Astroblog: Seeing Asteroid 3122 Florence tonight (3 September 2017)

Sunday, September 03, 2017

Seeing Asteroid 3122 Florence tonight (3 September 2017)

Location of 3122 Florence tonight as seen from Adelaide at 22:00 when it is highest in the sky. The asteroid is just below the constellation of Delphinus. Similar views will be seen elsewhere in Australia (and most of the southern hemisphere) at an equivalent local time. Click to embiggen.

Although NEO Florence (and its newly discovered Moons) has made its record breaking approach to Earth and is now heading away and fading, it is still an interesting telescopic object although dim (magnitude 9) that can be seen to visibly move over a reasonably short observation period.

Over the past few nights the asteroid has not had any good guide stars, making it hard for amateurs without GOTO scopes or modest equipment. Tonight the asteroid will be below the distinctive small constellation od Deplhinus, making for relatively easy star hopping.

Printable black and white chart showing the track of 3122 Florence from the 28th on. The Asteroid passes from close to Grus the crane, through and southern skies passing through Capricornius and Delphinus then Cygnus (click to embiggen and print).

After tonight as it passes through Cygnus it will be getting too low in the sky for Southern hemisphere obsevers.

Printable black and white chart suitable for telescope showing the track of 3122 Florence from the 3rd, the large circle is the field of view of 10x50 binoculars, he small circle is the field of view of a 23 mm eyepiece and a 114 mm reflector. The chart is oriented for a telescopes inverted view. The chart is set for 22:00 and each tick is at an hour interval (click to embiggen and print).
At 22:00 3122 Florence is 4 degrees below 3.8 alpha Delphinus (α on the chart) and 54' above 4.8 magnitude 29 Vulpernica (29 on the chart). As the night progresses the asteroid come nearer to 29 Vul, grazing it shortly after midnight.

The distinctive treadrop shape of the constellation of Delphinus and alpha Del will be reasonably easy to see in the Moonlight. Aim your scope at alpha Del and scan toward the horizon with a widefield eyepiece. The next brightest star is 29 Vul. With 29 Del at the edge of your field Florence should be just above it (or below it, in inverted telescope view), watching over 15-30 minutes you should see the asteroid move substantially against the background stars.

Labels: asteroids, NEO, telescope