Comet Holmes from Chicago

We had a great clear Monday after the RAS meeting so we got everyone to come up to the observatory to see the great outburst of Comet Holmes. Photometrically it seems the same brightness, but in binoculars or in the telescope it's much bigger and fainter than a few days ago.


Comet Holmes at Ryerson Observatory. 36x5s exposures, 0.25m f/6.

We imaged it through our 10-inch reflector while looking at it through the six-inch refractor. I processed the images to match the visual look. This comet is so bright I was able to take reasonable images with my digital camera just pointed at the eyepiece, with a few seconds of exposure, but I can't find my memory card reader, so those will have to wait.

So--it's still naked-eye, and now obviously not a star, so get out and take a look--the lower right "star" of an isoceles triangle containing Mirfak, above the bright star Capella in the northeast. (See a finder chart here).

A lot of people were asking details about why exactly the comet increased in brightness a millionfold. Without reading further, I vaguely heard a suggestion that the heat from perihelion takes a while to move deeper into the comet to where there is still volatile ices to blow out. Right now, the comet is moving out between Mars and Jupiter.

A fantastic historical read is Fred Whipple's paper in Icarus, volume 60, issue 3: "Comet P/Holmes, 1892III: A case of duplicity?" (link may need a subscription). I quote:

It may be added that the comet was discovered as a bright object nearly 5 months earlier than its perihelion passage, although the observing geometry was favorable all the time (at perihelion, the comet should have been only 1.5 mag fainter than near opposition 5 months later). It was also the first short period comet of q > 2 ever discovered.
Barnard's 1913) description on November 9.2 at Lick Observatory is revealing:
"'Its appearance was absolutely, different from any comet 1 have ever seen--a perfectly circular and clean cut disk of dense light, almost planetary in outline with a faint, hazy nucleus and a slight condensation some 5 seconds south following the nucleus (brightness -- Andromeda Nebula, diameter 260" at 8h0 '" P.S.T. and 286" at 9h40"').'" He observed the comet to brighten perceptibly by the next night at which time he saw an outer faint diffused envelope some 12' (800,000 km) in diameter.
Barnard's description carries great weight because he was a superb and experienced observer, having already discovered 15 comets and observed many more. His comments were generally confirmed by many other observers over thc world. Interest in the comet flared as the comet burst again to nearly naked eye brilliance on January
16, 1893, after having laded some 5-6 mag by late December and early January.
On subsequent returns P/Holmes hits remained extremely faint and inactive.

• Circular -- check


• Sudden nearly naked-eye burst -- check


• Andromeda galaxy reference -- looked at Andromeda tonight right afterwards -- check


• About 10 arcminutes in diameter -- check

Don't read anything into his comet satellite hypothesis though.

Reading further back, Bobrovnikoff wrote in 1943:

The comet was not well observed in December, 1892, and in the first part of January, 1893. On January 16, Palisa, in Vienna, found with the 27-inch refractor, instead of a diffuse comet of 10th or 12th magnitude as expected, a yellow star of 8th magnitude with an envelope of 20" in diameter. The comet increased in brightness the next day and could be seen with the naked eye. After January 18 it began to decline in brightness, and by the beginning of April it became very faint.

Go see Comet Holmes.

If it's clear where you are, go outside right now and see Comet Holmes with your eyeballs, even with a nearly full moon nearby and even if you live in a horribly light polluted city. Binoculars will help, but you can see the comet with just your eyes right now, although it looks just like a star.

Look to the Northeast. Capella is the bright white star. Look up further towards the zenith to a compact triangle of stars, with the brightest star on the top apex. That star is Mirfak. Comet Holmes is the one on the lower left, the one closest to the line between Mirfak and Capella. Tonight, Capella and the moon form the bottom two points of a skinny-ish trapezoid, with Mirfak and Algol the top two.

Binoculars will reveal the star as a glowing blob, much bigger than the nearly stellar yellow object I saw on Wednesday. A telescope will reveal a stellar nucleus and a glowing blob surrounding it, getting bigger every day.

Finding charts (albeit poor in magnitude distinction are here). Sky and Telescope has one too--just move Capella up higher in the sky the later in the evening. A report here

Mars color

A commenter on this image asked about the "blue" sky in my synthesized image, composed of UV, green, and near-IR frames. Color was suspect, but it's all I had at the time.

I took much more recent data from a few days ago (sol 1321) and used subframes that were actually blue, green, and red. With equal strengths you get the image above. The sky is essentially overexposed.

Without further investigation I'd guess the gradient across the frame is from dust accumulation on the camera lens.

Space station and Shuttle passes over Chicago

Why, yes, there are visible passes for them tonight.

Link to Heavens-Above.

Phil Plait talks about the Moon's orbital plane

Phil Plait looks at the low southern moon here that I mentioned last month

50th anniversary of Sputnik

Things have been very busy and as a result I've been unable to post--but today is the 50th anniversary of man's entry into space with the launch of Sputnik. Last night the visitors to the Ryerson Astronomical Society's Wednesday viewing saw the largest satellite (artificial) in orbit: the International Space Station, as it rose above the horizon, passed Jupiter, and went into the Earth's shadow. Tonight in Chicago, you can see it twice, once at 6:57PM and again, once around the Earth, at 8:30PM. Details are always at Heavens-Above.

P.S. It's also World Space Week. Go to the RAS lecture on Monday about Sputnik.

Fall equinox

It's the autumnal equinox today, the day when the Sun appears to cross over into the southern sky. The stirrings of winter are beginning--little reminders of the fragile nature of our comfort zone on this planet. This last week in the evening twilight the first-quarter moon barely peeked above the trees and buildings to the south, showing roughly where the Sun would be in three months time. It seemed a little low for the winter noon, though, so I checked and indeed the Moon is at its greatest distance from the ecliptic, some 5 degrees south. I have some discussion of the tilt at this previous post. And, to confirm it, there was a lunar eclipse in late August, meaning the nodes (the points where the Moon's orbit meet the ecliptic) of the Moon's orbit were aligned in the Earth-Sun line, which meant my first-quarter moon should have been above or below the ecliptic.

And it now occurs to me the root of eclipse and ecliptic are the same, a point I never realized. This will require another post.

Radiation doses from above ground nuclear testing

Estimated gamma-ray radiation doses from above-ground nuclear testing in Nevada, as of 1957. Above-ground testing continued, at a higher pace, until 1962.

This doesn't include radiation from non-gamma sources, including iodine-131, as shown here.

I personally spent a lot of time in the 2-4 Roentgen range as a kid.

French whine about spy satellite disclosure

Via an article in the Inquirer and the original Space.com article, the French military is threatening to publish US spy satellite orbital data, which has been left out of the official US catalog of orbiting objects. Amateur satellite observers find this stupid and just figure out the orbits themselves. What the French really want is a quid pro quo agreement to not publish French spy satellite orbits. But of course, all it takes are a couple of people with clocks watching the sky to figure the orbit, so why hide the orbit elements in the first place?

The French discovered these uncataloged satellites via radar returns. The US has a fence of VHF radars across the southern US, known as NAVSPASPUR, that can detect nearly every satellite in LEO orbit over a short time period. Amateurs can pick up the radar returns from meteors and other objects from these transmitters.

Iapetus

Are we freaking out about Iapetus yet? The equatorial ridge is ancient -- look at that crater density.

Rhea

Emily Lakdawalla at the Planetary Society Blog has spliced together Cassini images of Rhea and done a fantastic job of creating a massive image of a crescent Rhea.

It's really big, and really awesome. This deeply cratered moon is the second largest Saturnian satellite, with a bright (but not snow white) albedo.

The sunspot belts of Sir John Herschel

"On the conservation of solar energy : a collection of papers and discussions" by C. William Siemens. 1883, p.5.

Questions concerning the energy output of the Sun and how exactly it was doing so without shrinking or dimming.

Bruce Schneier on the politics of fear

Bruce Schneier should be on your list of regular reading--he's not voluminous, and when he says something, people should listen, and again he's done it: The Director of National Intelligence claims discourse about how our government functions will kill people!:

Q. So you're saying that the reporting and the debate in Congress means that some Americans are going to die?

A. That's what I mean. Because we have made it so public. We used to do these things very differently, but for whatever reason, you know, it's a democratic process and sunshine's a good thing. We need to have the debate.

As Schneier says, refuse to be terrorized! Don't let America turn into a Police State with State Secrets and Secret Courts. Don't let "exceptions" to the Bill of Rights destroy our freedoms.

Air Force discovers pulsars before Bell

You've probably already seen this, but it's interesting:

http://scienceblogs.com/catdynamics/2007/08/schisler.php

The Air Force early warning radars for the Arctic inadvertently discovered the pulsar before Jocelyn Bell Burnell did in 1967. This joins gamma-ray bursts and adaptive optics as another "thing invented or discovered by the military" before astronomers re-invented or discovered them.

True Patriotism and the REAL ID act

http://www.cnn.com/2007/POLITICS/08/16/real.id/index.html

After hearing claims that the REAL ID act wasn't about a national ID system, it wouldn't affect much, just standardizing the states' method of issuing driver's licenses, now we hear the truth from Michael Chertoff: They have created a domestic passport--you won't be able to travel without it. Some freedom of travel, eh?

The real patriots are the legislatures and governors of the free states, Idaho, Maine, Montana, New Hampshire (Live Free or Die), Oklahoma, South Carolina, and Washington, who stood up against the threats and FUD attacks of the neo-fascists.

Chertoff said there would be repercussions for states choosing not to comply.

Such as? Entering a national park? What fascist state is this? It is time everyone--all Americans, our elected representatives, and true patriots in the executive branch (wherever they might be hiding) to stand up and say NO! to this.

Many states have revolted. The governors of Idaho, Maine, Montana, New Hampshire, Oklahoma, South Carolina and Washington have signed bills refusing to comply with the act. Six others have passed bills and/or resolutions expressing opposition, and 15 have similar legislation pending.

and

New Hampshire passed a House bill opposing the program and calling Real ID "contrary and repugnant" to the state and federal constitutions. A Colorado House resolution dismissed Real ID by expressing support for the war on terror but "not at the expense of essential civil rights and liberties of citizens of this country."

I honestly hope the conservatives that are reasserting the states' rights which have been eviscerated in the past fifty years regain them at the Supreme Court, if only to remove the ironic ability of their sponsors' attempt to destroy what's left of our rights.

The ACLU has it right, too:

The databases will provide a one-stop shop for identity thieves, adds the ACLU on its Web site, and the U.S. "surveillance society" and private sector will have access to the system "for the routine tracking, monitoring and regulation of individuals' movements and activities."

The civil liberties watchdog dubs the IDs "internal passports" and claims it wouldn't be long before office buildings, gas stations, toll booths, subways and buses begin accessing the system.

Chertoff is, essentially, failing to uphold the United States Constitution, which he is bound to uphold. He is not a patriot, he is a fear-mongering statist, moving this country to the Police State which we used to fight against for so long.