Alien invasion or flares from satellites in multiple orbits? It depends on your point of view. We also check in on Comet Lemmon, poised to possibly reach binocular-visibility.
Early last month several of my friends drove to western Oklahoma to observe and photograph under some of the darkest skies in the country. Around 4 a.m. one morning a couple of the guys noticed slow-moving lights low above the horizon in a small patch of sky in the constellation Leo. They watched for about 20 minutes unsure of what they were seeing and then returned to observing, joking about aliens.
The morning after, Mike Brown, an avid astrophotographer from Eau Claire, Wisconsin, and member of the group, stayed up to watch Venus rise before heading back to bed.
"I told Don to come get me if the aliens showed up again," he recounted. "I walked back toward the guest house, maybe 20 feet, and Don called out that 'they' were back. So I turned around and we watched the lights for a good 45 minutes. The experience had a heavy 'freaky' moment to it. They would start dim, get quite bright, and then fade away again. They were moving in a downward direction but never upwards. Each light was visible for up to about a minute."
The group puzzled out potential explanations for what they saw — a military exercise with paratroopers wearing lights, sky lanterns, fireworks? Tongue firmly in cheek Brown hypothesized a portal in spacetime through which aliens entered. But after getting a close-up view through a telescope of one the lights, satellites seemed a better if prosaic explanation.
"So much for aliens and the portal idea," said Brown.
But they still had questions: Why at that particular time of morning? Why flares in just one small patch of sky? When I learned of the incident and saw Nick Hartman's amazing time-lapse video (above) one word came to mind: Starlinks. What else could produce multiple flares night after night? As it happened, I had observed a similar display of slow, downward-moving lights low in the northwestern sky after nightfall in northern Boötes about a week prior. I told Mike and the crew I'd look into it.
Orionids vs. Aliens
Then the Orionid meteor shower happened. While watching the show on the peak morning of October 22nd I noticed tiny lights low in the eastern sky just east of Leo's Tail. The aliens had returned! As the shower eked out a handful of zippy meteors, I simultaneously kept an eye on the slow eastern descent of one flaring satellite after another in western Coma Berenices approximately 7–10° high in the northeastern sky. Some grew as bright as magnitude –2 while others only reached 3rd magnitude. Typically, I saw one or two at a time but occasionally three would briefly glow and fade away. I watched this very slow-motion "meteor shower" for at least 40 minutes before turning in.
To confirm my suspicions I got help from members of the Visual Satellite Observer Mailing List (Seesat-l). Indeed, they were flaring Starlinks. Anthony Mallama, who worked as an astronomer on the Hubble Space Telescope and other spacecraft missions at NASA's Goddard Space Flight Center, confirmed that we all had observed flaring Starlink satellites. You may know Mallama from his tireless work monitoring the brightness of BlueWalker 3, AST-SpaceMobile's prototype for a new satellite constellation.
"The Sun’s azimuths at 3:15 and 4:15 CDT were 52 and 67 degrees respectively [on October 22nd]," he wrote. "Meanwhile the satellites were around 68 degrees. This near alignment suggests that the flaring was due to specular reflection from a flat surface on the nadir side [point directly beneath the satellite] of the various spacecraft. I have seen this occur with Starlink satellites."
Antonio Vilchez, another satellite enthusiast, explained that the Starlinks had reached their final orbits and that the zone of Starlink flares "moves during the night from west to east, following a Sun-satellite-observer line." In the Northern Hemisphere that transition occurs across the northern sky; in the southern hemisphere the satellites shift eastward across in the southern sky. Depending on the observer's latitude flares may be visible either throughout the year or only during the summer months.
Various apps will show this clustering of multiple Starlinks such as Orbitrack, available on Google Play for Android phones, and SkySafari Pro. To track the latest Starlink launches check out SpaceX Starlink or Heavens Above.
By now I suspect almost every amateur astronomer has had their fill of Starlink satellites, so consider these observations as a public service message. If you happen to see the slo-mo light parade at least you'll know we still haven't discovered that portal yet. Sorry, Mike.
Give Comet Lemmon a Squeeze
A 21st-magnitude comet discovered on April 23rd this year may reach binocular visibility during the second week of November. Dubbed Comet Lemmon (C/2023 H2), astronomers found it robotically during the Mount Lemmon Survey, which is part of the Catalina Sky Survey based at Stewart Observatory's Catalina Station near Tucson, Arizona.
Over the past few weeks the diffuse object has slowly ascended the northwestern sky, taking leave of the Big Dipper and climbing into better visibility. During November it will continue to brighten, gaining speed and elevation as it tracks from northern Boötes across Hercules. By good fortune the Moon won't be a bother until after mid-month by which time Lemmon will have begun to fade.
Perihelion occurred on October 29th at 0.9 a.u. Closest approach to Earth of 29 million kilometers (18 million miles) will happen on November 10.9 UT. I last observed the comet on October 11th at magnitude 10.5; current COBS observations peg it at around 9.5 and brightening. Through my 15-inch at 64× Comet Lemmon appeared quite diffuse with a moderately condensed 4′ coma. Although Saturn and Jupiter make fantastic observing targets right now, having a relatively bright comet on the evening stage gives observers yet another reason to comingle with the cosmos.