Comet Bradfield, which was discovered only last month and just rounded the Sun, was imaged in the predawn sky by Austrian skywatcher Michael Jaeger Thursday morning. It is now expected to be visible this weekend with the aid of binoculars or small telescopes.

Several other comet watchers could not pick Bradfield out visually on Thursday, but Jaeger's photo gives astronomers a clue as to how the ball of dirty ice might behave in coming days.

By Sunday morning the comet should be far enough out of the morning twilight glow for reasonably capable observers to find it using binoculars. The comet rises higher in the sky each morning at the same time, as it moves away from the Sun.

A clear view of the east-northeast horizon is necessary. Rao advises heading out one or two hours before sunrise and concentrating in that direction. A viewing location away from bright city or suburban lights is best.

Comet brightness is notoriously difficult to predict, but here's what Rao expects for viewers at mid-northern latitudes:

• Two hours before sunrise, the dust tail might be seen protruding up above the horizon.
• Ninety minutes before sunrise, the head of the comet should begin to appear, with the tail possibly shooting above it.
• One hour before sunrise, as the sky is starting to get bright with twilight glow, the entire comet might be visible, hovering low above the horizon. The comet's head should now be about 10-degrees above the horizon, or about the width of your clinched fist on an outstretched arm.

Last weekend, the comet put on a show in the field of view of the Solar and Heliospheric Observatory (SOHO) spacecraft. As it raced around the Sun inside the orbit of Mercury, Bradfield's surface ice and dust was boiled away dramatically, creating a large head, or coma, and a strong tail. The pictures were available on the Internet.

Astronomers did not know what to expect from Bradfield as it races away from the Sun. Its brightness will soon fade as it gets farther from the intense solar radiation.