The normally faint quasar CTA 102, once thought to harbor an advanced civilization and made famous in a 1967 song by the Byrds, is currently bright enough to see in an 8-inch telescope.
In the history of SETI, the Search for Extraterrestrial Intelligence, there have been two great false alarms. The first occurred in 1963 when powerful radio waves were detected from the source CTA 102 in Pegasus. Followup observations in 1965 showed that the source's radio emission was varying, prompting then-Soviet astronomer Gennady Sholomitskii to declare that an advanced civilization was behind the transmissions.
Not long after, observations made with the 200-inch Hale Telescope identified the fluctuating object as a quasar, a supermassive black hole at the center of a remote galaxy.
The second false alarm is associated with the discovery of the first pulsar by Jocelyn Bell in 1967. The steady "thunk" of radio signals every 1.33 seconds earned this object the nickname LGM-1, short for "little green men." Pulsars are rapidly rotating neutron stars that beam a narrow beacon of radio waves in our direction every rotation. Some rotate hundreds of times a second and sound like buzzing bees when the signals are converted into sound.
But back to CTA 102. The worldwide buzz about an alien origin for the quasar was still in the air in 1967 when the American rock band the Byrds recorded the song "C.T.A. 102" on their Younger Than Yesterday LP. The lyrics (below) offer a hopeful message, and the upbeat tune ends with a fun twist — be sure to give it a listen. This may be the only song ever recorded about a quasar!
Year over year receiving you
Signals tell us that you're there
We can hear them loud and clear
We just want to let you know
That we're ready for to go
Out into the universe
We don't care who's been there first
On a radio telescope
Science tells us that there's hope
Life on other planets might exist
Like many quasars, CTA 102 is subject to variations in its light depending on what the supermassive black hole is consuming and how it goes down. Powerful gravitational and frictional forces cause material in an accretion disk around the hole to radiate tremendous amounts of energy, primarily in X-ray wavelengths, but also in radio, visual, and other forms of light, before it's sucked into the black hole and disappears forever.
Normally, CTA 102 glows weakly at around magnitude +17, a terrifically tough target for most amateur astronomers. But in early November it underwent a dramatic outburst in brightness. I tracked it down Monday night (November 21st) in my 15-inch scope at magnitude +13.8! That's well within range of an 8-inch telescope.
Thomas Balonek (Colgate University) and team reported in Astronomer's Telegram #9732, that "to our knowledge, this is the brightest level reported in over 40 years of optical monitoring by several groups, including the well-documented optical outburst in 2012."
Others have recorded rapid variations in the quasar's light of up to 0.4 magnitude in the span of just two hours. With the Moon out of the sky and the target on the meridian at nightfall this month and early next, I encourage to feast your eyes on this rare event.
You'd be wise to start your observing session with CTA 102, making an estimate of its magnitude using the provided chart or download and print this sequence of AAVSO charts: B (wide field), D (narrower view) and E (close in). Note that the alternate name, 4C 11.69, is used by the AAVSO. Return an hour or two later, before finishing up for the night, and make another brightness estimate. Given the quasar's erratic behavior, you might just witness it in the act of choking on its food!
The "CTA 102" comes from the 102nd entry in the Caltech Survey, part A, a very early radio survey done at Owens Valley California, according to Matthew Lister, Professor of Physics and Astronomy at Purdue, who examined the quasar with the Very Long Baseline Array (VLBA). At 8 billion light-years distant, it might be the easiest, most remote object you'll ever see.
But be sure to look quick! There's no telling how long this outburst may last. Using the maps, star-hop to the erstwhile alien beacon with an 8-inch or larger telescope. Once you've arrived in the general vicinity with low magnification (50×-75×) and identified the brighter star patterns, up the magnification to 150x to pinpoint the quasar then increase the power to 200×. High magnification darkens the sky for a clearer, higher contrast view of those ancient photons.
The Byrds may have flown, but CTA 102 remains to thrill the visual observer with raw power and visions of long, long ago.