Archive for August, 2009

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Observatory trip preview: A night on Mt. Wilson

August 19, 2009
View from the Mt Wilson towercam.

View from the Mt Wilson towercam.

One of the perks of living in California is being close to several nice observatories. When I lived in Merced I got to visit the Lick Observatory on Mt. Hamilton above San Jose. A few months ago I visited the Griffith Park Observatory in Los Angeles, which is just a fantastic and beautiful place to tour, not least because it’s free. But the gleam in my eye has been a visit to Mt. Wilson (image above from UCLA’s Towercam; go here for a regularly updated Towercam picture).

The Mt. Wilson Observatory was founded in 1904 by George Ellery Hale, and for almost half of the twentieth century it was home to the largest telescopes on Earth. The 60-inch telescope was the world’s biggest telescope when it saw first light in December, 1908. It held that title until November, 1917, when it was eclipsed by the 100-inch Hooker telescope, which is also at Mt. Wilson. No larger telescope would see first light until January, 1949, when the monster 200-inch (5 meter) Hale telescope started operations on Mt. Palomar.

The 60-inch telescope as it appeared when my grandfather was born.

The 60-inch telescope as it appeared when my grandfather was born.

The 60-inch telescope is no longer used for research. Instead, ordinary citizens can rent it for $900 a night and spend the evening observing the heavens with what is, as far as I know, the largest telescope in the world still used for visual observations (image above from here; image below from here). Usually an astronomy club will get a couple dozen people together and everyone will chip in to cut down on the cost of the trip. The Pomona Valley Amateur Astronomers are going tonight, and they had a few extra slots available, sooo…

The 60-inch telescope as it appears today.

The 60-inch telescope as it appears today.

…I’m going with them!

And I’m FREAKING OUT!! I have gotten to look through the 36-inch Great Lick Refractor on two occasions, and both times the views were absolutely unbelievable. The 60-inch reflector at Mt. Wilson has almost double the resolving power and almost three times the light gathering ability as the Great Lick Refractor, so I don’t even have a reference standard for how awesome this will hopefully be. The only dark cloud on the horizon would be, well, a dark cloud on the horizon–the PVAA group has already gotten clouded out once this year. But currently the skies and the forecast are both clear, so with any luck I will have the mother of all observing reports up in a day or two. Stay tuned!

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In the footsteps of Galileo redux

August 18, 2009

Galileo_moon_phases

Hoo boy. So all of three days ago I started this blog with a post entitled, “In the footsteps of  Galileo”, about Galileo’s  achievements, IYA 2009, and starting out in astronomy (image above from Wikipedia).

All of three minutes ago I discovered that the Astronomical League has an IYA 2009 project called, “In the footsteps of Galileo”, with instructions for replicating Galileo’s discoveries for those starting out in astronomy. It’s a cool project, and all it takes is a pair of binoculars and some patience (or fortitude; the Pleiades [#4 on the list] rise about midnight right now and aren’t what you’d call “well placed” until 2 or 3 AM).

The duplicated title is a coincidence–Google lists almost 3000 hits for the exact phrase “in the footsteps of Galileo”–but a fortunate one, because the “Footsteps of Galileo” project hits some of the best stuff I was planning on covering on this blog anyway. In particular, I’ve got some posts lined up on how to take the binoculars you probably already have and make the most of them for stargazing. Stay tuned for more–or, if you’re chomping at the bit, download the “Footsteps of Galileo” observing guide, dig the binoculars out of the closet, and get going (don’t forget Stellarium if you need a little help finding things).

If you’re  looking for something just a little more challenging, the Astronomical League’s Galileo Club includes 12 projects for small telescopes or serious binoculars. You probably will need something with higher magnification (15x-20x) than your average birding binos for those, but even a very small telescope should be adequate. Like, er, this one (shown below), which people have been having a lot of fun with despite, or perhaps because of, its $20 price tag.

Galileoscope-with-Box

Both AL projects are also listed on the right under Observing Lists. “In the Footsteps of Galileo” appears as “5 binocular targets for beginning stargazers”, and the Galileo Club appears as “12 objects for binoculars and small telescopes”.

Have fun!

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Mission 2: Eye of the Scorpion

August 18, 2009

Mission Objectives: Bright star, Constellation

Equipment: Naked eye

Required Time: 1 minute

Instructions: Go outside after dark and look south. Look for a distinctly reddish or orangey star above the southern horizon. To the right of it you will see three bright stars making a short vertical arc.

Antares in Stellarium, as it appears right after sunset in the southern part of the US.

Antares in Stellarium, as it appears right after sunset in the southern part of the US.

The red star is Antares, a red supergiant star about 600 light years away. It is an immense star, with a diameter about 800 times larger than that of the sun. If you placed Antares at the center of our solar system, it would swallow Mercury, Venus, Earth, and Mars.

Antares comparison

Antares compared to another large star, Arcturus, and the sun. R stands for 'radius'. Image from Wikipedia.

Antares is near the end of its life. Smaller stars, like our sun, eventually turn into red giants and blow off most of their mass to form planetary nebulae (so named because the near-spherical balls of gas look  like planets in telescopes, not because they actually have anything to with planets), each with a white dwarf at the core. No such “out with a whimper” fadeout for Antares–one of these days it will suffer a core collapse and blow itself apart as a Type II supernova. When this happens, the explosion will briefly outshine the entire Milky Way galaxy. Fortunately, “one of these days” could be thousands or even millions of years from now, so there’s no cause for panic.

We’re actually catching Antares pretty late in the season. The best time to see it is in late May and early June, when it is exactly opposite the sun in the sky. That means it rises at sunset, sets at dawn, and is highest in the sky in the middle of the night. I don’t know about you, but I’m not up very often at those wee hours. By August, Antares is high in the sky at sunset, or as high as it’s going to get.

Here’s the rub: Antares is pretty far south, so observers in the US and Europe need a clear southern horizon to see it. And the farther north you are, the worse your chances get. Here’s what Antares looks like just after sunset in southern England (higher and to the east you can see Altair, which I’m sure you remember from Mission 1).

Antares just after sunset from southern England.

Antares just after sunset from southern England.

Antares is also known as Alpha Scorpii, because it is the brightest star in the constellation Scorpio. The three bright stars to the right of Antares are supposed to be the scorpion’s claws, and the J-shaped hook of stars trailing off to the south and east form its body and tail, complete with a stinger on the end. To see the body and tail I have to take a short walk. From my tree-shrouded driveway all I can see are the claws and the giant red eye, as terrifying in life as it is in mythology.

The constellation Scorpio as it appears from the southern US.

The constellation Scorpio as it appears from the southern US.

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Hubble Ultra Deep Field in 3D

August 16, 2009

Over at Deep Astronomy, Tony Darnell makes a pretty good case that the Hubble Deep Field pictures are the most important images ever taken. To drive his point home, he put together a video about the Hubble Ultra Deep Field, how it was made, and what it means. At the tail end of the video the camera flies through the HUDF to show how the galaxies are distributed in three dimensions. The whole thing is only four minutes long, and I guarantee that it will be time well spent.

Hat tip to the blogs at HowStuffWorks.

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Mission 1: The Summer Triangle

August 16, 2009

Mission Objective: Bright stars

Equipment: Naked eye

Required Time: 1 minute

Instructions: Go outside after sunset and look up. If you do so not long after dark, and you face east, you’ll see three bright stars making a big triangle high in the sky. The brightest star, at the top of the triangle, will be almost directly overhead. This is Vega, in the constellation Lyra. Down and to the left of Vega is Deneb, in Cygnus (off to the northeast if you’re facing east). Down and to the right is Altair, in Aquila. Vega, Deneb, and Altair make up an informal grouping known as the Summer Triangle.

If you live under a lot of light pollution–like I do–you’ll have no problem finding the Summer Triangle because the three stars will be pretty lonely up there. Even if you’re fortunate enough to live under dark skies, the Summer Triangle is easy to spot because its members are so much brighter than anything else in the area.

The Summer Triangle in Stellarium. Click to enlarge.

The Summer Triangle in Stellarium. Click to enlarge.

To get both the Summer Triangle and the horizon in the same shot in Stellarium, I had to zoom out a lot, which introduced some fish-eye distortion. This makes it look like a cozy little polygon high up in the sky. It’s not! When Vega is high overhead, Deneb and Altair are still climbing the eastern sky, and the whole triangle takes up a huge swath of cosmic real estate.

Two more things about the picture above. You can just make out the Milky Way as a band of faint light cutting across the triangle from north to south. The whole area is packed with star clouds and other deep-sky goodies for binoculars and telescopes. And the very bright light near the southeastern horizon is Jupiter, the king of the planets, just rising to begin his stately progression across the southern sky.

But those are missions for other evenings.

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Getting started for free

August 15, 2009

In the future I will add some more step-by-step how tos on things like recognizing constellations, tracking the phases of the moon, and finding planets and deep sky objects. But I can’t stand, even for a day, having a blog that is supposedly about helping people find their way the sky around that doesn’t actually help them find their way around the sky.

So if you’re chomping at the bit to get going, or you’re just looking for some free astronomy resources, here goes.

Detail of a free star chart from S&T

Detail of a free star chart from S&T

Sky & Telescope has a great 10-page guide called “Getting Started in Astronomy”. It has maps of the night sky and the moon and instructions on how to use them with the naked eye or with binoculars. If you’ve never picked out a constellation on your own and don’t know Aldebaran from Altair, this is Step Zero. There are lots more goodies in S&T‘s Stargazing Basics.

In my humble opinion one of the best free astronomy tools, and the one I use the most, is the free planetarium program Stellarium. You can see what the night sky looks like from any point on the planet, from the deep past to the far future, with optional constellation overlays from cultures around the globe. I use it to see when the moon will be high enough to clear the trees in front of my driveway, to find out what deep sky objects (DSOs) will be overhead at convenient observing times, and to identify things that I’ve stumbled across when I’m just plinking around with binoculars or a telescope.

Stellarium will show you moon phases, but if you really want to see the surface of the moon close up, you can’t do better than the Virtual Moon Atlas (at least without spending any money, and maybe not even then). Includes instructions on how to simulate the view of a spacecraft orbiting the moon, which, if you’re a space nut like me, is going to be irresistible.

If you want to track satellites or spot the International Space Station–which is frequently visible to the naked eye in the early evening!–head on over to Heavens Above for finder charts and instructions on where to look.

For going deeper or just seeing what’s up tonight and for the rest of the week, Almanako is a great resource. It’s more information-dense than most of the rest of these sites, so don’t get flustered if you can’t make sense of it all on your first visit. Things will shake out in time, and the sky isn’t going anywhere.

This is a very, very short list of the free astronomy resources available on the ‘net. If I was so inclined, I could stay busy at this blog doing nothing more than finding and linking to all the good stuff out there. But, as alluded to in the blog title, we all have far too much other stuff to be getting on with. These are the ones I found the most useful when I was getting started, and I use most of them to this day. Even if these particular tools don’t strike your fancy, hopefully they will help you get started on your journey farther up and farther in.

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In the footsteps of Galileo

August 15, 2009

iya_logo

This year, 2009, is the International Year of Astronomy. IYA2009 celebrates the 400th anniversary of the first observations of the heavens with a telescope, by Galileo in 1609.

It’s staggering how much Galileo did. If you look at the stuff out there that can’t be seen with the naked eye, he discovered a vastly disproportionate amount of it. Let’s break it down:

ANCIENTS
Sun
Moon
Mercury
Venus
Mars
Jupiter
Saturn
Milky Way

GALILEO, 1609-1612
Sunspots (= sun not perfect)
Moon craters and mountains (= moon not perfect)
Venus phases (= Venus circles sun, not Earth)
Jupiter’s moons (= bodies circling Jupiter, not Earth)
Saturn “appendages”
“Star” next to Jupiter (later shown to be Neptune)
Milky Way composed of stars (stars vastly more numerous than previously suspected)
Other bright patches composed of stars (ditto)

EVERYONE ELSE
Saturn “appendages” are rings – Huygens, 1655
Saturn’s moons – ditto
Uranus – Herschel, 1781
Ceres (first asteroid) – Piazzi, 1801
Neptune recognized as a planet – Galle, 1846
Asteroid belt – several, 1850s
Pluto – Tombaugh, 1930
Rings and moons of outer planets – Voyager probes, 1970s-1980s
dwarf planets beyond Pluto – Mike Brown, 1990s-2000s

Basically, the eras are “stuff everyone knew from when we lived in caves”, “Galileo figures out most of how the solar system works in the space of three years”, and “working out the details”.

Galileo_telescope

It’s all the more impressive when you realize that he was stuck with a 1″ telescope with a field of view of perhaps 5 degrees and a maximum magnification of 20x that, in the memorable words of someone I’ve forgotten, “suffered from every aberration known to optics”. As much as amateur astronomers complain about “department store trash scopes”, the worst plastic monstrosities sold as ‘educational toys’ are still about a thousand times better than what Galileo had to work with for his entire life.

Galileo did more than any other single person before or since to give us a perspective on the universe and our place in it. It’s a perspective that most people have little or no firsthand experience of. In an age when satellite TV is more than a generation old, mobile phones and dashboard computers can guide you around the world using GPS, remote controlled robots explore the surface of Mars, and mankind’s orbital population never drops below 6 (on the International Space Station), average citizens are strikingly disconnected from the wonders of the night sky. Too many people assume that looking up is the exclusive domain of professional astronomers, or that it’s too expensive, or too time consuming, or impossible under the glare of city lights.

2009-04-27 lights at night

None of these assumptions is accurate.

My ambition for this blog is to invite you to be at home in the universe. During the day we see only the world around us, but when darkness falls we can look out, see firsthand, and really get a gut-level understanding of our place in the cosmos. You can learn your way around the sky without spending a dime, and you will never be lost again. An ordinary pair of binoculars, which you probably have stashed in the closet already, will show you most of the wonders that first excited Galileo four centuries ago. If you decide to get a telescope, they are better designed, easier to use, and less expensive than at any time in history.

The slogan of IYA2009 is “The universe, yours to discover.” It is yours to discover, and it doesn’t take a lot of time or money to learn your way around the night sky and see the best and brightest that the heavens have to offer. The journey begins whenever you go out at night and look up. If you’re not sure where to start, that’s okay–that’s what this blog is for. Let’s go!