On April 19th a considerable sized asteroid will pass about 4.6 lunar distances (1.8 million km) from Earth. While there is no chance of it impacting our planet, this 650m asteroid was only discovered three years ago, and it will be the closest encounter of a large asteroid since asteroid Toutatis in September 2004. The next predicted fly-by of a large asteroid is 2027 with 800m wide 1990 AN10.
The expected magnitude could reach up to 11 during the close approach, hence a decent sized scope will be required, and due to the rapid movement may be hard to locate and track.
Sky chart for asteroid 2014 JO25 covering April 18th to 20th 2017
And as a bonus, comet PanSTARRS (C/2015 ER61) will also make its closest approach to Earth on the 19th, but 10 times farther away as the asteroid. I should be visible with small telescopes or binoculars in the constellation Aquarius in the dawn sky.
If you are able to get out of bed early and the sky is clear, equipped with binoculars you should be able to catch a fast-moving comet as it swings by Earth at about 32 lunar distances over the next few days. The best time is just prior to sunrise as the comet will be higher in the sky in the East. Use Jupiter as well as bright stars Vega and Arcturus to get your bearings. With each day the comet will rise earlier and will appear higher in the sky as the chart below shows; comet position at 5am for the next week. However it will diminish in brightness as it moves away from Earth on after February 11th.
Comet 45P over the next few days starting Feb 10th.
This isn’t the closest a recording of a comet passing near Earth, but it does make it to the 8th spot since modern observation and have been keeping track of near Earth objects (1950). Back in August 15 2011, it happen to pass even closer, only 23 lunar distances, making it also the 5th closest comet approach.
With a storm system moving up the eastern edge US and Canada, my chances of getting any clear morning sky is pretty slim…
Downloadable PDF Sky Chart: 45p_feb2017_chart
My challenge for the next two days (Clear Sky Chart is predicting clear skies) is to observe and capture comet 45P/Honda-Mrkos-Pajdusakova. It should be relatively easy to locate by hopping from Venus then down the bright stars of Capricorn starting with Delta, Gamma, Iota and ending with Theta. Then half a degree to the left of Theta Cap is magnitude 6 star HD201057. Comet 45P at magnitude 7 should be just next to that star.
The challenge will be its position low near the horizon, I may have obstructions before it sets. And the twilight may not be dark enough for a magnitude 7 object. The viewing time window will be quite small…wait for darkness and it will fall out of view.
Location of comet for January 5th 5:30pm EST
No need for telescope, it’s also a binocular object.
45P is the 45th periodic comet (Halley being the 1st identified periodic comet) with a 5.3 year period. Its orbit swings from just past Jupiter to in between Mercury and Venus.
December 31st will be your opportunity to easily locate and observe Neptune with a telescope as it will be within 1/3 degree of Mars low in the western part of the Sky. Mars will present a reddish magnitude 1 disk while Neptune will be much smaller, essentially a dimmer magnitude 7.8 dot. Large telescopes should reveal the blueish hue of Neptune when placed slightly out of focus.
Neptune and Mars 1/3 degree – December 31 (1 degree circle)
In the image above I’ve marked magnitude 7.9 star just outside the 1 degree circle to assist in the orientation.
However don’t wait too late in the evening, best may be shortly after 7pm once the Moon is below the horizon. Starting from the horizon you’ll able to easily locate bright Venus and about 10 degrees above will be Mars and Neptune. Bright stars Fomalhaut and Altair will be located east and west along the horizon.
Neptune Mars and Venus setting in the West – December 31 (7pm)
An easy target for anyone is the constellation Auriga and it’s three bright open star clusters. It may be considered a winter constellation, but there is still plenty of time for some decent observation. In the early April evenings , Auriga lies west about 45 degrees over the horizon. It’s brightest star, Capella, the sixth brightest in the night sky can easily be located. Therefore these open clusters are easy targets for a quick star-hopping observation for anyone with a small telescope or binoculars.
Auriga in April with three bright open clusters (boxed)
My last few posts have been the photos that I’ve captured of these three Messier objects: M36, M37 and M38. Below is a view if the boxed area from above but with the photos of the open clusters inserted at their correct location.
M37, M36 and M38 (respectively) in Auriga
To see larger images of the open clusters, refer to my following blogs:
Messier 36 – Open Cluster in Auriga
Messier 37 – Brightest Open Cluster in Auriga
Messier 38 and NGC1907 – Open Clusters in Auriga
In my previous post I’ve mentions that coment 67P/Churyumov–Gerasimenko is currently between the orbits of Jupiter and Mars, on a trip towards the Sun. While some comets take decades to become visible again this one has an orbital period of 6.44 years, therefore a frequent visitor. That was one of the selection criteria for the target comet: short orbital period such that it did not take too much fuel or planetary gravity assist to intercept.
On August 13th it will be at it’s closest position to the sun (perihelion), therefore brightest and a good time to observe. Afterwards it will be swinging back out towards Jupiter on its elongated orbit. For people in the Northern Hemisphere, the best time to observe comet 67P will be after this August date. Below is a chart showing that the comet will be visible in the early morning starting in June 2015, and will be visible at higher altitudes in the sky throughout the following months.
Comet 67P visibility for around 45 Latitude N.
Below is a chart (click to enlarge) showing the position of 67P until November 15th.
Comet 67P/Churyumov–Gerasimenko sky chart for Nov 2014 to Nov 201
A good photographic opportunity will be August 8th when comet 67P will pass right under open cluster M35.
Comet 67P passing under Open Cluster M35
Graphics generated with C2A Planetarium Software