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Re: (meteorobs) More Questions, RA,Decl
In a message dated 98-08-04 11:42:40 EDT, you write:
<<
OK, I've been trying to track this stuff down a little. If I understand
correctly RA 0, Decl 0, would be just South East of the great square of
Pegasus. Right? So the center of the Great Sq. would be about RA 355, Decl
22. Is that about right?<<
Correct.
John>>The approx center of Cassiopeia would be about RA
17, Decl 61. ? Am I getting this? So, according to my info ;<<
I get a RA of about 15: with a Declination around 61:...close enough.
John>>Perseids
"Activity from this meteor shower is visible from about July 23 until
August 22. At the time of Maximum on August 12/13 (J2000 solar
longitude=139.6 deg), the radiant is located at RA=47 deg, DECL=+57 deg.<<
The Perseids have been displaying two peaks these last several years. The
First peak(the new one) should occur near 14h UT on the night of Aug 11/12.
The second and traditional peak should occur near 22 hr UT on the night of Aug
11/12 also. At the time of maximum on Aug 11/12 the radiant is located at RA
= 45:, Dec = +58:.
John>>The hourly rate typically reaches 80, although some years have been as
low
as 4 and as high as 200. The meteors tend to be very fast, with an average
magnitude of 2.3, and about 45% leave persistent trains. The radiant
advances by a rate of 1.40 deg/day in RA and 0.25 deg/day in DECL."<<
The average magnitude can change as the earth passes thru the center of the
perseid stream. On peak night I often will get an average below 2.0. Don't
expect seeing as many this year due to bright moonlight after about 11 pm.
The perseid radiant advances by a rate of 1.4 deg/day in RA and +0.18 deg/day
in Dec.
John>>So tonight, Aug 4/5the radiant should be at RA 35.8 Decl +55? Is that
correct? ie just to the west of the "point" of Perseus?<<
This is correct.
George Zay