Centaur
06-March-2009, 07:16 PM
The inferior conjunction of Venus in late March will not be a transit like in 2004 or 2012, nevertheless it could be of special interest to northern hemisphere observers. Venus will appear to pass far north of the Sun, thus creating the opportunity for keen naked eyed observers to spot Venus as a morning star on a day that it will still be visible later as an evening star. Both observation attempts should be made while the Sun is beneath the horizon.
Here are the results of my calculations for Venus’ inferior conjunction related events (geocentric) in chronological order.
Conjunction in Right Ascension
MAR 25 at 13:37 UT
9.07° Elongation
59.14” Diameter
1.21% Illuminated
-2.1 Magnitude
Apparent Closest Approach to Earth
MAR 27 at 12:12 UT
0.2814716 AU
59.26” Diameter
0.99% Illuminated
-1.9 Magnitude
Conjunction in Celestial Longitude
MAR 27 at 19:24 UT
8.16° Elongation
59.26” Diameter
0.98% Illuminated
-1.9 Magnitude
Minimum Elongation
MAR 28 at 02:22 UT
8.15° Elongation
59.25” Diameter
0.97% Illuminated
-1.9 Magnitude
While the published conjunction date is usually for that in celestial longitude, the date of greater interest in this case is that of conjunction in right ascension. That is the date which will present the best opportunity to witness Venus’ apparition as a morning star commencing before the conclusion of its apparition as an evening star.
I’ve created five graphics related to these events. The first one is a panorama previewing the relative positions of the Sun and Venus in geocentric equatorial coordinates from MAR 17 through APR 06 at Noon UT. On that same graphic, enlarged depictions of a crescent Venus are shown for two key moments, although without the effect of Venus’ atmosphere that may make the crescent extend more than 180°. The second graphic previews the eastern sky with Venus and the Moon as viewed from Chicagoland 20 minutes before sunrise on MAR 25. The third one previews the western sky with Venus as viewed from the same location on the same day but 20 minutes after sunset. The fourth one is a panorama depicting Venus’ entire 2008-9 evening apparition. The fifth one is a panorama depicting Venus’ entire 2009 morning apparition. They can be seen by clicking: http://www.curtrenz.com/astronomical.html
Photos and descriptions of Venus around the time of its inferior conjunction would be welcome additions to this thread. The exercise described in this post assumes naked eye observations while the Sun is beneath the horizon. WARNING: They should not be done when the Sun is above the horizon, except by experts in the use of appropriate optical equipment for this situation. Otherwise, permanent blindness could result.
Here are the results of my calculations for Venus’ inferior conjunction related events (geocentric) in chronological order.
Conjunction in Right Ascension
MAR 25 at 13:37 UT
9.07° Elongation
59.14” Diameter
1.21% Illuminated
-2.1 Magnitude
Apparent Closest Approach to Earth
MAR 27 at 12:12 UT
0.2814716 AU
59.26” Diameter
0.99% Illuminated
-1.9 Magnitude
Conjunction in Celestial Longitude
MAR 27 at 19:24 UT
8.16° Elongation
59.26” Diameter
0.98% Illuminated
-1.9 Magnitude
Minimum Elongation
MAR 28 at 02:22 UT
8.15° Elongation
59.25” Diameter
0.97% Illuminated
-1.9 Magnitude
While the published conjunction date is usually for that in celestial longitude, the date of greater interest in this case is that of conjunction in right ascension. That is the date which will present the best opportunity to witness Venus’ apparition as a morning star commencing before the conclusion of its apparition as an evening star.
I’ve created five graphics related to these events. The first one is a panorama previewing the relative positions of the Sun and Venus in geocentric equatorial coordinates from MAR 17 through APR 06 at Noon UT. On that same graphic, enlarged depictions of a crescent Venus are shown for two key moments, although without the effect of Venus’ atmosphere that may make the crescent extend more than 180°. The second graphic previews the eastern sky with Venus and the Moon as viewed from Chicagoland 20 minutes before sunrise on MAR 25. The third one previews the western sky with Venus as viewed from the same location on the same day but 20 minutes after sunset. The fourth one is a panorama depicting Venus’ entire 2008-9 evening apparition. The fifth one is a panorama depicting Venus’ entire 2009 morning apparition. They can be seen by clicking: http://www.curtrenz.com/astronomical.html
Photos and descriptions of Venus around the time of its inferior conjunction would be welcome additions to this thread. The exercise described in this post assumes naked eye observations while the Sun is beneath the horizon. WARNING: They should not be done when the Sun is above the horizon, except by experts in the use of appropriate optical equipment for this situation. Otherwise, permanent blindness could result.