Archive
01/15/2016 – Ephemeris – The Comet Catalina is closest to the Earth this weekend
Ephemeris for Friday, January 15th. The Sun will rise at 8:16. It’ll be up for 9 hours and 11 minutes, setting at 5:27. The Moon, 1 day before first quarter, will set at 12:19 tomorrow morning.
Comet Catalina is near its brightest now that it’s closest to the Earth, or will be Sunday at about 67 million miles (108 million km), about three-quarters the distance to the Sun. It is also circumpolar, staying up all night for the entire IPR listening area. That’s not as big a deal as it sounds because the Moon won’t set till after midnight and it’s getting brighter as it moves to become full in a couple of weeks. So the best views are still in the morning for the next week. The comet can be spotted in binoculars as a fuzzy spot. The comet is now nearest the star Mizar in the bend of the Big Dipper’s handle. It’s slowly moving to split the distance between the Big and Little Dippers between now and the end of the month. Good comet hunting!
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Comet Catalina closest weekend to the Earth. Comet positions are for 4 a.m. January 16 to 19, 2016. Created using Cartes du Ciel (Sky Charts).
Comet C/2013 US10 (Catalina) at its closest approach to the Earth on January 17, 2016 of 0.725 AU, 67 million miles or 108 million kilometers. Credit NASA/JPL.
01/13/2016 – Ephemeris – Four bright planets are in the morning sky but one more is hiding
Ephemeris for Wednesday, January 13th. The Sun will rise at 8:17. It’ll be up for 9 hours and 7 minutes, setting at 5:25. The Moon, 3 days before first quarter, will set at 9:57 this evening.
Let’s check out the whereabouts of the bright naked eye planets. Mercury is now only one day from inferior conjunction, passing between the Earth and the Sun. The next inferior conjunction after this, May 9th Mercury will pass across the face of the Sun. In the morning sky there are four bright planets. Jupiter will be the first to rise, actually at 10:28 p.m., in the east. Mars will rise next at 2:11 a.m. in the east-southeast. It’s left of the bright star Spica. Saturn will rise at 5:19 a.m. Venus will rise at 5:47 a.m. again in the east-southeast, following Saturn. Comet Catalina is a binocular object near the star at the end of the handle of the Big Dipper named Alkaid. It’s heading to go between the Big and Little Dippers this week.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Here of the morning planets. From right to left, Jupiter, Mars, Saturn and Venus. Time: 6:30 a.m., January 14, 2016. Created using Stellarium.
Jupiter and its 4 Galilean moons at 6:30 a.m., January 14, 2016. Created using Cartes du Ciel (Sky Charts).
Saturn and its moons through a telescope at 6:30 a.m., January 14, 2016. Small telescopes will show only the moon Titan. Created using Cartes du Ciel (Sky Charts).
Comet Catalina’s path for the next week. Note the magnitudes for the comet are about correct. It will take binoculars or a small telescope to spot the comet which will not show a tail visually. Created using Cartes du Ciel (Sky Charts).
This is a chart showing the sunrise and sunset skies for January 13, 2016 showing the location of the planets, the Moon and Comet Catalina at that time. Created using my LookingUp program.
Several of the images above are shown smaller than actual size. Image expansion lately hasn’t worked. If you are using Firefox, right-click on the image, and then click on View Image.
01/06/2016 – Ephemeris – The bright planet action is in the morning
Jan 6. This is Bob Moler with Ephemeris for Wednesday, January 6th. The Sun will rise at 8:19. It’ll be up for 8 hours and 57 minutes, setting at 5:17. The Moon, 3 days before new, will rise at 5:46 tomorrow morning.
Let’s check out the whereabouts of the bright naked eye planets. Mercury is now too close to the Sun in the evening sky, and is only 8 days from inferior conjunction with the Sun. The next inferior conjunction after this, May 9th Mercury will pass in front of the Sun. In the morning sky there are four bright planets. Jupiter will be the first to rise, actually at 10:56 p.m., in the east. Mars will rise next at 2:20 a.m. also in the east-southeast. It’s left of the bright star Spica. Venus will rise at 5:30 a.m. also in the east-southeast. Saturn will rise at 5:47 a.m. following Venus. Comet Catalina is a binocular object about a third of the way from the bright star Arcturus, and the star at the end of the handle of the Big Dipper named Alkaid.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Here of the morning planets. From right to left, Jupiter, Mars and the traffic jam of Venus, Saturn and the Moon. Time: 7 a.m., January 7, 2016. Created using Stellarium.
The planets to, mostly, the same scale of apparent sizes. Venus is the size of the small gibbous center of the overexposed glow. Mars is smaller than it’s image, about half the size of Venus. Created using Stellarium.
Comet Catalina’s path for the next week. Note the magnitudes for the comet are about 1 magnitude too bright. It will take binoculars or a small telescope to spot the comet which will not show a tail visually. Created using Cartes du Ciel (Sky Charts).
This is a chart showing the sunrise and sunset skies for January 6, 2016 showing the location of the planets, the Moon and Comet Catalina at that time. Created using my LookingUp program.
Several of the images above are shown smaller than actual size. Image expansion lately hasn’t worked. If you are using Firefox, right-click on the image, and then click on View Image.
01/01/2016 – Ephemeris – Happy New Year – It’s a busy few days to start off the year
Happy New Year. This is Bob Moler with Ephemeris for New Years Day, Friday, January 1st, 2016. The Sun will rise at 8:20. It’ll be up for 8 hours and 52 minutes, setting at 5:12. The Moon, 1 day before last quarter, will rise at 12:54 tomorrow morning.
It’s always a busy time, astronomically speaking, around the start of the year. This year even more so. Comet Catalina is found near the bright star Arcturus now, which is a good way to find it in binoculars. Tomorrow at 7:59 p.m. (1:59 UT 3rd) the Earth will reach perihelion, the closest point in its orbit to the Sun at about 91.4 million miles (0.9833 AU). It doesn’t add much to the heat we get from the Sun, but it does make winter a couple of days shorter than summer. Monday at 3 a.m. will see the peak of the Quadrantid meteor shower. Unfortunately that’s about the time the Moon will rise. The radiant is north of the handle of the Big Dipper. Good news: tomorrow is the latest sunrise, it should be rising earlier until June.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addenda
January Star Chart
Star Chart for January 2016. Created using my LookingUp program. To enlarge in Firefox Right-click on image then click View Image.
The planets and stars are plotted for the 15th at 9 p.m. EST. That is chart time. Note, Traverse City is located 45 minutes behind our time meridian. To duplicate the star positions on a planisphere you may have to set it to 45 minutes earlier than the current time.
Evening astronomical twilight ends at 6:22 p.m. EST on January 1st, increasing to 6:55 p.m. EST on the 31st.
Morning astronomical twilight starts at 7:09 a.m. EST on January 1st, and decreasing to 6:57 a.m. EST on the 31st.
Add a half hour to the chart time every week before the 15th and subtract and hour for every week after the 15th.
For a list of constellation names to go with the abbreviations click here.
- Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.
- QuadR is the Quadrantid meteor shower radiant
Calendar of Planetary Events
Credit: Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC)
To generate your own calendar go to http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html
Times are Eastern Time. Some additions made to aid clarity.
Date Local Event Time EST Jan 01 Fr Venus: 37.9° W 02 Sa 12:30 a.m. Last Quarter 02 Sa 6:53 a.m. Moon Apogee: 404300 km 02 Sa 7:59 p.m. Perihelion: 0.9833 AU 03 Su 1:45 p.m. Moon-Mars: 1.6° S 04 Mo 3:01 a.m. Quadrantid Shower: ZHR = 120 06 We 6:57 p.m. Moon-Venus: 3.3° S 06 We 11:57 p.m. Moon-Saturn: 3.6° S 07 Th 6:32 a.m. Venus-Antares: 6.4° N 08 Fr 12:56 p.m. Moon South Dec.: 18.4° S 09 Sa 2:42 a.m. Venus-Saturn: 0.1° N 09 Sa 8:30 p.m. New Moon 14 Th 9:02 a.m. Mercury Inferior Conj. 14 Th 10:48 a.m. Moon Descending Node 14 Th 9:10 p.m. Moon Perigee: 369600 km 16 Sa 6:26 p.m. First Quarter 19 Tu 9:16 p.m. Moon-Aldebaran: 0.5° S (Occultation*) 21 Th 11:41 a.m. Moon North Dec.: 18.4° N 23 Sa 8:46 p.m. Full Moon 26 Tu 12:10 a.m. Moon-Regulus: 2.8° N 27 We 6:58 p.m. Moon Ascending Node 27 We 8:14 p.m. Moon-Jupiter: 1.6° N 30 Sa 4:10 a.m. Moon Apogee: 404600 km 31 Su 10:28 p.m. Last Quarter Feb 01 Mo Venus: 31.4° W
* Occultation of Aldebaran For the Grand Traverse Area ± 1-2 minutes:
Disappearance 9:06 p.m. Reappearance 10:25 p.m. I’ll have more information on the 19th.
Occultation Map
Occultation visibility map for January 20, 2016 (UT). Credit IOTA/Occult4 program.
Estimating occultation timings for your location
I used Cartes du Ciel the free software that I have a link to on the right. Make sure that the program is set for topocentric positions under Setup/Solar System. And you have entered your position under Setup/Observatory. You can find your location in Google Earth, or your GPS device or smart phone.
You can also use Stellarium. Just make sure the Moon is normal sized.
In both programs you can lock the Moon or Aldebaran in the center of the screen Pick a time in advance of the occultation and using the set time window walk the star towards the Moon, mark the time. Then walk the star out from the Moon and record the reappearance time. That’s it.
This should work with other planetarium programs too.
For better accuracy go to the International Occultation Timing Association (IOTA) website. Download and install their Occult4 program for Windows computers. Follow the instructions. When I ran the program for my location, the location I use for Interlochen/Traverse City (Since I live approximately half-way between the two). I got results within a half-minute of the IOTA Occult4 program results. So the approximation method using these planetarium programs is valid.
Comet C/2013 US10 (Catalina)
The track of Comet C/2013 US10 (Catalina) for January 2016. Created using Cartes du Ciel (Sky Charts).
The comet is roughly one magnitude fainter than given. Comet is plotted every day at 4 a.m. EST (9 hr UT) with the date and magnitude labeled every 5th day. According to the brightness graph the comet began to under perform in brightness back in September, however, according to a new brightness formula the comet may increase in brightness by a magnitude by late February when it will be well placed for viewing all night. To monitor the brightness reports from observers go to http://www.aerith.net/comet/catalog/2013US10/2013US10.html.
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12/30/2015 – Ephemeris – Last look at the bright planets for this year
Ephemeris for Wednesday, December 30th. The Sun will rise at 8:19. It’ll be up for 8 hours and 50 minutes, setting at 5:10. The Moon, 3 days before last quarter, will rise at 10:58 this evening.
Let’s check out the whereabouts of the bright naked eye planets. Mercury moved to its greatest separation from the Sun Monday night. It will be visible very low in the southwest before it sets at 6:42 p.m. in the west-southwest. In the morning sky there are four bright planets. Jupiter will be the first to rise, actually at 11:23 p.m., in the east. Tomorrow it will be just left of the Moon. Mars will rise next at 2:27 a.m. also in the east. It’s left of the bright star Spica. Venus will rise at 5:11 a.m. in the east-southeast. Saturn will rise at 6:10 a.m. in the east-southeast. Comet Catalina is a binocular object just below the bright star Arcturus, which is pointed to by the arc of the handle of the Big Dipper.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mercury at 6 p.m., 50 minutes after sunset, December 30, 2015. It may be visible as early as 5:30. Binoculars will help. Created using Stellarium.
The morning planets, Jupiter, Mars, Venus and Saturn, plus Comet Catalina at 7 a.m. December 31, 2015. Created using Stellarium.
Jupiter and the Moon tomorrow morning December 31, 2015 at 7 a.m. Created using Stellarium.
Telescopic view of Jupiter at 7 a.m. December 31, 2015. Created using Stellarium.
Telescopic view of Venus at 7 a.m. December 31, 2015. Created using Stellarium.
Telescopic view of Saturn at 7 a.m. December 31, 2015. The satellites would be pretty much invisible except for Titan with Saturn low in the sky in twilight. Created using Stellarium.
The three planet telescopic views are shown to the same scale, that is seen with the same magnification.
Comet Catalina’s path for the next week. Note the magnitudes for the comet are about 1 magnitude too bright. It will take binoculars or a small telescope to spot the comet which will not show a tail visually. Created using Cartes du Ciel (Sky Charts)..
This is a chart showing the sunrise and sunset skies for December 30, 2015 showing the location of the planets, the Moon and Comet Catalina at that time. Created using my LookingUp program.
Several of the images above are shown smaller than actual size. Image expansion lately hasn’t worked. If you are using Firefox, right-click on the image, and then click on View Image.
12/16/2015 – Ephemeris – The planet action is still in the morning
Ephemeris for Wednesday, December 16th. The Sun will rise at 8:13. It’ll be up for 8 hours and 49 minutes, setting at 5:02. The Moon, 2 days before first quarter, will set at 10:57 this evening.
Let’s check out the whereabouts of the bright naked eye planets. Mercury is becoming marginally visible very low in the southwest before it sets at 6 p.m. In the morning sky there are three bright planets. Jupiter will be the first to rise, at 12:15 a.m. in the east. Mars will rise next at 2:39 a.m. also in the east, followed by Venus at 4:41 a.m. in the east-southeast. Mars lies in line between Venus below and Jupiter above, almost halfway between the two. Don’t confuse Mars with the star Spica which is brighter and right below it. Saturn will rise at 6:54 a.m. in the east-southeast. Comet Catalina is a telescopic object about one and a half the width of a fist held at arm’s length above Venus and the same amount left of Mars.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The moon as it might look in binoculars at 8 p.m., December 16, 2015. Created using Stellarium.
The Morning planets at 7 a.m., December 17, 2015. Created using Stellarium.
Jupiter and moons in a telescope at 7 a.m. December 17, 2015. Created using Stellarium.
Venus as seen in a telescope as seen at the same magnification as Jupiter above, at 7 a,m. December 17, 2015. Created using Stellarium.
Comet Catalina and Mars for the next week. Note the magnitudes for the comet are about 1 magnitude too bright. It will take binoculars or a small telescope to spot the comet which will not show a tail visually. Created using Cartes du Ciel (Sky Charts).
This is a chart showing the sunrise and sunset skies for December 16, 2015 showing the location of the planets and the Moon at that time. Created using my LookingUp program. Click on the image to enlarge.
12/09/2015 – Ephemeris – The planet action is in the morning sky
Ephemeris for Wednesday, December 9th. The Sun will rise at 8:07. It’ll be up for 8 hours and 54 minutes, setting at 5:02. We’re at the time of the earliest sunset. The Moon, 2 days before new, will rise at 7:02 tomorrow morning.
Let’s check out the whereabouts of the bright naked eye planets. Saturn and Mercury are too close to the direction of the Sun to be seen now. In the morning sky there are three bright planets. Jupiter will be the first to rise, at 12:39 a.m. in the east. Mars will rise next at 2:47 a.m. in the east, followed by Venus at 4:28 a.m. also in the east. Mars lies in line between Venus below and Jupiter above, almost halfway between the two. Don’t confuse Mars with the star Spica which is brighter and closer to Venus. Comet Catalina will be about half the width of a fist held at arm’s length above and left of Venus and will slowly be moving farther above Venus as the days go by.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Jupiter, Mars and Venus appear with Comet Catalina in the southeast at 6 a.m., December 10, 2015. Comet Catalina is much fainter than shown and only sports a tail in photographs. Created using Stellarium.
Jupiter and moons in a telescope at 6 a.m. December 10, 2015. Created using Stellarium.
Venus as seen in a telescope as seen at the same magnification as Jupiter above, at 6 a,m. December 10, 2015. Created using Stellarium.
Comet Catalina and Venus for the next week. Note the magnitudes for the comet are about 2 magnitude too bright. It will take binoculars or a small telescope to spot the comet which will not show a tail visually. Created using Cartes du Ciel (Sky Charts).
This is a chart showing the sunrise and sunset skies for December 9, 2015 showing the location of the planets and the Moon at that time. Created using my LookingUp program. Click on the image to enlarge.
12/03/2015 – Ephemeris – The Moon will pass by the morning planets in the next few days
Ephemeris for Thursday, December 3rd. The Sun will rise at 8:01. It’ll be up for 9 hours and 1 minute, setting at 5:03. The Moon, at last quarter today, will rise at 1:11 tomorrow morning.
The Moon will be making a grand procession by the morning planets in the next few days, culminating with passing in front of Venus just after noon on Monday. This morning the Moon is approaching Jupiter to its lower left. By tomorrow morning Jupiter will be just above the Moon. Saturday morning the Moon will be approaching Mars, 12 of its diameters to its lower left. Sunday morning finds the crescent Moon between Mars and Venus with Mars 8 diameters above and right of the Moon. Monday Morning at 6 a.m. the Moon will be closing on Venus, with the brilliant planet just 4 moon diameters below left of the thin crescent Moon. Sharp eyed binocular and telescopic observers will be able see the Moon occult Venus after noon.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Animation of the Moon’s passage by the morning planets and Comet Catalina from December 2nd through the 7th, 2015. Created using Stellarium and GIMP.
12/02/2015 – Ephemeris – All the bright planet action is in the morning
Ephemeris for Wednesday, December 2nd. The Sun will rise at 8:00. It’ll be up for 9 hours and 2 minutes, setting at 5:03. The Moon, 1 day before last quarter, will rise at 12:12 tomorrow morning.
Let’s check out the whereabouts of the bright naked eye planets. Saturn and Mercury are too close to the direction of the Sun to be seen now. In the morning sky there are three bright planets. Jupiter will be the first to rise, at 1:03 a.m. in the east. Mars will rise next at 2:52 a.m. in the east, followed by Venus at 4:13 a.m. also in the east. Mars lies in line between Venus below and Jupiter above, almost halfway between Venus and Jupiter. The Moon will pass each of these planets in the next few days culminating by passing in front of Venus Monday. Comet Catalina will be about the width of a fist held at arm’s length below and left of Venus and will slowly be moving to the upper left and be level with Venus on the 6th.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon, Jupiter, Mars and Venus appear in the southeast at 6 a.m., December 3, 2015. Note that Comet Catalina is near Venus. Created using Stellarium.
Jupiter and moons in a telescope at 6 a.m. December 3, 2015. Created using Stellarium.
Venus as seen in a telescope as seen at the same magnification as Jupiter above, at 6 a,m. December 3, 2015. Created using Stellarium.
The Moon as seen in a binoculars or small telescope at 6 a,m. December 3, 2015. Created using Stellarium.
Comet Catalina and Venus for the next week. Note the magnitudes for the comet are about 2 magnitude too bright. It will take binoculars or a small telescope to spot the comet.
12/01/2015 – Ephemeris – Previewing December skies
Ephemeris for Tuesday, December 1st. The Sun will rise at 7:59. It’ll be up for 9 hours and 4 minutes, setting at 5:03. The Moon, 2 days before last quarter, will rise at 11:13 this evening.
December is the month with the shortest daylight hours. Winter will officially arrive at the winter solstice on the 21st at 11:48 p.m. There will be little movement in the sunset times: In the Traverse City/Interlochen area this will be from 5:03 tonight, down to 5:02 and then advancing to 5:11 at the end of the month. There is more movement in the sunrise times which will advance from 7:59 today to 8:20 on the 31st. There is also little movement of daylight hours. The noontime sun will hang around 22 to 23 degrees above the southern horizon all month. We have some great events this month, from an occultation of Venus by the moon on the 7th, to the Geminid meteors on the 14th and Comet Catalina will be seen in binoculars on mornings all this month.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addenda
Star Chart for December 2015. Created using my LookingUp program. Click on image to enlarge.
The planets and stars are plotted for the 15th at 9 p.m. EST. That is chart time. Note, Traverse City is located 45 minutes behind our time meridian. To duplicate the star positions on a planisphere you may have to set it to 45 minutes earlier than the current time.
Evening astronomical twilight ends at 6:48 p.m. EST on December 1st, decreasing a minute 9 days later before increasing to 6:57 p.m. EST on the 31st.
Morning astronomical twilight starts at 6:15 a.m. EST on December 1st, and increasing to 6:34 a.m. EST on the 31st.
Add a half hour to the chart time every week before the 15th and subtract and hour for every week after the 15th.
For a list of constellation names to go with the abbreviations click here.
- Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.
- The Summer Triangle is still up and is shown in red.
- GemR is the Geminid meteor shower radiant
Calendar of Planetary Events
Credit: Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC)
To generate your own calendar go to http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html
Times are Eastern Daylight Time. Some additions made to aid clarity.
Date Local Event
Time EST
Dec 01 Tu Venus: 43.3° W 03 Th 2:41am Last Quarter 04 Fr 1:21am Moon-Jupiter: 2° N 04 Fr 1:33pm Moon Ascending Node 05 Sa 9:56am Moon Apogee: 404800 km 05 Sa 9:40pm Moon-Mars: 0.1° N - Occultation ** 07 Mo 11:55am Moon-Venus: 0.7° S - Occultation * 11 Fr 5:29am New Moon 12 Sa 3:15am Moon South Dec.: 18.4° S 14 Mo 12:48pm Geminid Shower: ZHR = 120 17 Th 9:32pm Saturn-Antares: 6.2° N 18 Fr 10:13am Moon Descending Node 18 Fr 10:14am First Quarter 21 Mo 3:53am Moon Perigee: 368400 km 21 Mo 11:48pm Winter Solstice 22 Tu 9:00pm Ursid Shower: ZHR = 10 23 We 9:16pm Mars-Spica: 3.5° N 23 We 2:09pm Moon-Aldebaran: 0.7° S 25 Fr 2:30am Moon North Dec.: 18.4° N 25 Fr 6:11am Full Moon 28 Mo 9:59pm Mercury Elongation: 19.7° E 29 Tu 3:30pm Moon-Regulus: 2.9° N 31 Th 12:55pm Moon-Jupiter: 1.6° N 31 Th 3:19am Moon Ascending Node Jan 01 Fr Venus: 37.9° W
* The occultation will be visible in the US, except extreme southwestern Alaska and Hawai’i; and Canada down to Panama. In the Grand Traverse area of Michigan the occultation starts around 12:20 p.m. and ends around 1:27 p.m. This is a daytime event for most of the US. Note that the actual time depends on your exact location. I’ll have more information in a non Ephemeris post on Saturday the 5th. The Occultation map is here.
** On December the 5th there will be an occultation of Mars visible across the Indian Ocean and much of Australia. That occultation map is here.
Estimating occultation timings for your location
I used Cartes du Ciel the free software that I have a link to on the right. Make sure that the program is set for topocentric positions under Setup/Solar System. And you have entered your position under Setup/Observatory. You can find your location in Google Earth, or your GPS device or smart phone.
You can also use Stellarium. Just make sure the Moon is normal sized.
In both programs you can lock the Moon or Aldebaran in the center of the screen Pick a time in advance of the occultation and using the set time window walk the star towards the Moon, mark the time. Then walk the star out from the Moon and record the reappearance time. That’s it.
This should work with other planetarium programs too.
For better accuracy go to the International Occultation Timing Association (IOTA) website. Download and install their Occult4 program for Windows computers. Follow the instructions. When I ran the program for my location, the location I use for Interlochen/Traverse City (Since I live approximately half-way between the two). I got results within a half-minute of the IOTA Occult4 program results. So the approximation method using planetarium programs is valid.
Comet C/2013 US10 (Catalina)
This comet has been hiding for the last two years after its discovery, moving into the far southern hemisphere of the sky. However this month it has emerged into our morning sky. This comet is a one time visitor from the Oort Cloud to the inner solar system and will be ejected into interstellar space. It passed perihelion on November 15th, coming just inside the Earth’s orbit on the other side of the Sun from us. It’s orbit will be headed northward and a bit toward us, so it will keep its brightness steady.
The position marks in the chart have the date and the magnitude. However the comet is currently appearing one magnitude dimmer than shown. So instead of appearing as nearly 5th magnitude, it will really be 6th magnitude. It’s definitely a binocular or telescopic object.
According to the brightness graph the comet began to under perform in brightness back in September, however, according to a new brightness formula the comet may increase in brightness by a magnitude by late February when it will be well placed for viewing all night. To monitor the brightness reports from observers go to http://www.aerith.net/comet/catalog/2013US10/2013US10.html.
The tracks of Comet C/2013 US10 (Catalina) for December 2015 along with part of Venus’ track. Created using Cartes du Ciel (Sky Charts).
Bob Moler's Ephemeris Blog 