This post discusses the expected meteor activity and lunar conditions for the upcoming week. It is focused on North American latitudes but may be used in all locations. Sky charts displaying current radiant positions are provided for early evening hours, mid-night, and the hour prior to dawn. European readers may wish to use the charts in the same article at www.imo.net for better accuracy.
Meteor Activity Outlooks for observers in the southern hemisphere are available upon request at: lunro.imo.usa@cox.net
Clear Skies!
Robert Lunsford
ALPO Meteors Section Coordinator
Halley’s Comet particles
Every year between mid-April and the end of May, the Earth encounters the outbound debris from Halley’s Comet. Outbound describes the motion of each particle as it moves away from the sun and passes near the Earth on its way back to the outer realms of the solar system. Halley’s comet passes through the inner solar system every 76 years and each one of those passages creates a new stream of particles. These streams each have a slightly different orbit due to planetary perturbations. When a planet passes close to one of these streams the particles get moved ever so slightly out of their previous orbit. Since many of these particles have been orbiting for over two thousand years they can now encounter the Earth anytime during a six week span from mid-April to the last of May. The Earth encounters the mean position of these many orbits on May 5th or 6th of each year. That is when the particle concentration is greatest and we witness the maximum activity of the eta Aquariid meteor shower. It should be noted that the particles we see as meteors separated from the comet many hundreds of years ago as the current orbit of the comet does not cross the orbit of the Earth.
Meteor showers on Earth are caused by streams of meteoroids hitting our atmosphere. These meteoroids are sand and pebble-sized bits of rock that were once released from their parent comet. The above visualization shows the meteoroid streams of the Halley’s comet orbiting the Sun.
Eta Aquariids in 2022 will peak on May 5 and 6
Since the eta Aquariids are the outbound particles of the Halley’s comet, we see them radiate from a point west of the sun. This positioning only allows these meteors to be seen on the morning side of Earth. To make matters more restrictive, the source of these meteors, located in the constellation of Aquarius, does not clear the horizon until 2:00 to 3:00am local daylight saving time as seen from the lower northern latitudes. Viewing circumstances are even worse for mid and upper northern latitudes as the rising of the radiant and the start of morning twilight become closer together as one moves northward. Viewing circumstances for the eta Aquariids are best for those located in the southern tropics where the source of these meteors rises highest in a dark sky. Most observers in the northern hemisphere have only a one to two hour window prior to dawn to view these meteors.
In 2021, the moon was located near the radiant during the shower’s maximum and the display was slightly muted. This year, conditions are better at maximum as the moon sets long before the eta Aquariid radiant rises. To best see this activity one should view during the last two hours prior to dawn. For most of us located in mid-northern latitudes, this will roughly be 3-5am local daylight saving time. This will allow you to see the most possible activity which should be near 10-15 per hour from mid-northern latitudes and up to 30 per hour for southern tropical locations. While the peak is predicted to occur on May 5 and 6, the week centered on these dates will also provide rates near 10 per hour. By May 10, hourly rates will fall below 10 per hour and will slowly fall as the month progresses.
The above chart displays the eastern half of the sky near 4:00am local daylight saving time on the morning of May 6th as seen from mid-northern latitudes. Morning twilight will have just begun for higher northern latitudes, but those further south can view for another hour or so before the sky becomes too light. The “golden star” represents the area of the sky where eta Aquariid meteors emanate from. The lines represent examples of eta Aquariid meteors. They can be seen in all areas of the sky, but will all trace back to this area. It is suggested that you view toward the northeast to southeast quadrant of the sky with the center of your field of view about half-way up. This way the radiant area will be within your field of view, allowing you to easily determine which meteors are Aquariids an which are not.
Hourly observations are accepted by the International Meteor Organization. Simply register (it’s free) or log in at www.imo.net and enter your data on their visual meteor observing form. We ask for sessions of at least an hour long due to the fact that meteor activity is notoriously clumpy. This means you may see no activity for 10-15 minutes and then a many meteors within a few minutes. If you limit you watch to less than an hour, you may witness one of those short lulls and be dissatisfied with your results.
This is the beginning of what could be an exciting month for meteor observers. If your skies are clear I encourage you to take advantage of the chance to see bits of Halley’s comet encountering the Earth!
April 22, 2022
This post discusses the expected meteor activity and lunar conditions for the upcoming week. It is focused on North American latitudes but may be used in all locations. Sky charts displaying current radiant positions are provided for early evening hours, mid-night, and the hour prior to dawn. European readers may wish to use the charts in the same article at www.imo.net for better accuracy.
Meteor Activity Outlooks for observers in the southern hemisphere are available upon request at: lunro.imo.usa@cox.net
Clear Skies!
Robert Lunsford
ALPO Meteors Section Coordinator
During the second half of April every year, the Earth passes through debris shed by comet 1861 G1 Thatcher, which last passed through the inner solar system in 1861. Don’t expect this comet to return anytime soon as its orbit has been calculated to be near 415 years!
Two years after the 1861 passage of the comet through the inner solar system, an impressive display of Lyrid meteors were observed. This helped link the relationship between this comet and the Lyrids. It was also noted that another impressive display of the Lyrids had occurred in 1803, 60 years prior. Despite these facts, no one was looking for enhanced rates from the Lyrids in the early 1920’s. Yet in 1922, another strong Lyrid display occurred. You would have thought by now that astronomers would be eagerly anticipating the early 1980’s for more enhanced Lyrid activity. But unfortunately, meteor studies tend to fall off the grid, even with the tremendous Leonid display of 1966. So again in 1982, meteor watchers were caught off guard when another Lyrid outburst occurred. I can only hope that during the early 2040’s that we will be on guard for another grand meteor display from the Lyrids!
So, what is one to expect from Lyrid displays between these outbursts? Probably not much. There have been unverified reports of lesser outbursts which have led us to think that there may be debris from this comet trapped in shorter orbits with a 12- or 20-year return period. Therefore, we suggest that potential observers observe the Lyrids at every opportunity just in case something unusual occurs.
The normal Lyrid display, seen under moonless conditions, usually offers a peak of around 10 meteors per hour in addition to the normal random meteor rate of about 5 per hour. The peak is sharp, only a few hours long, so don’t be surprised if you see far less than 10 Lyrids per hour. Yet when compared to the normal low activity seen during the late winter and early spring nights, the nights around April 22nd offer a nice bit of entertainment to help one stay awake.
On April 22nd, the Lyrid radiant actually lies among the stars of eastern Hercules. There are no bright stars to pinpoint the radiant, yet the brilliant zero magnitude star known as Vega (alpha Lyrae) lies only 8 degrees to the northeast. As seen from mid-northern latitudes, this part of the sky rises around 9pm local daylight-saving time (LDST). It is not advisable to try viewing at that time as a great majority of the activity will be blocked by the horizon. It would be much better to wait until later in the night when the radiant has risen higher in the sky. The best Lyrid activity usually occurs during the last hour before the start of morning twilight. This is when the radiant lies highest above the horizon in a dark sky. This normally occurs between 4-5am LDST this time of year. Unfortunately this year a bright waning gibbous moon will rise between 1-2am LDST, obscuring all but the brightest meteors. This year it may be better to try to see these meteors between 11pm and 2am, while the sky is still dark. If your sky is clear and transparent you can also view between 2am and dawn as long as you keep the moon out of your field of view. The higher radiant elevation at that time will somewhat offset the brightening of the sky by moonlight.
Like all meteor showers, Lyrid meteors can be seen in all parts of the sky. If you face away from the radiant it is difficult to tell if the meteors you see belong to the Lyrid shower. Therefore, it is suggested that you face in the general direction of the Lyrid radiant, which will lie high in the northeastern sky as seen from mid-northern latitudes. That way you can easily trace the path of each meteor back to the radiant to see if it was a Lyrid or not. You don’t need to stare directly at the radiant as Lyrid meteors seen there will be short and often missed. Meteors seen further from their radiant are longer and easier to see.
Compared to other meteor showers, the Lyrids tend to produce bright meteors and an occasional fireball. This makes them easier to see and photograph. While the average Lyrid is fairly bright, this shower is not photogenic unless you take time exposures during maximum activity. The brightest meteors will show up well in prints but most of the captured meteors will only appear as faint streaks. Attaching your camera to a driven mount is highly recommended as this will keep the stars as pinpoints and the meteors as streaks.
Should the morning of maximum activity be cloudy, the next night will still be worth viewing as the maximum is predicted to occur during the daylight hours of April 22nd. By the morning of the 24th, rates will fall to only 2-3 per hour and will continue to fall with each successive night until activity gradually disappears by the end of the month.
To provide a scientific useful observing session one needs to carefully note the starting and ending time of your session and the time each meteor appears. The type of meteor needs to be recorded as well as its magnitude. Other parameters that can be recorded are colors, velocity (degrees per second or verbal description) and whether the meteor left a persistent train. Fireballs should be noted and a separate online form filled out after the session here.
Serious observers should watch for at least an hour as numerous peaks and valleys of activity will occur. If you only view for a short time it may coincide with a lull of activity. Watching for at least an hour guarantees you will get to see the best this display has to offer. The serious observer is also encouraged to fill out a visual observing form on the website of the International Meteor Organization. You must register to use the form, but this is free. The registration site is located here: Good luck with your observing attempts!
April 15, 2022
This post discusses the expected meteor activity and lunar conditions for the upcoming week. It is focused on North American latitudes but may be used in all locations. Sky charts displaying current radiant positions are provided for early evening hours, mid-night, and the hour prior to dawn. European readers may wish to use the charts in the same article at www.imo.net for better accuracy.
Meteor Activity Outlooks for observers in the southern hemisphere are available upon request at: lunro.imo.usa@cox.net
Clear Skies!
Robert Lunsford
ALPO Meteors Section Coordinator
April 8, 2022
This post discusses the expected meteor activity and lunar conditions for the upcoming week. It is focused on North American latitudes but may be used in all locations. Sky charts displaying current radiant positions are provided for early evening hours, mid-night, and the hour prior to dawn. European readers may wish to use the charts in the same article at www.imo.net for better accuracy.
Meteor Activity Outlooks for observers in the southern hemisphere are available upon request at: lunro.imo.usa@cox.net
Clear Skies!
Robert Lunsford
ALPO Meteors Section Coordinator
April 1, 2022
This post discusses the expected meteor activity and lunar conditions for the upcoming week. It is focused on North American latitudes but may be used in all locations. Sky charts displaying current radiant positions are provided for early evening hours, mid-night, and the hour prior to dawn. European readers may wish to use the charts in the same article at www.imo.net for better accuracy.
