Karen Masters shares her seasonal guide to stargazing, including her favorite JWST photos, Jupiter’s Opposition this September, and a calendar of major stargazing events this Fall.
Karen Masters is a Professor of Physics and Astronomy, Chair of Physics and Astronomy, and KINSC Director at Haverford College.
JWST Images
JWST, the “Just Wonderful Space Telescope” (here I am deliberately avoiding the official full name due to the ongoing name controversy, and instead amplifying Chanda Prescod-Weinstein’s excellent renaming suggestion), has been wowing astronomers all over the world with its images of the cosmos since it achieved first light in February of this year.
It’s tough to pick out just a couple of favorites from such a selection of beautiful images, but given my research interests in how spiral arms affect their host galaxy, my first pick has to be spiral galaxy IC 5332, seen with smooth spirals in the older Hubble Space Telescope image (which uses optical and UV light), but looking like a frothy mess in JWST (which uses infrared). Some fascinating astrophysics there for sure, which researchers will be spending time to work out.
Two views of IC5332. Left: HST shows large scale spirals, while at right, JWST shows how they are all connected with each other. Image via NASA.
Next up is Neptune’s rings. I bet you have all heard of Saturn’s rings, but did you know that all of the outer planets have rings of some kind? Neptune’s rings shine ethereally in this JWST image, the best view we’ve had of distant Neptune, famously the first planet discovered using calculus, since the Voyager mission flyby in 1989! The JWST image also features Neptune’s bright moon, Triton, shown surrounded by the beautiful, six spoked diffraction pattern of the telescope, which has hexagonal mirrors. I find this to be a fascinating illustration of the optics of light passing through apertures, which Haverford students can explore more in both PHYS102 and PHYS106 labs.
I’ll segue to Jupiter for my final JWST pick, with this stunning infrared image of the planet, revealing details of the cloud bands and storms, as well as light from Jupiter’s aurora. So beautiful.
Jupiter Opposition
You might have spotted Jupiter in the news a lot recently because of its recent “opposition.” The internet seemed to be overcome with how amazing Jupiter would look, urging people to get outside and view it. On September 26, 2022, Jupiter was at its closest point to Earth since 1963, however these close passes in general happen roughly annually, as the Earth overtakes Jupiter in its orbit.
Opposition literally means “opposite the Sun,” from our perspective on Earth. At these times, Jupiter is high in the nighttime sky, and bright because it’s relatively close. It makes a stunning sight every year. This year, the opposition happens close to a special point in Jupiter’s orbit, known as the perihelion — its closest distance to the Sun. This makes the distance between Jupiter and the Earth a tiny bit less than it usually is at opposition, inspiring refrains like “the giant planet’s closest approach to Earth in 60 years” and “closest in your lifetime.” You can explore the Earth-Jupiter distance online.
This year Jupiter is a bit less than 2% closer than it was last year. The students running Public Observing nights at the Strawbridge Observatory were delighted with a stream of requests to view Jupiter the day this happened, but don’t worry if you missed it — Jupiter remains very close, and a visually stunning sight for most of the rest of the semester. It’s well worth a look — both with the unaided eye in the East just after sunset, and through our on campus telescopes if you make it to a public observing night.
In fact the skies are full of planets this Fall, and these are some of the best sights to just enjoy in the night skies (if you can see them around the light pollution) as well as through small telescopes like the ones we have. As well as Jupiter, Mars will pass through opposition soon (December 8th) making it a bright object in the evening sky. Uranus also passes opposition, but that can only be seen in a telescope and isn’t that exciting unless you know what you’re looking at! Saturn passed through its opposition back in August, but remains also a bright evening object all Fall, a bit to the left of Jupiter.
Below is a screenshot from the free Planetarium software, Stellarium, showing the S-SE horizon around 10pm on Friday 21st October, with Mars, Jupiter and Saturn all lined up across the sky. From the Observatory, this is the direction back towards campus. You might need to head out across the athletic fields to get a low enough horizon to spot Mars.
Fall 2022 Stargazing Diary
September
26th: Jupiter at opposition (closest since 1963). Don’t worry that you missed this exact date. Jupiter will still be impressive for the entire Fall semester.
October
8th: Mercury at greatest western elongation (furthest angle from the Sun) in the morning sky
9th: Hunters Moon (A traditional name in many cultures for the Full Moon in October)
21/22nd: Orionids Meteor Shower
22nd: Venus passes behind the Sun (“superior solar conjunction”) to reappear in the evening skies later in the year
25th: Partial solar eclipse visible from Russia
November
4/5th; Taurids Meteor Shower
6th: Clocks “Fall” back, ending Daylight savings time. If the Sunshine Protection Act from last year passes the House and gets signed by the President, this could be the last ever Fall clock change in the USA.
8th: Beaver Moon (Native American name for the Full Moon in November) and a Lunar Eclipse (best visible across the African continent).
9th: Uranus at opposition (closest to Earth)
17/18th: Leonids Meteor Shower
December
7-8th: Moon and Mars close on the sky (from some locations Mars passes behind the Moon)
8th: Full Moon (the “Cold Moon”).
8th: Mars at opposition
13/14th: Geminids Meteor Shower
19th: Full Moon
21st: December Solstice (5.40pm ET). The longest night of the year in the Northern hemisphere, and the longest day in the Southern hemisphere.
21st: Mercury at greatest eastern elongation (furthest angle from the Sun) in the evening sky
January 2023
3/4th: Quadrantids Meteor Shower
6th: Wolf Moon (full Moon in January)
30th: Mercury at greatest western elongation (furthest angle from the Sun) in the morning sky
This article was edited by Emi Krishnamurthy.