Lowell and Clark

One hundred and fifty-eight years ago today, Percival Lowell was born, and I for one am glad of it. You see, having been born into an aristocratic family and  becoming passionate about astronomy, Percival Lowell founded the Lowell Observatory of Flagstaff, Arizona. Originally, Lowell built the observatory in 1894 to study Mars, in the hopes of conclusively supporting the idea that there were canals where alien life forms were growing large amounts of vegetation. Lowell spent fifteen years studying the surface of Mars, carefully drawing out the surface details, inclusive of the canals he was so convinced existed there; however, he was wrong about the existence of the canals, but that was not the end of his searching the night sky. During the time that Percival Lowell was actively observing the night sky, Newtonian physics (combined with Kepler's Laws of planetary motion) had been able to successfully predict the orbital motions of the planets, accounting for the gravitational effects of neighboring celestial bodies. Thanks to Lowell's background in mathematics, he was able to notice orbital discrepancies in the motions of Uranus and Neptune, suggesting the presence of another planet beyond them. Unfortunately, Lowell died in 1916, before his predictions of another planet could be fulfilled in 1930 by Clyde Tombaugh with the discovery of Pluto at the Lowell Observatory.

In 1896, the Lowell Observatory's most iconic telescope arrived, the Alvan Clark Refractor, more commonly called the Clark Telescope. This telescope is among the largest telescopes of its generation, being the first permanent telescope of the Lowell Observatory. It has two 24 inch lenses, encased in a rolled steel tube measuring 32 feet long, and weighs an impressive six tons when including all of the moving parts! Percival himself did his research of Mars and planet X on the Clark Telescope. Other notable research that has been conducted on the Clark Telescope includes V.M. Slipher's galaxy research (Slipher was the first to be able to detect the radial velocities of galaxies!) and detailed mapping of the Moon during the sixties by U.S. Air Force and Lowell cartographers. Interestingly, the Clark Telescope is still in use today, giving visitors to the observatory a chance to look into the night sky through the same telescope used by Lowell and Slipher! Being a private entity, Lowell Observatory is currently trying to raise enough money to refurbish the Clark Telescope so that many more people can have the chance to look through a piece of astronomical history and gaze in wonder at the sights it unveils. If you'd like to help them in their quest to refurbish the Clark Telescope, or would just like to get more information about anything Lowell, you'll find links in the sources below.

Further reading and Sources:

The Clark Telescope on FB
Lowell History
News at Lowell
Restore the Clark
Sea and Sky

3-D Astromania!

I have to tell you, I am completely blown away by astrophotographer, J-P Metsavainio's portfolio of astrophotography work. I mean, words fail when you start poking around his website, Astro Anarchy, and seeing some of the incredibly detailed photos that he has taken -- and that's not even the half of it! I originally found an article about his work on EarthSky after having clicked on a random link on Facebook, becoming mesmerized by his animated work. When I say animated work, I mean that he has taken data about the objects in his images, compiled with the actual images he took, and created three-dimensional animations that truly give you a sense of what that region of the universe may look like. As Metsavainio is quoted by EarthSky,

"The models are based on some known scientific facts and an artistic impression. They give an approximation to the real structure of the nebula, an educated guess … a feel to the object and an idea, what it must really be like."

He refers to these animations as being volumetric models where he has used his own two-dimensional images, having carefully analyzed the astrophotos for  all possible relationships between objects and known data to map the details into his animating software. The results are breathtakingly beautiful, and I highly encourage -- no, make that I insist -- that you look at his portfolio, his blog, and the EarthSky article (some of the volumetric models are here)!!!!

The Analemma Dilemma

For those of us that do not live along the equatorial region of the Earth, the amount of daylight we receive each day varies predictably with the seasons, with the longest days being near the summer solstice and the shortest being near the winter solstice. Most of us have probably even realized that the location of the sun in the sky during the year changes. Some may even notice that putting these details together suggests there is a connection between the seasons, amount of daylight in a day, and the location of the sun in the sky throughout the year -- and those individuals would be right! 

If you've never seen an image like the one above before, this is a phenomena known as an analemma, a series of pictures taken throughout a single year, from the exact same location at the exact same time every day (with corrections for people who live in daylight savings areas, of course!) and then superimposing those images to create an image similar to this one. Of course, where you are on the Earth, and when you choose to take a photo each day, will affect how your final image looks compared to this one, but that is to be expected from the celestial mechanics at work that make such an image possible in the first place.

Okay, so now you might be asking me, "What in the world are you talking about? This celestial mechanics gibberish is beyond me!" And if you've never taken an astronomy course, don't worry, I'm about to give you a simplified version of celestial mechanics in this post!

To start, you should all know already that the Earth orbits the sun once every 365 days (which defines one Earth year), while rotating about its own axis once every 24 hours (which defines the length of one Earth day). The Earth's orbit lies on the plane of the solar system, along with the orbits of most of the other planets. The Earth's axis, on the other hand, is tilted from the vertical by roughly 23.45 degrees and this tilt causes a plane drawn through the equator of the Earth to be tilted from the plane of the solar system (the ecliptic) by the same amount, and this plane is called the celestial equator. In the image above of the analemma, the white line drawn along the length of the analemma is caused by the tilt of the ecliptic as we move around the sun during the year. The figure 8 portion of the analemma is a result of the shape of the Earth's orbit, which is not perfectly circular but instead elliptical. The eccentricity of an orbit gives information about how elliptical an orbit is, where an eccentricity of zero would indicate no elliptical motion, or a perfectly circular orbit. The amount of eccentricity of the orbit causes the figure 8 shape, and the size of the two lobes are directly related to the eccentricity -- meaning large eccentricities have more even lobes and no eccentricity results in a straight line. With some information from Kepler's Second Law of Planetary Motion, which we can summarize as the area of the orbit traversed in a given amount of time is the same no matter where you are along the orbit (see image below for visualization), we can see that the Earth travels fastest when it closest to the sun (perihelion) and slowest when it is furthest from the sun (aphelion). It is this difference in speed along the orbit, caused by the eccentricity, that we see in the lobes of the analemma above.

In general, this phenomena is not unique to the Earth, but does vary in appearance on each planet. You can see a short animation and an explanation of analemmas on other planets in our solar system here. Also, I mentioned that your location on the Earth changes the appearance of the analemma you take. The reason for this is related to the angle at which the sun appears in the sky to you at your location, known as the declination. The effects of the declination of the sun at your location are explained pretty well in this blog, so check it out if you'd like more details of how the analemma changes with location.

Further reading and sources:

The Earth Story

Web Odysseum

Analemma

Starts With a BANG

Universe Today

Celestial Sphere