Sunday, March 14, 2010

Letter to the editor: Time to consider central time again

I just submitted the following letter to the editor of "The Republic" in Columbus, Indiana.

Exclusive extra online example at the end.

By the way, I see that this is my 1,800th blog post.

Published Tuesday, 16 March 2010.

Solar transit reveals DST problems (bottom of page; subscription may be required to view)

To: Bob Gustin
Sent: Sun, March 14, 2010 3:07:34 PM
Subject: Letter to the editor: Time to consider central time again

It would be interesting to have the solar transit listed with the daily sun/moon times in the daily paper.

The transit occurs at midday, when the sun is most directly overhead. Half the daylight for the day is behind and half remains.

This time also represents the amount of additional evening daylight that day due to the combined effect of daylight saving time and observing eastern time.

For example, on the first day of eastern DST (Sunday, 14 March 2010), the solar transit [ for Columbus, Indiana ] is at 1:53 pm. That's one hour and 53 minutes daylight shifted from morning to evening. 60 minutes is the nominal amount of daylight shifted by DST from morning to evening.

If we were back on central time with DST (which Indiana observed till the early 1960s), we'd still have 53 minutes of daylight shifted from morning to evening today. I'm among those who feel that 53 minutes of extra evening daylight is quite close enough to 60, without having to give up almost a second hour of daylight in the mornings.

If you feel likewise, I encourage you to join me in urging Indiana's legislators and governor to petition the USDOT to put Indiana back on central time.

If the paper decides not to add the midday time to its daily stats, here is a link to the U.S. Naval Observatory page where you can check the transit time for yourself.
Complete Sun and Moon Data for One Day: U.S. Cities and Towns — Naval Oceanography Portal

Bill Starr
Columbus, Indiana

Extra example for the online edition.

There are 11 hours 52 minutes from sunrise to sunset in Indianapolis today (Sun, 14 Mar 2010).

Dividing that in half would give 5 hours 56 minutes before midday and the same after.

If midday were at noon, that would give a sunrise time of 6:04 am and a sunset time of 5:56 pm.

If one hour of sun were shifted from morning to evening, that would give Indy a sunrise time of 7:04 am, transit (sun overhead) at 1:00 pm and sunset at 6:56 pm.

Now let's see which time zone puts us closer to these figures.

On central daylight time, the sun would rise and set at 6:58 am and 6:50 pm, only 6 minutes short of the nominal shift of 60 minutes of daylight from morning to evening.

On eastern daylight time, the sun rises and sets at 7:58 am and 7:50 pm. This is nearly two hours of daylight shifted from morning to evening. No wonder our grandparents called EDT "double-fast time".

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