Update: October 27, 2012, 6:20 am. The ride is on! A slight chance of a shower, but there's nothing major. 60-68 degrees during the ride. See you there.
How about a bike ride to check out the fall colors? Saturday, October 27, 2012 (rain date, October 28) 8:00 am (leaving Princeton at 7:30 am).
Forty-five mile round trip from Washington's Crossing to Frenchtown and back on the Delaware and Raritan Feeder Canal Towpath/Rail Trail with lunch in Lambertville/New Hope on the way back.
Click on the link for more info!
Teaching: In the recent past, I've taught the advanced Sophomore mechanics course, Physics 205; the Junior E & M course, Physics 304; and the introductory physics course, Physics 103. In the Spring of 2000, I managed the labs for Physics 102. In the Fall of 2000, I taught the first term of the three term introductory course, Physics 107, for the first time. In the Spring of 2001, I taught advanced E&M for freshmen for the first time, Physics 106. In the Fall of 2001, I taught the third term of the three term introductory course, Physics 109, for the first time. In the spring of 2002, I gave the lectures in Physics 102 for the first time. In the fall of 2002, I taught Thermal Physics, Physics 301 for the fourth time after a two year break. In the spring of 2003, E&M for freshman, Physics 104. In the fall of 2003, it's Thermal Physics, Physics 301 again. In the spring of 2004, FRS 142, a freshman seminar: "Where's Waldo? The Science and Application of GPS." In the fall of 2004, Thermal Physics, Physics 301. In the spring of 2005, I taught a section of Physics 102, premedical physics, and in the fall of 2005, it was Thermal Physics, Physics 301. For the spring of 2006, it was the freshman seminar on GPS again, FRS 144 (the number changed). Fall 2006 was Physics 105, Introductory physics for well prepared undergraduates. In the spring of 2007, "Where's Waldo" is back again, FRS 142. Fall, 2007, it's quantum mechanics for graduate students, PHY 505. In the spring of 2008, I taught a section of Physics 104, the calculus based introductory course and in Fall, 2008, it's quantum mechanics for graduate students again PHY 505. In the spring of 2009, I served as lab manager and taught a section of Physics 104, the calculus based introductory course and in Fall, 2009, it's quantum mechanics for graduate students again PHY 505.
Research: I'm interested in Cosmology and the Hubble Space Telescope - particularly, faint galaxies and clusters and their distributions.
Advising: If you're one of my advisees, my regular office hours are 2-4 Wednesday afternoons, but I'm often available at other times. Send an email to make an appointment. For the spring term and fall term course selection appointments, we'll use the on-line appointment system.
Last updated September 19, 2011 with pictures from September, 2011 rides, including Hurricane Irene and Tropical Storm Lee damage.
This image illustrates a comparison of a ground based image, an HST image before the spherical aberration was fixed, and an image after the fix - all on the same star field at the same scale. You can see more and fainter stars with the fixed HST for two reasons: first, the star images are smaller, so there's less overlap; second, the smaller images can be detected against a smaller patch of background light. (Even above the atmosphere, the sky isn't completely dark! Scattering of sunlight by dust particles in the solar system - the Zodiacal light - causes a diffuse brightness which is 23 magnitudes per square arcsecond at the darkest spots, close to the ecliptic poles.)
This image is a deep exposure with chip 2 of the HST WFPC2. There are many faint galaxies and only a few stars. Exactly how far away these galaxies are requires further study of this and other images. However, a typical faint galaxy in this image is probably at a redshift greater than 0.5 which makes it further than 5 billion light years.
The image is 748 x 768 pixels covering 74.8 x 76.8 arc seconds.
How this image was made: the exposures were obtained in parallel mode - that is the WFPC2 was used to take pictures while the FOS was used to obtain spectra of a galaxy. Exposures were made through the F606W (red) and F814W (near infrared) filters. Six red exposures with exposure times of 500 to 2100 seconds (total 7200 seconds) and seven infrared exposures totalling 10200 seconds were made. The exposures were reduced and stacked giving one red exposure and one near infrared exposure. The two exposures were combined to give a color exposure by normalizing them to the sky background and using the logarithm of the red exposure for the blue and green intensities and the log of the infrared exposure for the green and red intensities. The saturation of the colors is considerably enhanced over what can actually be seen!
A Survey with the HST.
A poster paper presented at the 185th meeting of the American Astronomical Society, Tucson, January 8-12, 1995.
Images of the Lick Galaxy Counts for the Northern and Southern Galactic hemispheres. These GIF images have a resolution of 20 x 20 arcminutes and the intensity in the image is proportional to the number of galaxies brighter than 19th magnitude counted at that spot in the sky.
The projection has the North or South Galactic Pole at the center with galactic latitude going linearly to 0 at the edge of the map. That is, the Northern or Southern Galactic hemisphere is projected onto a circle with the pole at the center and the equator at the outer boundary.
In the Northern hemisphere map, the galactic center is towards the bottom, while in the Southern hemisphere map, it's towards the top. In both maps, galactic longitude 90 degrees is towards the left.
There are no galaxies around the equator because the dust and gas in our own galactic plane obscures our view of the Universe in directions close to the equator. The `hard' edge of the map is the Southern limit of the Lick survey which was made from Mount Hamilton in California and did not go farther South than -23 degrees declination.
These images are also available in WFPC Team Format. Click here for a text file containing a description of this format. IRAF users can probably use this format directly if the header files are named something.hhh and the data files are named something.hhd. The data files contain two byte integers in VMS byte order (little endian) - big endian folks (e.g. Suns) will have to swap the bytes first!
The header files - Northern and Southern - should be downloaded in ASCII mode. The data files - Northern and Southern - should be downloaded in Binary mode. Warning: the data files are over 9 Mbytes each!
The team format maps are 2160 x 2160 with each pixel representing 5 x 5 arcminutes (so the maps are a factor of two oversampled compared to the original survey which used 10 by 10 arcminute cells). For more on the Lick Counts and the construction of these maps, see Seldner, Siebers, Groth, and Peebles, 1977, A. J., 82, 249.
GIF versions of the 2160 x 2160 images are here: North (1.2 Mbytes) and South (0.7 Mbytes).