SALT LAKE CITY (ABC4) — According to the National Aeronautics and Space Administration, a “once in a lifetime comet” is in plain view of Utahns, due to a near pass of Earth that occurs once every 80,000 years.
Comet C/2023 A3 Tsuchinshan-ATLAS can be seen from Earth with the right timing and equipment. “Oct. 14-24 is the best time to observe, using binoculars or a small telescope,” NASA said. As of the writing of this article, the comet is approximately 72.8 million kilometers (about 45.24 million miles) away from Earth, according to SkyLive.
According to NASA, while the comet will be difficult to see during the day, it has the chance to be seen during twilight hours.
Tonight, according to SkyLive’s Planetarium, the comet will appear nearly 40 degrees above the horizon, above both Mercury and Venus in the southwestern sky. With the sun setting just before 7:00 p.m. local time, the best time to view it is roughly 45 minutes after sunset during mid-twilight, NASA said.
The National Weather Service projects cloud cover for the next two nights (Monday and Tuesday) to be the best chance to view the comet in the short-term forecast this week. This comet has the potential to be seen with the unaided eye if conditions in space are right.
NASA states that data estimates Tsuchinshan-ATLAS’s stellar magnitude is between 2 and 4, making it hard to see during the day. Stellar magnitude is measured on a logarithmic scale, which makes a magnitude 1 star exactly 100 times brighter than a magnitude 6 star.
The lower the number, the brighter the celestial body is. For example, Tsuchinshan-ATLAS’s brightness is estimated at +2 to +4 versus Venus’s magnitude of –4 (Venus being the brighter of the two).
NASA says the comet might get a little bump in brightness due to what is called “forward scattering.” Forward scattering is defined as a phenomenon where scattered particles are deflected in the forward direction, which is utilized in determining intra-molecular and interatomic directions on surfaces in physics and astronomy research.
According to NASA’s calculations, the comet’s magnitude could reach a magnitude of –1 with forward scattering, a stellar brightness that is close to the star Sirius. That would make the comet visible to the unaided eye.