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Posted by: nprev Jul 21 2008, 08:59 PM

Maybe so. It's really hard to get a view of Mercury without a whole lot of sunset/sunrise skyglow, though (very favorable elongations aren't that common), and that's often reddish; might be predispositioning the observer's impressions. The last good look I had through a scope against a reasonably dark sky seemed brownish-gray to me; darker then the Moon, anyhow. Your colors seem reasonable, Gordan.

Posted by: ugordan Jul 21 2008, 09:09 PM

I think I actually only saw Mercury once in my lifetime, about a year ago. It wasn't through a scope but naked eye after sunset. It definitely looked more brownish than Venus which hanged somewhat higher in the sky, although it was twinkling at the time so I wasn't sure if that was it or some star.

Yes, it's hard to catch that thing in favorable viewing conditions!

Posted by: PDP8E Jul 21 2008, 09:21 PM

AGREED! I have seen it 4 times in over 50 years and only once through a telescope!
You have to plan - plan - plan - and then it only 'hangs' around for a few minutes.
The position in the sky (near the horizon, near the sun) is bright and dusty and has the biggest depth of atmosphere to look through). Winter is the best, but get to a latitude that favors Mercury's span from the sun.

Telescope observation: The limb looked less 'yellow' than Venus -- it seemed tawny, brushed metallic - no features - wavering in the atmospheric disturbances

Good Luck catching mercury!

Posted by: nprev Jul 21 2008, 09:21 PM

Oh, big-time, man. In fact, the apparition I referred to was in Montana back when I was a kid: nice dark sky, no light pollution, and it actually rose something like two hours before sunrise. Beautiful half-lit appearance through a 2.4 inch refractor, brownish-gray.

I've never had a better view since. The damn thing is elusive. Legend has it that Galileo never saw it and bemoaned the fact on his deathbed, but that's rather doubtful.

Posted by: Stu Jul 21 2008, 09:45 PM

I'm really lucky, in that I see Mercury quite easily and regularly from here; Kendal sits in a kind of natural "bowl" in the South Lakes landscape, with low hills rising up around it, giving a nice flat horizon to the west. So whenever Mercury puts on an evening show and is at its best, up to the ruins of Kendal Castle I go, and Mercury just pops out at us, glinting above the treetops on the hill opposite.

Posted by: nprev Jul 21 2008, 09:50 PM

Cool!

Yeah, northerly latitudes help a LOT for favorable viewing geometry. It's not worth a damn down here in LA, to say nothing of the light pollution, smog, people occasionally shooting at you, etc. Heck, I'm lucky to spot Jupiter.

Posted by: JRehling Jul 21 2008, 11:23 PM

Boy, I've had better luck than a lot of people. I've probably seen it at twenty or so elongations, and as many as four times during one of those. I took my only picture of it looking down a San Francisco street where it was so low that I literally had to wait for a bus to get out of the way. With Mercury, brightness per unit surface area is never the issue, at least.

I also spotted it at least once in the east where it was the brightest object in the entire sky. No Sun, Moon, Venus, or Jupiter. I think it's an interesting (open, AFAIK) exercise to determine how many objects are capable of being the brightest object in the sky, assuming clear skies, a flat horizon, no comets or freakishly close asteroid passes, etc.

And then there was the night I found all seven planets through my telescope, looking at each in the order it lies from the Sun, with the Moon spotted in between Venus and Mars.

Posted by: nprev Jul 21 2008, 11:37 PM

Yes, it can be surprisingly bright; I think the brightest stated magnitude I've ever seen for it is -1.8. Unfortunately, that's usually against a yellow sky at the end or beginning of an apparation, so getting a good read on the actual surface color is difficult in the extreme.

Man, JR: twenty times? You're good! I've actually given up on seeing pretty much anything from LA these days. I live just a few blocks from the Staples Center, and half the time they've got spotlights piercing the haze/smog right at sunset & beyond; it's horrible. Need to get some time to drive out to the Mojave & really see the sky again, though will probably have to go at least 200 miles to escape the bloody light (and other) pollution from this place.

Posted by: ugordan Jul 21 2008, 11:40 PM

Yep, it was pretty bright when I saw it, otherwise I'd have never seen it - was riding in a bus actually and just looking west in a clear late winter (I think) night. It was pretty neat, I suspected it to be Mercury, but had to check a sky map nevertheless. It would be great to see it through a scope next time...

Posted by: nprev Jul 21 2008, 11:45 PM

It's worth a look. You can almost see what look like large albedo features when the air isn't churning (not often given its proximity to the horizon), but it's tantalizing. IIRC, Dollfus published the first maps of Mercury many years ago, but he is a very patient man with access to a rather large telescope (Pic du Midi Observatory). Wouldn't be practical at all for most amateurs.

Posted by: Bjorn Jonsson Jul 22 2008, 01:05 AM

To add to the discussion, in my opinion Mercury actually *is* pretty easy to see if you know roughly where to look. It's really bright - the problem is the relatively bright background and also trees, buildings, hills/mountains etc. get in the way. I have seen it several times with the naked eyes but not yet through a telescope (not counting binoculars). The most memorable sighting came several years ago when I saw Mercury, Venus, Mars, Jupiter and Saturn all in the sky at the same time.

Posted by: ElkGroveDan Jul 22 2008, 01:15 AM

http://maps.google.com/maps?f=d&hl=en&geocode=&saddr=Los+Angeles&daddr=Templin+Highway,+Gorman&jsv=120&sll=34.58538,-118.67447&sspn=0.049959,0.10952&ie=UTF8&doflg=ptm, dude.

Posted by: David Jul 22 2008, 02:11 AM

The story is most often told of Copernicus. See http://adsabs.harvard.edu/full/1892Obs....15..321L and, in a lighter tone, http://blogs.discovermagazine.com/badastronomy/2005/03/14/got-mercury/.

As the first article's author hasn't bothered to translate Copernicus' Latin (in 1892, I suppose most astronomers were expected to know a little), I'll offer a provisional and not highly accurate translation:



And the last Latin quotation is from Gassendi, not Copernicus:



French is certainly much better known than Latin, and my efforts at French will doubtless be corrected (if not mocked) by the French-speakers on this board; but for the sake of completeness, I translate Arago's further transformed characterization in this Telephone game:

Posted by: mchan Jul 22 2008, 02:33 AM

I've seen it about half-dozen times. One of those was also on a San Francisco street except it was so high it overlooked the Bay and there it was off to the left from the Bay Bridge (before it got the string of lights on the suspension). I think my camera at the time as an Instamatic, so did not even bother trying to get a shot.

Posted by: tasp Jul 22 2008, 03:00 AM

I recall seeing Mercury at twilight ~20 years ago. It was setting towards a distant power line, and the rotation of the earth was easily apparent in the motion. Ingress and egress (behind the powerline) were instantaneous to my somewhat younger eye then.

Posted by: nprev Jul 22 2008, 03:21 AM

Yeah? Pretty dark there? Seems kind of close.

Posted by: dvandorn Jul 22 2008, 04:54 AM

I've only seen Mercury once, to my knowledge -- via telescopic projection during a transit of the Sun back in (IIRC) spring of 1973. I believe Mercury was in mid-transit at sunrise.

As such, of course, I have no commentary on color...

-the other Doug

Posted by: ilbasso Jul 22 2008, 08:04 PM

The first time I saw Mercury was during the May 9, 1970 transit. (That was a great year for my amateur astronomy! I also got to see the March 7, 1970 total solar eclipse!) I have seen Mercury 6 or 7 times since then, never telescopically, but usually when driving just after sunset and when there is a clear view of the western horizon. It is brighter than one would expect.

Posted by: JRehling Jul 22 2008, 09:15 PM

Another bit of luck was when I arrived home near sunset one fine November day in Indiana, noticed that the Sun was, unusually, not setting into clouds, set up my solar projection and witnessed the transit that I knew was occurring but was too pessimistic to have expected clear skies for.

I think the unstated factor that truly makes Mercury challenging is that the near-horizon sky is statistically more likely to be cloudy, because of the longer lines of sight. Otherwise, even in a big city, it's just a matter of timing. It's one of the five brightest sky objects (sometimes) and it appears several degrees above the horizon at least a couple of times a year. Clouds are the only real enemy. In a continental climate, this may favor morning observations over evening (?). I used to think of Mercury as easy pickings on a winter morning. Assuming you're willing to go outside when it's cold and an indecent hour for being out of bed.

Posted by: ElkGroveDan Jul 22 2008, 09:32 PM

This might be a good time for someone who uses all that sky viewing software to post a few predicted dates and places for optimum viewing of Mercury (...he said with lazy anticipation of hard work done by others.)

Posted by: Stu Jul 22 2008, 09:47 PM

Mercury will be putting on a pretty good show in middle to late August, when it will be an evening object, low in the west after sunset. On the evening of the 14th it will lie at the right end of a line of 4 planets: Mars... Venus, Saturn and mercury will all be on view together, with Venus, Saturn and Mercury quite close together hanging just above the treetops. On the last day of August Mercury, Mars and Venus will form a triangle low in the WSW, arranged Mars (highest)... Mercury (lowest) and Venus (brightest).

In December Mercury will be a dusk object again, visible low in the SW. Obn the evening of dec 28-29th we'll see a sickle thin crescent Moon just above the horizon, with Mercury just above it and Jupiter just above mercury, a great photo op! Then on Dec 30-31st Mercury and Jupiter will be very, very close together, and visible in the same binocular field of view... :-)

Posted by: nprev Jul 23 2008, 02:13 AM

I'll buy off on that for sunset views before all the lights come on. I drive to work @ 5:00AM here in LA, and honestly you just can't see a damn thing except at zenith then. It's better in the South Bay area near the coast, though.

Posted by: mchan Jul 23 2008, 06:22 AM

The few times I have seen it have always been on cold, cold mornings with the air clear and crisp. The first time, I woke up and climbed a hill to see it. The other times were because I had to be up early and had been alerted by the Sky and Telescope diagrams.

Posted by: elakdawalla Jul 23 2008, 12:14 PM

I just moved a bunch of posts from the "http://www.unmannedspaceflight.com/index.php?showtopic=5310" topic here.

--Emily

Posted by: PDP8E Jul 23 2008, 02:23 PM

Thanks Emily!

(if i knew how to do, I would have too, after seeing those posts stack up!)

Posted by: bkellysky Oct 15 2008, 09:22 PM

According to Sky and Telescope, the next two weeks, starting on October 17, will be reasonably good for finding Mercury.
It'll be up in the morning sky before sunrise. Look where the sky is brightening, it won't be more than 10 degrees (about a fist at arm's length) above the horizon. The best time is 60 to 45 minutes before sunrise. Mercury will appear farthest from the Sun about October 22nd and brightest a few days afterward.

Attached is a photo I took of Mercury (at far lower left just above a house) and Jupiter (far upper right) in the morning sky during December 2005 near my house north of New York City. Canon A40 on tripod, cropped from a larger photo. Mercury was about 11 degrees above the horizon at that time.

Posted by: bkellysky Oct 18 2008, 01:38 AM

For information about finding Mercury in the dawn sky over the next two weeks, check out the write-up at This Week's Sky at a Glance at the Sky and Telescope web site..... at skyandtelescope.com

They have a good diagram that shows where to look for Mercury (plus Saturn, which is further above the horizon and, in about a week, the Moon).

Posted by: bkellysky Oct 24 2008, 11:25 AM

Attached is a photo I took from the top of the parking deck at Montefiore Hospital in the Bronx, New York on Thursday morning. Five second exposure with my Canon A40 on a tripod.

Mercury is just visible on the full size version, between the center set of poles at the bottom of the photo. It was easy to see with the unaided eye. The short line well above Mercury is the International Space Station streaking across the sky. The streak of lights on the lower right is an aircraft.

The moon is moving further down toward the horizon each morning, hanging out with Saturn and then Mercury over the weekend. In my area, the northeastern United States, the ISS is making good appearances in the morning sky for the next week or so. Check out heavens-above.com or spaceweather.com for predictions for your location.


all the best,
bob

Posted by: PhilCo126 Oct 24 2008, 05:07 PM

Good news for those who want to spot the first rock from the Sun:
December 31, 2008 = conjunction of planets Jupiter and Mercury.
The year closes with Jupiter and Mercury appearing after sunset a little more than one degree apart in constellation Sagittarius. Jupiter will be magnitude -1.95 and Mercury -0.67. As a bonus, Mecury will be a mere 15 arcminutes from the globular cluster M75. Use binoculars to catch Jupiter, Mercury, and the magnitude 8.6 cluster in one view.

By The Way, if You know where exactly to look, You can see some planets in daylights if these don't appear too close to the Sun.
Use FREE software such as STELLARIUM which give online up-to-date information from Your viewpoint...

Posted by: bkellysky Oct 27 2008, 11:48 PM

Thanks for the heads up. I'm looking forward to helping people find Mercury in December with Jupiter as a pointer!

In the meantime, attached is a photo of a scene of the Moon with Mercury to its upper left. I took this at 6:25 am this morning (October 27th) with my Canon A40 on a tripod. 10 second exposure, 3x optical zoom. On my monitor, I can see the earthshine on the unsunlit part of the Moon.

At that time, the Moon was only 4 degrees above the horizon. (At least a normal horizon, since I was 6 levels up on a parking garage, the apparent altitude from where I was standing may be a bit higher.)

The Moon will already have moved on away from Mercury by the time you see this, but Mercury is still getting brighter, even though you'll need a clear view of the eastern sky to see it.

bob