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The Sky This Month - November 2017

Pegasus

Observing sessions begin a lot earlier this time of year. As you step after dinner in the cool night air, the familiar square of Pegasus greets you high in the eastern sky. The top of the square called Markab, a hot spectral class B9 star some 205 times the luminosity of our Sun. At 140 light years from us, Markab measures three times the mass of the Sun and only takes a day and a half to spin on its axis compared to our Sun’s 25 day spin. Both Pegasus and Andromeda seem to share a common star named Alpheratz. Although it is officially referred as alpha Andromeda, this B5 star located 97 light years away also forms part of the great square.

One of the best examples of a spiral galaxy is the Deer Lick. Also known as NGC 7331, the Deer Lick should be on your list to view and photograph. At 48 million light years away, this spiral is located to four farther and fainter galaxies (NGC 7335, 7336, 7337 and 7340). With magnitudes around 15th and fainter, dark skies and large telescopes are required to view these with your eye. Located a few degrees from NGC 7331 is the challenging cluster of galaxies called Stephan’s Quintet. At an estimated distance of 300 million light years, this group of distant galaxies range in brightness from magnitude 13.9 to 16.7. They are gravitationally bound and will eventually merge to firm a huge elliptical galaxy.

Of course we must cross over to the view the jewel of the night, the Andromeda Galaxy. Catalogued as M31 or NGC 224, the Andromeda Galaxy is an astounding object with the naked eye from dark sites, using binoculars or a telescope. The 2.5 million light year galaxy is flanked by its two satellite galaxies more commonly referred as M32 and M110. M31 measures three degrees or six full moons in width. With moderate to large telescopes, many globular clusters can be located in this distant galaxy. Four billion years from now, the Andromeda and Milky Way galaxies will merge to form a new galaxy called Milkomeda. Another favourite target to view and image is the face-on galaxy M33 located in Triangulum. It lies about 300 thousand light years farther than Andromeda and glows at magnitude 5.7. Embedded in its spiral are red energetic areas of star formation.

Recent observations and research have led to the discovery of thousands of exoplanets orbiting distant stars. This all began back in 1995 with 51 Pegasi. Located 50.9 light years away, it was the first exoplanet discovered orbiting a Sun like star. You can easily see this star with the naked eye on a clear night. It is located to the right of the Great Square. Now find Upsilon Andromeda with a distance of 44 light years from us. Named Titawin, this magnitude 4.0, F8 yellow-orange star is home to four exoplanets.

It is that time of the year when most locations turn their clock back an hour as Daylight Saving Time ends at 2 a.m. on November 5. When doing so remember your conversion to Universal Time is also adjusted. The planet Jupiter is now moving to the morning sky and on Nov 17 forms a lovely trio with Venus and the 1% lit moon. Jupiter continues to climb higher throughout the month as Venus sink towards the horizon. Saturn is the lonely naked eye planet seen after sunset, moving closer to the western horizon.

Comet C/2017 O1 ASAS-SN is still on its northern route through Cassiopeia. Meanwhile Comet 24P/Schaumasse is expected to brighten mid month and should be a great binocular target as it passes first through the constellation Leo and then Virgo. Two meteor showers are slated for this month. First the North Taurids is a weak shower with only five meteors per hour as it peaks on the night of the 11/12. This year’s Leonids peaks in the night of Nov 17/18 with about 15 meteors per hour. These low rates should continue until the year 2030 when we might see over 100 per hour. The Leonids are often bright meteors with a high percentage of persistent trains.

This month’s full Beaver moon occurs on November 4 with the new moon (lunation 1174) on the 18th.

Until next month, clear skies everyone.

Gary Boyle

Twitter: @astroeducator

 

Author: Gary BoyleeNews date: Wednesday, November 1, 2017Category: Northern SkiesFile:  2017 - 11 chart 1.jpgTweet::  Pages

The Sky This \month - October 2017

Aquarius 

Aquarius the Water Bearer ranks as the 10th largest constellation in area. With a total of 980 square degrees it is located in the southern part of the night sky between the constellations Capricorn on the right and Pisces on the left. The asterism consists of ten stars appearing as two side by side backward commas. The alpha star named Sadalmelik shines at magnitude 3.2 is a yellow G type star located some 750 light years from us. With luminosities some 3,000 times that of our Sun, this star is classified as a rare modest supergiant. Its enormous girth indicates it is starving for fuel and is dying. This starvation causes the star to balloon out to about the orbit of Jupiter if it were in our solar system. But some five billion years from now, our Sun will be following this same fate and expand to the orbit of Mars.

The beta star Sadalsuud, is located ten degrees from Sadamelik. By coincidence, this G class supergiant star is also going through its final stages of life. It measures 50 solar diameters across (10 diameters less than Sadamelik and has a surface temperature of 5,800 K or same as our Sun. The star Gliese 876 is the parent to four planets and is one of the closest group of planets to us. First locate the magnitude 3.2 star Delta Aquarii in the southern portion of the constellation’s boundary. Using the chart, Gliese 876 should be about two degrees north of this star. At only 15 light years away, Gliese 876 shines at about tenth magnitude and is a target of star parties or just showing off to the neighbours.

Moving back to the western section of Aquarius, relocated Sadalsuud and then move your scope about nine degrees south west until you come across the Saturn Nebula. Catalogued as NGC 7009, the Saturn Nebula has an overall brightness of magnitude 8.0 with a magnitude 11.5 central star. Its name comes from the somewhat resemblance of our famous ringed planet as seen almost edge on. This stellar corpse that was once a thriving star is located about 2,500 light years from us.

Continue almost in the same direction for another three degrees to the small and distant M72. The cluster is estimated to be 106 light years width with a population of about 100,000 suns. Appearing grayish in colour, M72 resides some 53,000 light years from us and is one of the most remote globular cluster. For a challenge, try to spot a magnitude 14.3 galaxy. Catalogued as UGC 11814, this smudge only measures .9 arc minutes wide. Good luck with this one.   

At the beginning of the month, the lonely planet Saturn sets just before 10 p.m. local time. Although Jupiter is technically in the west, it is low and soon lost in the Sun’s glare. Venus still owns the east with tiny Mars just below and to the left.

Of the dozen or so comets that are paying a visit to the inner solar system, comet C/2017 O1 ASAS-SN is an easy binocular or small telescope target as it heads north. Discovered on July 19, 2017 by the automated sky survey, the comet was a faint magnitude 15.3 but quickly brightened to magnitude 10 in a few days. Currently at magnitude 9.4, the comet is estimated to peak at magnitude 8 on October 14. Once the moon is gone, you should have a great opportunity to image this comet at its brightest. 

The full Hunter’s Moon will occur on October 5 and new moon will be on October 19. With the moon absent, try to locate the zodiacal lights in the east before astronomical twilight begins. This ghostly light is created by sunlight reflecting off interplanetary dust. The slanted triangular light can reach some forty degrees in height with Venus and Mars tucked inside. Zodiacal lights are seen close to autumn and spring.

Until next month, clear skies everyone.

Gary Boyle

Twitter: @astroeducator

Author: Gary BoyleeNews date: Sunday, October 1, 2017Category: Northern SkiesFile:  2017 - 10 chart 1.jpg 2017 - 10 chart 2.jpgTweet::  Pages

The Sky This Month - September 2017

Late Summer Observing

By now you have probably heard about the close approach of asteroid 3122 Florence on September 1. During the first few nights of September, you will have the opportunity for follow asteroid 3122 Florence on its northern trek. The asteroid is named in honour of Florence Nightingale – the founder of modern nursing in the early 1900’s. This 4.4 km long mountain is a member of the Athens asteroids that orbits the Sun every 859 days and range in distance from 1.0 to 2.5 astronomical units from the Sun. At 8:06 a.m. EDT on Sept 1 it will be some 18 times the distance between the Earth and the Moon and will not come this close until the year 2500. 

Estimated to be 9th magnitude, backyard telescopes and binoculars should be able to spot Florence as it races at 14 km/sec through Capricorn Aquarius and Delphinius. Photos will confirm motion after a few minutes. Ground based radar images may resolve detail some 10 metres across.

From a dark location – away from stray lights, the Milky Way is seen beaming overhead. Cooler nights give way to the hot hazy conditions of this past summer. With less atmosphere to contend with this would be a great opportunity to image objects in Cygnus such as NGC 6888 aka the Crescent Nebula. This emission nebula is located 5,000 light years away and is listed at magnitude 7.4 and measures 18 by 12 degrees. Then there is the North American and Pelican nebulas located close the Swan’s tail - the star Deneb.  

At the southern end of the Milky Way we see the ringed planet Saturn dip below the south-west horizon at midnight local time at the beginning of the month with the constellation Sagittarius following an hour later.

September 15 will mark the end of the highly successful 20 year Cassini mission. Launch in October 1997, Cassini took 7 years to reach the ringed planet and for the next 13 years studied Saturn and mysterious moon system. On its last day of work, Cassini will receive its last instructions to intentionally dive into Saturn’s atmosphere, never be heard again. This eliminates the chance of crashing into a moon and contaminating it for future missions. 

As the night goes on into the wee hours of the morning and the temperature drops to single digits, the Hyades cluster which outlines the horns of Taurus the Bull and Pleiades clusters (the bull’s heart) are well up in the east by 1 a.m. As if these two clusters still do not remind you of winter, Orion the Hunter is up by 4 a.m.

Starting from the 18th, you have a two week period to look for the zodiacal light in the east before dawn. Here we see the leftover interstellar dust of the solar system lit by sunlight. Try using a wide angle lens on your camera and image this impressive sight. It reaches about 40 degrees in height.

This month’s full Corn Moon occurs on the 7th with new moon on 20th lunation (1172).

Until next month, clear skies everyone.

Gary Boyle

Twitter: @astroeducator

Author: Gary BoyleeNews date: Thursday, August 31, 2017Category: Northern SkiesFile:  2017 - 09 chart 1.jpgTweet::  Pages