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 chart 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, for a total of 2796 stars in 88 constellations.
The star chart
It consists of a three-colour base sheet, a rotating transparent cover sheet and a rotating pointer, and provides a view from below into the spherical celestial vault.
This is depicted in equidistant azimuthal projection on a flat surface of paper. This can be recognised by the even, 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 chart.
The star chart also contains hundreds of special objects for observation with binoculars or a telescope, as well as a lifelike image 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 showing the moon with a detailed map and index of names, a fold-out leaflet showing the stars, and a current planetary chart.
ITALIAN VERSION
The construction of the celestial chart
The rotating star chart is primarily used to learn about the celestial vault at any given time and also to solve complex astronomical problems. The southern hemisphere is shown on the back of the northern hemisphere chart, both up to a limit of 54° of opposite declination, thus with a large overlap. All stars from magnitude -1.6 (Sirius) to +5.5 are drawn, for a total of 2796 stars, divided into 88 constellations.
The star chart
It is divided into three parts: a three-colour background drawing, a rotating transparent sheet pivoting on the centre and a movable index rotating around the same point. The chart represents the appearance of the celestial vault in equidistant azimuthal projection. This projection system is recognisable by the equidistance of the degrees on the declination scale shown in red on the movable index. Due to this type of projection, the constellations near the edge of the chart are distorted, "stretched" horizontally.
The stars are represented by black discs proportional in size to their apparent visual brightness. The chart also contains a few hundred special objects that can be observed with binoculars or a telescope, as well as a faithful reproduction 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 the job, but why settle for anything less than the best?
(Anderl Rodoscheg)
