No, there aren't any planets that have a Magnitude of exactly 4.
However, there are three planets with magnitudes fainter than 4. In TheSky 6
Uranus is listed as having a Magnitude of 5.9. Neptune has a Magnitude of
8.0. Pluto (Yes, I still consider Pluto a planet) has a Magnitude of 14.0.
You are absolutely correct about the poor time keeping of computer
clocks. I don't know how bad they are though. I would think the computer
would keep good enough time so that the time is correct if you synchronize a
few minutes before the event starts.
My hand held GPS displays time accurate to the second. GPS works by
comparing the time delay between several satellites. Therefore, the time
signal sent by the satellites has to be extremely accurate. Also, WWV and
the GPS constellation both receive their time signals from the same
location, the USNO. So, which is more accurate WWV or GPS?
Tandy W. Carter Jr.
[log in to unmask]
----- Original Message -----
From: "Howard L. Cohen" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, January 23, 2007 3:21 PM
Subject: Re: Up-Coming Occultation
> I'm puzzled. I don't know of any planets that have a mag. of +4.
> Also, typical Windows computers keep poor time. Even if you synchronize
> with WWV, they can be off after several minutes pass. Therefore, you need
> to continuously feed them WWV signals to keep the time correct or the time
> may wander in an unpredictable fashion.
> Many GPS devices were primarily built for location not for accurate
> times -- the displayed time is probably only accurate to a second. If the
> receiver does not correctly account for leap seconds, it may be many
> seconds off.
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