Function and features
The rotating star chart is used for orientation in the starry sky and for solving complex astronomical tasks. The front and back of the large map together cover the northern and southern hemispheres with an overlap of 54° declination beyond the celestial equator. All stars from magnitude -1.6 (Sirius) to +6.0 are marked, totalling 2796 stars in 88 constellations.
The star chart
It consists of a three-coloured base sheet, a transparent, rotatable cover sheet and a rotatable pointer, and provides a view from below into the spherical celestial vault.
This is depicted in equidistant azimuthal projection on the flat surface of the paper. This can be recognised by the uniform, i.e. not increasing towards the outside, red division of the declination on the pointer. As a result of this projection, the constellations are noticeably marked towards the edge of the map.
The star chart also contains hundreds of special objects for observation with binoculars or a telescope, as well as a lifelike representation of the Milky Way. The stars are represented as black discs in consecutive size gradations according to their apparent or visual brightness.
The scope of delivery includes a detailed instruction manual, a fold-out leaflet of the moon with a detailed map and index of names, a fold-out leaflet of the stars, and a current planetary chart.
The rotating map allows you to orient yourself in the sky and solve some complex astronomical problems. The front and back of the large map together cover the northern and southern celestial hemispheres, with an overlap in each direction of 54° of declination from the celestial equator. All stars with a magnitude of less than -1.6 (Sirius) and up to +6.0, i.e. a total of 2796 stars in 88 constellations, are represented.
The celestial map
It consists of the three-colour base sheet, the transparent rotating sheet and the movable index. It shows the celestial vault imagined as a hollow hemisphere seen from below. The firmament is represented on the sheet of paper in an equidistant azimuthal projection. This can be recognised by the regular scale (i.e. not spacing outwards) of the declinations printed in red on the index. Due to this projection, the representation of the constellations is visibly distorted towards the edge of the map.
The stars are in the form of small black discs whose diameter corresponds to their apparent brightness. The sky map also includes hundreds of special celestial objects visible through binoculars or a telescope, as well as an accurate representation of the Milky Way.
Our expert comment:
The Sirius Large Star Chart lives up to its reputation. Thirty years ago, there was no other rotating star chart that could match it in terms of accuracy, presentation, etc.
Now reissued, the Sirius star chart is experiencing a Renaissance in public observatories.
Of course, a slightly smaller chart would also do, but why settle for anything less than the best?
(Anderl Rodoscheg)
