The Southern Delta Aquariids
Based on NASA, AMS and IMO references, with Moon figures from USNO. Our calculations, suggested observing nights and plain-language guide are labeled separately.
Our guideWhat this means for your night
Our plain-language reading of the sources and calculations on this page. It adds no new facts; the quotes below are the evidence.
What to expect. NASA says these meteors are suspected to come from comet 96P/Machholz. The shower runs from mid-July to late August, and the AMS says rates are good for a week around the maximum. It's a southern-hemisphere favorite, and the AMS says rates are lower north of the equator because the radiant sits lower in the southern sky.
Latitude matters. Our radiant table makes the AMS point concrete: the radiant reaches about 44° at 30° north and only about 26° at 48° north, so the southern US has a real advantage. Our calculation puts it highest around 2 a.m. local mean solar time.
2027 Moon. USNO shows a waning crescent, 11% lit on Jul 30 and 4% on Jul 31, a dark sky for a shower that needs one: the AMS describes faint meteors without persistent trains or fireballs.
Tips that follow. NASA's advice is to look halfway between the horizon and the zenith and about 45 degrees from Aquarius.
Rare surprises. IMO reports rare outbursts with a ZHR of about 40, from Australia in 1977 and from Crete in 2003, both before the maximum date found in recent years. That's history, not a forecast, but it's a reason not to skip the nights just before the suggested one.
Who gets the most out of it. Put the AMS's latitude note together with our radiant table and the answer is families in the southern US, on a dark night like 2027's, watching for faint meteors rather than fireballs.
| Shower | Night | Published ZHR | Moon lit (USNO, each date) | Radiant highest: our calculation, approximate LMST |
|---|---|---|---|---|
| Southern Delta Aquariids 2027 | Jul 30–31, 2027 (our suggested night for the Eastern US; IMO gives the maximum as Jul 31, 2027) | 25 (IMO 2027 calendar) | Jul 30: waning crescent, 11%; Jul 31: waning crescent, 4% | 2 a.m. |
LMST is local mean solar time, which can differ from your clock by an hour or more. The time the radiant is highest isn't a recommended start time; it can fall in twilight or daylight. Moon figures: USNO's one-day figure for each calendar date, requested for 39.83° N, 98.58° W (near the center of the contiguous US) at UTC−6. USNO doesn't say what time of day the figure applies to. Illumination only; check local moonrise and moonset.
Where they come from
“The pieces of space debris that interact with our atmosphere to create the Southern Delta Aquariids are suspected to originate from comet 96P/Machholz.”
Source: NASA meteor shower page
When they're active
“The Southern Delta Aquariids are active beginning in mid-July and are visible until late August.”
Source: NASA meteor shower page
“These meteors produce good rates for a week centered on the night of maximum.”
Source: AMS meteor shower calendar
Where to look
“The third brightest star within this constellation is called Delta.”
Source: NASA meteor shower page
Southern Delta Aquariids: radiant height and rise time, Jul 30, 2027
Our calculationFrom the radiant position on our calendar: right ascension (RA) 340°, declination (Dec) -16° (IMO 2027 calendar). Method on our About page.
| Latitude | Places near this latitude | Highest altitude | Radiant rises (approximate LMST) |
|---|---|---|---|
| 30° N | Houston, New Orleans | 44° | 9 p.m. |
| 40° N | Columbus, Denver | 34° | 9 p.m. |
| 48° N | Seattle, northern Minnesota | 26° | 9:30 p.m. |
Highest altitude is when the radiant crosses due north-south. The rise time is when it clears a flat horizon, ignoring refraction, twilight and terrain.
How many to expect
“The shower is one of the most active annual sources in the southern hemisphere.”
Source: IMO 2027 Meteor Shower Calendar (PDF)
ZHR is a standardized rate: what one observer would count in an hour under a perfectly dark sky with the radiant straight overhead. It isn't a forecast, and what you count is usually lower.
What they look like
“They are usually faint meteors that lack both persistent trains and fireballs.”
Source: AMS meteor shower calendar
Famous displays
“Rare outbursts with a ZHR of about 40 were reported by Australian observers on 1977 July 28/29 and from Crete on 2003 July 28/29 – both before the maximum date found in recent years.”
Source: IMO 2027 Meteor Shower Calendar (PDF)
How to watch
“North of the equator, the radiant is located lower in the southern sky, and therefore rates are lower than those seen farther south.”
Source: AMS meteor shower calendar
“Looking halfway between the horizon and the zenith, and 45 degrees from the constellation of Aquarius will improve your chances of viewing the Southern Delta Aquariids.”
Source: NASA meteor shower page
For any meteor shower
“Most meteor showers are best observed between midnight and dawn.”
Source: AMS meteor FAQ
“Find a dark location with an unobstructed view and give your eyes at least 20–30 minutes to adjust. Full dark adaptation takes longer, so avoid bright lights and phone screens.”
Source: AMS meteor FAQ
“Meteor showers are best observed with the unaided eye. Binoculars and telescopes restrict your field of view, making it harder to catch meteors appearing across the sky.”
Source: AMS meteor FAQ
“Look toward a dark, clear part of the sky, roughly halfway between the horizon and directly overhead.”
Source: AMS meteor FAQ
“It is a standardized estimate of shower activity under ideal conditions: a very dark, clear sky with the radiant directly overhead. It is not the number most observers will actually see.”
Source: AMS meteor FAQ
How many meteors you actually see depends on the shower's activity that night, how dark your sky is, clouds, and how high the radiant is.
We don't know the weather on any given night. Check a forecast, and the calendar for the moon on each date.