In the video How to spot Comet NEOWISE, plus the largest 3D map of the Universe | Night Sky News July 20 after 05:28 Dr. Becky (Smethurst, Oxford astrophysicist) says:

…and it just so happens that we’ll be passing through the debris trail of two of the comets whilst comet NEOWISE is going to be visible in the sky, and so that’s going to cause to very popular meteor showers. There’s the Delta Aquariids meteor shower at the end of July, and then the Perseids meteor shower mid-August time.

And the Perseids meteor shower is just hands down the BEST meteor shower of the year. There’s something like sixty meteors per hour during its peak which this year is going to be the 12th of August.

Now the Delta Aquariidss are probably more like fifteen to twenty meteors per hour, so not quite as spectacular as the Perseids, but the Delta Aquariids really are more for the southern hemisphere where the Perseids is really going to be for the Northern hemisphere.

Question: Why are Delta Aquariids for the southern hemisphere while the Perseids are for the north? The Earth is moving along its orbit at 29 km/sec in both cases, why the big difference?

note: there are notes below the video that you might find helpful if looking for comet NEOWISE.


I suspect that that is simply a statement about where you would have the best visibility of each meteor shower. The name of each shower tells you where the radiant is, the point in the sky from which the trails of the meteors appear to originate. Perseus in the northern sky (with the specific radiant point of the Perseids at +58 degrees declination), while Aquarius is farther south (with the radiant of the delta Aquariids at about -16 degrees declination), so a northern observer would have the Perseids radiant higher in the sky and would see more of those meteors, and vice versa for a southern observer and the delta Aquariids.

Since the meteors go in all directions from the radiant, at least some from either shower would be visible for observers over a large range of latitudes, but you’d see the most if the radiant is high in your sky.

Edit: this nice image from spaceweather.com shows clearly why the radiants have their respective locations:

(From spaceweather.com, linked from Sky & Telescope.)

These are reconstructed orbits of fireballs seen as part of these showers. The light green are the delta Aquariids, and the darker green / teal are the Perseids. You can see that they have very different inclinations where they intersect Earth, so they appear to originate from different directions in our sky.

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