Ever since its discovery back in August 2001, this comet has been visible only to those south of the equator. But now as the comet sweeps past the Earth en route to its closest approach to the Sun, it will appear to race rapidly northward and should become visible to most northern sky watchers beginning on Wednesday evening, May 5.
On that evening, about an hour after sunset, look low in the southwest for blue-white Sirius, the Dog Star, the brightest star in the night sky. Comet NEAT should be hovering about 10 degrees to the left of Sirius (your clinched fist, held at arms length is roughly equal to 10 degrees). The following evening, the comet will be passing closest to Earth, only 29.8 million miles away.
The comet will move higher in the sky each night. It will likely be shining at its very brightest on these initial evenings, and for perhaps for a few more nights thereafter.
Originally, hopes were that comet NEAT would become as bright as magnitude 0.9. That would have placed it in the same brightness ranking as the orange star Aldebaran, in Taurus or the reddish star Antares, in Scorpius.
Instead, comet NEAT will probably only get about one-sixth as bright, reaching a plateau in brightness of around third magnitude. On the astronomers scale, larger numbers represent dimmer objects. The dimmest star that can be seen with the unaided eye, under perfectly dark conditions, is about magnitude 6.5.
If NEAT reaches magnitude 3, that would place it in the category as Megrez, the star that appears to join the handle and the bowl of the familiar Big Dipper.
Observers should look for a fuzzy star-like object of medium brightness and a short, slightly curving tail protruding out from it to the left (eastward). Binoculars will enhance the view.
The fact that comet NEAT is likely to end up fainter than originally hoped for is not a surprise. As we have noted since last May, NEAT is apparently making its very first approach to the vicinity of the Sun, having spent all its life in the deep freeze of the outer solar system. History has shown that most "first-timers" usually fall short of brightness expectations.
Initially, on Wednesday evening, the comets low altitude above the horizon, the unpredictable amount of horizon haze, the comets uncertain brightness and tail visibility, and the skill of the observer will complicate the picture as to whether a sighting can be made.
Nevertheless, anyone should be able to see comet NEAT that evening -- weather permitting -- if they follow some important observing tips:
The good news is, that in the evenings that follow, comet NEAT will be getting progressively higher up in the southwest sky and correspondingly easier to see.
The comet will be passing by to the east of the bright yellowish-white star, Procyon in Canis Major on the evenings of May 9 and 10. On May 13, a line drawn from Castor to Pollux (in Gemini) and extended out three times the distance between these two stars will bring you to comet NEAT.
On May 15, the comet will reach its closest point to the Sun, just over 89 million miles away. It will also be positioned just a few degrees from the prominent open star cluster, M44, popularly known as the Beehive. It should then fade rapidly from view as it moves away from both Sun and Earth, moving into Ursa Major by months end.
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