Eta Aquarid Meteor Shower

radiant   This weekend the Eta Aquarids Meteor Shower reaches its peak during the early morning hours before sunrise on Monday 6 May, however like all annual meteor showers there is a range of days, (19 April through 28 May), where meteors associated with the Eta Aquarids may be seen. This meteor shower radiates outward from the constellation Aquarius the Water Bearer; averages 55 per hour; are fast moving often leaving a glowing train that may lasts for several seconds. A ‘train’ is a persistent glowing streak of light left behind by the meteor as it vaporizes in the upper atmosphere. Interestingly the Eta Aquarids originate from debris left along the Earth’s orbit by Halley’s Comet.

   This region of the sky unfortunately rises only a couple of hours before sunrise and on the mornings of the 5th and 6th the waning crescent Moon will be above the eastern horizon. The slides below show the region of the sky set to 4:30 a.m. CDT on May 6th (2330 UT 5 May). Each slide depicts the constellations with and without the connecting lines forming the constellation pattern. I used several including the classical Astronomical patterns, and those by H.A. Rey in his book The Stars, A New Way To See Them. (You may know H.A. Rey as the author of Curious George)

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   Click here to go to the Qué tal in the Current Skies web site for more observing information.

A Tale of Two Showers

13 December - 10 pm CST

13 December – 10 pm CST

   After sunset on Thursday December 13th look toward the east or west for ‘shooting stars’, or meteors. Toward the east the short-lived streaks of light are radiating outward from the area of the Gemini Twins constellation. These are the annual Geminids – one of the best meteor showers each year, and at times rivaling the August Perseids. The Geminid Meteor Shower is named for the constellation that the meteors radiate outward from. This is the same for all meteor showers, and the ‘spot’ in the sky is known as the radiant. The Geminid radiant, as shown in the graphic, is just above the ‘twin’ star Castor, and under ideal viewing conditions an average of about 70 meteors per hour could possibly be seen. This year without the interference of moonlight will increase the chances of seeing the meteors.
   Meteor showers result from the Earth’s orbital path intersecting areas of comet debris. Comets, as they orbit the Sun, leave behind pieces of their icy, dirty, selves. If these debris clouds happen to be along the Earth’s orbital path then the Earth will regularly pass through the comet debris cloud. As this happens the small comet pieces hit our outer atmosphere and vaporize from the friction generated heat. We then see these as the shooting stars that make up meteor showers.
   There are, however, two exceptions to this. The January Quadrantid Meteors and the Geminids each come from their own respective asteroid rather than a comet. The source for the Geminids is Asteroid 3200 Phaethon
Un-named Meteor Shower   Looking toward the south to southwest and adding to viewing the Geminids is an un-named meteor shower with a radiant just below the bottom of the ‘Square of Pegasus’, between the ‘square’ and the ‘Circlet’ pattern of stars forming the head of the Western Fish of Pisces the Fishes. This meteor shower originates from Comet Wirtanen, a short-period comet orbiting the Sun every 5.5 years. The comet was discovered in 1948 and according to some predictions the Earth may pass through this comet’s debris cloud for the first time since the comet’s discovery. This part of the sky is over the south at sunset and as this graphic shows the radiant is over the southwest as the Geminids radiant is over the eastern horizon.

Click here to go to the Qué tal in the Current Skies web site for more observing information.

Here Come the Orinids

Sunday 21 October – 4 am CDT

   The Orionid Meteor shower reaches its peak on the morning of Sunday the 21st. Best viewing is looking toward the east to south part of the sky after midnight and before sunrise. Look for the stars of Orion – most find Orion from the 3 bright stars forming his belt. Look to the left from the belt stars for the bright reddish-orange star Betelgeuse (often pronounced ‘beetle juice’) that represents Orion’s right shoulder. A little further to the left from Betelgeuse is the radiant, the area where the meteors or shooting stars will seem to be radiating outward from.
   All annular meteor showers, like Orionids, and the more well-known August Perseids, are named for the constellation the radiant is located within. Meteor showers are the result of several factors including the reaction between the comet’s dirty, icy surface with the Sun’s radiant energy and the orbital path the Earth and comets follow around the Sun. All comets leave behind clumps or clouds of comet debris, their surface material, as they come closer to the Sun’s heat energy. Some of this comet debris is left along the Earth’s orbital path such that the Earth regularly passes through these debris clouds. As the Earth passes through the debris the small bits of rock enter the Earth’s atmosphere and as they heat from friction and melt they glow briefly appearing as streaks of light. Some meteors leave a bright glowing trail, called a train, for a few moments. The Orionids average around 20 meteors per hour, however this year estimates are that that number may go up to as many as 60 per hour.
   How the number per hour can increase is based on the debris cloud and where the Earth passes through it. The debris is cloud-like in its shape and there are parts of the ‘cloud’ where the particles are more numerous – the thicker parts of the debris cloud. Meteor showers, like the Earth’s orbit are pretty well known so part of the equation for determining the number per hour is based on knowing what part of the debris cloud the Earth will pass through. This year we apparently pass through a thicker part of the debris cloud.
   Hang on to your hat!

Click here to go to the Qué tal in the Current Skies web site for more observing information.