Tag Archives: Mercury transit

Sun streak ends! Whither Mercury?

All good streaks must come to an end, like Joe DiMaggio’s 56-game hitting streak or Cal Ripken, Jr.’s consecutive games-played record of 2,632. This morning Seattle Astronomy‘s personal mark of successful astronomical observations of Sun-related events was snapped at a modest four when we failed to spot Mercury during its transit across the face of the Sun.

Waiting for Mercury
Conditions looked semi-hopeful shortly after sunrise that we’d see the Mercury Transit. Photo: Greg Scheiderer

Hope of spotting Mercury remained alive until the bitter end. I arrived at Seattle’s Seacrest Park just before sunrise when the transit had already been under way and below our horizon for a couple of hours. We got a few glimpses of the Sun during the morning, most not enough to register even a glimmer of light through properly filtered optics. Then came proof that Mother Nature can be cruel and sadistic, especially to those who would practice astronomy in Seattle. With the transit slated to end at about 10:04 a.m. PST, the clouds parted a bit at about 10:02, setting off a mad scramble to point, focus, and look. I thought I caught the barest edge of Mercury leaving the disk of the Sun, but I couldn’t be sure. There were lots of clouds in the view. The Sun was there but Mercury, true to his fleet-of-foot reputation, was gone. I count it as a nice try.

Not everyone who came to our viewing event was skunked. Seattle-based Associated Press photographer Elaine Thompson caught this shot during a brief clearing:

It pays to be prepared! The day was not a total loss. Many folks enjoyed a look at the Mercury-free Sun after the transit, a nice woman named Liz brought some Top Pot donuts to share, and hanging around at the beach waiting to spot Mercury with some new friends was not a bad way to spend a Monday morning.

I’d successfully seen four recent Sun events: the August 2017 total eclipse of the Sun, the Mercury Transit in May 2016, a partial solar eclipse in 2014, and the transit of Venus in June 2012. Off to start a new streak.

There will not, however, be another Mercury transit until 2032, and not one visible from North America until 2049. See you down at Seacrest Park in thirty years!

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Mercury transit tomorrow!

The weather forecast is decidedly iffy for folks in Western Washington to view the transit of Mercury across the Sun on Monday morning, November 11. But a number of groups, including Seattle Astronomy, are planning to be out and waiting for breaks in the clouds in order to catch a glimpse of this relatively rare astronomical event.

Transit of Mercury
Our photo of the 2016 Mercury transit from Seattle. If you click on this photo to see the larger version you can see Mercury just to the left of the center of the disk of the Sun, and a sunspot cluster to the right. Taken with a Canon PowerShot A530 through an 8-inch Dob at 48 power. Photo by Greg Scheiderer.

Typically there are 13 Mercury transits visible in any given century, and there will be 14 of them during the 21st Century. We last had one visible from Seattle just over three years ago, in May of 2016. Tomorrow’s will be the last until 2032, but that one and the next won’t be visible from North America. Our next chance to see a Mercury Transit from Seattle will be in May of 2049.

Thus we’ll be down at Seacrest Park in West Seattle near the Water Taxi dock in hopes that we won’t have to wait 30 years or travel halfway around the globe to see Mercury in transit. We’re aware of a handful of other viewing opportunities tomorrow in the Northwest:

Watch our calendar page for others; we’ll add them if we hear about them for the rest of the day.

There are a couple of things to consider when viewing the transit. First, the requisite warning not to look at the Sun without eclipse glasses or a properly filtered telescope. Second, you’ll not likely see Mercury without some magnification; it’s pretty small. Third, don’t try to use eclipse glasses with a telescope or binoculars; the equipment itself must be properly filtered or severe eye damage will result.

Alan Boyle of Geekwire has a good article about the 2019 transit that includes some links for viewing the event online should our weather fail to cooperate.

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Catching the Mercury transit from Seattle

The weather gods smiled on West Seattle Monday and provided relatively clear skies that allowed us to catch much of the first transit of Mercury across the disk of the Sun in ten years. The event served as a reminder of how hyper-local the weather can be, as many other locations around the area did not fare so well.

Viewing the Mercury transit.

After about 8:30 a.m. May 9 the clouds parted and we had excellent viewing of the transit of Mercury. Spencer (left) and Ryan take a peek through Spencer’s homemade Dobsonian. Photo: Greg Scheiderer.

We thought we may have jinxed the weather when we wrote on Sunday in our weekly calendar post that, “(I)t’s pretty unlikely that we’ll see the transit constantly from sun-up to finish, but also looks pretty unlikely that we’ll get skunked.” I arrived with telescope in hand at Seacrest Marina Park just before 6 a.m. on Monday, and the clouds were solid. I was soon joined by Ryan “Tortuga” Carpenter and a young man named Spencer who brought his home-made Dobsonian telescope to the party. For a while we just watched the clouds roll by.

It was well after 7 a.m. before we got our first glimpse of the Sun, and Mercury in transit—a fleeting look that lasted less than a minute. For the next hour or so we had several similar quick peeks at the transit when the Sun found a hole in the clouds.

We finally got some longer looks after 8 a.m., long enough to actually snap photographs of the transit. Then, right about 8:30, we suddenly had clear, blue skies. We had a few interruptions from clouds after that, but these were brief and we had close to constant viewing of the transit until it ended around 11:40 a.m.

Other areas didn’t have so much luck, especially those sites east of the city. The Seattle Astronomical Society had a transit-viewing event scheduled from one of its preferred observing sites at Snoqualmie Point Park, but had already cancelled it by Sunday night because of inclement weather in the forecast. One member went there anyway and reported only brief views of the transit. Others reporting to the society’s Google forum, fittingly titled “Through the Clouds,” also noted limited success from Kent, Ellensburg, and Bellevue. The Green Lake neighborhood had decent weather and observers there reported more lengthy looks at the transit.

Transit of Mercury

If you click on this photo to see the larger version you can see Mercury just to the left of the center of the disk of the Sun, and a sunspot cluster to the right. Taken with a Canon PowerShot A530 through an 8-inch Dob at 48 power. Photo by Greg Scheiderer.

Our trio in West Seattle tried to do a little science, or at least figuring, at the end of the transit. We each clocked the time between third and fourth contact of the transit. Interestingly enough, our observations varied by about 15 seconds. Parallax doesn’t explain that; our telescopes were all set up within about 10 feet of each other! I would guess that the variation could be explained by differences in visual acuity, quality of telescope optics, and ability to find the start/stop button on the smartphone stopwatch. Carpenter did the math and said we were in the ballpark for determining the size of Mercury based on the length of time between the two contacts.

Mostly we just had fun seeing this rare celestial event, and sharing it with quite a number of interested passers-by. I chose the site because a lot of people are typically there, from those catching the West Seattle Water Taxi into the city to those just strolling in the park. Great weather was an unexpected bonus.

While there are only, on average, 13 transits of Mercury in a century, our next one is relatively soon: November 11, 2019. After that we’ll have to wait 13 years, until 2032, for another.

Catch the Mercury transit May 9

One of the rarest of predictable astronomical events will happen May 9 when we on Earth will be able to see Mercury move across the face of the Sun. Mercury transits happen about 13 times per century. The last one was in 2006 and the next is relatively soon, in November of 2019. After that there won’t be another until 2032.

By contrast, transits of Venus occur in pairs eight years apart separated by more than a century. There were Venus tranists in 2004 and 2012, and there won’t be another until December of 2117.

NASA illustration.

NASA illustration of the 2006 Mercury transit.

Julie Lutz, an emeritus research professor of astronomy at the University of Washington in Seattle, said the Mercury transit will be mostly spectacle, as there isn’t much science to be done.

“We’ve learned about all we can from previous transits of Mercury,” Lutz said. “Early on it was a matter of using the transit timings and things like that to confirm things about the orbit of Mercury, get it more and more accurately, try and deduce the size of the planet, things like that.”

During the transit Mercury will appear as a small, black dot crossing the face of the Sun. Lutz pointed out that watching for such occurrences at other stars is precisely how astronomers are detecting exoplanets.

“We can detect Earths now,” Lutz said. “The Kepler mission has changed the whole picture of planet distributions.” She added that if there is a planet the size of Mercury, which has a diameter of just over 3,000 miles, in orbit around a distant star, we couldn’t spot it in transit. We detect exoplanets by watching for slight reductions in brightness as the planets block some of the light as they transit. Our current instruments just aren’t sensitive enough to see the small change that would be caused by an exo-Mercury.

Mercury will even be a little tough to spot from Earth. While we could see the Venus transit just by looking at the Sun through eclipse glasses, that won’t work with Mercury.

“Mercury is smaller than Venus and further from the Earth, so the apparent size of the planet from our point of view is going to be smaller, so it will be harder to see,” Lutz said.

You’re going to need some magnification, according to Stephanie Anderson, co-owner of Cloud Break Optics in Ballard.

“In order to see Mercury well, you’re going to have to get to 20 to 30 power,” Anderson said. Binoculars with solar filters won’t be quite enough, as these typically have somewhere between eight and 10 power. Binoculars could be used to set up a projection of the Sun’s image on a screen or sheet of paper. Otherwise, Cloud Break’s Matt Dahl said almost any telescope would do the trick.

“You need a front aperture mask of some sort to minimize the light through it. Don’t ever use a telescope to look at the Sun without proper filtration,” Dahl warned. “If you want to see all of the other effects that are going on the Sun, the prominences and granularity all that kind of stuff, a specific solar telescope would be ideal.”

If you don’t have a telescope or a friend who has one, Anderson said they could set you up with a simple refracting telescope or a tabletop reflector for around $100. The aperture mask and solar filter will run $50 to $75, so for less than $200 you’d be ready to roll.

“Then you can use that cool thing to see the (solar) eclipse when it comes up next year in August, and then you can also use it to view the night sky,” Anderson said. “It’s good for more than just viewing the Mercury transit.”

Both Dahl and Anderson are accomplished astrophotographers, and Dahl said shooting the Mercury transit will be relatively easy. He said the Sun is a bright enough object that you wouldn’t really even need a tracking mount. Just hook up your DSLR or a webcam to your telescope. Anderson added that it might even be simpler than that.

“Just use your smartphone to snap a picture right through the eyepiece,” she said. “You might have the technology in your pocket already.”

It can be tough to get a good frame with a smartphone and a telescope, but Anderson said you’ll have time to experiment.

“The event will last for quite a while, so you’ll have some time to mess around with it,” she said.

The full Mercury transit will be visible east of the Dakotas, Kansas, and Nebraska. It will already be in progress when the Sun rises at 5:40 a.m. on May 9 in Seattle, and it will end at about 11:40 a.m. Pacific time. Dahl and Anderson are considering setting up viewing at Magnuson Park, and Seattle Astronomy may be down at Anchor Park at the far north end of Alki Beach Park if the weather is good. If it looks like it will be a cloudy day, we all might hit the road in search of clearer weather, because transits are cool.

“The thing that excites me the most about them is that you get to see the pieces of the solar system moving together,” Anderson said. “You get to see that the Sun has planets going around it. It’s really an amazing thing to see with your own eyes.”

“It gives you a really humbling size reference when you contrast the size of the Sun to the size of the tiny little dot,” of a transiting planet, Dahl said. “The Venus transit four years ago was awe-inspiring for me that way.”

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