Archive

Archive for September, 2024

Ephemeris: 09/30/2024 – Andromeda’s treasure, its great galaxy

September 30, 2024 Comments off

This is Bob Moler with Ephemeris for Monday, September 30th. Today the Sun will be up for 11 hours and 43 minutes, setting at 7:24, and it will rise tomorrow at 7:41. The Moon, 2 days before new, will rise at 6:27 tomorrow morning. | For at least the last thousand or so years a fuzzy spot in the constellation of Andromeda has been known. It was known as the Great Andromeda Nebula until about 100 years ago. Nebula means cloud, and it belonged to the Milky Way. At that time it was finally recognized as another Milky Way just like ours. So the word to call it was galaxy, a word that means Milky Way. It looks to be among the stars of Andromeda, but it’s far beyond the stars that we make of the constellation Andromeda. Current estimates place it at about two and a half million light years away, well beyond the stars that we see in Andromeda that range to only a few thousand light years distance. It will collide with our galaxy in about 4 billion years.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.

Addendum

Andromeda Galaxy finder chart
Andromeda Galaxy finder chart. Click on the image to enlarge it. Created using Stellarium.
Andromeda Galaxy by Dan Dall'Olmo
Andromeda Galaxy and its two companion galaxies. Credit: Daniel Dall’Olmo.
Categories: Deep Sky Object, Galaxies, Observing Tags: , ,

Ephemeris: 09/27/2024 – Finding Andromeda

September 27, 2024 Comments off

This is Ephemeris for Friday, September 27th. Today the Sun will be up for 11 hours and 53 minutes, setting at 7:29, and it will rise tomorrow at 7:37. The Moon, 3 days past last quarter, will rise at 3:11 tomorrow morning.

The constellation of Andromeda is famous mainly for the galaxy visible to the naked eye that is contained within it, called the Great Andromeda Galaxy, which is actually visible to the naked eye. Andromeda is found in the east northeast these evenings connected to the Great Square of Pegasus, the square of stars standing on one corner in the east. It shares a star with that square called Alpheratz, the leftmost star, and from that star two curved lines of stars are seen to the left that is the body of Andromeda. She was a Princess and daughter of Queen Cassiopeia, and was fated to be devoured by the monster Cetus. She was saved by the hero Perseus who flew in on his flying horse Pegasus.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.

Addendum

Locating Andromeda in this animated finder chart
Locating Andromeda in this animated finder chart is by using the Great Square of Pegasus as the starting point. The position of the constellation is for 9 PM in late September. The bright star on the right is not a star, but where Saturn is this year .
Categories: Constellations, Ephemeris Program, Mythology, Observing

Ephemeris: 09/26/2024 – Finding Cassiopeia the queen

September 26, 2024 Comments off

This Ephemeris for Thursday, September 26th. Today the Sun will be up for 11 hours and 56 minutes, setting at 7:31, and it will rise tomorrow at 7:36. The Moon, 2 days past last quarter, will rise at 2:02 tomorrow morning.

High in the northeast sky at 9:00 PM can be found the constellation of Cassiopeia the queen. Its stars make a letter W in the sky. It is circumpolar, meaning that it never sets, as it appears to move around the North Pole of the sky. In the summer it is a W low in the north. It becomes kind of an open and angular number 3 in the autumn. In the winter it is overhead and looks like an M. In springtime it looks like the Greek capital letter Sigma in the northwest. I will visit Cassiopeia later this autumn and relate her story and other autumn constellations including her daughter Andromeda, husband King Cepheus, future son-in-law Perseus and his horse Pegasus, and the sea monster, Cetus.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.

Addendum

Cassiopeia finder animation
Cassiopeia finder animation looking in the northeastern sky around 9 PM tonight. One cannot miss the distinctive W, or in this orientation 3. Created using Stellarium.

Categories: Constellations, Ephemeris Program, Observing Tags:

Ephemeris: 09/25/2024 – Looking for the naked-eye planets for this week

September 25, 2024 Comments off

This is Ephemeris for Wednesday, September 25th. Today the Sun will be up for 11 hours and 59 minutes, setting at 7:33, and it will rise tomorrow at 7:35. The Moon, 1 day past last quarter, will rise at 12:53 tomorrow morning.

Let’s take our weekly look at the whereabouts of the naked-eye planets. Venus might be spotted in the West southwest only 6° above the horizon at 8 PM, 30 minutes after sunset. It will set at 8:38. Saturn will be low in the east-southeast at that time, but you might have to wait another half hour for it to appear. Saturn may look disappointing in telescopes this year since its rings are nearly edge on and appearing as a line through the planet like it’s stapled onto the sky. Jupiter and Mars will be up in the morning sky, with Jupiter rising about 11 PM now and by 6:30 AM tomorrow, Jupiter will be brighter than the winter stars in the south-southeast. Mars and the Moon will be left and below Jupiter.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.

Addendum

Venus in evening twilight
Venus in evening twilight, approximately 30 minutes after sunset. For the Grand Traverse area of Michigan that would be about 8 PM, where Venus is very close to the horizon, due to the low angle of the ecliptic. Created using Stellarium.
Saturn in the southeastern sky by 9 pm. Created using Stellarium.
The morning planets Jupiter, Mars and the Moon are seen among the winter stars at 6:45 AM or about an hour before sunrise in the South southeast. Though Comet Tsuchinshan-ATLAS ia shown, it is too low and faint to be able to spot. Created using Stellarium.
The Moon two days past last quarter. Selected features are labeled. Created using Stellarium, LibreOffice Draw, and GIMP.
Telescopic Venus, Saturn and Jupiter (north up) as they would be seen in a small telescope with the same magnification. Venus and Saturn are from the evening of the 25th 2024, Jupiter is for 6:45 am on the 26th. Apparent diameters: Venus 12.0″, 86.1% illuminated; Saturn 19.0″, its rings 44.5″, 4.4 degrees from edge on (opening up a bit); Jupiter 41.6″; Mars, too small to be represented here, is 7.4″. Saturn’s rings are actually much brighter than depicted here. The ” means seconds of arc, or 1/3600th of a degree. Click or tap on the image to enlarge it. Created using Cartes du Ciel (Sky Charts).
The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on September 25, 2024. The night ends on the left with sunrise on the 26th. Comet Tsuchinshan-ATLAS is moving northeastward in the sky. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.
This is a low precision ephemeris of the Sun Moon and naked eye planet positions for today and tomorrow, September 25 and 26, 2024. Some of the columns are self-explanatory, others not. The transit column is the time that the body crosses the meridian and is due south. Elong, for elongation, is the angle between the Sun and that body. RA is right ascension, which is the object’s east-west position on the celestial sphere in hours and minutes. Dec is declination which is the north-south position of the object on the celestial sphere in degrees and minutes. R is the distance of that object from the Sun in astronomical units. An astronomical unit is about 93 million miles or 150 million kilometers. And Delta is the distance of that object from the Earth, also in astronomical units. I omit the ‘m’ in am and pm for compactness. The data was generated using my LookingUp for DOS app and displayed as a table by my Ephemeris Helper app.
Categories: Ephemeris Program, Naked-eye planets, Observing, Planets Tags: , , , , ,

Ephemeris: 09/24/2024 – Pegasus is rising on autumn evenings

September 24, 2024 Comments off

This is Ephemeris for Tuesday, September 24th. Today the Sun will be up for 12 hours and 2 minutes, setting at 7:35, and it will rise tomorrow at 7:34. The Moon, at last quarter today, will rise at 11:47 this evening.

While we’ve been watching the stars and constellations of summer and the Milky Way, the constellations of autumn have been sneaking up on us from the east. About halfway up the sky in the east at 9 PM is one of the greatest constellations of autumn, Pegasus the flying horse. Her body or at least the front part of it is a large square of stars called the Great Square of Pegasus. It is an almost perfect rectangle. However, as she’s rising, it’s standing on one corner. From the upper star are her front legs, from the rightmost star her neck and head extend in the stars. And from the left star of the square are what might look like her hind legs but aren’t. Only half of her body is in the stars. It’s another constellation, Andromeda, which we’ll talk about later.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.

Addendum

Pegasus-Andromeda finder
Pegasus & Andromeda animated finder chart for about 9 p.m. in the second half of September. Created using Stellarium and GIMP.
Categories: Constellations, Ephemeris Program, Observing Tags: , ,

Ephemeris: 09/23/2024 – Scanning the Milky Way with binoculars

September 23, 2024 Comments off

This is Ephemeris for Monday, September 23rd. Today the Sun will be up for 12 hours and 5 minutes, setting at 7:37, and it will rise tomorrow at 7:33. The Moon, 1 day before last quarter, will rise at 10:50 this evening.

Now that the Moon has fled the early evening skies the Milky Way is showing up again, if you’re at a dark site. I’ve always said that August and September are the best times to view what I call the summer Milky Way, even now that it’s not technically summer anymore. The Teapot asterism in the constellation of Sagittarius is low in the south-southeast, pouring its tea on the horizon. It is in that direction we are looking towards the center of our Milky Way Galaxy. The Summer Triangle is high in the South with Vega and Deneb, two of its stars near the zenith. All the Milky Way is an invitation to scan it with the pair of binoculars or a very low power telescope. One doesn’t need a chart. Just wander through the Milky Way to find many star clusters, groups of stars and nebulae.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.

Addendum (Some binocular wonders)

The Coathanger

Coathanger finder animation
How to find the Coathanger. Look for the Summer Triangle. On the line from Altair to Vega the Coathanger can be found. Star imaged by Bob Moler.
Binocular view of the Coathanger
Binocular view of the Coathanger. From the original resolution of the above photograph. Most telescope finders present an inverted image, so the Coathanger appears upright.

The North American Nebula

Deneb & North American Nebula
One of my old photographs of Deneb and the North American Nebula digitized from a slide. It can also be barely seen in the top Coathanger finder image just to the left of Deneb.
North American and Pelican Nebulae
The North American (center left) and Pelican (right) nebulae is seen here in an astrophotograph by Grand Traverse Astronomical Society member Dan Dall’Olmo. The red color is due to the element hydrogen. Our eyes can’t perceive red very well with our night vision. However, hydrogen also emits in the green, which along with doubly ionized oxygen also emitting green light, makes it bright enough to be discerned visually. Click or tap on the image to enlarge it.

Categories: Binoculars, Ephemeris Program, Nebulae, Observing, Star Clusters Tags: ,

Ephemeris: 09/20/2024 – Fall will fall upon us Sunday

September 20, 2024 Comments off

This is Ephemeris for Friday, September 20th. Today the Sun will be up for 12 hours and 14 minutes, setting at 7:42, and it will rise tomorrow at 7:29. The Moon, 3 days past full, will rise at 8:55 this evening.

The season of fall is about to, well, fall upon us and in a few weeks so will the leaves. At 8:44 Sunday morning (12:44 UT Sunday) the Sun will cross the celestial equator heading southward. The celestial equator is an imaginary line in the sky above the earth’s equator. At that point, the Sun will theoretically set at the North Pole and rise at the South Pole. The day is called the autumnal equinox and the daylight hours of Sunday will be 12 hours and 8 minutes instead of 12 hours exactly. That’s due to our atmosphere and our definition of sunrise and sunset. The reason for the cooler weather we are heading into is that the length of daylight is shortening, and the Sun rides lower in the sky, spreading its heat over a larger area, thus diluting its intensity.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.

Addendum

Sun's path on the equinox for TC-Interlochen
The Sun’s path through the sky on an equinox day from the Traverse City/Interlochen area in Michigan. The Sun is plotted every 15 minutes. This is a stereographic projection which compresses the image near the zenith and enlarges the image towards the horizon. Created using my LookingUp program.
Sunrise on the autumnal equinox
That is not a pumpkin on the head of the motorcyclist. That’s the Sun rising as I’m traveling east on South Airport Road south of Traverse City, MI on the autumnal equinox. This is the east-west section of the road. The Sun is rising over the hills some 6 miles to the east. When the Sun is on the celestial equator, it rises due east and sets due west. Credit: Bob Moler.

Categories: Ephemeris Program, Equinox, Seasons Tags:

Ephemeris: 09/19/2024 – The Chinese Mid-Autumn Festival

September 19, 2024 Comments off

This is Ephemeris for Thursday, September 19th. Today the Sun will be up for 12 hours and 17 minutes, setting at 7:44, and it will rise tomorrow at 7:28. The Moon, 2 days past full, will rise at 8:30 this evening.

Our Harvest Moon also marks the Chinese Mid-Autumn Festival. I’ve been too busy with the lunar eclipse to cover it on Tuesday. It is to honor the Moon and the story of Chang’e a mortal woman who took an elixir and flew off to the Moon and became a goddess. Another story revolves around the Jade Rabbit pounding Medicine. I sometimes talk about the figure of a rabbit seen on the face of the Moon. He is a companion to Chang’e, and has a mortar and pestle on the Moon with him. He pounds out the medicine that makes the inhabitants of the sky immortal. The Chinese lunar probes are named Chang’e. Chang’e 3 landed on the Moon in 2013 and sent out a lunar rover named Yutu, the Jade Rabbit. They have made other landings since.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.

Addendum

Jade Rabbit on the Moon
Jade Rabbit and Mortar on the Moon. Credit: Zeimusu, Creative Commons.
Categories: Celebration, Chinese, The Moon Tags: , , ,

Ephemeris: 09/18/2024 – Checking out where the naked-eye planets are this week

September 18, 2024 Comments off

This is Ephemeris for Wednesday, September 18th. Today the Sun will be up for 12 hours and 20 minutes, setting at 7:46, and it will rise tomorrow at 7:27. The Moon, 1 day past full, will rise at 8:08 this evening.

Let’s take our weekly look at the whereabouts of the naked-eye planets. Venus might be spotted in the West southwest only 5° above the horizon at 8:15 or 30 minutes after sunset. It will set at 8:48. Saturn will be low in the east-southeast at that time, with the Moon just rising in the east. Saturn may look disappointing in telescopes this year since its rings are nearly edge on and appearing as a line through the planet like it’s stapled onto the sky. Jupiter and Mars will be up in the morning sky, with Jupiter rising before midnight now and by 6:30 AM tomorrow, Jupiter will be the brightest starlike object in the sky among the winter stars in the south-southeast. Mars will be left and below Jupiter.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.

Addendum

Venus in evening twilight, approximately 30 minutes after sunset
Venus in evening twilight, approximately 30 minutes after sunset. For the Grand Traverse area of Michigan that would be about 8:15 PM, where Venus is very close to the horizon, due to the low angle of the ecliptic, even though Venus is about 27 degrees east of the sun, it is only 10 degrees above the horizon at sunset. It would be higher from the south of us, below 45° N latitude, and lower for those north of us. Created using Stellarium.
At the same time we see Venus setting in the West around 8:15 PM we see the Moon rise in the east, and Saturn close by in the east-southeast
At the same time we see Venus setting in the West around 8:15 PM we see the Moon rise in the east, and Saturn close by in the east-southeast. Saturn may not be quite as visible as this, but it will be shortly. Created using Stellarium.
The Moon one day past the full Harvest Moon
The Moon one day past the full Harvest Moon and shadows are beginning to creep onto the west, or right side of it. Created using Stellarium, LibreOffice Draw, and GIMP.
The morning planets Jupiter and Mars are seen among the winter stars
The morning planets Jupiter and Mars are seen among the winter stars at 6:30 AM or about an hour before sunrise in the South southeast. Created using stellarium.
Telescopic Venus, Saturn and Jupite
Telescopic Venus, Saturn and Jupiter (north up) as they would be seen in a small telescope with the same magnification. Venus and Saturn are from the evening of the 18th 2024, Jupiter is for 6:30 am on the 19th. Apparent diameters: Venus 11.7″, 87.6% illuminated; Saturn 19.2″, its rings 44.6″, 4.2 degrees from edge on (opening up a bit); Jupiter 40.7″; Mars, too small to be represented here, is 7.1″. The ” means seconds of arc, or 1/3600th of a degree. Click or tap on the image to enlarge it. Created using Cartes du Ciel (Sky Charts).
The naked-eye planets and the Moon at sunset and sunrise on a single night
The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on September 18, 2024. The night ends on the left with sunrise on the 19th. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.
Low precision ephemeris
This is a low precision ephemeris of the Sun Moon and naked eye planet positions for today and tomorrow, September 18 and 19, 2024. Some of the columns are self-explanatory, others not. The transit column is the time that the body crosses the meridian and is due south. Elong, for elongation, is the angle between the Sun and that body. RA is right ascension, which is the object’s east-west position on the celestial sphere in hours and minutes. Dec is declination which is the north-south position of the object on the celestial sphere in degrees and minutes. R is the distance of that object from the Sun in astronomical units. An astronomical unit is about 93 million miles or 150 million kilometers. And Delta is the distance of that object from the Earth, also in astronomical units. I omit the ‘m’ in am and pm for compactness. The data was generated using my LookingUp for DOS app and displayed as a table by my Ephemeris Helper app.
Categories: Ephemeris Program, Naked-eye planets, Observing, Planets Tags: , , , , ,

Ephemeris: 09/17/2024 – Super Harvest Moon Eclipse tonight

September 17, 2024 Comments off

Note: the eclipse isn’t that super, however tonight’s full moon is a supermoon, and the Harvest Moon to boot. On with the program.

This is Ephemeris for Tuesday, September 17th. Today the Sun will be up for 12 hours and 23 minutes, setting at 7:48, and it will rise tomorrow at 7:25. The Moon, at full today, will rise at 7:47 this evening.

Tonight’s full Harvest Moon* is also a supermoon and on top of that it will be partially eclipsed in Earth’s shadow. The Moon will just clip the bottom or south part of the Earth’s inner shadow called the umbra between 10:13 PM and 11:15 PM. Only 8% of the Moon’s diameter will be covered by the umbra at maximum eclipse at 10:44 PM. However, the Moon will spend a fair amount of time in the Earth’s penumbra, the outer part of the shadow, where the Sun is only partially blocked. So the moon will appear dimmer than normal at its upper parts from about 9:45 to 11:45 PM or so. Viewing the moon through a pair of sunglasses will enhance the effects of the dimming of the penumbra, cutting down the Moon’s glare.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.

* The Harvest Moon is the full moon nearest the date of the autumnal equinox which this year is on the 22nd of September. What makes the Harvest Moon special is the Harvest Moon Effect. Check it out this previous post where I explained more about it: Here

Addendum

A preview of the Moon in five stages before during and after the eclipse
Here we have a preview of the Moon in five stages before during and after the eclipse. In time we’re moving from right to left just as the Moon moves against the background of the sky and the Earth’s shadow. Of course during all this period of time the Earth’s rotation is moving the sky in the opposite direction much faster. Be that as it may, before the Moon enters the Earth’s penumbra it is evenly eliminated by the Sun. At 10:18 PM the Moon has been immersed 5 minutes into the umbra so it’s taking a little bite out of its upper left part. The effect of the Moon being deeply immersed in the penumbra is also visible. Mid eclipse is at 10:44 PM. At 11:10 PM the Moon is 5 minutes before leaving the umbra. By 12:48 AM the Moon has cleared the penumbra and is again fully illuminated. Click or tap on the image to enlarge it. The Moon images were created using Stellarium, assembled using GIMP and annotated using LibreOffice Draw.
Categories: Astronomical Event, Ephemeris Program, Observing Tags: , , ,