Tag Archives: Woody Sullivan

Herschel’s observation of comets

To say that Woody Sullivan is interested in William Herschel would be quite an understatement.

“I have dressed up as Herschel for Astronomy 101 half a dozen times,” said Sullivan, a professor emeritus of astronomy at the University of Washington. He started a file on Herschel, the 18th and 19th Century astronomer, some 30 years ago, but can’t exactly pin down why he was so drawn to him.

“I have eclectic interests,” Sullivan said. “I’m always looking for what I call astronomy on the edges: astronomy and music, astronomy and astrology, history, literature, sundials.”

“Herschel was that way to some degree,” Sullivan added. “Perhaps that was it; I saw a fellow traveler there.”

Woody Sullivan

Prof. Woody Sullivan at the May meeting of the Seattle Astronomical Society. (Photo: Greg Scheiderer)

Sullivan noted that it was nine years ago that he started doing more serious research into Herschel with the intent to write a biography. While there have been many penned, including a couple in the last decade or so, Sullivan noted that none have been particularly scholarly, and so that’s a void he’s aiming to fill. After all of that research, the actual writing has begun.

“I do need to get on because I’m getting on,” Sullivan quipped. He spoke about his work at the most recent meeting of the Seattle Astronomical Society, discussing Herschel’s work on comets, about which few biographers have gone into much detail.

While his sister Caroline Herschel discovered eight comets, six of which bear her name, William never found one, though he came close a couple of times. He once reported a comet discovery, but the French astronomer Jean-Louis Pons had already found it a month before. Then in 1781 Herschel reported another comet discovery. But after six or eight months of observation, astronomers more skilled in the calculation of orbits found this new object to be in a nearly circular one well beyond Saturn’s. It was a new planet: Uranus.

First to “discover” a planet

“It’s hard to think about what a new planet means. What planets did we have before? We had the same planets that we had had since Ogg the caveman,” Sullivan noted. “Herschel was the first one to find a planet telescopically, and this made him instantly famous.”

William Herschel

William Herschel. (Photo: Public domain)

Herschel parlayed that into a gig as the court astronomer for King George III. It was actually a pay cut from Herschel’s work as a professional musician in Bath, but he supplemented his income by building and selling telescopes, and by marrying a rich widow. Herschel was mostly interested in deep-sky objects, but comets came to his attention on occasion, in part because he was interested in change.

“A comet is change par excellence,” Sullivan said. “It just appears in the sky, it’s different every day, you never know what’s going to happen.”

While Caroline wanted to discover them, William aimed to understand what they were. Sullivan noted that this wasn’t what most astronomers were doing then.

A different sort of astronomer

“Astronomy at that time was measuring accurate positions of things; planets and their moons and comets and stars for catalogs,” he said. “That’s why you had the Greenwich Observatory. The government was paying for that, not because they loved astronomy but they loved the navy, and you needed that for navigation.”

Herschel’s observations of the great comets of 1807 and 1811 were interesting. Sullivan pointed out that astronomers at the time thought there might be a planet or other object at the nucleus of a comet. Herschel was the first to claim he’d spotted one. When others couldn’t find it, Herschel chalked it up to the superior optics of his telescope. By the 1811 comet, he was trying to figure out if the nucleus reflected light from the Sun, or generated its own light. Herschel declared that the nucleus of this comet was perfectly round, and thus self-illuminated, because if it reflected light it would show phases. Sullivan, after poring through Herschel’s logs, concluded that he had fallen into a trap that scientists need to avoid.

“There’s just no doubt that he was picking and choosing the observations that fit into his concept,” Sullivan said. It was a bit of a reach to claim to be able to determine the roundness of an object of perhaps an arcsecond in width within the fuzzy coma of a comet.

“He’s getting all of his theory and observations mixed up,” Sullivan said. “This can get you in trouble.”

Though Herschel missed on this particular analysis, Sullivan noted that Herschel made some interesting conclusions, particularly in describing the tail of a comet as its atmosphere being pushed away by pressure from the Sun. Though it’s not the atmosphere, but dust and gasses, nobody to that point had really postulated that the Sun might be pushing on things. Other descriptions Herschel made of the mechanics of comets are not so far off from what is held true today.

Sullivan’s presentations are always interesting, and we look forward to the completion of the book and to learning about William Herschel, a fascinating character in the history of science.



Lots of great choices for astronomy events this week

There are tons of great astronomy events on the calendar this week, topped by the opening of the Museum of Flight’s Apollo exhibit and a visit from the Night Sky Guy.


ApolloA couple of years in the making, the new Apollo exhibit opens Saturday, May 20 at the Museum of Flight, though museum members can get an early sneak-peek Wednesday evening. The exhibit includes the F-1 engine parts fished out of the Atlantic Ocean by Bezos Expeditions, an intact F-1, and many more great space exploration artifacts. Check out our recent article and podcast previewing the exhibit.

The Museum will also hold its annual Space Fest over the weekend with a variety of presentations, exhibits, and discussions focused on Apollo and the Moon.

The Night Sky Guy and Mars

Andrew Fazekas, aka The Night Sky Guy, is in Seattle for three talks at Benaroya Hall. Titled “Mankind to Mars,” the event will be an exploration of what it will take to get humans to the Red Planet. It’s produced in conjunction with the Mars miniseries created by the National Geographic channel. One show was Sunday afternoon, and Fazekas also appears on Monday, May 15 and Tuesday, May 16, both at 7:30 p.m.

Fazekas is the author of Star Trek: The Official Guide to Our Universe: The True Science Behind the Starship Voyages (National Geographic, 2016).

AstronoMay at PacSci

Pacific Science CenterAstronoMay is under way at the Pacific Science Center, and a couple of interesting events are on the calendar for this week. Astronaut Nicholas Patrick will host a viewing and discussion of the film A Beautiful Planet 3-D at 7 p.m. Tuesday, May 16. The film is a portrait of Earth from space captured by the astronauts aboard the International Space Station. Patrick will introduce the show and lead a Q&A session after. He’s now with Blue Origin; see our article about Patrick’s recent talk at Astronomy on Tap Seattle. Admission is $10, or $5 for science center members.

Then learn the ABCs of total solar eclipses, and get ready for the one that will be visible in parts of the United States in August, with Dennis Schatz, nationally recognized astronomy educator and Pacific Science Center senior advisor. Total Solar Eclipse 101 happens at 7 p.m. Wednesday, May 17. Cost is $5, free for members.


RiekeNASA’s next great space observatory, the James Webb Space Telescope (JWST), is scheduled for launch in October 2018. George Rieke, a professor of astronomy at the University of Arizona and science team lead for the Mid-Infrared Instrument (MIRI) that will fly onboard the scope, will speak at the University of Washington astronomy colloquium at 4 p.m. Thursday, May 18. The talk will focus on the capabilities of JWST, emphasizing the advances over present (and even some future) facilities, with examples of the science it will enable.

Club events

Rose City Astronomers will hold their monthly meeting at 7:30 p.m. Monday, May 15 in the OMSI auditorium in Portland. It will be their annual swap meet and astronomy information fair. The club, along with OMSI and the Vancouver Sidewalk Astronomers, will host public star parties at 8 p.m. Saturday, May 20 at both Rooster Rock State Park and L.L. “Stub” Stewart State Park.

The Island County Astronomical Society will hold its monthly meeting at 6:30 p.m. Monday, May 15 at the Oak Harbor Library.

The Seattle Astronomical Society monthly meeting will be at 7:30 p.m. Wednesday, May 17 in room A102 of the Physics/Astronomy building on the University of Washington campus in Seattle. Guest speaker Woody Sullivan, professor emeritus of astronomy, will talk about the contributions of William and Caroline Herschel to our understanding of comets. Sullivan is working on a biography of William Herschel.

The Tacoma Astronomical Society plans one of its free public nights for 9 p.m. Saturday, May 20. The topic for the indoor presentation will be black holes. If the weather cooperates they’ll break out the telescopes for some observing.


Theodor Jacobsen ObservatoryThe bi-monthly open house at the UW’s Theodor Jacobsen Observatory is set for 9 p.m. Wednesday, May 17. The topic for the evening’s astronomy talk has not been published. It’s a good idea to make reservations early, as these typically are filled up. Volunteers from the Seattle Astronomical Society will conduct tours of the observatory dome and, weather permitting, offer a look through its vintage telescope.

Planetarium shows

The Bellevue College Planetarium will run a public show about black holes at 6 p.m. and again at 7 p.m. on Saturday, May 20. The show will include animations of the formation of the early universe, star birth and death, the collision of giant galaxies, and a simulated flight to a super-massive black hole lurking at the center of our own Milky Way Galaxy. It’s free, but reservations are suggested. See the website for registration info and other details.

The Willard Smith Planetarium at the Pacific Science Center offers a variety of shows every day. Their full schedule is posted on our calendar page, where you can also scout out more future astronomy events.


Seattle as sundial capital of North America

“I am passionate about sundials,” says Woody Sullivan, professor of astronomy at the University of Washington. “I have a goal to turn Seattle into the sundial capital of North America.”

Most of us don’t think of Seattle as the capital of anything related to the Sun, and we’re especially grumpy about it in the midst of a relentlessly gloppy March. But Sullivan points out that the second half of our year has long, clear days, and he observes that while people in, say, Phoenix often seek to escape from the Sun, we celebrate it.

“In Seattle, when the Sun comes out you go running out to see your sundial!” Sullivan says.

Sullivan gave a talk titled “Sundials Around Seattle and Beyond: Fascinating Mixtures of Astronomy, Art, Design, and History” at a recent meeting of the Eastside Astronomical Society in Bellevue. While the designation of sundial capital is hardly an official one, Sullivan thinks Seattle is on the way because of its large collection of interesting, well-cared-for public sundials.

The sundial on a SW-facing wall of the University of Washington Physics/Astronomy building was the first Sullivan helped build and design, 20 years ago.

The sundial on a SW-facing wall of the University of Washington Physics/Astronomy building was the first Sullivan helped build and design, 20 years ago.

Sullivan’s academic interests include astrobiology, the search for extraterrestrial intelligence, and the history of astronomy. His passion for sundials came about almost by accident. When the UW was constructing a new physics/astronomy building in the early ’90s, he suggested that a sundial should be placed on one of its large, outside walls. The architects went for it, and Sullivan spent a couple of years supervising the design and installation of the sundial.

“This is what got me into sundials, and ever since my life has been changed,” he says.

Inspired by the design of a sundial at the Sorbonne in Paris, the UW dial is on a wall that faces southwest. That means it’s design is asymmetrical, “which I think is more interesting from an aesthetic point of view,” Sullivan says.

Sullivan notes that all good sundials have a motto, and the one for the UW dial is “What you seek is but a shadow.”

“I thought that was good for a university,” he says. “It feels like it’s making progress.”

In a nod to our northwest weather the dial also is inscribed with a little poem:

I thrive on the Sun
Can’t work in the rain
So if I’m beclouded
Please come back again.

There’s a wealth of information about the UW dial on the web, including a webcam.

If you visit a Seattle sundial you will notice that the it doesn’t agree with your watch.

“Sundials do not tell you clock time,” Sullivan explains. “Your watch is off because we keep the same time as the people in Spokane. That ain’t right! Solar noon”—the moment when the Sun is due south and highest in the sky—”happens there 20 minutes before it happens here.”

Mars dials.

Sullivan helped design pancam calibration targets like this one that also serve as sundials on the three rovers on Mars.

Sullivan gave us a look at numerous other sundials in the area, and he’s had a hand in the design and construction of many of them. They’re in parks and at schools and even on picnic tables. He supported the Battle Point Astronomical Association in its successful effort to fund a new sundial on Bainbridge Island which is scheduled to be completed this summer.

In addition to all of those here on Earth, Sullivan also helped design three sundials that are now on Mars. The rovers Spirit, Opportunity, and Curiosity all have targets that are used for color calibration of their cameras in light and in shade. Bill Nye the Science Guy, who is now CEO of the Planetary Society, saw a mockup of the target, a disk with a post in the middle of it, and immediately thought it should be a sundial. Nye got Sullivan involved in the design. Coincidentally, Tyler Nordgren, astronomer who keynoted the Seattle Astronomical Society‘s annual banquet in January, was also part of the team that put it together.

Woody Sullivan

Woody Sullivan brought a variety of small sundial samples to his talk, and the conversation continued well past the end of his formal presentation.

There’s also a bit of baseball on the Red Planet. As Sullivan and Nye share a passion for baseball in addition to their love of sundials, they made weight-saving cutouts in the bases of the Mars dials in the shape of home plate. Seattle’s Museum of Flight has Sullivan’s copy of the Mars dial on display in its space gallery.

Sullivan’s talk was tremendously well received. One EAS member noted that she switched her scheduled night at the opera to be at the talk instead. Staff at the library at which the talk was held booted us out well after closing time, and even at that the discussion continued in the parking lot for a good 45 minutes more.

Check out Sullivan’s sundial trail website for a guide to visiting Seattle sundials.

Other reading:


BPAA shoots for summer solstice for sundial dedication

We received a nice package in the mail this week: a wonderful, clear-sky-blue Battle Point Astronomical Association Sundial t-shirt, the perk for our support of last year’s Indiegogo campaign that helped finalize funding for the project. (Here’s our story with details about the planned sundial.)

Sundial t-shirtBPAA reports that work on the sundial is progressing in earnest. They’ve completed the engineering on the foundation and are working with the artist on the details of the construction of the 12-foot-tall equatorial bowstring sundial near the association’s Edwin Ritchie Observatory in Battle Point Park on Bainbridge Island. Once those are finalized they’ll arrive at the price for construction and get under way. They’re hoping to be able to dedicate the sundial on the summer solstice. In the meantime watch for the handsome t-shirts around town. They include the coordinates of the sundial so you’ll be able to find it easily once it is built!

You probably won’t get a t-shirt, but you can still donate to the sundial project by visiting the BPAA website. Make sure to designate your contribution for the sundial. Funds received in excess of the cost of the sundial will be applied to a planned plaza around it.

Sundials at EAS

Speaking of sundials, “Mr. Sundial” himself, UW astronomy Prof. Woody Sullivan, will be the guest speaker at Wednesday’s meeting of the Eastside Astronomical Society. Sullivan will give a talk titled, “Sundials Around Seattle and Beyond: Fascinating Mixtures of Astronomy, Art, Design and History.” Sullivan is a sundial buff who helped design the sundial on the southwest wall of the UW astronomy building as well as the small sundials used on the Mars Exploration Rovers that landed in 2004. He also has designed many sundials around Seattle, and created the Seattle Sundial Trail, mapping 21 sundials around the city. Sullivan lent his expertise to the video that supported the BPAA’s Indiegogo effort.

The meeting begins at 7 p.m. Feb. 26 at the Newport Way Library, 14250 SE Newport Way in Bellevue.

Watch the Seattle Astronomy Calendar to find out about space and astronomy events in the area, and visit the Seattle Astronomy Store to purchase our favorite astro books and gear.


Weather angst and the Venus transit

Venus will transit across the face of the Sun Tuesday afternoon. This rare celestial event won’t happen again until the year 2117, and Northwest astronomy hobbyists, for good reason a highly pessimistic bunch when it comes to matters of cloud cover, have been warily watching the long-range forecasts since June 5 started to show up on the weather radar.

It is not looking pretty.

2004 Venus transit

The 2004 Venus transit was captured from Germany in this image by Jan Herold. Creative Commons, GNU free documentation license.

As of this writing, Saturday, June 2 at 4 p.m., the Seattle forecast for Tuesday afternoon was for clouds and a 30 percent chance of rain. The prediction for much of the Northwest looks similar. Our best bet as of the moment looks like Goldendale, with a forecast of merely partly cloudy and just a 10 percent chance of rain. (Really, we don’t care so much if it rains as long as it’s not cloudy!) Yesterday Moses Lake and Wenatchee looked promising, but those forecasts have flipped. We’d also been eyeballing the “rain shadow” of Sequim, but even that Olympic Peninsula town now has a wet forecast for Tuesday. The closest “sunny” forecast I am able to find is for Red Bluff, California. Do you roll the dice on an 11- or 12-hour drive, or hope for the best somewhere a little closer?

Many of us will likely be watching the weather forecasts up until Monday evening or Tuesday morning, making some last-minute decisions about where our chances look best for transit viewing, and then high-tailing it to those spots.

Of course, it’s possible, maybe even likely, that we’ll out-think ourselves on this decision. The lore of celestial event chasing is full of accounts of people who have made extreme travel efforts to get to places certain to be clear, only to find those locations socked in while the sky above their own backyards was crystal clear.

Why are we making such a big deal of this? Due to the peculiar geometry of the orbits of Earth and Venus around the Sun, we can only see a Venus transit occasionally. They come in pairs separated by eight years, and either 105.5 or 121.5 years go by before the next pair comes along. Tuesday’s transit is the second of a close pair. Unfortunately, the 2004 event wasn’t visible from the West Coast, and only the end of the transit was visible from the Eastern U.S. as the Sun rose that day. Europe, Asia, and Africa had the best views last time. So this is your last chance unless you make it to December of 2117.

There will be plenty of opportunities to enjoy the 2012 transit from Seattle if the weather cooperates. Events actually begin the evening before, Monday, June 4, at the University of Washington. Astronomy Professors Woody Sullivan and Victoria Meadows will give lectures about the significance and history of Venus transits. The talks begin at 7 p.m. in room 120 of Kane Hall on the UW’s Seattle campus. It’s free, but registration is required.

The UW will have several locations for viewing the transit when it begins at about 3 p.m. June 5. Viewing will also take place at the Pacific Science Center, Solstice Park in West Seattle hosted by Alice’s Astro Info, Battle Point Park on Bainbridge Island hosted by the Battle Point Astronomical Association, and others listed here by the Seattle Science Festival. Many of these sites will at least have online feeds, so participants can watch the transit as viewed from less weather-challenged areas. Other astronomy clubs are likely to be holding formal or informal transit viewings. Check their websites; links to them are at the right.

Seattle Astronomy will likely be at the Solstice Park event, unless we’re beating it to Goldendale.

Remember, don’t look at the Sun without proper protection. You’ll zap your eyeballs. Standard sunglasses are not good enough. This NASA website has some good pointers about transit viewing, eye protection, and pinhole projectors, as does transitofvenus.org.

Let’s hope we don’t miss our chance to see an astronomical rarity!