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The Sky This Month - June 2010

Posted in
Written by Gary Boyle, Ottawa on
Post Date: 
Thu, 2010/06/03

Draco – Circumpolar Beast

The dragon of the night is out there. Not behind the bushes at your favourite out of town dark observing site, nor is it hibernating in an isolated cave. The dragon of the night hangs high overhead, wrapped part way around Ursa Minor in the north. With our beasty friend located between the two celestial bears, it never appears to set. Constellations and stars that are visible all year round are called circumpolar.

During my outreach program at campgrounds and parks, the most asked constellation was about the Big Dipper. But now thanks to the Harry Potter series of books and movies, Draco is the constellation of question. It amazes me on how certain characters tend to stand out with children.

 

 

 

The dragon of the night is out there. Not behind the bushes at your favourite out of town dark observing site, nor is it hibernating in an isolated cave. The dragon of the night hangs high overhead, wrapped part way around Ursa Minor in the north. With our beasty friend located between the two celestial bears, it never appears to set. Constellations and stars that are visible all year round are called circumpolar.

 

During my outreach program at campgrounds and parks, the most asked constellation was about the Big Dipper. But now thanks to the Harry Potter series of books and movies, Draco is the constellation of question. It amazes me on how certain characters tend to stand out with children.

 

Taking a look at some of the bright suns that make up Draco, we see that Rastaban has the same spectral type as our Sun (G2) but is of the giant or super giant category. Rastaban is roughly the same temperature as the Sun but because of its size, shines 950 times greater. Rastaban is listed at magnitude 2.8 and is 360 light years from Earth.

 

Going back in time to Egyptian times, the Eltanin (magnitude 2.2) was considered the pole star. It currently resides 148 light years away but is on the move – toward our neck of the cosmic woods. A million and a half years from now, Eltanin will pass our solar system by only 28 light years and rival Sirius in the brightness category.

 

But not all bright stars are interesting. SAO 29583 is a 6th magnitude star that is 396 light years from us. Just over three billion years old, it measures about 12 times the radius as the Sun. However SAO 29583 is not just a star but a parent star to an exoplanet orbiting it. The planet is close to 10 times the mass of Jupiter (superjovian) and orbits once in just over three Earth years.

 

 

 

 

Not far away from SAO 29583 is Edasich (Iota Draconis) that also has a planet that is about 9 Jupiter masses and orbits in 511 Earth days. There are another four stars in Draco alone that harbours single planets. As of May 31st the number stands at 425 planets and counting.

 

With Draco being so high in the northern sky, we have a good chance to hunt illusive galaxies all year long. A great one to begin with is NGC 5965. The near edge-on galaxy reveals a well defined dust lane. It measure 5.4 X 0.7 arc minutes with an estimated distance of 179 million light years from us. Now from the 13th magnitude galaxy, nudge your scope one and a half galactic widths to the south and you will stumble upon the 12th magnitude NGC 5963. Both will fit nicely in the eyepiece of a telescope.

 

NGC 4236 is a very elongated galaxy. It is as long as half a full moon and glows at magnitude 10.3. The strange part about this 1.5 million light year galaxy is the lack of a bright nucleus. There is however a lot of mottling in the spiral arms.

 

The only planetary nebula located in all of Draco is the Cat’s Eye Nebula. Catalogued as NGC 6543 the Cat’s Eye resides a mere 3,000 light years from us. This is what is to come when our Sun uses up its fuel and dies of some 5 billion years from now.

 

 

 

 

Mars now seem in the western half of the sky. As the first week of June opens we see the red planet fly above Regulus in an easterly direction and will be a little less than two degrees south of Saturn at the end of July. During the month of June, Mars will move some sixteen degrees of sky and set at midnight local time at the end of the month.

  

Saturn is starting to show its rings system a little more. After its ring crossings when the magnificent system was perfectly lined us with Earth and thus disappeared, the angle is increasing and will keep doing so till they reach the maximum 27 degree tilt in October 2017. After that, the system begins to slowly close till the next ring crossing on March 23, 2025.

 

The King of planets Jupiter rises at 2:19 a.m. local time in the east at the beginning of June and up by 12:30 by the end of the month. Look for Uranus about one degree to its north east. 

 

 

Object

Type

Magnitude

Coordinates

NGC 4236

Galaxy

10.3

RA:12h 16m 41.9s  Dec:+69d 28s

NGC 5963/65

Galaxy

13.0 and 12.0

RA:15h 34m  0.0s  Dec:+56d 42s

NGC 6543

Planetary nebula

9.0

RA:17h 58m 35.9s  Dec:+66d 38s

 

 

 

Full moon occurs on June 26, with a partial lunar eclipse best seen in central and western Canada at moonset. And lastly, summer solstice occurs on the 21st at 7:48 a.m. EDT

 

Till next month, clear skies everyone.

Gary Boyle