Early April Astrominute

The early April Gettysburg Astrominute is online and on WZBT. Once again, we made a video to go with it. Hope you're looking forward to the lunar eclipse in the early morning hours of April 15!

Audio MP3: http://public.gettysburg.edu/~iclarke/hatter/podcasts/astrominute040114.mp3

Planetarium Presentation by Caitlin Hay, '14

Gettysburg College

Department of Physics

Senior Presentation          

Caitlin Hay

Gettysburg College Class of 2014

The Exploration of Mars  Senior physics major and planetarium assistant Caitlin Hay will show off her planetarium presentation skills with help from Annie Skrabak and planetarium director Ian Clarke. The show will explain the current appearance of Mars in the sky as it reaches opposition this April. Then we will take a multimedia tour of current and future missions to explore the Red Planet.

Thursday, March 27, 2014 at 12:00 p.m. (lunch provided)

and

Friday, March 28, 2014 at 3:00 p.m. (refreshments provided)

Masters Hall, Room 115

HATTER PLANETARIUM

New astrominute, now with video

The late-March astrominute is now online and on WZBT. As a bonus, we've made a version of this one with video. Will this become a permanent addition? Hard to say, it will depend on how busy we are (it's spring break at the moment) and on the feedback and number of views we get on this one.

Audio MP3: http://public.gettysburg.edu/~iclarke/hatter/podcasts/astrominute31514.mp3

Video:

What not to like about Daylight Saving Time

No, I do not like daylight saving time. It moves the clock further from, and even obscures, the rhythms of nature. So here's my case. First, it's confusing. There are folks who will tell you that the days get longer because we "spring forward." Nope. Absolutely no effect. In mid-northern latitudes the length of day will go from about 9 hours, 30 minutes in December to 15 hours in June, whatever the clock hours read. DST only changes the clock hours in which we experience that daylight, displaces them, if you will, as anyone who has started to enjoy the earlier sunrises of the first week of March can tell you.

Most people, I admit, probably get that, so here is my deeper gripe. Daylight Time is arbitrary and has no basis in nature. You might think that's true of any attempt to assign numbers to times of day, but no. Our 24-hour day was based on noon, which occurs every day when the sun reaches it highest point, even as the days and nights contract and expand. Well, actually it was based on Local Solar Noon, the moment the sun crosses the meridian as seen from your location, the moment when a correctly constructed and aligned sundial will read noon.

We have adjusted sundial time in two ways (not counting daylight time) over the centuries as technology has changed. Interestingly, the time from one noon to the next is not quite equal through the year. The earth's rotation rate remains (practically) constant, but the its speed in its elliptical orbit increases when we are closest to the sun and slows when we are farther away. Thus the length of a sundial hour varies a little, according to the Equation of Time. This was no problem until we invented clocks whose error was less than that caused by the EoT. We averaged those variations out by using Mean Solar Time. Still, the concept of noon was the foundation.

Local Mean Solar Time in Action

Mean solar time, however, was local. A clock set to mean solar noon in one city would not read the same as another. Gettysburg, for example, would be nine minutes behind Philadelphia and 10 minutes ahead of Pittsburgh. Every town having its own local time worked until travel and communication became fast enough to render it impractical. Thus, we got standard time, in which the time of one location became standard for a whole region. In the case of the Eastern Time Zone, we use the time for 75 degrees west longitude, or around Philadelphia. For the most part, we change clocks one hour after about every 15 degrees of longitude traveled, though there are a few half-hour time zones in the world. Still, with a couple of allowances, noon on your clock is near noon in the sky, especially if you do not live near the edge of a time zone. Noon connects us to the motion of the sun and to the day, in the literal sense of the word.

Daylight time discards that principle of time tied to the sun's peak. Solar noon, from the second Sunday of March to the first Sunday of November, will be around 1:00 PM. I don't like it one bit. I know we can't all "make our noon" like ship captains of old. Standard time is fine; it makes necessary accommodations, but remains tied to the sun's rise and fall.  Daylight time is a government-created chimera that makes our clocks tell time, but not the time of day.

Two Stellarium panoramas, one local

We may operate a vintage optical-mechanical planetarium, but we do love astronomy software. We recently made a couple of 360-degree landscape images, ready to use in the free and beautiful Stellarium program. I can't recommend it enough! It comes with a number of landscapes installed, but a user can add more. Here's how to install.

Freedom Township, Adams County, PA.

http://public.gettysburg.edu/~iclarke/hatter/downloads/freedomtwp.zip

Abbott's Lagoon, Marin County, CA.

http://public.gettysburg.edu/~iclarke/hatter/abbottslagoon.zip

Show today is on as of now

We are planning to have the show as scheduled today at 4 PM today. Here's our inclement weather policy:

Check the Gettysburg College web site first. If the College is open, we will make all reasonable efforts to hold the shows as scheduled. In the unlikely event that we cannot hold the show for our own reasons (e.g., the presenter is ill and no substitute is available, equipment failure, etc.) an update will be posted to this site and to the Gettysburg Skiesblog.

Since this is a Sunday, the College is very unlikely to officially close, so this decision is on us. At this point it appears that the heavy snow will fall later in the evening, so we should be OK with the 4 PM show. If anything changes, announcements will go out via the @GCPlanetarium twitter account and this blog. Thanks!