I have just finish reading all about time and I thought I understood it. I learned about universal time, ephemeris time, mean sidereal time, true sidereal time, terrestrial dynamic rime, barycentric dynamical time, and atomic time.

It was a bit confusing, but I found that universal time was really varying since it is based upon the spin of the earth and that’s slowing down -- it has to do with moon drag. So also was mean sidereal time based upon the same spin and true sidereal time which brings in the pull of the moon.

Astronomers then went to ephemeris time which is based upon the time it took the earth to circumnavigate the sun in the year 1900 with all planetary effects removed mathematically. Then came Albert Einstein and his relatively theory -- the general one and the hardest, of course. This predicted that even this yearly motion was varying and so someone thought of using the emissions of the cesium atom - hyperfine, of course - to measure time intervals. This is extremely constant and will be assumed absolutely constant until we find something more nearly constant. So astronomers invented the Systeme International - that’s French for pegging the second (I mean seconde) to 9,192,631,779 cycles of hyperfine radiation of cesium 133.

Of course, with the General Theory in play one has to account for atomic clocks all around the world and consider their position with respect to the gravity fiend and rotation of the earth. Oh, yes, also the revolution of the earth around the barycenter of the solar system. And so we go to barycentric dynamic time which is the atomic time at that solar system barycenter. This, of course, is not the same as the time at the center of the earth which is terrestrial dynamic time. All the tables in the Astronomical Almanac refer to these last two times.

Now I thought I had it all down pat. I finally understood time. And then I read the latest Asterism. On page 2 it urged me to set my clock back on April 4th for Daylight Savings Time. I was about to do just that on one of my clocks to be ready for DST when I flipped the page and read "Turn clocks forward one hour...." So I hesitated. I really didn’t understand time after all. George Skidmore thought he had trouble with just a leap second. Now I have a whole hour to contend with...or is it two hours? Boy am I confused. I’m going back to Julian Day Numbers which haven’t changed since 4713 BC.

H

For everyone who’s been running two hours late since the last Asterism…..

Sorry I said to set your clocks "back", I meant forward. I suffer from occasional brain freeze…or April Fools! Your Editor J

H

On March 25th 1999, quite a crowd had gathered to see our facilities. They came with Karl Hricko. He was having a special class about astronomy and AAI's facilities. However we solved this scheduling conflict amicably.

The usual suspects were in attendance for the Research Meeting. Mike Luciuk led off giving the facts about the upcoming Lyrid Meteor Shower. (Those interested in participating, should contact Hank Adams or Mike Luciuk by phone). This was followed by a general discussion. Since the sky was clear, we decided to use our ST6

. When we opened up we found that the computer couldn't access the hard drive. Fortuntely Hank had his laptop with the appropriate software to operate the ST6. We focussed on a small group of stars, the brightest being 4th magnitude. Hank estimated the faintest stars to be about 14th magnitude. At that point our time had run out. We closed the meeting at that time.

H

Will be held on Thursday March 25^th

at 8:00 PM

All are welcome to come explore and get involved with many various projects being conducted by club members!

H H H H H H H H H H

The Asterism

can be contacted at:

Or

Asterism

59 Dyckman Place

Basking Ridge, NJ 07920