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(3200) Phaethon in December 2017
#1
On the Minor Planet Mailing List today (19-Nov-2017), Alan Hale, of Comet Hale-Bopp fame, posted this alert...

Quote:Just to remind everyone, Phaethon passes 0.069 AU from Earth on December 16 [2017] — the closest it has approached Earth since its discovery in 1983, and it won’t make a closer approach until 2093. Right now it’s  moving rather slowly – barely over 10 arcminutes per day — since it’s coming almost right at us; when closest to Earth it will be traveling at 15 degrees per day and should be as bright as 10th magnitude.

Will this be close enough to require special elements in ST3? Since 0.069 au is about 6.4 million miles (10.3 million km), I'm guessing it won't, but I'm not the expert on this.

BTW, 15 degrees per day is about 37.5 arc seconds per minute of time, or roughly a Jupiter diameter per minute. I then checked it in ST3, and for December 16 at 6:45 pm EST (when it transits for my location), the total motion is given as 38.6"/min.
Joe Stieber
http://sjastro.org/
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#2
I'll keep an eye on it. At the very least I will put it up on the Current Minor Planets list with fresh element.
Clear skies,
Greg

SkyTools Developer
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#3
(2017-11-19, 10:21 PM)Joe Stieber Wrote: On the Minor Planet Mailing List today (19-Nov-2017), Alan Hale, of Comet Hale-Bopp fame, posted this alert...

Quote:Just to remind everyone, Phaethon passes 0.069 AU from Earth on December 16 [2017] — the closest it has approached Earth since its discovery in 1983, and it won’t make a closer approach until 2093. Right now it’s  moving rather slowly – barely over 10 arcminutes per day — since it’s coming almost right at us; when closest to Earth it will be traveling at 15 degrees per day and should be as bright as 10th magnitude.

Will this be close enough to require special elements in ST3? Since 0.069 au is about 6.4 million miles (10.3 million km), I'm guessing it won't, but I'm not the expert on this.

BTW, 15 degrees per day is about 37.5 arc seconds per minute of time, or roughly a Jupiter diameter per minute. I then checked it in ST3, and for December 16 at 6:45 pm EST (when it transits for my location), the total motion is given as 38.6"/min.

(2017-11-19, 10:43 PM)theskyhound Wrote: I'll keep an eye on it. At the very least I will put it up on the Current Minor Planets list with fresh element.

@Joe - thanks for the heads up. Smile

@Greg - yes please! Add this NEO to the CMP list! Smile
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#4
At closet approach the parallax is between 2 and 3 arc minutes, or about three Jupiter diameters. At the speed it is travelling I guess that it will be easy to identify it by its motion, without special correction in SkyTools.
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#5
(2017-11-28, 04:48 AM)Dennis Wrote:
(2017-11-19, 10:21 PM)Joe Stieber Wrote: On the Minor Planet Mailing List today (19-Nov-2017), Alan Hale, of Comet Hale-Bopp fame, posted this alert...

Quote:Just to remind everyone, Phaethon passes 0.069 AU from Earth on December 16 [2017] — the closest it has approached Earth since its discovery in 1983, and it won’t make a closer approach until 2093. Right now it’s  moving rather slowly – barely over 10 arcminutes per day — since it’s coming almost right at us; when closest to Earth it will be traveling at 15 degrees per day and should be as bright as 10th magnitude.

Will this be close enough to require special elements in ST3? Since 0.069 au is about 6.4 million miles (10.3 million km), I'm guessing it won't, but I'm not the expert on this.

BTW, 15 degrees per day is about 37.5 arc seconds per minute of time, or roughly a Jupiter diameter per minute. I then checked it in ST3, and for December 16 at 6:45 pm EST (when it transits for my location), the total motion is given as 38.6"/min.

(2017-11-19, 10:43 PM)theskyhound Wrote: I'll keep an eye on it. At the very least I will put it up on the Current Minor Planets list with fresh element.

@Joe - thanks for the heads up. Smile

@Greg - yes please! Add this NEO to the CMP list! Smile

Already added! I went ahead and included multiple sets of orbital elements from JPL just in case. So it should be quite accurate throughout the pass.
Clear skies,
Greg

SkyTools Developer
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#6
(2017-11-28, 04:29 PM)theskyhound Wrote:
(2017-11-28, 04:48 AM)Dennis Wrote:
(2017-11-19, 10:21 PM)Joe Stieber Wrote: On the Minor Planet Mailing List today (19-Nov-2017), Alan Hale, of Comet Hale-Bopp fame, posted this alert...

Quote:Just to remind everyone, Phaethon passes 0.069 AU from Earth on December 16 [2017] — the closest it has approached Earth since its discovery in 1983, and it won’t make a closer approach until 2093. Right now it’s  moving rather slowly – barely over 10 arcminutes per day — since it’s coming almost right at us; when closest to Earth it will be traveling at 15 degrees per day and should be as bright as 10th magnitude.

Will this be close enough to require special elements in ST3? Since 0.069 au is about 6.4 million miles (10.3 million km), I'm guessing it won't, but I'm not the expert on this.

BTW, 15 degrees per day is about 37.5 arc seconds per minute of time, or roughly a Jupiter diameter per minute. I then checked it in ST3, and for December 16 at 6:45 pm EST (when it transits for my location), the total motion is given as 38.6"/min.

(2017-11-19, 10:43 PM)theskyhound Wrote: I'll keep an eye on it. At the very least I will put it up on the Current Minor Planets list with fresh element.

@Joe - thanks for the heads up. Smile

@Greg - yes please! Add this NEO to the CMP list! Smile

Already added! I went ahead and included multiple sets of orbital elements from JPL just in case. So it should be quite accurate throughout the pass.

Hi Greg, I no longer see (3200) Phaethon in the current minor planets list for Dec 16, I did update current lists from the web, which show Dec 1. It did show a few weeks ago when you first added it. Thanks, Doug
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#7
(2017-12-11, 02:01 PM)bellpilot2002 Wrote: Hi Greg, I no longer see (3200) Phaethon in the current minor planets list for Dec 16, I did update current lists from the web, which show Dec 1. It did show a few weeks ago when you first added it. Thanks, Doug

I forgot to add it this month! Sorry. I will go do that now. It turns out that this is the first close pass that crossed from one month into another, so I never had to think about holding one over before. These things usually take a night or two, but this one goes on for weeks.
Clear skies,
Greg

SkyTools Developer
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#8
I found (3200) Phaethon at 2:40 am EST this morning, 13-Dec-2017, from my semi-suburban site near 40°N-75°W. I used an 85 mm spotting scope at 60x and a printed ST3 chart, then confirmed that it was indeed Phaethon by its subsequent movement compared to the nearby field stars.
Joe Stieber
http://sjastro.org/
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