>(This article originally appeared in the Q2 2003 STAR Newsletter and was written by Jerry Watson. -Ian) Astronomical Refraction- The Basics – by Jerry Watson At a Club meeting some time ago the subject of the computation of the time of sunset was discussed. We noted that when the visible Sun is just sitting on the horizon the ‘real’ Sun is already just below the horizon. The visible (apparent) Sun sets a few minutes later than the real Sun; likewise…
(This article originally appeared in the Q1 2002 STAR newsletter and was written by Jeff Polston. -Ian) The Moon Illusion by Jeff Polston I think just about everyone is familiar with seeing the moon or the sun near the horizon, seemingly looking larger than normal. The moon can really look kind of eerie. It hangs above the tree tops, usually an orange color. And it looks huge! (though I admit that the image you see here is one I artificially…
(This article originally appeared in the Q2 2000 STAR news letter. -Ian) Indulgence In Obscurity Part III – The Summer Planetaries by Eric Honeycutt Ever since last October, I have been waiting in earnest for the Summer Milky Way to present itself in an early enough hour to spend appreciable time hunting down the many wonderful and obscure objects that lie behind its structured and highly detailed, star-strewn belt. Now, of course this isn’t to rule out the many wonderful…
(This article appeared in the Q1 2000 STAR news letter. -Ian) An Indulgence In Obscurity – Part II. The Spring Sky by Eric Honeycutt Finally, Spring is here! After a winter that brought record snowfall and quite a few cold observing sessions, the Triangle is beginning to warm up. The birds are singing, the flowers are blooming, the grass is growing and greening up, um…the pollen count is rising, the humidity and dew are getting heavier, and there has been…
(This article originally appeared in the Q4 1999 STAR newsletter. -Ian) Indulgence in Obscurity by Eric Honeycutt The following is a scenario that I would like to present and see if it sounds at least somewhat familiar to you: It is a Saturday evening in late January. Temperatures are hovering around freezing and Greg Fishel promises that skies are going to be “clear as a bell”, dew points and humidity are going to be extremely low, and water vapor imagery…
(This article originally appeared in the Q3 1999 STAR newsletter. -Ian) Dealing With Dew by Jeffrey L. Polston It happens to the best of us. Our telescopes are setup. Our charts are laid out. We’re cruising from one object to the next. It’s a beautiful night. The sky is crystal clear and all the stars are calling your name. But slowly, something begins to happen. You notice that the view through the telescope is not quite as good as it…
(This article originally appeared in the first quarter 1997 STAR Newsletter and was written by Eric Douglass – Ian) Geologic Processes on the Moon by Eric J. Douglass I – INTRODUCTION This article discusses the processes that form the features we see on the moon. Its sister paper, ‘The Geologic History of the Moon’, deals with how each of these processes fit into the moon’s The primary geologic processes that shaped the moon are the formation of craters, volcanic activity,…
(This article originally appeared in the Q3 1995 STAR newsletter and was written by Greg Gittings. -I) Polarization of the Sky – A Daytime Test for Transparency A Short History by Greg Gittings Looking at the northern or southern polar section of the sky with an analyzer (a pair of Polaroid sunglasses will do) can tell you if the atmosphere is dry or humid in the upper levels. Dry air is highly polarized and it becomes almost blue-black in the…
(This article originally appeared in the Q1 1993 STAR news letter) The Basics of Gravitational Force and Motion by Jerry Watson In the latter 1660’s when Isaac Newton was about 25 years old, much of his innovative work concerning the relationship of force and motion had already been formulated. Of particular interest here are his three laws of motion and the law of universal gravitation. These insights into the physical workings of the natural world, and the new mathematics needed…
(This article originally appeared in the Q4 1991 STAR newsletter.) Chemistry of an Interstellar Cloud by Mike Albers Chemical reactions between hydrogen, carbon and other atoms in interstellar clouds form molecules. Moving in random paths, atoms must collide with other atoms before a chemical reaction takes place. The more atoms in a volume of space, the more collisions and chemical reactions. Thus, cloud density affects the reaction rate, giving dense cores in a GMC an advantage over the rest of…
(This article originally appeared in the Q3 1991 STAR newsletter.) Forming Type OB Stars by Mike Albers< Small stars (less than 10 solar masses) form throughout a giant molecular cloud (GMC). The really big hot stars, type B2 and up, containing over 10 solar masses, form through a different route. These stars can't form in the small cores located throughout the cloud; fragmentation breaks these cores into too small of pieces. Instead, large stars form in large dense clumps at…
(This article originally appeared in a 1990’s STAR newsletter.) Clyde Tombaugh’s Pluto By Sean League At four o’clock on 18 February 1930 an unbelievable amount of patience and effort paid off. A new planet was discovered. The planet, Pluto, was at last discovered by Clyde Tombaugh. Clyde Tombaugh was born on 4 February 1906 on a farm near Streator, Illinois. He had four brothers and sisters, all of which were younger. Clyde and his family often visited his Uncle Lee…
(This article originally appeared in the fourth quarter 1990 STAR Newsletter. Also references to BC and AD changed to the modern versions BCE/CE) Origin of Julian Days by David Williams One of the most ancient uses of astronomy was timekeeping. In every civilization, the motions of the Moon and Earth were used to calculate the time and the date. In ancient Greece, each community kept a separate calendar, and all were based on the lunar cycle. The earliest Roman calendars…
(This article originally appeared in the Q4 1988 STAR news letter.) Timing Occultations By Mark Lang Observing an occultation is both exciting and scientifically valuable. I would like to get more RAC members active in observing occultations, so hopefully this article will show those who haven’t tried one how easy it can be. Weather permitting, observers can time several more occultations this year. The most common type of occultation is a total lunar occultation. The Moon, in it’s eastward motion…
(This article originally appeared in the Q3 1987 star news letter) The Great Attractor by David Moore In the early part of this century, V. M. Slipher and later Edwin P. Hubble measured displacements of spectral lines in the light from other galaxies. Such shifts reflect the Doppler effect: the change in the wavelength of radiation or sound that results from motion of the source with respect to the observer. Most of the galaxies showed a red shift, meaning that…
