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10/05/2021 – Ephemeris – Can you spot the North American Nebula?

October 5, 2021 Comments off

This is Bob Moler with Ephemeris for Tuesday, October 5th. Today the Sun will be up for 11 hours and 29 minutes, setting at 7:15, and it will rise tomorrow at 7:47. The Moon, 1 day before new, will rise at 7:46 tomorrow morning.

Most of what we see in the Milky Way are just masses of stars, but there are bright clouds of gas, or to name them properly: emission nebulae. These bright clouds are areas of star formation. It is the ultraviolet light from young massive stars that light up the clouds they were formed from. A bright one, easily visible in binoculars, is just about overhead at 9 p.m. Called the North American Nebula, a glow, that in photographs is shaped much like our continent, is just east of the star Deneb which is practically overhead in the evening. Deneb is the northernmost star of the Summer Triangle, and brightest star in Cygnus the swan or Northern Cross. There are many other nebulae in the Milky Way, visible in binoculars and small telescopes. Many enjoyable hours can be spent sweeping the Milky Way for nebulae and star clusters.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT-4 hours). They may be different for your location.

Addendum

North American Nebula finder animation

North American Nebula finder animation. I’ve dimmed down the stars a bit and increased the brightness of the Milky Way to aid in spotting the nebula. It requires dark skies to see it. I believe I can make it out with the naked eye too. Click on the image to enlarge it. Created using Stellarium and GIMP.

Deneb & North American Nebula

One of my old photographs of Deneb and the North American Nebula, digitized from a slide.

Better view of the North American Nebula taken by Scott Anttila.

Better view of the North American Nebula taken by Scott Anttila.

08/13/2021 – Ephemeris – Rescheduled virtual star party tonight

August 13, 2021 Comments off

This is Bob Moler with Ephemeris for Friday, August 13th. Today the Sun will be up for 14 hours and 8 minutes, setting at 8:51, and it will rise tomorrow at 6:44. The Moon, 2 days before first quarter, will set at 11:36 this evening.

The Grand Traverse Astronomical Society will try again to hold a virtual star party starting at 9:30 pm tonight via the Zoom app on the Internet. We were clouded out last Friday night. Jerry Dobek, professor of astronomy at Northwestern Michigan College, will host the event with the 16-inch telescope at the College’s Observatory and an imager, but only if it’s clear in Traverse City. It should feature a look at Venus and the crescent Moon to start. Saturn and Jupiter will be up by then, but they’re quite low in the sky. We might take another look at them later on when their images are steadier. The wonders of the Milky Way are all available. Instructions and a link can be found on the society’s website, www.gtastro.org.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

The Southern Milky Way from Traverse City

The southern Milky Way from Aquila to Sagittarius taken from my backyard with light pollution from businesses on US 31 in Chums Corners and Grawn south of me.  I live about 7 miles west of the NMC Observatory. These bright lights are to its southwest and farther away. Click on the image to enlarge it.

08/05/2021 – Ephemeris – Looking toward the center of the Milky Way in Sagittarius

August 5, 2021 Comments off

This is Ephemeris for Thursday, August 5th. Today the Sun will be up for 14 hours and 29 minutes, setting at 9:02, and it will rise tomorrow at 6:35. The Moon, 3 days before new, will rise at 4:09 tomorrow morning.

Let’s look around the Teapot shape of stars that is the constellation of Sagittarius. A pair of binoculars or a telescope with a very low magnifying power is all that’s needed. The purpose here is not so much to make things bigger, but make them brighter. Right off the tip of the teapot’s spout is a large and bright patch of light. This is the farthest we can see, in visible light that is, toward the center of our galaxy, part of the central bulge. Astronomer Walter Baade discovered that fact in the mid 1940s. The center of the galaxy is 4 moon-widths or 2 degrees to the right of it, but obscured by a cloud of interstellar dust. It is called the Large Sagittarius Star Cloud or Baade’s Window. The glow there comes from 25 thousand light years away.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

Baade's Window AKA Large Sagittarius Star Cloud

Baade’s Window, aka Large Sagittarius Star Cloud. A finder animation created from my photograph taken August 23, 2016, at 11:23 pm. Click on the image to enlarge it.

06/28/2021 – Ephemeris – The summer Milky Way

June 28, 2021 Comments off

This is Ephemeris for Monday, June 28th. Today the Sun will be up for 15 hours and 32 minutes, setting at 9:32, and it will rise tomorrow at 6:00. The Moon, 3 days before last quarter, will rise at 12:50 tomorrow morning.

Last night we had the latest sunset of the year. That’s great news for star gazers who like dark skies and the Sun is not among the stars they want to gaze at. But it won’t get noticeably darker earlier in the evening until late July. But when that does happen, the glory of the summer Milky Way becomes visible. On top of that, the peak night of the Perseid meteor shower, the night of August 11th and morning of the 12th. The three-day-old Moon that night won’t bother the meteor shower at all. The winter sky has the Milky Way also, but we are then looking out, away from the center of our galaxy. It’s hard to tell there’s a milky band there at all. In summer, we are looking toward the more populated parts of our galaxy. It’s a wonder to behold.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT-4). They may be different for your location.

Addendum

The Milky Way from Cygnus to Scutum

The Milky Way from Cygnus to Scutum. This image, actually a stack of 5 images, was taken on August 12, 2018. I was hoping to record Perseid meteors. It was a poor showing, as none appeared in these images. We were hampered that year by smoke from the western US wildfires, which really affected the lower part of this image, which was still pretty high up in the sky, by giving it a red tinge. Featured here is the Great Rift, a series of dust clouds that split the Milky Way into two sections, subject of previous and future programs. Click on the image to enlarge. Credit: Bob Moler (me).

08/20/2020 – Ephemeris – Where are we in the Milky Way Galaxy?

August 20, 2020 Comments off

This is Bob Moler with Ephemeris for Thursday, August 20th. Today the Sun will be up for 13 hours and 47 minutes, setting at 8:39, and it will rise tomorrow at 6:52. The Moon, 2 days past new, will set at 9:59 this evening.

If we are in the Milky Way galaxy, where are we, and where’s the center of this vast spiral? Astronomers have found that the Sun is located in an offshoot of a spiral arm called the Orion Spur and the naked eye stars in the sky are also in it. In the winter constellation of Orion we are looking away from the center of the galaxy. This time of year, looking to the south in the evening at the Teapot of stars that is Sagittarius we look toward the center, which we can’t see due to the gas and dust in the way. It’s there, just above the spout of the Teapot. It can be seen, but not in visible light. It was the first thing detected with a radio telescope and it can be seen in the infrared. But there, 27,000 light years away is a 4 million solar mass black hole at the center.

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

Addendum

The Sun in the nearby spiral arms of the Milky Way Galaxy

The Sun in the Orion Spur and the nearby spiral arms of the Milky Way Galaxy. The direction to the center of the galaxy is down. Click on the image to enlarge. Public Domain, Wikimedia.

Our place in the Milky Way.

Our place in the Milky Way. Note that we appear to be in a barred spiral galaxy. The arms are numbered and named. 3kpc is the 3 kiloparsec arm. 3kpc = 9,780 light years. The Sun is about 27,000 light years from the center. Credit NASA and Wikimedia Commons, via EarthSky.org.

Location of the center of the Milky Way and the Teapot of Sagittarius.

Location of the center of the Milky Way and the Teapot of Sagittarius. It is blocked by gas and dust in visible light.

Image of the heart of the Milky Way galaxy

An image from the Chandra X-ray Telescope of the center of the Milky Way. SGR A or Sagittarius A is a radio source. SGR A*, pronounced Sagittarius A Star, is the 4 million solar mass black hole in the center of the Milky Way Galaxy. Credit NASA.

08/18/2020 – Ephemeris – What is the Milky Way really like?

August 18, 2020 Comments off

This is Ephemeris for Tuesday, August 18th. Today the Sun will be up for 13 hours and 53 minutes, setting at 8:42, and it will rise tomorrow at 6:50. The Moon is new today, and won’t be visible.

Last Friday and yesterday we looked at what the Milky Way looked like, but what is the Milky Way really like. It’s hard to tell, being inside it. In the 1920s astronomers gradually learned that the Milky Way was similar to the great number of spiral nebulae seen outside of the milky band. It was a flattened pinwheel of stars, gas and dust. At first they and the Milky Way were called island universes because until then it was thought that the Milky Way was the entire universe. The word for the Milky Way and those other structures is galaxy. The word galaxy is related to the Greek word for milk. Astronomers in the latter half of the 20th century using radio telescopes were able to trace out the clouds of gas that give our galaxy its spiral structure.

The event 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 that block the light of the stars behind it, not the lack of stars in that direction that he thought. The Great Rift is easily seen in the summer sky running through the Milky Way.

1950's radio map of the Milky Way Galaxy

1950’s radio map of the Milky Way Galaxy. The original source is for the map is The galactic system as a spiral nebula Oort, J. H.; Kerr, F. J.; Westerhout, G. MNRAS 118, (1958) p. 379.

Our place in the Milky Way.

Our place in the Milky Way. Note that we appear to be in a barred spiral galaxy. The arms are numbered and named. 3kpc is the 3 kiloparsec arm. 3kpc = 9,780 light years. The Sun is about 27,000 light years from the center. Credit NASA and Wikimedia Commons, via EarthSky.org.

M101

One of the many spiral nebulae visible, namely the Pinwheel Galaxy, M101 near the handle of the Big Dipper. Credit Scott Anttila.

 

08/17/2020 – Ephemeris – The Milky Way’s Great Rift.

August 17, 2020 Comments off

This is Ephemeris for Monday, August 17th. Today the Sun will be up for 13 hours and 56 minutes, setting at 8:44, and it will rise tomorrow at 6:49. The Moon, 1 day before new, will rise at 5:53 tomorrow morning.

High overhead the Milky Way is seen passing through the Summer Triangle of three bright stars. Here we find the Milky Way splits into two sections. The split starts in the constellation of Cygnus the Swan or Northern Cross very high in the east. The western part of the Milky Way ends southwest of Aquila the eagle. This dark dividing feature is called the Great Rift. Despite the lack of stars seen there, it doesn’t mean that there are fewer stars there than in the brighter patches of the Milky Way. The rift is a great dark cloud that obscures the light of the stars behind it. Sometimes binoculars can be used to find the edges of the clouds of the rift, as stars numbers drop off suddenly. This is especially easily seen in Aquila.

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

Addendum

Great Rift in the Summer Triangle

The Great Rift finder animation as seen in the Summer Triangle, also showing the constellations of Cygnus the swan and the the northern part of Aquila the Eagle. This image a stack of 5 30 second exposures taken the morning of the Perseid meteor shower in a vain attempt to capture some meteors.

Actual Aquila

Annotated and animated photograph taken of Aquila August 13, 2018 during the Perseid meteor shower, the same night the image above. Taken by me and processed using Registax and GIMP.

08/14/2020 – Ephemeris – Seeing the summer Milky Way

August 14, 2020 Comments off

This is Bob Moler with Ephemeris for Friday, August 14th. Today the Sun will be up for 14 hours and 4 minutes, setting at 8:49, and it will rise tomorrow at 6:45. The Moon, 3 days past last quarter, will rise at 2:39 tomorrow morning.

Now is the time the summer Milky Way is displayed to its fullest to the southern horizon. We have a week before the Moon begins to encroach on our dark skies after 10 pm. City folk come to our area and are sometimes fooled by the brightness and expanse of the Milky Way and think it’s a cloud. Yes those are clouds indeed, but they are star clouds. Binoculars will begin to show them to be millions of stars, each too faint to be seen individually to the eye, but whose combined glow give the impression of a luminous cloud. Binoculars are the ideal tool to explore the Milky Way. Objects still too fuzzy can be checked out with a telescope to reveal their true nature. The dark nights of August and September are my favorites.

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

Addendum

August Milky Way sky dome

The summer Milky Way spans the sky dome at 11 pm tonight, August 14, 2020. Created using Stellarium.

 

05/11/2020 – Ephemeris – Looking out of the Milky Way in May

May 11, 2020 Comments off

This is Ephemeris for Monday, May 11th. Today the Sun will be up for 14 hours and 41 minutes, setting at 9:00, and it will rise tomorrow at 6:17. The Moon, 3 days before last quarter, will rise at 1:51 tomorrow morning.

When it’s finally dark enough to see the stars in a dark sky at the end of astronomical twilight at 11 p.m. the question might be: “Where did the Milky Way go?” The band of the Milky Way is actually nearly ringing the horizon. Part of it runs through the W shaped constellation of Cassiopeia, just above the northern horizon. But the great amount of the Earth’s atmosphere we have to look through that low in the sky dims it to invisibility. The Milky Way is what we see of our galaxy, or more accurately our part of our galaxy whose shape has the rough proportions of a pancake. Remember, we’re in it. In spring we’re mostly looking through the thin side past relatively nearby stars to the intergalactic space beyond.

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

Addendum

Milky Way on May 15 11 pm 2020

The Dome of the sky on May 15, 2020 at 11 pm with the Milky Way at its lowest in the sky. Credit my LookingUp program.

Our place in the Milky Way.

Our place in the Milky Way. Note that we appear to be in a barred spiral galaxy. The arms are numbered and named. 3kpc is the 3 kiloparsec arm. 3kpc = 9,780 light years. The Sun is about 27,000 light years from the center. Credit NASA and Wikimedia Commons, via EarthSky.org.

The summer and winter Milky Way viewing directions.

The summer and winter Milky Way viewing directions. During Spring and Autumn, we look out the sides to the universe beyond. Credit Credit: NASA with annotations by Bob King at Universe Today.

Categories: Ephemeris Program, Milky Way Tags:

08/02/2019 – Ephemeris – The Milky Way

August 2, 2019 Comments off

Ephemeris for Friday, August 2nd. Today the Sun will be up for 14 hours and 37 minutes, setting at 9:07, and it will rise tomorrow at 6:31. The Moon, 2 days past new, will set at 10:31 this evening.

We’ll get darkness tonight, but that will erode night by night as the Moon waxes in our evening sky. At mid month this month and September will be the start of about two weeks of the best evening sky viewing of the year. This is the period the summer Milky Way is displayed to its fullest to the southern horizon. City folk come to our area and are sometimes fooled by the brightness and expanse of the Milky Way and think it’s clouding up. Yes those are indeed clouds, but they are star clouds. Binoculars will begin to show them to be millions of stars, each too faint to be seen by themselves to the naked eye, but whose combined glow give the impression of a luminous cloud. Binoculars are the ideal tool to begin to explore the Milky Way. Objects still too fuzzy can be checked out with a telescope to reveal their true nature.

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

Addendum

Great Rift in the Summer Triangle

The Milky Way in the Summer Triangle, also showing the constellations of Cygnus the swan and the the northern part of Aquila the Eagle. This image a stack of 5 30 second exposures taken the morning of the Perseid meteor shower the is year in a vain attempt to capture some meteors.  I was hampered by a smoky haze blown in all the way from the West Coast from forest files out there.