Posts Tagged ‘Shadows’

01/26/2015 – Ephemeris – First quarter Moon, a telescopic asteroid misses the Earth tonight and a Jupiter shadow recap

January 26, 2015 3 comments

Note:  Ephemeris program generally features objects in the sky that are visible to the naked eye or binoculars.  However in the blog, with the ability to expand in both content and illustrations I can add information for telescopic observers and expand postings.

Ephemeris for Monday, January 26th.  The sun will rise at 8:08.  It’ll be up for 9 hours and 34 minutes, setting at 5:42.   The moon, at first quarter today, will set at 1:30 tomorrow morning.

The Moon will be perfectly half illuminated by the sun at 11:48 p.m.  The gray patches that appear on the Moon’s surface were called by early telescopic astronomers: seas; because they thought they were bodies of water.  The Moon is pretty much bone dry, except for some eternally shadowed craters at the poles, which still aren’t wet because the water is frozen.  Anyway the seas or maria on the moon are indeed low spots.  The seas, from the top center of the moon down to the lower right are Serenity, Tranquility, Nectar and Fertility.  To the upper right all by itself is the Sea of Crises.  From Serenity to Fertility some can imagine an upside down rabbit, with ears of unequal sizes.  In a few more days we’ll see the face of the man in the Moon.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.


First Quarter Moon

Rabbit in the Moon

Rabbit in the first quarter Moon. Created using Virtual Moon Atlas.

Tonight Asteroid 2004 BL86 will pass three times the Moon’s distance from the Earth

This evening a rather large asteroid for a Near Earth Object or NEO will pass three-quarters of a million miles from the Earth.  The asteroid has the designation 2004 BL86. The cool thing is that this asteroid is half a kilometer or so meters across, that’s 5 soccer or football fields in diameter.  Radar from this close passage should nail down the size and shape.  Between Goldstone Tracking Station and Arecibo Observatory in Puerto Rico the asteroid should be mapped down to 2 to 4 meters.  It would be definitely not cool if this asteroid ever hit the Earth.  It will be 9th magnitude, and so will be visible in small telescopes, and it will cross the east or left side of the Beehive star cluster also designated M44 starting about midnight tonight.

If you want to observe the event and don’t have the equipment head on over to  This is the site for Slooh (pronounced “slew”) Community Observatory which has observatories in the Canary Islands and Chile, and partners with others.  Besides these events, members can schedule time and use the telescopes via the internet.  Check the above link for more information.

The chart below is from NASA/JPL’s Near Earth Object Program: Updated Charts for Asteroid 2004 BL86 Earth Flyby on Jan 26, 2015

Three Day track of 2004BL86

The track of asteroid 2004 BL86 as viewed from the Earth, plotted on a star chart with an equatorial coordinate grid. The asteroid location is shown at four-hour intervals from January 26 to 28. The indicated times are Universal Time; subtract 5 hours for Eastern Standard Time (EST), 6 hours for CST, and 8 hours for PST. On January 26, the asteroid will pass within 11 degrees of Jupiter, now shining brightly in the east in the evening sky. Image and caption credit: NASA/JPL-Caltech. JPL orbit solution #43, with star chart graphics produced using C2A.  Click to enlarge.

Below is a chart from Universe Today.  Here’s a link to their web page.

Finder chart for 2004BL86 as it sails past the Beehive Cluster

A Black on white chart of asteroid 2004 BL86 crossing to the right of M44. Note that the actual path depends on your location since the chart is based on the center of the Earth. The closer to your horizon the greatest deviation from the path shown. Time Ticks are for CST. Add one hour to them for EST. The Midnight tick mark is 0 h UT or GMT the 27th. Credit Universe Today and created with Chris Marriott’s SkyMap software.

Sky and Telescope has charts that have BL86’s track plotted about 15 minutes ahead of the track above.  It is a newer chart, so the asteroid’s position may have been updated.  The Sky and Telescope narrative and charts are here.

Results from Jupiter’s early Saturday satellite shadow play

The video live feed from the Griffith Planetarium in Los Angeles was a bust.  It suffered from what astronomers call bad seeing.  I mean really horrible seeing.  Astronomers ascribe at least two qualities to the sky, other than brightness due to the moon or light pollution.  That is transparency and seeing.  Seeing is the steadiness of the sky.  What Jupiter looked like was looking at a small disk at the bottom of a swimming pool while the kids are still playing in it.  At first I ascribed it to Jupiter being low in the LA sky, being 3 hours west of here.  But it didn’t get better as the night progressed.  I could occasionally make out Callisto’s shadow, just because I knew where it’s supposed to be.  But that’s it.

However my friend from the Detroit area, Scott Anttila, blessed at least for a while with clearer and calmer skies got some wonderful pictures of the first part of the multiple shadow event.

Satellite shadows 1

Left to right the shadows of Io and Callisto crossing the face of Jupiter at 12:52 a.m. January 24, 2015. Credit Scott Anttila.

Note that Callisto has a larger shadow than Io.  That’s mainly due to it’s greater distance from Jupiter that makes its shadow larger and fuzzier than the closer Io.


Satellite shadows 2

In this picture Io’s shadow has just caught up with Callisto’s shadow. Credit: Scott Anttila.

Shadow annimation

Rocking animation of the early stages of the shadow show on Jupiter. Callisto’s shadow already on the planet while Io’s shadow is just entering. Also Io’s transit is starting, following its shadow on the planet. Credit: Scott Anttila

01/23/2015 – Jupiter will experience three simultaneous total solar eclipses tonight!

January 23, 2015 1 comment

Total solar eclipses on Jupiter are nearly a daily occurrence on Jupiter.  However what we’ll see is the shadows of the moons crossing the face of the planet.  Shadows of the Jovian moons on the fave of Jupiter are difficult to see with small telescopes.  The look like tiny inky black dots.

Another way to watch the event is via Griffith Observatory in Los Angeles.  The link is here.  Their event starts at 11:30 p.m. EST because Jupiter rises later there.  The email I received from them says the next triple shadow event on Jupiter won’t occur until 2032,

Here’s the schedule:  Moons:  I = Io, II = Europa, IV = Callisto; SHA = Shadow,  Tra = Transit (a moon crossing disk of Jupiter)

Moon Event      UT Date    hh:mm  EST Date    Time
 IV: Sha start: 24 Jan 2015 3:11  23 Jan 2015  10:11 p.m.
  I: Sha start: 24 Jan 2015 4:36  23 Jan 2015  11:36 p.m.
  I: Tra start: 24 Jan 2015 4:56  23 Jan 2015  11:56 p.m. 
 IV: Tra start: 24 Jan 2015 6:20  24 Jan 2015   1:20 a.m.
 II: Sha start: 24 Jan 2015 6:28  24 Jan 2015   1:28 a.m.
 I:  Sha end  : 24 Jan 2015 6:53  24 Jan 2015   1:53 a.m.
 II: Tra start: 24 Jan 2015 7:08  24 Jan 2015   2:08 a.m.
 I:  Tra end  : 24 Jan 2015 7:13  24 Jan 2015   2:13 a.m.
 IV: Sha end  : 24 Jan 2015 8:02  24 Jan 2015   3:02 a.m.
 II: Sha end  : 24 Jan 2015 9:23  24 Jan 2015   4:23 a.m.

Note: All three shadows will be on Jupiter at the same time from 1:28 to 1:53 a.m. EST.
Times provided by the Jevent.exe DOS program downloaded from

Here’s an animation of what the event might look like at half hour intervals look like starting at 9:45 p.m.

Jovial Shadow Play

Animation of Jupiter’s satellite shadows starting at 9:45 p.m. and ending at 4:45 a.m. Created using Cartes du Ceil Sky Charts) and GIMP.  The circle in the center of Jupiter is an artifact of the program.  Click for a larger view.

05/08/2014 – Ephemeris – Saturn will reach opposition from the Sun this weekend

May 8, 2014 Comments off

Ephemeris for Thursday, May 8th.  The sun rises at 6:23.  It’ll be up for 14 hours and 32 minutes, setting at 8:55.   The moon, 2 days past first quarter, will set at 3:37 tomorrow morning.

In two days Saturn will be in opposition from the sun.  That means the Earth will be nearly directly between the Sun and Saturn.  Saturn will be the closest it gets to the earth all year, at 828 million miles (1,334 million km).  Saturn, being about nine and a half times the earth’s distance from the sun, doesn’t vary its distance from the Earth by a great percentage, so it’s a great telescopic object at any time it’s visible.  Mars, being closer and smaller is best seen near the time of opposition.  One effect of opposition is the minimum amount of shadows between the planet and the rings visible.  The shadows will increase until Saturn is 90 degrees from the sun, or quadrature, on August 10th.  Then they will diminish again until it’s in conjunction with the sun.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.


Saturn's shadows

Saturn at opposition and quadrature showing the maximum shadow at quadrature. Created using Cartes du Ciel (Sky Charts).

Note that the different tilt of Saturn in these two views is due to the fact that Saturn is in the east at opposition and in the southwest at quadrature, helped out by the fact that we’re viewing it from 45 º north latitude.  The different sizes of Saturn is due to Saturn’s greater distance of 919 million miles  (1,481 million km) on August 10th.  The little circle artifact in the center of the planet is due to telling the program that I’m tracking Saturn, so I wouldn’t have to re-find the planet when I shifted 3 months.