Sommers-Bausch Observatory - University of Colorado

Comet Hale-Bopp (C/1995 O1)

Last Updated on May 15th, 1997

Index to Topics Below

Recent News

Here's a March 27th press release regarding recent findings and discoveries made with the Hubble Space Telescope. Simultaneously, the Space Telescope Science Institute released these images of the comet's nucleus taken over a two-year period, with the accompanying explanatory text.

Images of Hale-Bopp

These images were taken at Sommers-Bausch Observatory by students, staff, or guest observers.

When and Where to Look

By mid-March, Hale-Bopp will be visible both in the morning and evening skies, about an hour to an hour-and-a-half before sunrise, or after sunset.

Both charts show azimuth (compass headings) in degrees along the horizon, plus the comet's altitude (angle above the horizon) measured in degrees at the indicated time. Use your fist held at arm's length as a yardstick for measuring angle: the width of your fist will be about 10 degrees across.

The charts above show you where to look above the horizon, but they don't show you how the comet appears against the background stars. The combined effects of the Earth's and the comet's orbits make Hale-Bopp appear to wander around against the backdrop of stars - even making it appear to halt and change direction in 1996.

So - here are sky maps showing where Hale-Bopp can be found among the constellations during 1997:

Finally, a time-line of the favorable observing windows for viewing Hale-Bopp.

How The Comet Should Appear

We've put together (using Voyager II and Photoshop software) some "snapshots" of how the comet, the horizon, and the sky itself should appear for selected dates for the coming months. The times are optimum viewing times - with the comet at its highest above the horizon just before twilight interferes.

Each view spans a field that is 75 degrees wide and 45 degrees up from the horizon, and approximates the entire view that you can see at one time with your naked eye. Of course, the true sky won't have constellation stick figures or star names floating in space!

How to Look

First of all, do not expect to be able to come to Sommers-Bausch Observatory on open house nights and expect to take a peek at the comet through the big telescopes. We wish we could show it to you, but we can't - the comet will be too far northward along the horizon line for either of our observing deck scopes to acquire it (the north wall gets in the way). (However, we are able to show you the comet in the evening using binoculars and a small portable telescope set up at a location that clears the roof.)

But why come to a light-polluted site in the middle of Boulder, when a similar drive would take you into much darker skies where the view will be all the more dramatic? A bright comet such as Hale-Bopp is pretty much a naked-eye, do-it-yourself kind of thing!

Some observing tips:

Where Is It Really?

If we could step off of the Earth and stand motionless in space, we could see the true path of the comet (as well as the Earth and other planets) around the Sun in three-dimensional space.

The space-view was derived from computer a simulation of the comet's orbit, which is in turn described by its "orbital elements". Here is a description of Hale-Bopp's orbital elements - what they are, what they geometrically mean.

Once you've loaded the orbital elements into your computer, you can determine how far away the comet is from the Earth, its orientation in space, and exactly where it is in relationship to the Sun.

For example, you'll find that the comet passed closest to the Earth on March 22nd at a distance of 122 million miles (no close encounter here!), and passed closest to the Sun (perihelion) on March 31st at a distance of 85 million miles. During the ten days from April 1st to April 10th, Hale-Bopp only moves away from the Sun by 1 million miles to 86 million, but increases its separation from the Earth from 126 million to 136 million miles. During this period, the comet appears to move 3 degrees closer to the Sun as seen from Earth, to a 39-degree separation on April 10th, and that we view the comet from an oblique angle of about 45 degrees (90 degrees would be a side, or profile, view).

For more details, here is a table with explanations of distances and angles to provide you with the information.

If you want daily details such as equatorial coordinates (right ascension and declination), Steve Albers has provided this Hale-Bopp ephemeris and accompanying explanatory guide, computed for Boulder-area observers.

Teacher's Workshop Information

On March 8th, 1997, Mary Urquhart, Niescja Turner, and Henry Throop hosted a workshop at Sommers-Bausch Observatory to provide information and activities for grade-school through middle-school teachers for teaching about Comet Hale-Bopp to their students. Here's an on-line summary of the material presented in the Hale-Bopp Teacher's Workshop.

Other Comets

There are comets out there all the time. Here are some recent ones.

Links to Other Hale-Bopp Sites

There are plenty of other places out there where you can find out more information about Hale-Bopp and other comets. We include here only a few of our favorites, which will in turn will provide you with even more links, etc., etc., etc.

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