|Evening sky showing the location of the asteroid 4 Vesta on
20 June when at opposition. The view is looking east as seen from Adelaide at
22:00 ACST. Saturn is high above the horizon and Mars is clearly visible. The
Asteroid Vesta is visible to the north near Saturn. (click to embiggen, similar views will
be seen elsewhere at the equivalent local time).||Simulated binocular view of the region near Saturn showing the open cluster M24
and Vesta on Monday June 4 looking east as seen from Adelaide
at 22:00 ACST. Vesta is above M24 and in a direct line with Mu Sag and Kaus Borealis. Similar views will be seen throughout Australia at the
time (click to embiggen).|
The Asteroid 4 Vesta
is one of the iconic minor planets, and
one of two orbited by the Dawn spacecraft
. Importantly at favourable
oppositions Vesta is bright enough to be seen with the unaided eye under dark
Black and white binocular chart suitable for printing showing the
movement of 4 Vesta over the next 30 days. Click to embiggen and print.
This year is one of the best oppositions of Vesta, when it will
reach a magnitude of 5.3-5.4 at its brightest. Vesta is at opposition on June
20, and is the best opposition since 2000 (and will not be surpassed until
2029). For those interested it is in a series of oppositions this year (Jupiter
May 9, Saturn June 27, and Mars July 27 (best Mars opposition since 2003). Vesta will also pass by some interesting clusters and Nebula.
Vesta will be potentially visible under dark sky conditions.
While it is substantially above the magnitude 6 limit for unaided eye
visibility, local sky conditions, the number of stars of similar brightness,
interference from moonlight and how good your eyesight is may conspire to make
it difficult to see. It is however easily visible in binoculars, and if you locate it in binoculars first it will be easier to pick up. You may need to watch it over several nights to see it move and confirm its identity.
On the other hand this year Vesta has some excellent
signposts to it, early in June it can be triangulated using Saturn, Mu
Sagittarii, the star that forms the “lid” of the teapot of Sagittarius and Kaus Australis at the top of the teapot and the brightest star just above Saturn.
On the 4th and 5th, Kaus Australis, Mu Sagittarii and Vesta are almost in a straight line. Vesta is around half the distance between Mu Sag and Kaus Australis in a straight line north of Mu Sag above M24.
first half of June, sweep north from Saturn until you reach the last
obvious brightish star, this is Mu Sagittarii, just beyond and blow this is the
obvious and rambling open cluster M24. Just above M24, almost in line with Mu
Sagittarii the brightest object visible is Vesta. You may need to watch it over
several night to see it move to ensure you have the right object.
From around the 14th sweep up from Mu Sagittarii
to the iconic and beautiful Trifid nebula, then sweep across (north) to the dim open cluster M23.
Vesta will be near this cluster.
While Vesta will be at opposition on the 20th, it will be
brightest from the 19th to 22nd. Unfortunately by then
the waxing Moon will begin to interfere, but if you find a large object to block the Moons light out and preserve your might vision, you should have no problems seeing Vesta.
Labels: 4 Vesta, asteroids, binoculars, unaided eye