DEEP SKY AURORAS: This weekend, April 2-3, Northern Lights spilled across the Canadian border into the United States with sightings as far south as Wisconsin, Minnesota, and Michigan. To the naked eye, the auroras were mostly pale-white, but exposures of 10 or more seconds with off-the-shelf digital cameras revealed spectacular color. Brian Larmay sends this picture:



"It has been a while since the auroras visited my latitude. Finally, the dry spell is over!" says Larmay. "Although dim, the lights showed up rather well on my Canon 40D."

These are called "deep sky auroras" because like other deep-sky objects (e.g., galaxies and nebulae) they are best seen using optics and timed exposures. More of them could be in the offing. For the third night in a row, a solar wind stream is buffeting Earth's magnetic field. Moreover, the Moon is new, so the night sky is dark enough for long exposures. Photographers, grab your cameras and be alert for auroras.