The Perseid meteor shower is active between 17 July and 24 August this year, reaching its peak on 13 August. It is estimated that the zenithal hourly rate (ZHR) of the meteor shower can reach 100 during the peak period. The peak lies on the twenty-seventh day of the lunar calendar, the neglectable influence of the moonlight provides an excellent observation condition.  

In mid-August, the radiant of the Perseid meteor shower will rise in the northeast at about 10 pm. More meteors should be seen when the radiant is higher above the horizon. The best observation time would be at around 3 to 4 am on 13 August. It is recommended to observe the meteor shower from 10 pm on either 12 or 13 August. Under favourable conditions, it is possible to see more than 10 meteors per hour in the early hours.

The parent body of the Perseid meteor shower is a comet called 109P/Swift–Tuttle. When it travels through the Solar System, a large amount of debris is left. When the Earth passes through these debris in space as it orbits around the Sun, a large amount of debris falls into the Earth's atmosphere, forming a meteor shower. Since these debris are from the same origin, all meteors emanate from the same point called the radiant. When the radiant of the meteor shower is in the constellation Perseus, we call this meteor shower as the Perseid meteor shower.

Information about the peak of Perseid meteor shower 2023:

Date and time	Maximum zenithal hourly rate*
13 August	100

* The zenithal hourly rate (ZHR) is the extrapolation hourly rate of meteors observable in an extremely dark and wide sky with the radiant located at the zenith. As some meteor showers have very short peak periods, observers sometimes extrapolate the number of meteors observed in ten and a few minutes to an hourly number in proportion. Therefore, the zenithal hourly rate cannot be regarded as the actual number of meteors visible in one hour. Yet, it can be used as a meaningful comparison between the activity of different meteor showers. Some meteor showers can be as inactive as having single digit zenithal hourly rates. There are "three major meteor showers" (Quadrantid meteor shower, Perseid meteor shower, and Geminid meteor shower), which have the ZHRs reaching 100 or even higher values, and hence worth watching.

(Source: International Meteor Organisation)

Best local observation time	Expected maximum number of meteors within one hour
3 - 4 am, 13 August	City outskirts1	Nearby countryside2	Remote area3
	2	5	14

¹ Region where stars brighter than magnitude 3 are visible (about 100 stars) and with an unobstructed view of about 60% of the entire sky.
² Region where stars brighter than magnitude 4 are visible (about 300 stars) and with an unobstructed view of about 70% of the entire sky.
³ Region where stars brighter than magnitude 5 are visible (about 1,000 stars) and with an unobstructed view of about 80% of the entire sky.

For information about star magnitude, please check the online education resources of the Space Museum.

Live streaming of Perseid meteor shower

The Perseid meteor shower will peak on 13 August this year. During the peak, we have a better chance of seeing meteors. The Hong Kong Space Museum will live stream this meteor shower event and provide insights on how to observe a meteor shower with related astronomical knowledge.

 Speakers: Assistant Curators of the Hong Kong Space Museum

Date: 13.8.2023 (Sunday)

Time: 9:00 - 11:00 pm

Platform: YouTube Channel of the Hong Kong Space Museum

Please check the latest news on the website of the Museum. The live streaming programme is subject to change without prior notice.

Here are some tips for watching the Perseid meteor shower:

1. There are still a certain number of meteors around the peak period. 1-2 days before and after the peak period is also suitable for observation as long as the weather is fine.
2. Meteors do not necessarily appear near the radiant, and most of the meteors are dim. Observers should choose a site with a large unobstructed view and low light pollution. Staying away from other light sources can help your eyes become more sensitive to light.
3. Basically, a telescope is not required as meteors are better observed by naked eyes. You may bring along with you a star-map, a red torch, a deck chair and a sleeping bag or blanket. Please observe stargazing manner and refrain from using excessive light as this will affect other stargazers.
4. To photograph meteors, a camera with long-exposure function and a wider angle lens are essential. After focusing on starlight, point the camera to the zenith or the darkest area on the sky and set an appropriate aperture and ISO value (such as F2.8 or lower, ISO 800 or higher, depending on the design of the lens and camera, as well as the nearby environment). Then select the time of exposure based on whether a star tracker is used. In general, a longer exposure gives you a higher chance of capturing unexpected meteors. For long exposure you may consider stepping down the aperture to say, F4 or F8 and ISO value to 400 for better image quality. The star image distortion due to camera shaking can be solved by using a remote control or the self-timer function on the camera.