Monday, December 17, 2018
Comet 46P Wirtanen at its closest to Earth (16-17 December 2018)
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| My sketch of 46P tonight at 12:38 am ACDST from suburban Adelaide. Made with 10x50 binoculars. Atlas in the Pleiades is indicated. click to embiggen | Simulation of 10x50 binoculars view of the same field at the same time in SkyMap. The location to the Pleaides is the big cluster at the bottom left. click to embiggen. |
After days of cloud and rain I finally got to see 46P again tonight. Star hopping to the comet was much easier, once I had done a bit of dark adadption, as the Pleiades made and obvious signpost, but even with the moonlight comet 46P was readily see as a large fuzzy patch. Despite being closer and more bright it was not as obvious as the first time, due to the Moonlight, but still obvious. The justaposition of the comet and Pleaides was marvellous. Like last time, the sketch is a bit wobbly from trying to juggle sketch pad, binoculars and red light torch, but not too bad.
Trying to get some camera images now, hope the cloud stays away.
Thursday, December 13, 2018
Comet 46P aaproaches Earth, Geminid Meteors ramp up.
Tonight Comet 46 P is closest to the Sun, over the next few days, as the comet heads towards its closest approach of Erath on the 16th, the comet will be at its brightest and best to view (even though it is basically a fuzzy patch, even under the best viewing conditions). For detailed maps and viewing instructions see my 46P page.
The next few days also see the Gemenids ramp up towards their peak on Saturday morning, good rates have already been reported in the northern hemisphere.
The Geminids are a fairly reliable meteor and this will be a good year for them with little moon interference.
The radiant doesn't rise until just before midnight (daylight saving time) in most of Australia, so you will still have to disturb your sleep for this one. The peak is not until next Saturday when Australians should see a meteor every one to two minutes under dark skies in the early morning of the 14th, between 1:00 am and 4:00 am local time. However, in the lead up to the peak you should see some decent meteors under dark skies. The further north you are the better the meteor rates. You can find predictions for your local site at the meteor flux estimator (choose 4 Geminids and date 14-15 December, don't forget to change the year to 2018). For more details see my Geminid page.
Of course, most of Australia is currently under thick cloud, but lets hope for a break.
Labels: 46P, comet, geminids, Meteors
Thursday, December 06, 2018
My First View of Comet 46P Wirtanen (6 December 2018)
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| My sketch of 46P tonight at 10:57 pm ACDST from suburban Adelaide. Made with 10x50 binoculars | Simulation of 10x50 binoculars view of the smae field at the same time in Stellarium. |
I finally got to see 46P tonight (after cloud, rain and a range of other issues). Took a while to sort out the star hopping to Azha (eta (η) Eridani, but once that was done comet 46P was readily see as a large fuzzy patch. The sketch is a bit wobbly from trying to juggle sketch pad, binoculars and red light torch, but not too bad after a long break fro sketching.
Hopefully the weather will stay clear and I can get some camera images as well.
Seeing comet 46P Wirtanen at its brightest from Australia
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| Location of Comet 46 P Wirtanen as seen looking north-east from Adelaide at 22:10 ACDST on Tuesday the 13th of December (90 minutes after sunset), when the comet is closest to the Sun. Similar views will be seen throughout Australia at the equivalent local time (90 minutes after sunset). Click to embiggen. | Location of Comet 46 P Wirtanen as seen looking north-east from Adelaide at 22:13 ACDST on Sunday the 16th of December (90 minutes after sunset), when the comet is closest to the Earth. Similar views will be seen throughout Australia at the equivalent local time (90 minutes after sunset). Click to embiggen. |
Comet 46P is on track to be the brightest comet of this year. Currently magnitude 5.0, it is set to pass pass Earth at 0.0781 AU (~30 time the distance between the earth and Moon), this makes it the 10th closest comet to pass Earth in the modern era.
It is still a bit uncertain how bright it will get but it should get to between magnitude 4 and possibly as bright as magnitude 3 (about as bright as gamma Crucis, the fifth brightest star in the Southern Cross).
The comet will be brightest between December 13 to December 19. It will be closest to the Sun on the 13th, and closest to Earth on the 16th (just after midnight on the 17th of AEDST).
However, although potentially bright, its fussy, diffuse nature means it will be difficult to spot with the unaided eye under suburban conditions. Even under dark sky conditions it will be a faint fuzzy dot. Despite breathless statements about it being "as big as the full Moon" the comet is so diffuse you can only see this extended coma with long exposure camera images, not with the eye.
However, there are already reports of the comet being visible to the unaided eye under dark sky conditions in Australia, and it is being picked up by simple DSLR cameras. It is readily visible in strong binoculars and small telescopes, but you will need a serious telescope and astronomical camera to pick up any detail, including the faint tail.
The comet is a reasonably easy target for binoculars, unfortunately the waxing moon will make it harder to spot during the time when it is brightest.
However, if you wait until Moon set (around midnight on the 13th and 2 am on the 17th (actually, for the east coast on daylight savings time the comet is closest just after midnight), the comet will be reasonably high above the northern sky and in a good position to view.
The comet is now is an area where there are useful guide stars.
At the moment the best way to find it is draw an imaginary line between Sirius and Rigel, then continue on until you reach the next brightest star Menkar (α Ceti) that is the constellation of Cetus. Then back off about a hand-span and up two and you will come to the brightish star Azha (eta (η) Eridani) on the 6th the comet is above, and on the 7th below this star.
The comet is moving rapidly as it comes close to the Earth. While it won't "whizz" across the sky it will move substantially night to night.
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| Black and white printable binocular chart for locating comet 46P between 6- 14 December as seen from Adelaide at 22:06 ACDST (90 minutes after sunset, basically a black and white version of the chart at the top). The circle is the approximate field of view of 10x50 binoculars. Click to embiggen and print. Use in conjunction with the spotters maps for orientation. | Black and white printable binocular chart for locating comet 46P between 13- 21 December as seen from Adelaide at 22:10 ACDST (90 minutes after sunset, basically a black and white version of the chart at the top). The circle is the approximate field of view of 10x50 binoculars. Click to embiggen and print. Use in conjunction with the spotters maps for orientation. |
On the 10th and 11th the comet is within a binocular field of Menkar. On the 13th if you look for the distinctive upside down V shape of the head of Taurus the Bull, then follow the line of stars up from the bright red star Aldebaran you will come to a pair of brightish stars, the comet is just under that. On the 16th the comet is between the distinctive cluster the Pleiades and bright red Aldebaran.
PDF versions of the black and white charts above which are higher quality print are linked below. Spotters chart
Binocular Chart 6-14 Dec
Binocular Chart 13-21 Dec
Tuesday, November 20, 2018
Seeing comet 46P Wirtanen from Australia
46P is a short period comet which ahas an orbital peiod of 5.4 years. This year is a particularly favourable year and the comet may become as bright as magnitude 3 (about as bright as gamma Crucis, the fifth brightest star in the Southern Cross)
The comet will pass at 0.0781 AU (~30 LD) from Earth, on 16 December 2018 making this the brightest close approach for the next 20 years.The comets magnitude might peak as bright as magnitude 3 near its December 16, 2018 closest approach.
However, although potentially bright, its fussy, diffuse nature means it will be difficult to spot with the unaided eye under suburban conditions. Even under dark sky conditions it will be a faint fuzzy dot.
The comet is currently around magnitude 6, and a reasonably easy target for binoculars, unfortunately the waxing moon will make it harder to spot for the next week or so.
Also unfortunately it is in an area pretty much devoid of useful guide stars.
At the moment the best way to find it is draw an imaginary line between Rigel and Achernar, then draw a line perpendicular to this and continue on until you reach the boxy shape that is the constellation of Cetus. then around halfway
Black and white printable binocular chart for locating comet 46P over the coming month as seen from Adelaide at 21:42 ACDST (90 minutes after sunset, basically a black and white version of the chart at the top). The circle is the approximate field of view of 10x50 binoculars.
Within a binocular distance of Upsion Ceti are the two dimmer stars nu (ν) Fornacis and mu (μ) Fornaci. The comet will form a shallow triangle with them becoming a steeper triangle over the following days.
Click to read about or order
Click to read about or order
Click to read about or order
Click to read about or order
