Bob’s Ephemeris Blog

The Lyrid meteor shower will reach peak on the evening of the 22nd. Up to about 12 per hour may be seen at its peak. The entire duration of the shower runs from April 16th to the 25th. This shower is thought to be related to Comet Thacher (1861-I) . Note the radiant in the chart below. It lies between the distinstive small parallelogram of Lyra and the Keystone of Hercules.  The radiant will be nearly overhead at 5 a.m.  The best time to view them will be in the early morning of the 23rd (Monday Morning).

Tags: Events, Observing by Bob Moler
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M95 and M96 - galaxies on the underbelly of Leo

Scott Anttila sent me this image of the galaxies M95 and M96. M95 is on the left. Click on the thumbnail below to see the full size image.

They represent two of my Messier Marathon failures last month. With the pending encroachment of clouds and cold, I simply gave up on them and the nearby M105. I’ll get back to them when it gets warmer.

These galaxies along with nearby M105 just north of them belong to a small cluster of galaxies called the Leo I group, which like our own Local Group or galaxies are gravitationally bound to the Virgo Cluster to the east. Though at first glance the two galaxies look similar, M95 is a barred spiral, while M96 is a normal spiral. Looking closer to M96, you’ll spot what looks like a red star at the galaxy’s right edge. It’s actually a more distant edge on spiral galaxy.

Below is a chart, based on Stellarium, that shows the location of these galaxies to the stars of the constellation Leo.

Tags: Astrophotography, Scott Anttila by Bob Moler
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Hey, what can I say. It cleared up last night. Scott got this great shot of Venus passing the Pleiades. Click on the thumbnail below for a full screen shot!  It looks a whole lot better than this thumbnail.

Tags: Events, Observing, Astrophotography, Scott Anttila by Bob Moler
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Over the six nights April 9th through the 14th the brilliant evening star, the planet Venus, will pass the beautiful star cluster called the Pleiades or Seven Sisters.  Venus will seem the closest on the evening of the 11th.  The times and positions of Venus in the chart below are for the longitude and time zone of Michigan, around 85 degrees west, and 4 hours behind UT.

The chart was created using the free program Cartes du Ciel.

Tags: Events, Observing by Bob Moler
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April 2nd 2007 is the day of the Paschal full moon, the full moon after the first day of spring, which is defined by Christian churches as March 21st.  The church had adopten the Roman Juloan Calendar.  By the 16th century the discrepency between the assumed first day of spring, March 21st, and the actual first day of spring had grown to 10 days.  The pope of the time Gregory XIII commissioned the calendar reform that bears his name, the Gregorian Calendar, and deleted the ten days from the calendar between October 4th and the 15th of the year 1582.
For the date of Easter the actual full moon isn’t used, but a value called Epact, or the age of the moon on January 1st.  This year it is 11.  This value is then used in a table to find the new moon of March 20th, 13 days later will be a full moon.  This year that formula works out to be April 2nd, and matches the actual full moon.  It can be a day off either way, however.  The next Sunday then is Easter.  Orthodox churches use the Julian calendar and a different formula but they will also celebrate Easter this Sunday.  This whole formula was set up to approximate the Jewish lunar calendar.  It works this year because Passover starts at sunset on the 2nd.

Tags: Events by Bob Moler
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