Hi Gianni and others: The summer solstice will be a little unusual this year because several astronomical events will occur on this day. There will be a total eclipse of the sun (in Africa), and Mars will be in conjunction with the Earth. (It will be at its closest distsance in many many years). Because a total solar eclipse implies a new moon, the sky will be nice and dark for viewing Mars.
The night of June 21, I'd like to look at Mars with the telescope (I saw it last night, it's really big!). Since Mars is low in the Southern sky, near Scorpio, optimal viewing conditions will be when Mars is at culmination ( its highest alititude above atmospheric interference along the horizon). This will happen sometime in the early morning hours I think. Here's my question : How can I determine the time of culmination of Mars for June 21 at Latitude 32.5*N, Longitude 111*W? I need to set the alarm clock! Thanks John John L. Carmichael Jr. Sundial Sculptures 925 E. Foothills Dr. Tucson Arizona 85718 USA Tel: 520-696-1709 Email: [EMAIL PROTECTED] Website: <http://www.sundialsculptures.com> ----- Original Message ----- From: "Gianni Ferrari" <[EMAIL PROTECTED]> To: "Sundial Mail List" <[email protected]>; <[EMAIL PROTECTED]> Sent: Monday, June 18, 2001 2:45 AM Subject: R: meridian or culmination ? > Hallo Alain, > > in astronomy the two words "meridian passage" and "culmination" are > (almost) synonymous and therefore I think that, in the software of which > you speak, they are used for the same phenomenon. > > In page 724 of the Explanatory Supplement to the Astronomical Almanac we > may read: > " CULMINATION : culmination passage of a celestial object across the > observer's meridian; > also called "meridian passage." More precisely, culmination is the passage > through the point of greatest altitude in the diurnal path. Upper > culmination (also called "culmination above pole" for circumpolar stars and > the Moon) or transit is the crossing closer to the observer's zenith. Lower > culmination (also called "culmination below pole" for circumpolar stars and > the Moon) is the crossing farther from the zenith." > > The height above the horizon at upper culmination of a celestial body with > Declination = d is H_uc = 90 - Lat + d (measured from South) or = 90 + > Lat - d if measured from North > > For example with Lat = 50d , if the declination of the Sun is d = 20d , we > have H_uc=60 d (measured from South) > For a star with declination = 80d we have H_uc=60d measured by North > > The height above the horizon at lower culmination of a celestial body with > Declination = d is > H_lc = Lat + d - 90 (measured from North) > > For example with Lat = 50d, if the declination of the Sun is d = 20d , we > have H_lc= -20d (the Sun is under the horizon) > For a star with declination d = 80d, we have H_lc=+40d > > For a place with Lat = 75d and with the Sun with d = 20d , we have at upper > culmination H= +35 measured from South and at lower c., H = + 5 measured > from North (the Sun doesn't set) > > Regards - > > Gianni Ferrari > > ----- Original Message ----- > From: Alain MORY <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Saturday, June 16, 2001 10:25 PM > Subject: meridian or culmination ? > > > > > > Hello, > > > > I was surprised to sea a software dedicated for astronomy showing other > > times for "passage au mČridien" and for "culmination" of the sun. > > > > Why is there such a difference between these two notions ? > > > > Alain MORY > > 48N 7E > > > > > > >
