Re: (meteorobs) Degrees

• To: Meteor Observing Mailing List <meteorobs@atmob.org>
• Subject: Re: (meteorobs) Degrees
• From: Lew Gramer <dedalus@latrade.com>
• Date: Wed, 19 Dec 2001 17:01:36 -0500
• Delivered-To: meteorobs-mh@atmob.org
• Delivered-To: meteorobs@atmob.org
• In-Reply-To: Your message of "Wed, 19 Dec 2001 20:43:51 +0100." <00a401c188c7$fb5e1140$93aa86c2@latitude>
• Reply-To: meteorobs@atmob.org
• Sender: owner-meteorobs@atmob.org

Robert, all Solar Longitudes quoted by IMO (the canonical source used by
most amateurs and professionals for such shower data) are epoch J2000.0.

Nor is there any reason for you to have to perform laborious calculations
to convert these "lambdas" (solar longitudes) quoted by IMO into UT time:
IMO's website provides convenient conversion tables up to 2005 for that!

Go ahead and browse the IMO Web site more thoroughly, and it should clear
up many of these questions for you. In particular, I recommend:

    http://www.imodot net/calendar/cal01.html
    http://www.imodot net/calendar/cal02.html
    http://www.imodot net/solarlong/index.html

As for why meteor calendars often quote radiant positions using degrees
("alpha") rather than hour/min/sec ("right ascension") on the East-West
axis, Marco did a great job explaining this as a simple convenience for
calculating radiant positions throughout a shower's activity period...
(I have asked this very question myself in the past... Thanks, Marco!)

Clear skies,

Lew Gramer
North American Meteor Network

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• Re: (meteorobs) Degrees
• From: "Marco Langbroek" <marco.langbroek@wanadoodot nl>

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