08/12/2022 – Ephemeris – The Perseid meteor shower reached its peak tonight with a bright moon

This is Ephemeris for Friday, August 12th. Today the Sun will be up for 14 hours and 11 minutes, setting at 8:53, and it will rise tomorrow at 6:42. The Moon, 1 day past full, will rise at 9:48 this evening.

The Perseid meteor shower will reach its peak tonight as the nearly full Moon rises. Only the brightest of these meteors will be visible in the bright moonlit sky. Next year the Moon will be less bright and will only interfere in the early morning hours. Comet Swift-Tuttle is responsible for shedding the tiny bits of rock that end up orbiting the Sun near its path. The Earth plows through these particles every year at this time, giving us a great sky show, which at peak on a dark morning provide 60 or more of these so-called shooting stars per hour. The members of the Perseids will all seem to come from the northeastern sky, from the top of the constellation of Perseus the hero. The star figure to me instead looks like the cartoon roadrunner running up the sky.

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

Perseid fireballs in one of NASA’s all sky cameras during the morning hours of August 13, 2017. This is a long time exposure. The bright swath in the image is the Moon that morning. Since it is a time exposure, the radiant is also moving with the earth’s rotation, so the meteors only seem to come from the northeastern sky. North is at the top, and East is to the left. The Moon that morning was 1 day before last quarter, so tonight’s Moon will be even brighter. Credit NASA.

Screen capture of an interactive animation of the orbits of the Perseid meteoroids and the inner planets. The planets move counterclockwise, while the meteoroids move clockwise and cross the Earth’s orbital plane at a high angle. Image taken from the International Meteor Organization, imo.net. Interactive animation by MeteorShowers.org.

07/25/2022 – Ephemeris – Getting an early look at the Perseid Meteor Shower

This is Ephemeris for Monday, July 25th. Today the Sun will be up for 14 hours and 55 minutes, setting at 9:16, and it will rise tomorrow at 6:22. The Moon, 3 days before new, will rise at 3:57 tomorrow morning.

The annual Perseid meteor shower, which will reach its peak on the evening of August 12th has the full moon to contend with. So the best time to spot these meteors is before the peak. Members of this meteor shower can be spotted from July 17th to August 24th, but in much reduced numbers. They are best seen after midnight, however since the point in the sky they seem to come from, the radiant, is always above the horizon, they can be spotted any time at night. They will seem to come from the northeastern part of the sky, and below the letter W shaped constellation of Cassiopeia. The Southern Delta Aquariid meteors coming from the southeast after 11 pm will predominate. Its radiant, the point from which the meteors will seem to come from, will be near the Moon. The Southern Delta Aquariids will reach their peak on the 30th of this month, with dark skies. The Southern Delta Aquariid radiant will rise about 11 pm now, and it will be possible to spot one of its meteors until the Moon rises. The hourly rates of the Perseids will increase each night until the Moon starts to interfere with the shower in early August.

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

Finder chart for Perseid Radiant for August 25, 11pm. The radiant point will move slowly to the left for the duration of the meteor shower over the next month. By August 12th, the shower’s peak, the radiant will be just left of the top star of Perseus. Created using Stellarium.

08/12/2021 – Ephemeris – It’s not too late to see the Perseids

This is Ephemeris for Thursday, August 12th. Today the Sun will be up for 14 hours and 10 minutes, setting at 8:52, and it will rise tomorrow at 6:43. The Moon, 3 days before first quarter, will set at 11:13 this evening.

It’s not too late to see the Perseid meteors. The projected peak of the shower is expected to be between 3 and 6 this afternoon. So the meteor shower should still be quite active. It has been my experience that the numbers of meteors decline more rapidly than they increase before the peak. NASA can determine their orbits using all sky cameras placed at different locations to get their paths by triangulation. The cameras have shutters the interrupt the meteor track at a specific interval, which allow them to determine the meteor’s speed and are able to calculate the particle’s orbit of the Sun. An animation of these orbital tracks can be found on the International Meteor Organization website imo.net.

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

I’ve been talking about the Perseid meteor shower all week, so far. Click on the calendar dates to the upper right to review those posts.

A Perseid outburst from 2009. Credit NASA/JPL via Phil Plait’s Bad Astronomy.

Perseid fireballs in one of NASA’s all sky cameras during the morning hours of August 13, 2017. This is a long time exposure. The bright swath in the image is the Moon that morning. Since it is a time exposure, the radiant is also moving with the earth’s rotation, so the meteors only seem to come from the northeastern sky. North is at the top, and East is to the left. Credit NASA.

 

08/11/2021 – Ephemeris – Let’s search for the naked-eye planets for this week, and meteors tonight

This is Bob Moler with Ephemeris for Wednesday, August 11th. Today the Sun will be up for 14 hours and 13 minutes, setting at 8:54, and it will rise tomorrow at 6:42. The Moon will be 3 days past new tonight.

Let’s search for the naked-eye planets for this week. Venus and the Moon will be close together tonight, with Venus below and right of the waxing crescent Moon by 9:30 tonight. Venus will set at 10:18 pm. With the Moon following at 10:50. By 10 pm, Jupiter and Saturn will be seen low in the southeastern sky. The brighter Jupiter will be easy to spot at that hour. Saturn will be dimmer, but a bit higher and to its right. Tonight and especially in the morning hours tomorrow, the Perseid meteors will be at their peak. These bits of Comet Swift-Tuttle, liberated by the comet’s prior passes in through the warmth of the inner solar system, will flash into incandescence as they enter the Earth’s atmosphere at interplanetary speeds.

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

Venus and the 3-day-old Moon ion evening twilight at 9:45 tonight, August 11, 2021. Created using Stellarium.

The Moon as it might appear in binoculars tonight, August 11, 2021, with earth shine on its night side, illuminated by the bright Earth in its sky.
Created using Stellarium.

Jupiter and Saturn in the southeastern sky at 10:30 in the evening tonight, August 11, 2021. Created using Stellarium.

Telescopic view of the bright planets (north up) as they would be seen in a small telescope, with the same magnification, this evening, at 10 pm August 11, 2021. Apparent diameters: Venus, 13.40″; Saturn 18.57″, its rings 43.26″; Jupiter, 49.00″. Jupiter’s moon have a cluster of events in the evening. See below. The ” symbol means seconds of arc (1/3600th of a degree.) Click on the image to enlarge it. Created using Cartes du Ciel (Sky Charts).

                Jupiter's Satellite events
Moon      Event            EDT (pm-11th, am-12th) UT (12th)
Europa    Shadow enters    10:00 pm               02:00
Europa    Transit starts   10:25 pm               02:25
Io        Eclipse starts   10:41 pm               02:41
Europa    Shadow exits     12:51 am               04:51
Ganymede  Occultation ends  1:06 am               05:06
Io        Occultation ends  1:11 am               05:11
Europa    Transit ends      1:12 am               05:12

The above times were determined using Stellarium, and may be off by several minutes.
Shadow events are when a satellite’s shadow is cast onto the face of the planet
Transit events are when the satellite passes in front of the planet
Eclipse events are when a satellite  passes through the planet’s shadow
Occultation events are when the satellite passes behind the planet

Planets and the Moon at sunset and sunrise of a single night, starting with sunset on the right on August 11, 2021. The night ends on the left with sunrise on the 12th. Click on the image to enlarge. Created using my LookingUp program.

Perseid Radiant finder automation for midnight, August 11th. Created using Stellarium and GIMP.

More on the Perseids on Monday and Tuesday’s posts.

 

08/10/2021 – Ephemeris – Tomorrow night, all night, will see the peak of the Perseid Meteor Shower.

This is Bob Moler with Ephemeris for Tuesday, August 10th. Today the Sun will be up for 14 hours and 16 minutes, setting at 8:55, and it will rise tomorrow at 6:40. The Moon, 2 days past new, will set at 10:27 this evening.

Back before astronomers recognized the major meteor shower that occurs at this time of year, the streaks of light in the sky of “falling” or “shooting” stars were called, by Christians, the Tears of Saint Lawrence, who was martyred on this day in the year 258. The bits of comet debris ranging in size from the size of sand grains to that of a pea hit our atmosphere at 38 miles (59 kilometers) per second and quickly vaporize due to friction, causing the streak of light we call meteors. They are called the Perseids since they appear to come from the constellation of Perseus, located in the northeastern sky. They will be best seen tomorrow night and into Thursday morning, with rates of up to one a minute, on average, in the early morning hours.

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

Perseid Radiant finder automation for midnight, August 11th. Created using Stellarium and GIMP.

My best Perseid photo. From the 70s. The stars are trailed because this is a time exposure of perhaps 15 minutes and the camera is on a fixed tripod which rotates with the Earth.

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

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. 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).

07/27/2020 – Ephemeris – Two meteor showers, one near peak, another just starting

This is Ephemeris for Monday, July 27th. Today the Sun will be up for 14 hours and 49 minutes, setting at 9:13, and it will rise tomorrow at 6:25. The Moon, at first quarter today, will set at 1:18 tomorrow morning. | Tonight’s first quarter Moon will hinder the viewing of Comet NEOWISE and the Southern Delta Aquariid meteor shower until after moonset at 1:18 am. The meteor shower radiant will start out low southeastern sky and end up in the south as twilight brightens. It is usually during this meteor shower that the first Perseid meteors show up. The Perseid meteor shower is the most watched meteor shower of the year. It’s great every year except when there’s a bright Moon. This year the Perseids will reach their peak hourly numbers on the morning of August 12th after sunrise, unfortunately. The Moon will interfere after it rises at 12:46 am, which leaves two hours of moonless meteor viewing earlier on the evening of the 11th.

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

Addendum

The Sky Dome at 2 am tomorrow morning July 28, 2020 at 2 am. DAqr is the approximate location of the Southern Delta Aquariid meteor shower and PerR is the approximate location of the Perseid radiant. Created using my LookingUp program.

Comet NEOWISE in the evening for July 14, 2020 to July 31, 2020. The horizon is for July 14th at 11 p.m. Click on the image to enlarge. Created using Cartes du Ciel (Sky Chart).

08/05/2019 – Ephemeris – Previewing the Perseid meteor shower

Ephemeris for Monday, August 5th. Today the Sun will be up for 14 hours and 30 minutes, setting at 9:03, and it will rise tomorrow at 6:34. The Moon, 2 days before first quarter, will set at 12:01 tomorrow morning.

After the Moon sets in the morning hours for the next week and a half the numbers of meteors visible will increase each night. These are members of the Perseid meteor shower of August. The peak this year is expected to be during the morning of the 13th. However by then the Moon will be nearly full. These meteors are the result of debris left along the orbit of Comet 109P/Swift-Tuttle shed by innumerable visits to the inner solar system. Every year at this time the Earth passes through this trail of debris which intersects its orbit giving rise to the meteor shower. We call them the Perseids, because they appear to come from the direction of the constellation Perseus the hero, which is first seen in the early evening low in the northeast.

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

Addendum

The Perseid radiant is located off the highest star in Perseus as it ascends the sky at about 10:30 p.m. The Perseid radiant is circumpolar for observers in northern Michigan. Click on the image to enlarge. Created using Stellarium.

The passage of Comet 109P/Swift-Tuttle through the inner solar system November 1, 1992 to January 30, 1993. The meteoroids shed by the comet on its numerous trips close to the Sun lie close to that orbit. Note that its orbit intersects with the Earth’s orbit. That’s where the Earth will be around August 12-13 every year. Created using my LookingUp program.

 

08/10/2018 – Ephemeris – A busy weekend here and in the skies

Ephemeris for Friday, August 10th. The Sun rises at 6:39. It’ll be up for 14 hours and 16 minutes, setting at 8:56. The Moon, 1 day before new, will rise at 6:45 tomorrow morning.

It’s a busy weekend for the Grand Traverse Astronomical Society. Members will be on Front Street in Traverse City tonight for Friday Night Live with views of the Sun and later a look at the planet Saturn and its rings, weather permitting. On Saturday, again weather permitting members will be part of Sleeping Bear Dunes Port Oneida Fair with a Sun ‘n Star Party from 4 to 6 p.m. and from 9 to 11 p.m., though members will still be there in between. The location for that event is the Thoreson Farm on South Thoreson Road off M22, near Port Oneida Road. On tap will be Venus, Jupiter, Saturn, Mars and some of the Perseid meteors on the night before its peak night, plus some of the deep sky wonders of the summer Milky Way.

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

Addendum

Viewing the Sun with a while light filter at Friday Night Live using Ron Uthe’s telescope at Friday Night Live. Credit Bob Moler

After Friday Night Live was over Saturn was visible until about 11 p.m. Credit: Bob Moler.

Star Party at the Sleeping Bear Dunes National Lakeshore, Thoreson Farm August 2013. Credit Eileen Carlisle.

08/09/2018 – Ephemeris – How to observe the Perseid Meteor Shower

Ephemeris for Thursday, August 9th. The Sun rises at 6:38. It’ll be up for 14 hours and 19 minutes, setting at 8:57. The Moon, 2 days before new, will rise at 5:30 tomorrow morning.

Now through most of this month and reaching peak numbers Sunday evening and Monday morning the Perseid meteors will be shooting through our skies. Where to look? Up is the direction. All over the sky. They will seem to come from the northeast on parallel paths, like driving through a snow storm at night, the snowflakes will diverge from right in front of you. The numbers will generally increase as that radiant point rises higher in the sky. A diligent experienced, and undistracted, observer may see up to 100 or more an hour. Casual observers will see much less. The longest meteor streaks will be seen early in the evening when the meteoroids enter the atmosphere at 37 miles (59 km) per second at a very shallow angle, so last a bit longer.  Bring a blanket, dress warmly and enjoy the show!

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

Addendum

The sky dome for the night of the Perseid shower maximum at 1 hour intervals from 10:30 p.m. to 4:30 a.m. Click on image to enlarge. Created using my LookingUp program and GIMP.

For locations other than the Traverse City/Interlochen area the 10:30 step is approximately an hour and a half after sunset.

My best Perseid photo. From the 70’s.

Here are some meteors seen in the 2007 Perseid meteor shower taken by Scott Anttila. The image is centered on Cassiopeia. The radiant is low and a bit left of center in the image. The Double Cluster is seen below center and the Great Andromeda Galaxy is seen on the right just above center.

The logic of taking meteor photos pointing near the radiant is the he meteors appear to travel slower there because they are coming mostly toward the camera and have a better chance of being picked up.  My photograph was unguided, so the stars trailed.  Scott’s was guided.