Archive
12/07/2015 – Ephemeris – Today the Moon will pass in front of the planet Venus
Ephemeris for Monday, December 7th. The Sun will rise at 8:06. It’ll be up for 8 hours and 56 minutes, setting at 5:02. The Moon, half way from last quarter to new, will rise at 5:04 tomorrow morning.
The Moon will pass in front of Venus between about 12:20 p.m. and 1:27 p.m. for the Interlochen, Traverse City Area. Times will vary as much as 5 minutes over the IPR listening area. Some sort of telescopic aid is needed to see Venus and the crescent Moon in daylight. The crescent Moon is quite faint, though Venus should be easier to spot because it’s brighter. I have a special post on my blog dated Saturday December 5th.. It’s titled Venus Occultation December 7, 2015 from Northern Michigan with all the details. My blog is bobmoler.wordpress.com, or do an Internet search for Bob Moler, That’s Moler spelled M-O-L-E-R, no extra letters. And hope for clear skies.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Animation of the occultation. Created using Cartes du Ciel (Sky Charts) and GIMP.
Venus Occultation December 7, 2015 from Northern Michigan
What is an occultation? An occultation is when one nearer celestial body covers or hides another, more distant body. The word occultation comes from occult which simply means hidden. No black magic is involved.
The occultation of Venus will occur on December 7, from 12:21 p.m. to 1:27 p.m. for the Grand Traverse Area, give or take a few minutes either way. The exact time depends on your location. This event would be a great sight if it occurred in the early morning skies before sunrise. Unfortunately it’s centered on 1 p.m. Venus and the Moon are visible in the daytime with a telescope and even binoculars, but are difficult to find. The Moon and Venus do make a beautiful sight in the morning in the 5 to 7 a.m. hours.
Disappearance of Venus at 12:20 p.m. Created using Cartes du Ciel (Sky Charts).
The trick to viewing this event is even finding the Moon or Venus. One could set up a telescope with tracking ability to track Venus throughout the morning. Unless you have a telescope Go To mount and can track the Moon, track Venus instead. The Moon moves about its own diameter with respect to the stars in an hour, so it will have to be constantly adjusted to keep pointed at the Moon. Actually Venus has a higher surface brightness than the Moon, so it should be easier to track, especially if the sky is hazy and the Moon isn’t visible.
Disappearance of Venus at 1:27 p.m. Created using Cartes du Ciel (Sky Charts).
Unlike a stellar occultation Venus will disappear over several seconds. A telescope capable to seeing Venus’ gibbous phase will see the bright edge of the Moon actually pass in front it. Venus will emerge from the Moon’s dark side which will be invisible. So Venus will slowly reappear next to the crescent Moon. Hoping for clear skies, and good luck.
If you are not located near Traverse City, you can use my technique to estimate the occultation times. I used Cartes du Ciel the free software found on the Internet at http://www.ap-i.net/skychart/en/start. 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.
You can also use Stellarium (http://stellarium.org). 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.
Animation of the occultation. Created using Cartes du Ciel (Sky Charts) and GIMP.
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.
Sun and Moon’s positions at the start of the occultation from northern Michigan. Note the Moon and Venus will be invisible to the naked eye. Created using Stellarium.
Sun and Moon’s positions at the end of the occultation from northern Michigan. Note the Moon and Venus will be invisible to the naked eye. Created using Stellarium.
When I made up the above images I really thought there would be snow on the ground by now. But what little we had has come and gone.
Occultation of Venus Visibility Map for North America. Credit: Astronomical Almanac Online -U.S. Nautical Almanac Office, United States Naval Observatory (USNO), in the United States and Her Majesty’s Nautical Almanac Office (HMNAO), United Kingdom Hydrographic Office (UKHO), in the United Kingdom.
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).
11/27/2015 – Ephemeris – C/2013 US10 (Catalina)
Ephemeris for Friday, November 27th. The Sun will rise at 7:54. It’ll be up for 9 hours and 10 minutes, setting at 5:05. The Moon, 2 days past full, will rise at 7:12 this evening.
This Comet Catalina, and there are many Comet Catalinas has the unique designation C/2013 US10. This comet was found by the Catalina Sky Survey which looks for near Earth objects called NEOs, so there are lots of little Comet Catalinas running around. I’ll just refer to it as US10 in honor of the downstate highway. It’s like the comet with the unpronounceable name that the Rosetta spacecraft is orbiting is now known as 67P, and that new Kuiper Belt object 2012VP113 is known as Biden, because Joe Biden is our VP or Vice President. See we astronomers do have a sense of humor. We were hoping that US10 would reach naked eye brightness, but it’s under performing now appearing about half as bright as we thought it should be.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Comet Catalina, Venus and Mars tracking for 7 days starting November 27, 2015 for 7 days. The at 6 a.m. or about 2 hours before sunrise at around +45 degrees latitude. Created using Cartes du Ciel. Note that the comet magnitudes are still at least two magnitudes too bright. JPL Horizons Ephemeris shows the current estimates. Altitude and Azimuth grids are at 10 degree intervals.
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09/03/2015 – Ephemeris – Jewels in the shield
Ephemeris for Thursday, September 3rd. The Sun will rise at 7:07. It’ll be up for 13 hours and 9 minutes, setting at 8:16. The Moon, 2 days before last quarter, will rise at 11:26 this evening.
The teapot pattern of stars that is the constellation of Sagittarius lies at the southern end of the Milky Way this evening. It appears that the Milky Way is steam rising from the spout. The area above Sagittarius in the brightest part of the Milky Way is the dim constellation of Scutum the shield. Don’t bother looking for the stars that make up the constellation; what’s important is the star clouds of the Milky Way. Scan this area with binoculars or small telescope for star clusters and nebulae or clouds of gas. In binoculars both clusters and nebulae will appear fuzzy, but a small telescope will tell most of them apart. Even if you’ve never been able to find anything in your telescope, you’ll find something here.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Scutum between Sagittarius below and Aquila above at 10 p.m. September 3, 2015. Created using Stellarium.
How to find the three brightest deep sky wonders around Scutum by star hopping. Created using Stellarium, annotated by myself.
Star hopping is a method to find objects from familiar star patterns. At the top my method to find M11, the wild duck cluster is to locate the three stars at the tail of Aquila the Eagle and follow them to M11. M11 takes a little bigger telescope to resolve. I remember having trouble resolving it is a 5″ telescope. It looks like a triangular cluster with all the stars of the same dimness except one brighter one.
At the bottom of Scutum, I locate that distinctive 5 star group circled. Directly west is M16, the Eagle Nebula and star cluster. The star cluster is easy to spot, the nebula is hard. The Hubble space telescope made the nebula famous in the 1990’s as the Pillars of Creation.
Below and west is M17, the Omega Nebula, or the Swan Nebula. To me it looks like a swan swimming or a check mark of nebulosity. The associated star cluster is much less noticeable.
Happy star hopping.
08/18/2015 – Ephemeris – The autumn queen is rising
Ephemeris for Tuesday, August 18th. The Sun rises at 6:48. It’ll be up for 13 hours and 55 minutes, setting at 8:44. The Moon, half way from new to first quarter, will set at 10:31 this evening.
A look to the northeast at 10 p.m. or later will reveal a letter W pattern of stars. This is the constellation of Cassiopeia the queen. Cassiopeia is so far north that it never sets for us in Michigan. It is opposite the pole star Polaris from the Big Dipper. So as the Big Dipper is rotating down the sky in the northwest, Cassiopeia is rotating up in the northeast. The pivot is the star Polaris, the north star. There’s a dim star that appears above the middle star of the W which turns the W into a very crooked backed chair. Above Cassiopeia is a dim church steeple shaped constellation of Cepheus the king. The Milky Way flows through Cassiopeia and a corner of Cepheus and up through Cygnus, and on to the south.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Cassiopeia and nearby constellations mentioned in the above program. Created using Stellarium.
08/12/2015 – Ephemeris – One ringed planet and a sky full of meteors
Ephemeris for Wednesday, August 12th. The Sun rises at 6:41. It’ll be up for 14 hours and 12 minutes, setting at 8:53. The Moon, 2 days before new, will rise at 5:49 tomorrow morning.
Lets take a look for the bright planets for this week. Our brightest evening planets Venus and Jupiter are leaving the evening sky in the west. Venus is 3 days from inferior conjunction with the Sun. Saturn is in the south-southwest in the evening twilight. It can be spotted just to the right of the constellation of Scorpius the scorpion and its bright red star Antares below and right of it. Even small telescopes can see Saturn’s rings. The Perseid meteor shower will reach its peak overnight tonight. Your back yard is a fine spot to view the meteors, or for dark skies, I’ll be leading an all night meteor watch at the Sleeping Bear Dunes National Lakeshore’s Dune Climb if it’s clear. I’ll be there by 9 p.m. and it will be dark enough by 10:30.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Saturn and the summer Zodiacal constellations in the south at 10 p.m. August 12, 2015. Created using Stellarium.
Saturn through a telescope at 10 p.m. on August 12, 2015. Created using Stellarium.
Next week Wednesday we will also turn to the morning sky looking for Mars and awaiting Venus’ grand entrance into the dawn skies.
All-sky meteor charts from yesterday’s post
“PerR” is the Perseid radiant.
11 p.m. August 12, 2015. Created using Bob Moler’s LookingUp program for Windows.
2 a.m. August 13, 2015. Previewing autumn stars. Created using Bob Moler’s LookingUp program for Windows.
5 a.m. August 13, 2015. Good morning Orion! Created using Bob Moler’s LookingUp program for Windows.
08/11/2015 – Ephemeris – Perseid meteor shower is tomorrow night
Ephemeris for Tuesday, August 11th. The Sun rises at 6:40. It’ll be up for 14 hours and 14 minutes, setting at 8:55. The Moon, 3 days before new, will rise at 4:51 tomorrow morning.
The Perseid meteor shower is growing in numbers of meteors seen per hour. The expected peak is Thursday morning about a quarter after 2. However the peak time is only really known statistically after the event. The point in the sky from which the meteors or shooting stars seem to come from is called the radiant and it is near the constellation of Perseus. The meteors will appear all night from dusk to dawn. The peak number of meteors can be up to 90 an hour. No telescope is needed. Just lie down on a blanket and look up. The darker your sky the better. One of the darkest skies around is at the Sleeping Bear Dunes National Lakeshore. I will be leading an all night meteor shower watch at the Dune Climb Wednesday night til dawn if it’s clear.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Here are some meteors seen in the 2007 Perseid meteor shower taken by Scott Anttila. The image is centered on Cassiopeia. The radiant is low and a bit left of center in the image. The Double Cluster is seen below center and the Great Andromeda Galaxy is seen on the right above center. Click on the image to enlarge.
Position of the Perseid radiant and stars in all-sky plots for 3 times during the night: 11 p.m., 2 a.m., & 5 a.m.
11 p.m. August 12, 2015. Created using Bob Moler’s LookingUp program for Windows.
2 a.m. August 13, 2015. Created using Bob Moler’s LookingUp program for Windows.
5 a.m. August 13, 2015. Created using Bob Moler’s LookingUp program for Windows.
05/21/2015 – Ephemeris – Saturn will reach opposition tomorrow
Ephemeris for Thursday, May 21st. Today the Sun will be up for 15 hours and 1 minute, setting at 9:10. The Moon, 3 days past new, will set at 12:21 tomorrow morning, and tomorrow the Sun will rise at 6:07.
The Planet Saturn will be at opposition from the Sun tomorrow, meaning that it is opposite the Sun in the sky, rising at sunset and setting at sunrise. It also means that Saturn is about it’s closest, brightest, and its largest appearing in telescopes. It will be 835 million miles (1,344 million km) away tomorrow. It’s rings should also be at their brightest. The rings are made of billions of particles, mostly ice. At opposition we are essentially viewing Saturn from the same direction as the Sun, and ring particle shadows on one another disappear, so the rings are brighter. Other defining shadows also disappear such as the planet’s shadow on the rings and the ring’s on Saturn, so the planet may appear kind of flat.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Saturn at opposition, May 22, 2015. Compare the shadow of the planet on the rings with the quadrature image below. Created using Cartes du Ceil (Sky Charts).
Saturn near quadrature, August 23, 2015. Compare the shadow of the planet on the rings with the opposition image above. Created using Cartes du Ceil (Sky Charts).
A superior planet’s quadrature position (90 degrees from the Sun) is the time we are the maximum amount out of line with the Sun from them. Any phase of shadows are the most pronounced. From the planet’s point of view the Earth is at greatest elongation from the Sun.
05/04/2015 – Ephemeris – Last good evening appearance of Mercury for the year*
Note: This program was recorded before the MESSENGER spacecraft crashed into Mercury.
Ephemeris for Monday, May 4th. Today the Sun will be up for 14 hours and 22 minutes, setting at 8:51. The Moon, 1 day past full, will rise at 9:29 this evening. Tomorrow the Sun will rise at 6:27.
The tiny and elusive planet Mercury will be making its final easily observable evening appearance of the year. For the next week or so. Not that Mercury is ever easy to spot. The MESSENGER spacecraft, which has been orbiting Mercury for the past four years is out of fuel and is descending to an impact any day now. It may already have. Mercury is the smallest planet only 50% larger than the diameter of our Moon. There are two planetary satellites larger than it: Jupiter’s Ganymede and Saturn’s Titan. It is a whole lot larger than Pluto, which was demoted to dwarf planet 9 years ago. Mercury is the second densest planet after the Earth. And even Venus with its greenhouse effect is hotter.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
*For northern hemisphere viewers.
Addendum
Mercury, Venus and the setting stars of winter at 10 p.m., May 4, 2015. Created using Stellarium.
Four views of Mercury with colors based on the mineralogy seen. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington. Click on image to enlarge.
