Amateur astronomer Gus Johnson talks about his black hole discovery 31 years ago
AMATEUR ASTRONOMER GUS JOHNSON, using a relatively simple instrument, keen eyes and a dark sky, was only the third person to find a supernova in another galaxy by direct observation when he made his discovery in 1979. Over the next 30 years, scientists observed that supernova, with powerful instruments such as NASA's Chandra X-ray Observatory, and believe they have witnessed the birth of a black hole 50 million light-years away. Johnson, now 72, works at Deep Creek Park in Western Maryland, where he does maintenance work and leads astronomy programs and an occasional nature walk.
- Peter Edmonds, astronomer, Chandra X-Ray Center
How did you develop an interest in astronomy, and particularly the Virgo Cluster?
Astronomy captured my interest around 1952 after browsing through an encyclopedia in my eighth-grade classroom. A year later, I started getting Sky & Telescope magazines and now have about 55 years' worth. The February 1954 issue had a chart for finding galaxies in the Coma-Virgo cluster, a chart made by Leland Copeland. I had neither dark skies nor a reasonable-size telescope for actually seeing the fascinating objects described.
Around 1967, I had a fine Cave six-inch reflector and relatives with a farm in central Pennsylvania, and it was there that I took my first tour of those galaxies. I was living at Deep Creek Lake in Western Maryland with fairly dark skies, though many trees limited my sky. By the mid-1970s, I had moved to a small place with a less-obscured sky. I liked to make at least one annual tour through those galaxies, with no scientific purpose, just enjoyment.
What are some of the details behind your discovery of SN 1979C?
In 1979, the minister of my church was a young man interested in astronomy, so I took him on a tour of the Coma-Virgo cluster. And it was on that night that when we viewed M100 that for some reason I felt I should check on a little star near the galaxy's edge. I think I put off checking until the next day, April 19, when I did not find that star on a [Mount Palomar Observatory] photo, after which I phoned the American Association of Variable Star Observers of a possible supernova. They sent out the alert, and soon it was confirmed by Asiago and McGraw-Hill observatories. I followed its progress until it slipped into the trees west of my home. I have strange quirks of memory and don't know why that little star caught my attention; maybe I had a subconscious memory of a photo of it. I still use Leland Copeland's chart and recently made a larger one strongly based upon Copeland's. This is a cloudy area, so I am limited in how many tours of the region I can make, and [I like to check] numerous other galaxies around the sky for supernovae, having some supernova search charts, photos and my own sketches. It was an exciting discovery for me.
What do you think your chances would be of repeating this discovery today?
With all the competition of large amateur telescopes and computer-animated systems, I have little hope of finding another supernova, yet it is fun to try. Back in 1979 there were some automated systems, but they missed the M100 supernova. Maybe they had cloudy skies or the computer was "down." I felt rather like the mythological John Henry, who beat the machine.
Did you have competition for this discovery?
Sky & Telescope reported the supernova in its June and July 1979 issues. The July issue, Page 90, reports that on April 18-19, 1979, G. Kuipers, of Zuidhorn, the Netherlands, noted a star in M100 that caught his attention, but then he found it on a photo, "but had doubts when he could not recall another star which appeared of equal brightness in the photograph. Cloudy weather prevented further observation until Mr. Kuipers learned of the supernova's discovery." How well I know that cloudy weather problem!
How do you like to make observations?
I have about a dozen telescopes, from 1.6-inch to eight-inch diameters. All are portable, since a fixed observatory here would have too restricted skies. I like observing in a low-tech manner using star trails to my target objects and not using go-to computerized telescopes. I feel a bit like the British astronomy popularizer, Patrick Moore, who prefers to not use computers and uses an antique typewriter. I've memorized the positions of about 250 objects and have made many charts for at-the-telescope use.
After retiring as a middle school teacher, what other work have you been involved in?
For decades I did volunteer work at several local state parks: Swallow Falls State Park, Herrington Manor State Park, New Germany State Park and Deep Creek Lake State Park, as well as at two in West Virginia, mostly helping with astronomy programs. For about a decade now I have been a paid employee (and volunteer) at the Deep Creek Park. At the Deep Creek Park, I work at its Discovery Center; my boss, Caroline Blizzard, also enjoys astronomy and is a big help. One of our programs is the raising of monarch butterflies, and in this I may have made a minor discovery, that their chrysalises, of somewhat irregular shape, align in a certain direction, suggesting to me that they may use the Earth's magnetic field, in part, for their amazing migrations.