​Last week we were lucky enough to see a celestial event that could be seen across our entire northern sky; the Aurora Borealis.
 
Last night, 19 October 2024, we experienced a celestial event that was much harder to see; comet Tsuchinshan-ATLAS; also known as Comet C/2023 A3. The comet came from the Oort cloud and was only discovered on 9 January 2023 by the Purple Mountain Observatory in China when the comet was ~7.3 AU (1.09 billion km; 680 million mi) from the Sun.

The first naked eye observation of the comet from Earth was reported on 23 September 2024. It made its closest approach to Earth on 12 October, at a distance of 71 million km (44 million mi). When visible the tail was reported to be 10 degrees long under dark skies and 17.5 degrees long photographically. By 2 November the comet had faded to below magnitude +6 and was no longer visible to the naked eye.
 
Based on astronomical calculations the Tsuchinshan-ATLAS comet came from the Oort Cloud - which lies far beyond Pluto and the most distant edges of the Kuiper Belt. The Oort Cloud is believed to be a giant spherical shell surrounding the Sun, planets and Kuiper Belt Objects (KBOs). It's like a big, thick bubble around our solar system, made of icy, comet-like objects.

​
​Because of the comet's orbit (a retrograde orbit, lying at an inclination of 139°) Tsuchinshan-ATLAS did not approach close to the giant planets of our Solar System. Consequently, the comet is only weakly bound to the Sun and it is calculated that the outbound orbit will become a hyperbolic trajectory that will most likely result in the comet being ejected from the Solar System - never to return.

​Here are some of the photos of the rare sight that we saw last night between 6:30 PM and 7:30 PM here on the East Coast: ​​(click on any photo to start the slideshow)

​In addition, here’s a 1-minute time-lapse video of the Comet Tsuchinshan-ATLAS captured from space by Astronaut Matthew Dominick onboard the International Space Station (ISS).

The past two nights the conditions were good for potentially seeing the Northern Lights here in New England once again. One chance to see the Aurora Borealis as far south as the Boston area is very rare; twice in the same year is unheard of. So, on the nights of 10 and 11 October 2024, we ventured out in the late evening and luckily got to see some amazing sights.
 
As with the last time earlier this year (on 10 May 2024), prior to heading out we consulted the National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center (https://www.swpc.noaa.gov/) to check the forecast to find out if the conditions were actually good for seeing the Northern Lights in our area – since they’re the authoritative source for solar and space environment data.

We also checked our “Sky Live”, “Moon Calendar” and “Lumnos” apps once again to see what the sky conditions were, the phase of the moon, and the location of the moon in the night sky.  

The air was crisp, the skies were clear, and the moon was in the Southern sky – so the viewing conditions were excellent. As mentioned in our previous Aurora blog from earlier this year (11 May 2024), we found that our cameras “saw” the lights (which are caused by charged particles from the Sun interacting with the Earth’s electromagnetic field) much better than our eyes. So, we had to shoot lots of photos and then see what showed up on our cameras. Again, we were surprised many times because the faint colors and striations that we saw in the sky were much brighter and more pronounced in the images that our cameras captured. Here's a great write-up by Ewen Bell explaining why this occurs: "Why Auroras Look Different on The Camera"

The gallery below shows photos of the Northern Lights that appeared in our town’s skies during the two nights – along with a couple photos of our Town Center that was coincidentally lit up that week: ​ ​(click on any photo to start the slideshow)