Mercury transits the Sun

By Phil Plait | November 7, 2006 6:28 pm

Many people think of the planets as orbiting the Sun in a flat plane, like a CD. If that were true, then we’d see Mercury and Venus cross the face of the Sun — what astronomers call a "transit" — every few months! But the orbits of all the planets are tilted a bit. Not a whole lot, really, but enough to prevent the tiny eclipses from happening all the time.

So they’re actually rather rare. Venus transits happen very rarely, and are spectacular! Mercury transits the Sun about 13 times per century… and the next time is Wednesday, November 8 (or the 9th depending on your time zone). Here in California we get to see the whole thing (it starts at 11:12 local time and ends a little under five hours later). I just hope it’s clear!

Wanna watch? It’s not too hard.

First, duh, don’t look at the Sun! It’s very bright. You may have noticed. Anyway, Mercury is too small to see with your unaided eye. You’ll need binoculars at least… and if you look at the Sun through binoculars you’ll cook your retinae for sure. I plan on mounting my binocs on a tripod and projecting the Sun’s image on paper. That’s a safe way, though you have to be careful not to cook your optics.

If it’s cloudy where you are, or this happens at night where you are, or you’re just lazy, about a million sites are going to webcast the hours-long event, and many more have general info. Here’s a list:

Have fun! This is not as spectacular an event as some, but it’s rare, interesting, and pretty cool anyway.

CATEGORIZED UNDER: Astronomy, Cool stuff, NASA, Science

Comments (26)

Links to this Post

  1. A Ler…-- Rastos de Luz | November 8, 2006
  2. FirstStep » Blog Archive » Mercury transits the sun | November 8, 2006
  1. Grand Lunar

    Looks like I’ll get to see just over 3 hours of the transit before sunset.

    Of course, I lack a telescope with a solar filter, and don’t have the material for a pinhole viewer.

    Good thing there’s a view via the web. I hope you can do better than me, Phil.

  2. Mark Hansen

    With any luck the weather will be fine enough here (Campbelltown, NSW, Aust.) for me to show the kids at the local school the transit with my ancient 3″ reflector projecting onto a screen. The only hitch: clouds!! We’ve had clear skies for weeks and as soon as I suggest this to the principal, we get rain for the first time in weeks.

  3. myronwls

    My astronomy club was hoping for clear skies here in Western Oregon for the transit
    we had schedules a viewing for the public, but we have had heavy rains this week and will most likely be rained out. The entire event would have been visable from here. Hopefully we will have few cloud breaks and see a little of it.

  4. hale_bopp

    I will be at Kitt Peak tomorrow for the transit…I will sneak into see it on the McMath-Pierce while I am there :)

    Rob

  5. Cindy

    Heavy rain forecast for Wednesday. Of course in NJ we would get less than half before the sun sets. Thank Goodness for the web!

    Hey, Hale-Bopp, what ‘scope will you be on? I was a grad student at Dartmouth so was on MDM quite a bit. Will there be any room at McMath-Pierce? I’m guessing it will be a tad crowded.

  6. antaresrichard

    Ouch! I just kicked myself remembering the November 15th, 1999 transit of Mercury. It was a beautiful, clear day but I entirely missed the tiny planet’s “graze” of the solar disc! And all on account of a star of the glam-rock variety.
    Back then, I was on my way home, intent on viewing the celestial phenomena, and absent-mindedly passing a downtown theatre when, out of the blue, my attention span was concussed and eclipsed by the name of that night’s stellar luminary emblazoned on the marquee*.
    Alas, only after emerging from the dark of the ticket office sometime later and looking at my watch, did I realize my horror. Bitter irony indeed was the fact that the same unused binoculars set aside for the safe viewing of Mercury, would next be employed to discern the teeny, tiny speck transiting the stage.
    Now, seven years out with a chance to redeem myself, I learn heavy weather is expected blanket our area . Excuse me while I – OUCH!!

    *The name of the artist shall remain anonymous. More than this I dare not say.

  7. antaresrichard

    Ouch! I just kicked myself remembering the November 15th, 1999 transit of Mercury. It was a beautiful, clear day but I entirely missed the tiny planet’s “graze” of the solar disc! And all on account of a star of the glam-rock variety.

    Back then, I was on my way home, intent on viewing the celestial phenomena, and absent-mindedly passing a downtown theatre when, out of the blue, my attention span was concussed and eclipsed by the name of that night’s stellar luminary emblazoned on the marquee*.

    Alas, only after emerging from the dark of the ticket office sometime later and looking at my watch, did I realize my horror. Bitter irony indeed was the fact that the same unused binoculars set aside for the safe viewing of Mercury, would next be employed to discern the teeny, tiny speck transiting the stage.

    Now, seven years out with a chance to redeem myself, I learn heavy weather is expected blanket our area . Excuse me while I – OUCH!!

    *The name of the artist shall remain anonymous. More than this I dare not say.

  8. antaresrichard

    Ouch! I just kicked myself remembering the November 15th, 1999 transit of Mercury. It was a beautiful, clear day but I entirely missed the tiny planet’s “graze” of the solar disc! And all on account of a star of the glam-rock variety.

    Back then, I was on my way home, intent on viewing the celestial phenomena, and absent-mindedly passing a downtown theatre when, out of the blue, my attention span was concussed and eclipsed by the name of that night’s stellar luminary emblazoned on the marquee*.

    Alas, only after emerging from the dark of the ticket office sometime later and looking at my watch, did I realize my horror. Bitter irony indeed was the fact that the same unused binoculars set aside for the safe viewing of Mercury, would next be employed to discern the teeny, tiny speck transiting the stage.

    Now, seven years out with a chance to redeem myself, I learn heavy weather is expected blanket our area . Excuse me while I – OUCH!!

    *The name of the artist shall remain anonymous. More than this I dare not say.

  9. antaresrichard

    Holy cow!

    Sorry about that!

  10. Melusine

    I’m bummed…I have a training class from 1:00 to 4:00 today and I have a solar telescope. Hmm, maybe there will be a bad accident tying up traffic on the West Loop… [evil grin]

  11. Michelle Rochon

    It’s overcast here! I’m so bummed. I really wanted to see it with my own eyes.

    I had even planned to skip out of work for a few minutes!

  12. Gary Ansorge

    Bummer! Rain, clouds, and Republican governors abound here in Georgia. Ah well, glad we have the internet. What an incredible invention.

    GAry 7

  13. Kyle_Carm

    Beautiful clear sky Jackson, WY is have a warm cloudy, rainy day :-( Yea for the net.

  14. Hey all,

    I was watching Daily Planet last night (show on the Discovery Channel) and they mentioned they are having a LIVE webcast of the Transit today.

    I just checked the website out, and they have a feed from a Arizona observatory.

    If any of you are interested check it out here:

    http://discoverychannel.ca/mercury/live/

    I hope the weather clears so I can see it with my own equipment though!!

    Cheers,

    Matt

  15. antaresrichard

    Oh joy! Can that be? I see skies of blue! And I think to myself: “What a mercurial world!”

  16. Tom K

    Clear here in Tulsa. I’m at work so I just went out for a few minutes and set up my telescope by my vehicle. Nice distinct black dot, but tiny. I’ll check back again from time to time until sunset, I guess.

  17. Melusine

    Cool!! I got home from class and just got through watching it through my PST…it looks like a black mole moving off to the right. It’s getting hard to see now since the sun is going down below rooftops – wish I was on a skycraper. Gorgeous day here, we were lucky. I enjoyed that! Little Mercury buzzing around…

  18. Melusine

    Spaceweather has a very easy animated chart to see where it’s at, at what time. Mercury was right where they said it would be at 5:00 pm CST.
    http://spaceweather.com/

  19. Melusine

    I’m still thinking about the Mercury transit…it’s the first event of this kind I’ve been able to see through my solar telescope. The PST makes the Sun appear a solid pinkish-red, so any spot on the surface looks like something special. What looked to be a mere fleck on the lens was a planet orbiting!…I mean, here we are this collection of atoms down here, or across here, however you want to describe space and time, and there’s all this stuff happening out there in the universe that I can see with my own eyes for a mere $500. That’s quite a bargain – to see the Sun showing off Mercury, eating comets, throwing out coronal mass ejections…without singing your retina…for $500…plus tax. Remarkable.

    OK, I’m a total Solar Sycophant. (-8~

  20. Wayne

    I had a good time today hosting a transit viewing. I used an 8″ Celestron and a small refractor that belong to my University. We don’t have a camera adapter, but I did snap a few shots through the eyepiece with my digital camera. I put a couple of pictures up at
    http://members.cox.net/keithfiles/PB080800.JPG
    and
    http://members.cox.net/keithfiles/PB080803.JPG

  21. Was cloudy all day where I am. Bummer. Had the telescope ready to go too.

  22. Melusine

    …that should be “without singeing your retina.” Grrr, I hate typos – maybe I need glasses – I think the glare hurts my eyes.

  23. Dave Kary

    Lovely day here in southern California, and we set up telescopes at our college to show off the transit. I had lots of fun saying “No, it’s not that big dot. That’s a sunspot. It’s the smaller round dot just below it.” No matter how many times we talk about the scales of objects in the universe, there is nothing like letting them see it with their own eyes.

    DK

  24. Troy

    It was overcast here, got a view of blue for about 2 minutes so I think I managed to spot it by projecting the sun onto paper. The Venus transit 2 years ago was definently more conspicuous, I had better weather too.

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