Meteor Section        

 
 
Quadrantids
Quadrantids radiant seen near 5am EST on Jan 4 from the US East Coast

Ever wonder why the moon is mentioned so often in reports on this website? The reason is simple; the visibility of a meteor shower depends greatly on the phase of the moon. An observer will see many more meteors in a moonless sky than one with a full moon. Contrary to popular belief, most of the meteors we see in the sky are on the faint side, equivalent to 3rd or 4th magnitude stars. These meteors are easily obscured by moonlight, especially if the sky is hazy. While successful meteor watching sessions can be carried out with a moon in the sky, you will see more activity on moonless nights or when the phase is thin.

As for the Quadrantid meteor shower of 2016, this shower is predicted to peak on Monday morning January 4th over North America and the western Atlantic rigion. On that morning the 30% illuminated moon will rise at approximately 0200 (2am) local standard time for most observers in the northern hemisphere. This timing will vary according to your exact location. 30% does not sound like much but if your face toward the moon during your observations it will be a nuisance and will cause you to miss some fainter meteors. If the moon is above the horizon during your Quadrantid observations I would advise you to face toward the northern half of the sky with the moon at your back.

This shower has a very sharp peak that is predicted to occur near 4am AST, 3am EST, 2am CST, 1am MST, and midnight PST. The moon will be above the horizon for the eastern half of North America. While the western half may have darker skies, the radiant (the area of the sky where Quadrantid meteors come from) will be located lower in the sky. This means that there will be less activity. So despite the moonlight, the east half of North America will be favored for this display if it occurs at the predicted time.

As you see from the chart above, the Quadrantid radiant is located in a blank part of the sky. The nearest recognizable star pattern is the Big Dipper, which is part of the constellation Ursa Major. Quadrantid meteors can be seen in all parts of the sky but they will all trace back to this radiant area. These meteors possess medium speeds and the brighter members can produce persistent trains which linger after the meteor itself has vanished. Not all meteors you see on Monday morning will be Quadrantids. There are minor showers and random meteors also active which should add at least 10 meteors per hour to your totals.

A good viewing strategy would be to watch for at least an hour centered on the times above. This prediction is based on returns of this shower for the last 20 years but it may be off by an hour or two. If the maximum occurs earlier then activity will be far less for everyone in North America. If it is late then the entire continent has the opportunity to see an excellent display. This shower has the potential to produce in excess of 100 meteors per hour if viewed from rural locations. Unfortunately these rates are rare and we usually end up seeing a peak of around 25 Quadrantids per hour. If you view from the eastern half of North American and your rates are low at the predicted time then try to stay out longer as the activity may still be on the increase. So if your skies are clear on Monday morning then bundle up and and try your luck at seeing some celestial fireworks!

quad_pic
Long exposure photo with several Quadrantid meteors from Florida Keys – Jan. 2, 2012 © Jeff Berkes.

I should also mention that there is another prediction for an earlier peak that is favorable for European observers. So before you head out you may wish to check the internet to see if strong rates were seen over Europe. If the peak occurs over Europe then there will be little activity left for North American observers.

History

When the first report of the Quadrantids came public (around 1825), the radiant appeared in the constellation Quadrans Muralis, located between the constellations Draco and Boötes. In 1922, the International Astronomical Union formed a list of modern constellations and elected not to include Quadrans Muralis. As the name “Quandrantids” remains, some astronomers suggest the meteor shower could new be called the Boötids,since the radiant falls in the constellation Boötes. However, there is already a meteor shower by that name, which occurs in late June in the Northern Hemisphere.

Quadrans Muralis can be seen at the top left of this 1825 star chart from Urania's Mirror.
Quadrans Muralis can be seen at the top left of this 1825 star chart from Urania’s Mirror (1824).

Parent Body

The Quadrantid meteor shower influx is sharply peaked: six hours before and after maximum, these meteors appear at only half of their highest rates. This means that the stream of particles is a narrow one, possibly derived relatively recently from a small comet. The parent body of the Quadrantids was tentatively identified in 2003 by Peter Jenniskens as the minor planet 2003 EH1, which in turn may be related to the comet C/1490 Y1 that was observed by Chinese, Japanese and Korean astronomers some 500 years ago.

 
 
 
fireball
Fireball over the Mojave Desert (Southern California)- © Wally Pacholka – December 14, 2011.

The Geminid meteor shower is the favorite of most meteor observers as it usually provides the strongest display of the year. On the peak night (December 13/14) between the hours of 1:00 and 2:00am local standard time (LST), an observer located in mid-northern latitudes under clear skies has the opportunity to view at least 75 Geminid meteors. If you watch from a rural setting far from city lights then your counts could exceed 100. If watching from urban locations you will be limited to around 50 meteors during this period.

The Geminids are one of the few annual meteor showers that are active all night long. The radiant (the area of the sky where the meteors seem to come from) is located near the bright star Castor (Alpha Geminorum). This star rises in the northeast near 1800 (6pm) LST as seen from mid-northern latitudes. At the time a few Geminid meteors may be seen streaking slowly upward toward the zenith or shooting parallel to the northern or southeastern horizons. These early Geminids are special as the geometry at this time of night only allows them to skim the top of the atmosphere. Therefore these meteors will last longer and will produced longer streaks in the sky compared to Geminids seen later on in the night. These meteors are referred to as “earthgrazers”. The number of meteors seen at this time will be low, but they will be impressive nonetheless.

Geminids radiant
Geminids radiant

As the night progresses the Geminid radiant will rise higher into the sky. The meteors will seem quicker and shorter than those seen at dusk. Their numbers will also increase with each passing hour. The radiant will lie highest above the horizon near 0200 LST. This will be the best time to view activity as the radiant will lie overhead and Geminid meteors will be shooting downward in all directions. This is also the only good time to view the Geminids from the southern hemisphere. As seen from latitude 25S, the radiant will lie 1/3 the way up in the northern sky. Viewers there will only be able to see half the activity compared to mid-northern locations. As the morning progresses the radiant will set into the western sky and rates will fall with each passing hour. As dawn breaks the radiant will lie low in the west.

Your average Geminid meteor is usually as bright as the brighter stars, 2nd or 3rd magnitude. Of course it all depends on the darkness of your sky. Rural observers will be able to see more faint meteors while urban observers are limited to seeing only the brighter ones. Brighter Geminid meteors can produce a color, usually yellow or orange. Fireballs (extremely bright meteors) are common during the Geminids and some of these are intensely green.

The Geminids are also easy to photograph as they are bright and slower moving than most meteors. Meteors will appear as straight streaks on your pictures. Star trails are curved. Any camera that can expose for a minute or longer can capture meteors. The best area to aim a camera is not straight up but toward the darkest direction available with the camera aimed half-way up in the sky.

People often ask where to look in the sky for meteors. The first thing I tell them is to be comfortable and don’t stand and watch. Sit in a comfortable chair aimed toward your darkest direction. Meteors will appear in all areas of the sky but are best seen away from bright lights that affect your vision. Also, don’t look straight up, rather look roughly half-way up in the sky, high enough to avoid hills or trees that may block your view. Meteors will appear in bunches so there will be periods of no activity and times of high activity. This is why we suggest watching for as long as possible. This will assure that you will see both slow and strong activity and not just some short period of inactivity.

stargazers
The Dark Sky Viewing Area offers a night sky experience very similar to what was available more than 100 years ago. (photo © Terence Dickinson)

Not all the meteors you see will be members of the Geminid shower. There are also other weaker minor showers active this time of year in Orion (Anthelions), Monoceros (Monocerotids), Vela (Puppid-Velids), Hydra (Sigma Hydrids), and Leo Minor (December Leonis Minorids). These meteors will appear differently than the Geminids as they possess different velocities and will have different tracks across the sky.

If the night of December 13/14 is cloudy don’t despair. The Geminids are strong for several nights, most notably the weekend of the 12/13. So if Sunday night/Monday morning look to be cloudy then watch earlier. Monday night/Tuesday morning will be good too but weaker than rates seen over the weekend.

The Geminids reappear each year in mid-December. Unfortunately the display in 2016 will occur with a full moon in the sky, severely limiting the number of meteors seen next year. Not until December 2017 will the Geminids appear under favorable conditions again. So don’t waste this opportunity to see an impressive display of natural fireworks!

 
 

taurids2

Taurids radiants

Every October and November the two branches of the Taurid meteor shower become active. The Taurids are not known for their high numbers, rather they are known more for the fireballs they produce. Occasionally there are more Taurid fireballs than normal. 2015 may be such a year. These increased numbers of fireballs are due to the fact that the Earth encounters larger than normal particles shed by comet 2P/Encke, the parent comet of the the Taurids. These fireballs are thought to be active between October 29 and November 10. Luckily, this at time of year the area of which these meteors appear to come from lies above the horizon all night long. During the evening hours Taurid meteors will shoot upwards from the eastern sky. Near midnight they sill shoot from an area high in the southern sky (as seen from mid-northern latitudes). In the late morning hours they will shoot upwards from the western sky. Unlike most meteors, the Taurids are not fast. The fireball class meteors are usually vividly colored and may fragment before they completely disintegrate. Not every meteor or fireball will be a Taurid as there are other minor showers active plus random activity.

We encourage you to report any fireballs you may witness. If you happen to see one of these bright meteors, we invite you to fill out a fireball report at: fireball report.

 
 

Examples of Perseid meteors as seen at 4am local daylight time while facing northeast.

Examples of Perseid meteors as seen at 4am local daylight time while facing northeast from mid-northern latitudes.

Unlike last year when the Perseid maximum was subdued by the intense moonlight from the full moon, the Perseids in 2015 peak under ideal conditions with a new moon occurring on August 15th. Another positive note is that astronomers expect an above average display peaking over American longitudes. Another highlight is the possibility of enhanced rates for several hours centered on 19 Universal Time, which is favorable for Asian longitudes.

The Perseids first begin to encounter the Earth near July 13th, when members of this stream who have been perturbed from the main orbit first begin to appear. Rates remain below 5 per hour throughout July but then increase dramatically beginning the second week of August. Rates reach 10 per hour near August 8th and 20 per hour near the 10th. The morning of the 11th should produce rates near 30 per hour and the 12 near 50. On the night of maximum activity rates could peak anywhere from 80-120 per hour. After maximum rates fall rapidly and are back down to 5 per hour by the 17th.
The key to success in viewing the Perseids is to view from skies as dark as possible. This often means travelling to rural sites but the dramatic increase in activity you will experience is well worth it. Observers in the western portion of North America also have an added advantage of transparent skies. The dry air is more transparent compared to hazy conditions therefore fainter meteors can be seen.

On the night of maximum activity the Perseid radiant is located at 3:12 (140.1) +58. This position lies near a point where the constellations of Perseus, Camelopardalis, and Cassiopeia meet. The closest recognizable star is 4th magnitude Eta Persei, which lies 4 degrees to the southwest. The closest bright star is 2nd magnitude Mirfak (Alpha Persei) which lies 7 degrees south of the Perseid radiant. This area of the sky lies at its lowest point at sunset. Therefore the evening hours will produce little Perseid activity. The Perseid meteors you do see at this time are called “Earthgrazers” as they just skim the atmosphere above you. These meteors are few but they last for several seconds and often streak across a long portion of the sky. As the evening progresses the Perseid radiant rises into the northeastern sky and more activity will begin to appear. By midnight, the radiant will have reached a sufficient altitude to begin serious observations. The highest activity will occur between 3:00-4:00am local daylight saving time when the Perseid radiant lies highest in a dark sky. Perseid meteors will appear in any part of the sky but they will all trace back to the radiant. Not all meteors appearing that night will be Perseids. There are several minor showers also active at that time plus you can count on at least a dozen random meteors appearing each hour.

Meteor showers produce activity in “clumps”. This means that there will be periods when no activity is seen followed by periods of intense activity. This is why we urge observers to view for at least an hour so that a good sampling of activity can be seen. If you stand outside and watch for only 15 minutes, you might be watching during one of the lulls and will be disappointed with what you witness. Watching for longer periods of time ensures that you see both the peaks and valleys of activity. For extended watching it is highly suggested that you lie in a comfortable lawn chair. This will save your neck muscles and will produce a much more enjoyable experience compared to standing up.

A majority of the meteor activity seen above will occur in the lower half of the sky. The reason for this is that when viewing lower in the sky you are looking through a thicker slice of the atmosphere. Viewing straight up presents the thinnest slice of air therefore less meteors. One problem with viewing lower in the sky is that the lower portion of your field of view is wasted on the ground. The best strategy would be to view high enough in the sky so that you cannot see the ground, hills, or trees that would prevent you from seeing meteors. Aiming about half-way up in the sky is the best all around compromise for seeing the most activity.
Perseid meteors appear in all ranges of brightness ranging from barely detectable to blinding fireballs. Unfortunately dim meteors are much more numerous than bright ones. This is why we urge observers to view from dark rural locations away from city lights. The brighter Perseid meteors can also exhibit vivid colors. The colors most mentioned for the Perseids are orange and yellow. These colors are most likely produced by sodium present in the meteoroids. The brighter Perseids can also exhibit a phenomenon known as persistent trains. These appear as smoke trails that remain after the meteor has disappeared. These are not really smoke, but a column of gas that glows after the passage of the meteor. If the train lasts long enough it can be seen twisting and turning in the winds of the upper atmosphere.

While the ALPO Meteors Section urges you to view meteor activity, we also wish for you to share your experience with us. This can range from general descriptions to detailed reports on each meteor witnessed. Send your reports via email to: lunro.imo.usa@cox.net.

We look forward to hearing from you!

 

 

 
 

Examples of Lyrid activity seen on April 23, from 40 N latitude, just before dawn while facing north.

After three months of low rates, April ushers in two major showers and a temporary upswing in meteor activity. The first of these showers is the Lyrids, which are active from April 16 through the 25th. Activity for this shower is low away from the peak night which expected to occur on April 22/23. Peak rates are predicted to occur near 4:30 Universal Time on April 23, which corresponds to 0030 EDT and 2130 PDT (on the 22nd). This timing is better for the eastern portion of North America as the Lyrid radiant will lie higher in the sky. Rates seen from the western half should not be that much lower so all of North America is well placed to view this display. Average ZHR’s are eighteen for this shower so visual rates in excess of ten per hour should be seen from North America on the morning of the 23rd.

On the night of maximum activity the Lyrid radiant is actually located in eastern Hercules, seven degrees southwest of the brilliant star Vega (Alpha Lyrae). This area of the sky lies below the horizon during the early evening hours. It attains a decent elevation between midnight and 0100, depending on your latitude. It is best situated high in a dark sky just before the start of morning twilight. While the Lyrids are not the strongest shower, it is notable that shower members will occasionally reach fireball intensity.

On the night of maximum activity the moon will be at its waxing crescent phase and will have set by the time the radiant reaches a decent altitude. Lunar conditions could not be much better for this display. Observers in the Southern Hemisphere will see very little Lyrid activity as the radiant will be located low in the northern sky. All Lyrid meteors will trace back to the radiant area in eastern Hercules. There will be other showers and random activity visible during this period so not all meteors will be members of the Lyrid shower. Lyrid meteors will appear to travel swiftly through the sky unless they are seen near the radiant or near the horizon. Lyrids seen there will move more slowly as they are moving towards you (if seen near the radiant) or away from you (if seen near the horizon).

The Lyrids are particles from Comet Thatcher (C/1861 G1). This comet has an orbital period of 415 years and the last time it was a perihelion was back in 1861. This shower has produced several notable outbursts. These occurred in the years 1803, 1849, 1850, 1884, 1922, 1945, and 1982. The 1803 event seems to the strongest as rates exceeded 500 Lyrids per hour at maximum. The 1982 event was seen from eastern USA where rates were estimated near 100 per hour at maximum. I witnessed the final portions of this outburst as I drove out to dark sky site. Lyrid meteors were seen shooting upward from the northeastern horizon. Once I arrived at my site the outburst was over and very little activity was seen the remainder of the night. The next possible outburst for this shower is predicted to occur in 2040 and 2041.

 
 

Examples of Ursid meteors seen just before dawn while facing north

The week before Christmas is not one usually devoted to meteor observing. That is unfortunate as an obscure shower known as the Ursids reaches maximum activity during this period. It is not a strong display like the Geminids, but is capable of producing 10-15 shower members per hour under ideal conditions. Luckily this year the moon is not a factor. I have seen the Ursids as high as 25 per hour from the low latitudes of southern California. This shower is expected to reach maximum activity near 1600 Universal Time on December 22nd. This corresponds to 11am EST and 8am PST. Obviously locations further west such as Alaska are more favored to see Ursid activity. There also exists the possibility that another small display of activity may also occur later near 0040 UT on the 23rd. This corresponds to 2200 (7:40 pm) EST and 1900 (4:40 pm) PST on the evening of December 22nd. Locations further east are favored for this activity. Don’t expect much from this secondary maximum as the dust trail is over 600 years old. The Ursid radiant, located near the bright orange star Kochab (Beta Ursae Minoris), is also better situated higher in the morning sky during the morning hours. Rates are weak away from maximum so do not expect to see more than 1-2 per hour on any morning other than December 22nd. It would be wise to face toward the northern half of the sky to view these meteors. While some activity can be seen toward the south, more meteors will be shooting downward and sideways out of the radiant and cannot be seen if facing south. These meteors are slightly slower than the Geminids and have a different look to them compared to other showers. It is also unusual to see such activity from such a northern radiant. This also prevents these meteors from being visible from the southern hemisphere.

If your skies are clear on Monday, you should try viewing some of this activity!

 
 

Geminid Meteors seen at 7pm

Geminid Meteors seen at Midnight

Geminid Meteors seen at 5am


The Geminid meteor shower is now active and will reach maximum activity on Saturday evening/Sunday morning December 13/14. Activity is currently low with less than 5 meteors per hour appearing from this source. Rates are usually twice this number but the nearly full moon obscures all but the brightest meteors. Activity will increase each night until maximum activity is reached on the 13/14. After maximum, rates will fall swiftly and Geminid meteors will soon disappear.

On the night of December 13/14, Geminid meteors will appear as soon as becomes dark. Activity will be low but the meteors you see will be long and long-lasting. They will shoot from the northeastern horizon in all directions. Most of them will hug the north or southeastern horizon. Occasionally you will see one shooting straight up and these will be a real treat.

As the night progresses the Geminid meteors will become shorter and will move in all directions, including downward toward the eastern horizon. Activity will also increase as the Geminid radiant (the area of the sky Geminid meteors appear to shoot from) climbs higher into the eastern sky. Near 10pm local standard time (LST), the Geminid radiant will lie approximately half-way up in the eastern sky. At this time viewers from the city can expect to see 10-20 Geminids per hour. If you live in the suburbs then hourly rates should be 20-30 Geminids per hour. If you live in rural areas then hourly rates should be 30-40 Geminids per hour. The reason for this difference is that most of the Geminid meteors are faint. Faint meteors, just like faint stars, are obscured by city lights. The darker your environment, the more meteors you will see.

Geminid activity will continue to increase until around midnight, when the half-illuminated moon rises in the east. Rates near 60 Geminid meteors should be seen between midnight and 2am from rural locations. After that, the Geminid radiant begins to set in the western sky and the moon gains altitude in the east. Geminid rates will then begin to fall due to the increased intensity of the moonlight and the declining horizon distance. Geminid meteors, like all shower meteors, will appear in “clumps”. One may see nothing for 5 minutes and then see 5 meteors within the next minute. This is why it is important that observers watch for as long as possible. If you watch for a short time you may be watching during a slump in activity and will be disappointed.

Not all meteors seen this time of year are Geminids. There are other minor showers active which are both faster and slower than the Geminids. There are also random meteors not associated with any known shower. Roughly 80% of the meteors should be Geminids on December 13/14. This percentage will be less on nights away from maximum. Geminid meteors are of medium speed and their average duration is on the order of a half-second. Brighter Geminids will last longer and Geminid fireballs can last several seconds and exhibit brilliant colors such as orange and green.

I would advise potential viewers not the wait until December 13/14, just in case this night is cloudy. The night of December 11/12 is good and the 12/13th is almost as good as the night of maximum activity. Rates will fall by at least 50% each night after maximum.

Viewers all over the world can see this display of meteors. The only continent where the display is invisible is Antarctica. From there the radiant never rises above the horizon plus daylight lasts 24 hours this time of year. Viewers in the northern hemisphere have a distinct advantage as the nights are longer plus the Geminid radiant rises higher into the sky. Observers in Australia, southern Africa, and South America can best see Geminid activity near 0200 LST or 0300 local daylight saving time, when the radiant lies highest in their northern sky.

 
 

Radiant drift for the Orionids during October and early November (Courtesy the International Meteor Organization)

The next few nights will provide the best Orionid rates of the year. The peak is predicted for the night of October 21/22 but the maximum is not sharp so rates will be near maximum between October 20-24. The exact rates are difficult to predict for this shower. Normally, around 20 shower members can be seen each hour before between midnight and dawn near maximum. 10 years ago rates equaled the Perseids with 75 Orionids appearing each hour. Currently though rates have fallen back down to normal so 20 Orionids each hour is a good guess under suburban skies. If you watch from town only the brighter meteors will be seen so expect to see only 10 Orionids each hour.

The radiant, located on the Orion-Gemini border, rises near 2200 (10pm) local daylight time (LDT). This is not the best time to see them though as some of the activity will occur beyond your line of sight. I would be better to wait until after midnight when this area of the sky has risen higher into the sky. At that time Orionid meteors can be seen shooting in all directions. The radiant is best placed near 0500 LDT when it lies highest above the horizon.

If you watch the same place in the sky all Orionid meteors will have the same characteristics. They will move in parallel paths and will posses the same velocity. These paths will lead back to the radiant in Orion. These characteristics change if you look somewhere else. In general, Orionid meteors will appear to be swift unless you see them near the radiant or near the horizon. Also the paths will appear shorter near the radiant and near the horizon. Therefore it is advisable to have the Orionid radiant near the edge of your field of view so that you will see longer meteors. I would suggest facing eastward or south. Personally, I prefer facing due south so that I may also see members of the south Taurids. There are also other minor radiants active in Gemini, Leo Minor, and Lynx this time of year.

Luckily the moon is approaching new so it will rise just before dawn and will be too thin to interfere with meteor observing. Next year, we will not be so lucky as the bright waxing gibbous moon will be sky most of the night. If your skies are clear this week, get out and watch the show!

Simulated Orionid meteors as seen near 4am local standard time looking north from mid-southern latitudes

Simulated Orionid meteors as seen near 5am local daylight time looking south from mid-northern latitudes

 
 

Examples of Perseid meteors as seen at 4am local daylight time while facing northeast.

Examples of Perseid meteors as seen at 4am local daylight time while facing northeast from mid-northern latitudes.

Conditions for viewing the Perseids are not favorable this year. The full moon will occur on August 10 and the shower peaks only 3 nights later. Yet I would still make an effort to view meteor activity on the nights of August 12 and 13 despite the less than favorable conditions. The Perseids are a strong shower that produces many bright meteors. Despite the bright moonlight an observer should be able to see at least 20 Perseids per hour between midnight and dawn. These are better rates than 95% of all other nights regardless of lunar conditions. Therefore if your skies are clear these nights, make an effort to see this display of celestial fireworks.

As the sun sets in mid-August, the Perseid radiant lies near the northern horizon for viewers located in mid-northern latitudes. This is certainly not the prime time to view Perseid activity but it may be worth your effort to try and catch some Perseid earthgrazers at this time. This year on the night of August 12/13, the 90% illuminated moon will rise at approximately 21:00 or 9pm local daylight time. With the moon low in the east its brilliance will be diminished by the atmosphere. For an hour or so beginning at the time you can see stars in the dimming skies, you have the opportunity to see Perseid meteors that just skim the upper atmosphere. These are much different than Perseid meteors you see later in the night. With less resistance from air molecules these meteors last much longer and create long trails across the sky, often nearly stretching from horizon to horizon. With the low radiant altitude there will not be many of these meteors to see. Any that you do manage to witness will be memorable. Sky & Telescope magazine has a nice article on these meteors in their August 2014 issue.

As the night progresses the Perseid activity will continue to be low as the moon rises higher in the sky, attaining it full brilliance. Not until after midnight will the Perseid radiant gain sufficient altitude to produce pleasing results. Anytime from midnight to dawn will be the best time to see the most activity. I would suggest facing away from the moon and concentrate your view at approximately one-half the way up in the sky. Most of the faint Perseids will be obscured by the bright moonlight. But the bright meteors you do manage to see will often be colorful and the brightest may leave persistent trains that remain in the sky after the meteor itself has disappeared.

If your skies are cloudy on August 12 or 13, the following nights should also produce decent activity with the moon rising slightly later in the evening. Note that the activity will fall approximately 50% each night after maximum so there will not be much left of this shower by the time the moon is out of the way. The two nights prior to maximum are usually good too but the moon will be closer to full and will lie above the horizon the entire night.

Regardless of what night you view, be sure to share your counts and impressions of the display with us!

 

 
 

These are examples of Delta Aquariid activity seen from 40 degrees north latitude while facing south near 0300 local daylight time on July 30.

These are examples of Delta Aquariid activity seen from 20 degrees south latitude while facing south near 0200 local standard time on July 30.

While the Eta Aquariid meteor shower produces the strongest hourly rates seen from the southern hemisphere, it is the Delta Aquariids (SDA) that produces the most total activity during its entire activity period. The Delta Aquariids (aka Southern Delta Aquariids) can be successfully observed from the northern hemisphere but their numbers are reduced due to the lower radiant altitude.

This shower is active for more than a month stretching from July 21st through August 23rd. Some other studies have stretched this period from July 19th through September 3rd, but shower membership of possible SDA’s at these extremities are dubious at best. Peak rates occur on July 29 or 30 with stated ZHR’s of 15-20. I have personally seen hourly rates of 25 from latitude 33 N. and experienced observers have seen hourly rates as high as 40 from equatorial locations. Of course these rates were seen under near perfect skies where faint meteors made up a majority of the activity.

In 2014, the lunar conditions for viewing the Delta Aquariid maximum is extremely favorable. On July 30th (the predicted maximum date for this year) the moon will be a waxing crescent phase. It will set well before midnight allowing the prime morning viewing hours to be free of interfering moonlight. Moonlight will not encroach on viewing this activity until the second week of August, well past the time of maximum activity.

On the date of maximum activity the radiant for the Delta Aquariids lies at 22:42 -16. This position lies in southern Aquarius just a couple of degrees west of the 3rd magnitude star known as Skat (Delta Aquarii). This area of the sky rises in the east around 22:00 (10pm local daylight time). Serious observations should not begin until after midnight, allowing the radiant to gain sufficient altitude. The radiant lies on the meridian near 0300 LDT when it lies highest above the horizon. This is the best time to view the Delta Aquariids. As seen from latitude 40N the radiant will lie 34 degrees above the southern horizon. At this elevation above the horizon this will allow you to see slightly more than one-half of all the SDA activity. The other half of the SDA activity will occur beyond your line of sight. The best location to view the SDA activity is from latitude 16 S., where the radiant will pass directly overhead.

The Delta Aquariid meteors strike the atmosphere at a velocity of 26 miles per second (42km). This is an average velocity therefore few persistent trains are expected from these meteors. Unfortunately the SDA’s are not known for bright meteors and a majority of the activity is on the dim side. This fact, along with the low radiant altitude, makes it a challenge to view these meteors during the normally hazy July mornings.

A suggested strategy to view this activity would be to watch these meteors on or near the date of maximum activity from a rural site away from city lights. The best time lies between 0200 and 0400 local daylight time. Face southward with your field of view centered approximately one-half high in the sky. SDA meteors will shoot in all directions from the lower portion of your field of view. There will also be other weaker showers active at this time. Most notable will be the well known Perseids that will produce swift meteors entering your field of view from the upper left. The much slower Alpha Capricornids are also active with a radiant in the right portion of your field of view. Of course there will also be random activity with various velocities occurring at this time.

With the Perseids peaking near a full moon in August, the Delta Aquariids will offer the best opportunity to view meteor activity under favorable conditions this summer. Make an effort to see these meteors and be sure to let us know your results!

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