February 2018 Skygazing from the Robert Ferguson Observatory Featured

Moon - There is no full moon in February this year. Instead, February is bracketed by two months each with "Blue" moons! As the month begins we will have a couple of days of high tides remaining from the January 31 full moon near perigee. This is the last of a sequence of large tides around the full moon. Look for the moon very near the bright blue star Regulus in Leo around 5 am on 2/1 (use binoculars to enjoy the star's color). The moon is very near Jupiter around 5:30 am on February 7. Last Quarter is also that morning. The moon is near Mars around 3:30 am on February 9. The crescent moon is very near Saturn around 5:30 am on February 11. New Moon is midday on February 15. Look for an ultra-thin 1.5% crescent moon 6° high and 17° south of due west 30 minutes after sunset (or at 6:19 pm calculated for the RFO site) on February 16. Use binoculars to help you spot this thin crescent in the twilight glow. On February 17 a thin 5% crescent moon is in the west around 6:30 pm. First Quarter occurs shortly after midnight on the morning of February 23. On the evening of February 24 the moon will occult the bright star 64 Orionis (see below). Finally, on February 28 around 10 pm the moon again approaches the bright blue star Regulus, this time coming VERY close. Again, use binoculars.



Mercury - Mercury is at superior conjunction (far side of the sun) on February 17 so is not viewable this month.

Venus - Venus, just past superior conjunction, emerges into the evening sky late in the month so is mostly not viewable.

Mars - Mars moves from Scorpius to Ophiuchus early in the month and rises around 2:30 am mid-month. It lies between Jupiter and Saturn in the morning sky all month. The moon is near Mars around 3:30am on February 9.

Jupiter - Jupiter, in Libra, rises around 1 am mid-month. The moon is near Jupiter around 5:30 am on February 7. Jovian satellite events become readily observable in the later part of this month. Details on these are on the RFO website.

Saturn - Saturn, in Sagittarius, is in the southeast morning sky, rising around 4 am mid-month. The crescent moon will be very near Saturn around 5:30 am on February 11.

Uranus - In Pisces, Uranus sets around 10:30 pm mid-month so is a scope target only for a short time around the end of twilight early this month. After this month it will fade into the evening twilight.

Occultation of 64 Orionis - At about 8:59 pm on February 24 the magnitude 5.1 star 64 Ori will disappear behind the moon's dark limb 36° from the north cusp. 64 Ori is an extremely close double so this event may be non-instantaneous (about 0.2 sec lag) for those with suitable equipment. (Calculated using Occult4 for the RFO site. Details will differ as distance from RFO increases and no occultation may occur for those far away.)

Zodiacal Light - A few times each year, we get a chance to see a very interesting phenomenon: the "Zodiacal Light". This is a faint glow in the sky caused by sunlight reflecting off dust and debris in the plane of our solar system. For about two weeks during this month and again next month, the Zodiacal Light will be viewable in the west after twilight. You will need a good, dark (no light pollution!), clear western sky to observe this. A clear night along the coast (especially from the hills above the ocean mists) should be good.

If you have a planisphere or star chart that shows the line of the Ecliptic, this is where you should see the glow. It will be broadest near the horizon and taper gradually in a long tall triangle as it rises into the sky, losing itself in the glow of the Milky Way, which it intersects. The base of the triangle will be in Pisces, south of the Great Square of Pegasus. It will rise through Aries toward the Pleiades and the bright red-orange star Aldebaran, continuing on toward Gemini. If you are in a sufficiently dark location and realize what you are seeing, it is unmistakable. The dates for looking this month are February 3 to February 16. Start viewing at about 7:10 pm until about 8 pm. There will be another chance to see this phenomenon next month, though Venus will interfere somewhat by that time.

Algol Eclipses - The sky position and long nights of fall and winter make this the best time to observe the famous eclipsing variable star Algol (beta Persei) in Perseus. The orbital plane of this close pair of stars coincides with our line of sight. Once every orbit the dimmer star eclipses (actually, occults) the brighter star and the light we see from what appears to us as a single star grows dimmer. This happens every 2 days 48 minutes 56 seconds. The eclipse lasts about 10 hours, though the most obvious dimming lasts about 6 hours, centered around the eclipse minimum.

Normally, Algol is at magnitude 2.1 (similar in brightness to the North Star) but dips to magnitude 3.4 at eclipse minimum. Algol is in a trapezoid arrangement with 3 other stars: pi, rho and omega Persei. Most of the time Algol is much brighter than the other 3 stars. However at eclipse minimum it is the same brightness as rho Persei, the star diagonally opposite Algol in the trapezoid. Use binoculars to help observe these 4 stars easily. The nearby star gamma Andromedae, at magnitude 2.2, can be used as a reference for Algol at its normal brightness. Convenient eclipse minimum times are listed below. Those in early evening allow for watching Algol return to normal brightness after minimum. Those in morning hours allow watching Algol dim before minimum.

Algol minima:

February 1 9:11 pm

February 4 6:00 pm

February 16 5:16 am

February 19 2:05 am

February 21 10:54 pm

February 24 7:43 pm


TIME SEQUENCE SUMMARY OF EVENTS:

Capitalized items refer to the sections above.

January 31 to February 2 - Large Tides due to Full MOON near perigee

February 1 - MOON very near Regulus

February 1 - ALGOL ECLIPSE minimum

February 3 to February 16 - ZODIACAL LIGHT in the west

February 4 - ALGOL ECLIPSE minimum

February 7 - MOON near JUPITER

February 7 - Last Quarter MOON

February 9 - MOON near MARS

February 11 - Crescent MOON very near SATURN

February 15 - New MOON

February 16 - ALGOL ECLIPSE minimum

February 16 - 1.5% Crescent MOON in west

February 17 - 5% Crescent MOON in west

February 19 - ALGOL ECLIPSE minimum

February 21 - ALGOL ECLIPSE minimum

February 22 - First Quarter MOON

February 24 - ALGOL ECLIPSE minimum

February 24 - OCCULTATION OF 64 ORIONIS

February 28 - MOON Very near Regulus

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