radio Astronomy Observatory Karl G. Jansky Very Large Array, NRAO VLA, is one of the great telescopes of the world. The VLA is located in central New Mexico, just west of the town of Magdalena, New Mexico, on U.S. Highway 60. The nearest city, Socorro on Interstate Highway 25, is about an hour away. The cool dry air at the VLA’s altitude of 7,000 feet (2,100 meters) makes it a wonderful site for astrophotography. It has been used as a location in feature films, including the 1997 movie “Contact” (1997), based on the novel by astronomer Carl Sagan and starring actress Jodie Foster. The 10-story, 230-ton, array antennas are a perfect symbol for humanity’s exploration of the universe silhouetted against the brilliant sky.
Because of the safety issues inherent in such a large outdoor facility, and the sensitivity of the telescopes to electronic interference, amateur photography is only permitted from the self-guided walking tour, which is only open during daylight. Nighttime photography on the VLA grounds, amateur or commercial, requires an approved application and payment of a large location fee. Fortunately there is an alternative on a public highway right of way.
Traffic on U.S. highway 60 is usually light late at night, but caution is advised due to the remote location. Emergency services, food, water, and other supplies are many miles away. Cell phone signals are weak and phones should be off except in emergencies. The highway right-of-way is wide. However, the terrain is rough and it is easy to fall in the dark. A fence marks the boundary of the VLA facility. Under these very dark remote conditions, an observing buddy, red light flashlight, water, snacks, warm clothing, and first aid supplies are important for a good experience and safety.
The antennas can be deployed in configurations ranging from 22 miles (35 km) in diameter (A) to a tightly packed configuration just 0.6 miles (1 km) wide (D). The D configuration shows multiple antennas well, but is not accessible to the public at night.
The wider A and B configurations use an antenna location on the north arm just off of U.S. 60 directly across from a public parking area. This is in the highway right of way, past the turnoff for the visitor center when headed west, near where the north arm rail tracks cross the highway. Nighttime amateur photography is possible from here which captures the antenna against the northern sky.
The NRAO VLA Configurations page can be used to identify dates that the array will be in the A & B configurations. Remember that snow is possible in winter months at this 7,000-foot (2,100 m) altitude. Thanks to earlier monsoon rains, we encountered dew problems before dawn and were able to make good use of some hand warmers to keep our camera lenses clear. Don’t forget to check the local weather forecast as your date comes close. Astrospheric is a great resource for detailed astronomical forecasts a few days out. The NOAA National Weather Service has many forecast products for longer range predictions.
This location offers many creative possibilities. For your equipment, you need a camera and lens suitable for astrophotography and a sturdy tripod. Short to medium focal length lenses allow you to trade off the size of the antenna and amount of sky captured. Different locations along the fence can juxtapose the antenna with the northern Milky Way or Polaris. Longer exposures can capture star trails around Polaris.
Creative use of options allow stacking and post processing images for different interpretations.
Shorter exposures (20 to 30 sec) capture the Milky Way from a fixed tripod.
The antenna can be captured in silhouette or illuminated by passing cars. Headlights from approaching cars are visible for miles. As a car approaches lighting on the antenna and foreground landscape can vary dramatically.
Another possibility, capture a time lapse video of the antenna as it switches from target to target. Sunrise on an early morning can be spectacular, be sure to wait for daylight images after sunrise, before heading in to Magdalena for breakfast.
Bottom line: Tips from an astrophotographer for making photos at the Very Large Array radiotelescope site in New Mexico.