Auroras in Evenings Only?

The auroral displays I have observed overe the past two nights (Oct 29-30, 2003) have only been visible from sunset-9:30pm. After that, I find nothing. Have other SDopers observed this? (I am in the Mid-Atlantic area.)

I hypothesize that, later in the night, the earth has turned too far away from the sun, and hence turning me away from the solar winds carryinging the stream of particles? …Maybe some SDopers might know more about this?

Wearing my sunglasses at night, :cool:

  • Jinx

I saw a craking aurora nr Edinburgh last nite 12:30 but it had gone by 1am. Hope this helps.

It’s got little to do with the time of day. Auroral storms are just flaky that way. NASA’s Auroral Activity page shows a satellite based map of the display intensity, and as you can see, the storming usually reaches it’s maximal southward extension at around local midnight. However, the flux from the sun that drives the display changes on an hourly basis, as does the earth’s response to the stress.

It’s really more tied into when the charged particles arrive and when the interplanetary magnetic field cooperates by turning southward. Last night’s event (on the East coast) was associated with a geomagnetic storm beginning at around 2:00 PM local time, so the display became visible once it got dark (although it really picked up around 6:45). Most of the aurora viewing sites indicate that local midnight is the best time to see an aurora. This site gives a reason for this:

“The auroral oval, looks like an oval donut and the earth rotates underneath it. For this reason, the oval is furthest south at your location near local midnight (12am-3am local time).”

But that assumes a relatively constant auroral oval. What happened last night is that the aurora oval expanded dramatically when the storm hit.

Same for us, Jinx. Mid-Atlantic (in the mountains) and we’ve had great red displays in the evening the last two nights.

NASA says its Astronomy Picture of the Day for 5 August 2002 is a morning aurora.