Astroblog: Geminid Meteor Shower 13-15 December 2023

Thursday, December 07, 2023

Geminid Meteor Shower 13-15 December 2023


The northern horizon at 3:13 am ACDST as seen from Adelaide on Friday December 15 when the Geminid radiant is at its highest. The Geminid radiant is marked with a starburst. Similar views will be seen elsewhere in Australia at a similar latitude and the equivalent local time. (click to embiggen).	The northern horizon at 2:13am AEST as seen from Brisbane on on Friday December 15 when the Geminid radiant is at its highest. The Geminid radiant is marked with a starburst. Similar views will be seen elsewhere in Australia at a similar latitude and the equivalent local time. (click to embiggen).	The northern horizon at 3:17 am AEDST as seen from Melbourne on Friday December 15 when the Geminid radiant is at its highest. The Geminid radiant is marked with a starburst. Similar views will be seen elsewhere in Australia at a similar latitude and the equivalent local time. (click to embiggen).

This year is a good year for the Geminid meteor shower. The Geminids are unusual meteor shower in that their parent body is 3200 Phaethon, an asteroid, rather than a comet. It is speculated though that Phaeton is actually a "gassed out" comet, and so the debris that makes up the Geminids may still be cometary particles, but is more likely broken rock fragments from its close approach to the sun.

The Geminids are usually a fairly reliable meteor shower and this year promises to be a good one as there will be no interference from the Moon.

The Geminids have a broad peak and normally show good activity well before and after the peak on the day before and after. The nominal peak is December 14, 19h UT, that means in Australia this year most of the activity is concentrated on the morning of the 15th. Yes, it's week day, but it's a Friday, so you can afford to lose a little sleep. As the radiant doesn't rise until just before midnight (daylight saving time) in most of Australia and the radiant is highest (with the best meteor rates) in the early hours you are going to lose some sleep for this.

Northern Australians should see a meteor every 1 to 2 minutes under dark skies in the early morning of the 15th between roughly midnight (14th) and 3:00 am local time (15th). Obviously under suburban skies you will see fewer.

You can find predictions for your local site at the meteor flux estimator (choose 4 Geminids and date 14-15 December, don't forget to change the date to 2023). You will have to enter your local latitude and longitude for your site. I have also made a table for major cities below.

Unfortunately, both Chrome and Firefox have changed their security settings to prevent plugins from running, and the flux estimator only runs under Internet Explorer now OR Edge in Internet Explorer mode (click on the triple dots one the page has loaded ), you have to have the JAVA plugh-in loaded

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You can follow the progress of the shower at the IMO Geminids Live page.

At 1.00 am in the morning AEDST (midnight, AEST) Castor (alpha Geminorum) is about three hand-spans above the horizon and roughly north-east. Pollux, the other twin, is less than a hand-span to the right again. The radiant is just below Pollux. The best rates is when the radiant is highest,when it is due north.

City	Time Radiant Highest
Adelaide	3:13 ACDST
Brisbane	2:13 AEST
Darwin	2:43 ACST
Hobart	2:38 AEDST
Melbourne	3:17 AEDST
Perth	2:13 AWST
Sydney	2:52 AEDST

When you get up, allow at least 5 minutes for your eyes to adjust and become dark adapted (even if you have stumbled out of bed in the dark, here's some hints on dark adaption of your eyes so you can see meteors better).

Be patient, it may be several minutes before you are rewarded with you first meteor, then a couple will come along in quick succession (a meteor every 1 to 2 minutes is an average, they won't turn up like a ticking clock but more or less randomly).

Predicted meteor rates for selected towns

Locations on the same latitude as...	Morning December 13	Morning December 14 (UT peak)	Morning December 15 (best)	Morning December 16
Darwin	6 meteors/hr	14 meteors/hr	63 meteors/hr	14 meteors/hr
Brisbane/Perth	8 meteors/hr	16 meteors/hr	45 meteors/hr	11 meteors/hr
Sydney/Adelaide/Canberra	6 meteors/hr	13 meteors/hr	35 meteors/hr	8 meteors/hr
Melbourne	6 meteors/hr	11 meteors/hr	31 meteors/hr	7 meteors/hr
Hobart	5 meteors/hr	10 meteors/hr	30 meteors/hr	6 meteors/hr

Locations at similar latitudes to the towns in the list will have similar rates, the more north you are the higher the rate. Choose a viewing spot where you can see a large swathe of sky without trees or buildings getting in the way, or with street lights getting in your eyes. The darker the spot the better (but do be sensible, don't choose a spot in an insalubrious park for example).

While the radiant is where the meteors appear to originate from, most of the meteors will be seen away from the radiant, so don't fixate on the radiant, but keep your eye on a broad swath of sky roughly centered just above the radiant (as the radiant doesn't rise very high, looking exactly at the radiant will mean you miss some higher up).

A lawn chair or something similar will make your observing comfortable (or a picnic rug spread on the ground and a nice pillow), and having a Thermos of hot coffee, tea or chocolate to swig while watching will increase your comfort. Despite it being summer, make sure you have a jumper or something as the night can still get cold. Also, plenty of insect repellent is a good idea.

Guides to taking meteor photos are here and here.

As well, Orion and the Hyades will be visible, with Jupiter setting in the west and Venus rising in the twilight. So it will be a quite nice morning for sky watching. Keep an eye out for satellites! There may be a bright ISS pass on the morning of the 15th from your location.

Cloud cover predictions can be found at SkippySky.
Here is the near-real time satellite view of the clouds (day and night) http://satview.bom.gov.au/

Labels: geminids, Meteors, unaided eye