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Posts Tagged ‘Whirlpool Galaxy’

04/12/2018 – Ephemeris – Where did the Milky Way go in the spring?

April 12, 2018 Comments off

Ephemeris for Thursday, April 12th. The Sun will rise at 7:03. It’ll be up for 13 hours and 20 minutes, setting at 8:24. The Moon, 3 days before new, will rise at 6:14 tomorrow morning.

The Bright stars of winter are sliding into the western twilight in the evening. Taking their place in the south and east are the much more sparse stars of spring. The Milky Way passes through the winter and summer skies as well as the northern autumn sky. In the spring it runs below our southern horizon. Way back 200 years ago William Herschel realized that the stars around us lie in a flattened disk, that it was deeper in the direction of the milky glow than 90 degrees from it. It wasn’t until a bit less than 100 years ago that astronomers realized that there was anything outside this disk of stars. Today we call the fuzzy objects we find out there galaxies after the Greek word for Milky Way. They were seen in the 18th and 19th centuries, but were not recognized as such.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Herschel's Universe

The shape of the universe (Milky Way) as measured by William Herschel by counting stars in the eyepiece fields of his telescope pointed in various directions. The large indent on the right is caused by the Great Rift, clouds of gas and dust the block the light of the stars behind it, not the lack of stars in that direction. The Great Rift is easily seen in the summer sky running through the Milky Way.

Spring sky dome

The dome of the spring sky showing the Milky Way visible mostly on the northeastern sky. In spring, we are looking out the thin side of the Milky Way. Created using Cartes du Ciel (Sky Charts).

Some Spring Galaxies

M51 photo

The Whirlpool Galaxy, M51 in Canes Venatici. Credit Scott Anttila.

M101

The Pinwheel Galaxy, M101  near the star Mizar in the handle of the Big Dipper. Credit Scott Anttila.

Markarian Chain of galaxies in Virgo. Credit Scott Anttila.

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03/17/2017 – Ephemeris – When Ireland had the largest telescope in the world

March 17, 2017 Comments off

Ephemeris for St. Patrick’s Day, Friday, March 17th.  The Sun will rise at 7:50.  It’ll be up for 12 hours even, setting at 7:51.  The Moon, 3 days before last quarter, will rise at 1:01 tomorrow morning.

In the 19th century Ireland laid claim to having the largest telescope in the world.  It was a reflecting telescope with a mirror diameter of 72 inches.  It was built by William Parsons the Third Earl of Rosse.  The base of the telescope tube rested in a pit between two massive walls and could only look in a north-south direction.  It saw first usage in 1847.  The telescope was called the Leviathan of Parsonstown, and was in use until 1890.  Mirrors in those days was made of a silvery alloy called speculum.  Two mirrors were used alternately because speculum tarnished.  The mirror not in use would have to be re-polished and swapped in from time to time.  It was the largest telescope until the 100 inch at Mt. Wilson was put in service in 1917.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Leviathan of Parsonstown

The 72 inch Leviathan of Parsonstown. source: http://www.klima-luft.de/steinicke/ngcic/persons/rosse3.htm

M51 drawing

A drawing of the Whirlpool Galaxy, M51 (NGC 5194 & 5195) by Lord Rosse with the 72 inch telescope. Public Domain.

M51 photo

The Whirlpool Galaxy, M51. Credit Scott Anttila.

The Whirlpool Galaxy is the only galaxy that I’ve actually visually seen spiral arms on.  It was seen using a Celestron 14″ telescope at Northwestern Michigan’s Joseph H. Rogers Observatory.  That was a looong time ago.

05/27/2016 – Ephemeris – Alkaid, the star at the end of the Big Dipper

May 27, 2016 Comments off

Ephemeris for Friday, May 27th.  Today the Sun will be up for 15 hours and 14 minutes, setting at 9:17, and will rise tomorrow at 6:02.   The Moon, 2 days before last quarter, will rise at 1:40 tomorrow morning.

The star at the end of the handle of the Big Dipper is named Alkaid.  It is the bright star that’s closest to the zenith at 11 p.m.  It is a rare blue-white star.  Alkaid and Dubhe, at the other end of the Big Dipper are stars that do not belong to the Ursa Major Association.  And thousands of years from now these two stars will leave the central stars of the dipper behind, and deform the Big Dipper.  Over the millennia the Big Dipper would look like a tin cup.  Near Alkaid are two popular deep sky objects.  And being this far from the hazy band of the Milky Way one would guess that they would be galaxies.  And they are. The Whirlpool Galaxy and the Pinwheel Galaxy.  Two gorgeous spiral galaxies.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

The change in the Big Dipper over time.

The change in the Big Dipper over time. Source: stargazerslounge.com.  Ultimate source:  Stellarium.

Alkaid and the Big Dipper

The Big Dipper and Alkaid with the Whirlpool (M51) and Pinwheel (M101) galaxies. Created using Stellarium.

M51

The Whirlpool Galaxy, M51. Credit Scott Anttila.

M101

The Pinwheel Galaxy, M101. Credit Scott Anttila.

06/16/11 – Ephemeris – Supernova in the Whirlpool Galaxy

June 16, 2011 1 comment

Thursday, June 16th.  Today the sun will be up for 15 hours and 33 minutes, setting at 9:29.   The moon, 1 day past full, will rise at 10:23 this evening.  Tomorrow the sun will rise at 5:56.

One of the coolest galaxies visible in a telescope is the Whirlpool Galaxy, also known as M51, near the handle of the Big Dipper.  With a large enough amateur telescope, the spiral pattern can just be glimpsed.  Usually it takes long exposure photographs to reveal the spiral structures of the galaxies that have them.  A few weeks ago a supernova appeared in the outer spiral arm of the Whirlpool galaxy, visible in medium size telescopes of 8 inch diameter and up.  Based on the study of the light given off by the supernova it appears that this is was a massive star whose core collapsed allowing the rest of the star to explode briefly making the star billions of times brighter than the sun.  The supernova will gradually fade in an expanding cloud of gas.

* Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.