March 19th's "Super Moon" Over Boston

Like many of you, I was curious to see last month's "super Moon" — when the Moon became full within an hour of its orbital perigee. The numbers told me that its diameter would be about 14% greater than it is at apogee and consequently look about 30% bigger by area. Technically, though not by much, it was the closest and biggest full Moon in 18 years.

As it turned out, the full Moon happened during the busiest part of Sky & Telescope's editorial cycle; my colleagues and I were in the final stages of readying the June issue for the printer. But that evening was superbly clear in Boston, and I figured I really needed to take time to record the moonrise.

I have several favored locations for shooting astronomical events above the Boston skyline, but it was a rather last-minute decision to use Prospect Hill in Waltham. This location has several good viewing spots, and I decided to set up at the base of the radio tower. Since the access road is gated in the winter, I walked from the parking lot. Reaching my spot, I had a commanding view of the city skyline about 10 miles away. Luckily, someone had recently cleared brush from around the radio tower (probably a "fire" thing), which made it a lot easier to find a viewing spot low to the ground and away from the guy wires for the tower.

My setup consisted of a Nikon D700 camera body set at ISO 200. The “lens” was a Tele Vue NP-101 refracting telescope — effectively a superbly sharp 540-mm f/5.4 “telephoto” lens. I used a handful of the D700’s features: live focus, shutter delay, auto-bracketing, matrix metering, and auto white balance, to name a few. To improve stability, I put a clamshell ring on the telescope's front end and attached that to one tripod, then put the camera body on a second tripod.

Then I waited in the gathering darkness. While I have the ability to calculate the precise location of the rising Sun and Moon from a given spot, the last-minute nature of this photo shoot ruled out doing the math. I did know that the Moon would rise behind the “interesting” part of the skyline, but not exactly behind which features.

The full Moon rose along the distant horizon, its shape grossly distorted by atmospheric refraction. Just to the left of the orange lunar disk is the distinctive control tower at Boston's Logan International Airport. To its right, topped by lights, are the tall, twin towers of the cable-stayed Zakim-Bunker Hill Bridge that spans the Charles River near its mouth.

Well, despite the last-minute preparations, it all worked. My photograph was eagerly shown by several Boston television stations and on the Boston Globe’s website. On March 24th, it was NASA’s "Astronomy Picture of the Day." Thanks to all of you who sent me messages and kind comments about the photograph.

A final thought: If you managed to miss March's perigee full Moon, you won't have to wait too long for another chance. It'll again become this large and bright next year on May 6th, when full Moon falls within only a few minutes of lunar perigee.