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Hipparcos: Educational Resources |
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| Variable Stars | Double and Multiple Stars | High Proper Motion Stars |
| The Millennium Star Atlas | Solar System Objects | Further Resources and Educational Links |
The Hipparcos and Tycho Catalogues contain a wealth of information in a user friendly format. Available in both printed and machine readable form, these catalogues can be exploited by both professional and amateur astronomers. This section is generally aimed at amateur astronomers, and also at teachers and students of physics and astronomy.
We have started to link a series of "projects" to this page showing how the catalogues can be used to conduct interesting observations by such users. In addition, several research tools which allow the user to access data from some of the Hipparcos and Tycho Catalogues and Annexes may be accessed at the research tools page or via the animations page.
Interested users will find that the Hipparcos data base contains a treasure trove of new information which can be applied to theoretical or observational teaching or research projects. We highlight, specifically, areas of the Hipparcos and Tycho Catalogues which contain some data suitable for these applications, and indicate some specific areas where enthusiastic amateur astronomers may play a role.
You may wonder what role amateur astronomers have to play in contributing to the Hipparcos mission. They have already played rather an important one, as illustrated by the Sky & Telescope article [external link] "Amateurs and the Hipparcos Mission" by Janet A. Mattei and Grant Foster of the American Association of Variable Star Observers [external link] (AAVSO). By compiling large numbers of observations by amateur observers on large numbers of objects over many years, the AAVSO was able to characterise the variability of many large-amplitude variable stars, permitting their observations to be made efficiently by the Hipparcos satellite.
The Hipparcos data have been reduced and made fully available. In addition to the star positions and distances, the catalogues contain a wealth of variability data - the observations of each of the 120000 Hipparcos stars at each of about 100-150 epochs throughout the four-year observing period are available. Already some analysis has been made on the resulting light curves; and the published catalogue includes nearly 4000 plotted light curves. These are sub-divided into Annex A (2693 objects for which a variability period has been identified); Annex B (274 objects with Hipparcos light curves superimposed on AAVSO derived light curves); and Annex C (827 `unsolved' objects with significant variability, for which a period has not been determined so far).
In the post-Hipparcos age regular observations by amateurs of variable stars (in particular those variable stars classified by Hipparcos as `unsolved') will certainly lead to a better characterization and understanding of these stars. In addition, high-proper motion stars can be observed without the need for very high-tech equipment.
A popular exposition of some of the goals of Hipparcos, based on the poster: Hipparcos pinpoints the stars is reproduced here. Copies of the original 90 x 60 cm poster (with text in English and French) can be obtained on request from: The Public Relations Office, ESTEC, Noordwijk 2200AG, The Netherlands.
Among the 118218 stars measured by Hipparcos, 11597 were found to be (possibly) variable. Of these more than 8000 are new. If you want to find some background to understanding what variable stars are, and why they are important in astronomy, take a look here and follow the links to the home page of the American Association of Variable Star Observers. Further information is also available from the Variable Star Network [external link] (VSNET) web site.
The variability parameters derived by Hipparcos for these systems are so important that they merit two volumes of the catalogues:
Clicking on the highlighted text will bring up an example page from these tables of the Hipparcos Variability Annex in pdf format.
Clicking on the highlighted text will bring up 10 examples of the light curves from each of the different parts of the Variability Annex. The light curves are given in pdf format: you can examine them in greater detail; or you can experiment by trying to determine the periods of these variables yourself using the interactive software tool provided!
Approximately one-fifth of the stars observed by Hipparcos belonged to systems with two or more stars. In addition to the five astrometric parameters which Hipparcos provided for each observed star (the two position components, the two proper motion components, and the parallax or distance), several extra parameters were produced for these double and multiple systems (e.g. orbital period, system geometry, etc.). The main Hipparcos Catalogue entry for each component provides a summary of the multiplicity data and points to the more extensive tabulation of the solutions in the Double and Multiple Systems Annex (Volume 10). Take a look here for further details about double and multiple stars, and for some example charts showing the geometrical and brightness configurations for a few of the double and multiple systems measured and catalogued by Hipparcos.
The Hipparcos Catalogue include charts - and the detailed properties - of more than 12000 such systems. Choose a system with the right level of complexity for your observational equipment, and see if you can resolve all of the components - or see some of the orbital systems change their configuration with time!
In addition to the coordinates of the stars, Hipparcos also measured the movement of stars: their proper motion. Most stars are so distance that their apparent motion even over hundreds of years is all but negligible to naked eye observers. The proper motions of all stars in the Hipparcos Catalogue are tabulated. Some stars have very significant movements compared to the background stars, and these are referred to as `high-proper motion stars'. Check here for some further details, an animation facility to visualise motions anywhere on the sky, and some observing suggestions.
The Hipparcos and Tycho data have been used to create the Millennium Star Atlas: an all-sky atlas of one million stars to visual magnitude 11 (from the Hipparcos and Tycho Catalogues) and 10,000 nonstellar objects included to complement the catalogue data. The Millennium Star Atlas is available either as part of the Hipparcos and Tycho Catalogues (Volumes 14-16) or as a separate three volume atlas from [external link] Sky Publishing Corporation.
The Millennium Star Atlas is a remarkable map of the celestial sphere, undertaken by Sky Publishing Corporation in collaboration with the European Space Agency and the Hipparcos scientific community. Very simply, the Millennium Star Atlas comprises 1548 star charts, using them to show the location of all 1,058,332 stars included in the Tycho Catalogue. It superimposes on these stars a wealth of material - from the Hipparcos Catalogue - illustrating their proper motion, their variability characteristics, their distance (if closer than 200 light years), and the details of their close companions.
Take a look at some example pages from this Millennium Star Atlas, and follow the links to examine the properties of some of the stars included in the Atlas in greater detail.
48 minor planets (and a few other solar system objects) were
included in the Hipparcos Catalogue observations. An animation shows the
smoothed motion of these objects with time.
A list of astronomical software is maintained at the Sky & Telescope site.
The [external link] VSNET (Variable Star Network) web site provides bulletins on currently active or flaring variable stars, in addition to general information, light curves and recent observational data on these objects.
A sky plot resource is available which generates an interactive image of a given region of the sky showing HIP/TYC objects, and includes hyperlinks to further information for each displayed object.
The Hipparcos and Tycho Catalogues can be searched on-line at the Catalogue search page.
The Hipparcos Intermediate Data Catalogue and the Hipparcos Epoch Photometry Catalogue can also be accessed on-line.
The Canadian Astronomy Data Centre also provides online access to the Hipparcos main catalogue and some of the annexes.
The Hipparcos main catalogue of 118218 objects has been converted to an [external link] xephem compatible database (1.8Mb compressed, 6.4Mb compressed), available from our anonymous ftp site.
Visit the [external link] Pupil Researcher Initiative Web Site for some ideas on science investigations.
If you want further guidance, or if you have specific ideas for developing access to the Hipparcos and Tycho Catalogue for teaching purposes, contact us through the `Feedback' service on the home page, or through the `Help desk' on the Catalogue page.
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Contact Us Updated on: April 2, 2003 |
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