Re: [guide-user] C/2002 X5

Juan Carlos Rosso Dec 22, 2002

That morning-evening 'simultaneous' appearence effect is a common behaviour
for objects close to the sun (stars, DSOs, etc) although it is only
'noticed' when bright or closely followed ones are concerned. That is
specially true of comets and planets (Venus and Mercury are prime examples
of the latter). Objects will always be very low above the horizon, that's
why it is not obvious to the casual observer.
In other words, it is noticed only when you are following some object in
particular but happens all the time.

Juan
Madrid

----- Original Message -----
From: Chris Marriott
To: guide-user@yahoogroups.com
Sent: Sunday, December 22, 2002 2:20 PM
Subject: Re: [guide-user] C/2002 X5



----- Original Message -----
From: "Jeff Medkeff" <jeff@...>
To: <guide-user@yahoogroups.com>
Sent: Sunday, December 22, 2002 1:12 PM
Subject: Re: [guide-user] C/2002 X5


>
> It is not at all rare for a comet to be observable in both the morning and
> evening sky of the same day at either northerly or southerly latitudes.
The
> farther poleward the observing site and/or comet, the more common the
> circumstance is.

Indeed. The obvious case when this is true is when the comet is sufficiently
close to the pole to be a "circumpolar" object, which is always above the
horizon. In that situation it is, self evidently, visible whenever the sky
is sufficiently dark!

Regards,

Chris
---------------------------------------------------------------
Chris Marriott, SkyMap Software, UK
e-mail: chris@... Web site: http://www.skymap.com
Astronomy software written by astronomers, for astronomers


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