A star atlas for observers, by observers - the most practical there has ever been!

Visibility of deep sky objects: Bright stars are big dots, faint stars are small dots: For centuries, this simple principle has been used. But on the objects between the stars, the targets of today's users, star atlases give no information except size. interstellarum Deep Sky Atlas is changing this: Bright objects are bold, faint objects light. You can see at one glance which object will be within reach with your telescope, and which will not. This delineation is not based simply on object brightness - it's the actual visual perceptibility that is shown here. This quantity is influenced by the object's total brightness, surface brightness, telescope size, and limiting magnitude. The deep sky object database for the atlas was prepared with Eye & Telescope, a powerful software capable of this calculation.

Categories of deep sky objects: interstellarum Deep Sky Atlas puts all deep sky targets in three categories: objects visible in 4-inch telescopes, in 8-inch telescopes, and 12-inch telescopes under a reasonably dark rural sky (fst 6,5mag, SQM 21,3mag/sqarcsec). The three categories can be discerned by font size, outline strength, and color intensity. At a glance, you can see if the desired object is visible in your telescope or not. Additional objects of interest which are not visible in 12-inch scopes are displayed in a fourth category.

Number of deep sky objects: As a consequence, the atlas will show all deep sky objects in the sky that are visible in 4-inch, 8-inch, and 12-inch telescopes. Different to other atlases, you will not miss any object in reach. At the same time, the atlas does not show objects that cannot be seen with a 12-inch telescope. While other star atlases boost exceptional numbers of deep sky objects, most of them are out of reach for most users. About 1000 objects of special interest to the visual observer, that are beyond a 12-inch scope, are covered nevertheless: This includes all galaxies of the local group, M 81 group, Abell planetaries, Arp galaxies, and many more that are of interest to users of large telescopes.

Features for visual deep sky observers: interstellarum Deep Sky Atlas has been designed with the visual observer in mind: Object outlines, especially of bright and dark nebulae, are given according to actual visual observations. For all emission nebulae, there's a label naming the preferred nebula filter. Small objects that cannot be found with the atlas alone are depicted as a cross, so deeper finding charts can be prepared in advance. There is a set of 29 detailed charts of densely populated regions of the sky. In contrast to other atlases, interstellarum Deep Sky Atlas contains more than 500 galaxy groups and 530 asterisms. For several hundred objects, popular names are given. And finally, a lot of those catalogs with a special appeal to visual observers are covered completely: Abell planetaries, Arp galaxies, Barnard dark nebulae, Hickson galaxy groups, Holmberg galaxies, Palomar globulars, Stock open clusters, Terzan globulars, and many more.

Use: The page size is generous with 26cm x 28cm (10.2" by 11.0"). 114 double spreads cover the entire sky at a scale of 1.5cm per degree. The maps run right to the edge of the sheets to allow maximum overlap of maps. The limiting magnitude is 9.5mag, with about 200.000 stars covered.

Navigation: The maps are arranged in a very simple and straightforward manner: Each double spread shows 2h in R.A. and 15° in Decl. Due to the large page size, many constellations are covered by only one double spread. Browsing through the atlas is as simple as using a road atlas: If you want to go to the right (west), simply scroll right. If you want to go to the left (east), scroll left. There is always exactly one chart to each direction, except in the polar regions. A label on the edge of each map allows you to find the desired region quickly. Much emphasis has been laid on the 6 key maps. As the main charts, they'll show constellation lines, so it's easy to find your way and you'll hardly get lost.

Editions: There are two editions: The Desk Edition comes with a sturdy spiral binding and is made of robust paper that will last for many years of use. The Field Edition is made of Polyart, a sophistcated plastic foil which feels like paper, but it's 100% waterproof and tear-resistant. It can be put in an aquarium and remains fully usable. This edition is virtually indestructible.

Eye & Telescope: The atlas is compatible with Eye & Telescope software (Cambridge University Press). This program will allow more detailed object data and visibility analysis. Here you can filter and select objects to your criteria, plan observations, print finder charts, and log your results.