What are the .apd files that are included with CSOG?
They are AstroPlanner planfiles.
Wat are the .txt, .lst, .hct and .mtf files that are included with CSOG?
They are, respectively: Argo Navis User Catalogs, EQTours, NexTours and Autostar Tours.
Why are CSOG's observing guides pdf's?
PDF is the only truly cross-platform format. An image or e-book just won't do.
How many CSOG editions are there?
58 + 2 Observing aids: 3 Constellation editions by telescope aperture, 6 Catalogs & Lists, 14 Galaxy editions, 3 Nebula editions, 23 Star Cluster editions, 5 Observing Programs, 1 Double Star edition and 3 Other editions.
In addition to the regular CSOG content there a periodical observing guides for Deep Sky Forum's Object of the Week, the Webb Deep-Sky Society's Objects of the Month and Object of the Season and Astrotreff's Object(s) of the Month.
How many objects are in CSOG?
CSOG 2.4, published in June 2021, CSOG contains over 15000 (fifteen thousand) individual objects. Quite a few galaxy pairs and groups, or open clusters with an involved nebula, are combined into single CSOG objects.
What is the most "complete" CSOG edition?
There is no single edition that contains every objects that is included in CSOG collection. But if I had to pick one, I would pick the 12-14" Constellation edition; only extremely faint objects such as some of the Arp galaxies, Hickson groups, Abell nebulae, etc. are not included in that edition.
Is there an image for every single object in CSOG?
With the exception of double star editions, all but one object have a DSS image centered on the object: A depiction of the constellation Ursa Major taken from AstroPlanner is used for the open cluster Collinder 285.
Guides in the Arp, Hickson, Holmberg Galaxies, Holmberg Double and Multiple Galaxies, KTG, KTS, Rose and Abell Nebulae editions also contain an SDSS image, where available.
Why are CSOG guides such large files?
The images in CSOG are uncompressed. This allows zooming in on objects on a computer or tablet, without the image immediately becoming blurred and grainy. The uncompressed images are a feature of CSOG.
Will there be updates?
Yes. CSOG is a digital publication, allowing for relatively easy updates.
V1 was published in October 2012. CSOG 2.0 was released in December 2013, an interim update followed in January 2014, alongside the release of the Herschel edition. CSOG 2.1 was released on 18 March 2015, along with the new Arp, Holmberg, Dolidze, Dolidze-Dzimselejsvili and Stock editions. The number of editions doubled with the release of CSOG 2.2 in September 2016. With the release of CSOG 2.3 the number of observing guides doubled compared to CSOG 2.2.
In July 2020 CSOG's first double star edition was published: Struve Double Stars. In January 2021 Deep Sky Forum's Objects of the Week were added as weekly downloads, in April 2021 the Webb Deep Sky Society's Objects of the Month and Objects of the Season were added.
CSOG 2.4 was published on 23 June 2021 and brought further improvements and new editions. Click here for the CSOG 2.4 release notes.
For more information, please read Future CSOG.
How long did it take to write CSOG?
CSOG V1 took 4½ years to complete: Compiling and sorting object lists, creating observing guides, collecting (and correcting) data and coordinates, adding images, creating AstroPlanner planfiles, compiling tours, creating mirrored editions, exporting content for publication, etc. Compiling guides for the constellations of Dorado and Mensa that include the Large Magellanic Cloud, took a complete year.
Updating CSOG 2.2 to 2.3 took 3 1/2 years.
Is CSOG for GOTO telescopes only?
To the contrary. All CSOG objects include epoch J2000.0 coordinates. The coordinates can be plotted on the starchart you already own. If your starchart does not include the object, simply plot the position and make your starhop. Once close to the object's position, the DSS image in the guide takes over, leaving no doubt whether or not you found the targeted object.
Tours and AstroPlanner planfiles, but no SkySafari observing lists..? Celestron's SkyPortal app..?
SkySafari is an application that allows creation of custom observing lists. However, objects have to be present in the SkySafari object database. If an object is not in the database, it can not be added. As CSOG contains many thousands of objects that are not included in the SkySafari database, CSOG SkySafari observing lists can not be created at this time.
Hopefully a true "user objects" feature will be added to SkySafari in a future update. A simple "R.A. / Dec. / Object name" format will do. Until then, SkySafari will remain just a toy when it comes to use for visual astronomy.
The same goes for Celestron's SkyPortal application.
As the WDS catalog is (for the most part...) included in SkySafari, Skylists are added to the Struve Double Star edition.
DSS Images, but no sketches?
CSOG contains over 15000 objects. Sketches for all of these objects do not exist.
But what about sketches for a limited number of objects, such as the Messier edition? The problem is that sketches do not provide for a standard candle. By definition they are a subjective representation of any object, dependent on the sketcher's equipment, eyesight, artistic abilities, atmospheric conditions at the time of observation and of course the objects' elevation.
For sketches to be truly useful and an objective representation of what any object looks like through the eyepiece, all drawings must be comparable. A star of any magnitude must be drawn equal in size every time so as not to confuse them with brighter or fainter ones. Orientation and image size must be identical and, preferably, the object must be at similar elevation to limit atmospheric effects.
To the best of my knowledge, such sketches do not exist. No matter how beautiful a sketch may look, the usefulness for visual astronomy is limited, especially when considering the huge number of objects in reach of moderately large amateur telescopes.