May-June daytime showers

Most showers in May and June are daytime-only and unobservable visually.

For observers at northern latitudes the Eta Aquariids are almost a daytime-only shower. Several other meteor showers during May and June are even less well placed for night time observation. The radiants of these showers are only above the horizon during daylight hours (although in a few cases, some activity may be detectable late in the night by observers in tropical latitudes). Consequently, observation of these showers is limited to radio methods.  However, with most amateurs being restricted to forward scatter methods, their observations cannot differentiate between showers for individual meteors and instead they look for peaks in the overall daily counts and at the timing within the day of that enhanced activity.

The table below shows the IMO’s predictions for daytime activity in 2020.
April Piscids (144 APS) – April 22, 10h;
ε-Arietids (154 DEA) – May 9, 3h;
May Arietids (294 DMA) – May 16, 4h;
o-Cetids (293 DCE) – May 20, 3h;
Arietids (171 ARI) – June 7, 4h;
ζ-Perseids (172 ZPE) – June 9, 6h;
β-Taurids (173 BTA) – June 28, 5h.

ZHR level and radiant location information for these showers is often poorly known and some published guides have made the mistake of quoting (higher) radio count numbers as the visual ZHR value, giving the impression that some of these showers could be on a par with the Perseids.

It does seem likely, however, that the most active of these showers are the Arietids (max Jun 7) and the Zeta Perseids (max Jun 9) and that these two showers are probably comparable in strength with the night time Lyrids or Orionids. Also clearly active are the Omicron Cetids (max May 20), and the Beta Taurids (max Jun 28) but the activity levels of these are more in line with that of the night time Taurids.

An overview of radio meteor observing can be found in  this guide.