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Question
i need the name of any star that would set/rise in the skies of cape town at around the middle of the night for a particular length of time ie for the next month or for the next three months etc.thank you
Hi Ighsaan,
I don't have Cape Town on my skyglobe program, but I do have Johannesburg a few hundred miles
to your north, so you may have to make just a minor change on my times.
Since stars set 4 minutes earlier each night (because it's all based on our revolution around
the sun, and that's 1 degree per day, or 4 minutes of time)... all you need to do is time it
one night, and then subtract 4 minutes for each succeeding 24 hours.
I show Rigel and the bright stars of Orion setting in your due west at 1:05 am local standard
(not daylight time) time for Johannesburg tonight (March 1st) and at 12:25 am standard time
10 days later (40 minutes earlier) on March 11th. This would be close for Cape Town too, within 15 minutes.
Or you can use Sirius, the dog star, brightest real star in our night sky, setting in the WSW tonight at 2:52 am and 40 minutes earlier on March 11th, at 2:12 am.
You can find later dates by simply subtracting 4 minutes each day. So time a setting star
tonight, then you can just subtract 4 minutes for each 24 hours as the days pass by.
In 30 days, a star will set in the west exactly 120 minutes, or 2 hours, earlier.
That's the way it works all the time.
So in 3 months, or 90 days, any particular star will set 360 minutes, or 6 hours earlier,
then tonight's setting time. You can easily prove all this by direct observation.
Clear Skies,
Tom Whiting
Erie, PA USA
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Answers by Expert:
Tom Whiting
Expertise
Astronomy has been my hobby/pasttime for over 50 years. Currently own 3 telescopes, the largest of which is a 30 inch Newtonian truss Dob that is portable.I taught Astronomy/Meteorology at the University Level for 13 years before retiring in 1995. Being retired and home most of the time, I am able to answer all questions relatively quickly, unless it's a new moon weekend with good observing conditions. No astrology questions please, or questions about alleged UFO picture identifications.
Experience
Experience: Astronomy has been my hobby and study for over 50 years. We currently now own a 30 inch portable telescope (Updated - Pennsylvania`s largest portable telescope). It can be seen on our website at:http://www.velocity.net/~bwhiting and also attend several regional starparties during the year, and have been on 5 total solar eclipse expeditions.
Organizations: President, Erie County Mobile Observers Group for over 15 years.
Publications: Wrote the "Over Erie Skies" newspaper article in our local newspaper for 11 years (1975-86).
Education: Masters Degree- Taught at the University level for 13 years. Retired 20 years -USAF Pilot - KC-135 with 180 combat missions; Also Eagle Scout, Philmont staff 2 Yrs, Order of Arrow Lodge Chief, Ham Radio (inactive).
Awards: two discoveries: The mini-coathanger asterism in Ursa Minor (the little dipper) And the mini-ladle- another asterism in the bowl of Ursa Minor. Clients: Currently President of the ECMOG as mentioned above.
Education/Credentials
BS Metallurgical Engineering Grove City College, PAMaster's Degree, Gannon University, Erie, PA
Also retired USAF pilot, 20 years.
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