Release Notes & Statistics

CSOG Release Notes & Statistics

Current day

There are now 105 unique CSOG editions + 22 'Periodicals': Objects of the Week / Month / Season for complete years. Please click here for the complete list of current editions.

Editions added after the September 2025 update

• Deep Sky Forum's Objects of the Week for the year 2016 - 15 November 2025
• Deep Sky Forum's Objects of the Week for the year 2017 - 15 October 2025
• Star Party Observing Program: Eldorado Star Party 2025 - 15 October 2025

Versioning

As described below, every CSOG edition was updated with the publication of CSOG 3.0 in November 2024. Going forward, due to the size of CSOG, there will not be another complete re-publication of all editions simultaneously. Instead, there will be interim updates, publishing only updated content: Observing guides, index files, AstroPlanner planfiles & Tour files.

This means that an edition can contain content that is marked either V3.0 or V3.0.1. The V3.0 designation means the file was not updated since November 2024, or its initial publication date, whichever comes later. The V3.0.1 designation means the file was updated with the interim update of September 2025.

With every update, the edition's index file will always contain the new version number, regardless of changes to the index itself. Version numbers can be found in the index file and observing guides' footers, in the AstroPlanner planfile 'plan information' and in the tours' headers.

New CSOG editions will always be marked as V3.0.

CSOG's Double Star editions, the Binocular editions and the Observing Aids use their own numbering.

No version numbers are used for CSOG's 'Periodicals' (Objects of the Week / Month / Season) and for the Star Party Observing Programs.

Regardless of versioning, the date of initial publication or the date when an edition was last updated, is displayed for every edition. In case you wonder if you have the latest version of an edition, please look at the version number in the footer of the edition's index file and compare it to the latest download version number.

What to do with earlier editions..?

While earlier CSOG editions can and will of course provide you with unique content suitable for many years of celestial observations, the September 2025 interim update brought so many improvements that it is best to download all editions anew. Thanks to the digital nature of CSOG, that is really only a matter of a few mouse clicks and waiting for downloads to finish.

CSOG Interim update - 22 September 2025

An interim CSOG update was published on 22 September 2025, along with 9 new editions. Where applicable, new objects and new or updated information was incorporated into existing content.

The interim update to existing content encompasses many changes. Ranging from tweaks as small as additions of periods and commas, to errors corrected, information updated and new objects added. For example, 201 objects were added to the 12-14" Constellation edition.

Updated content is marked V3.0.1.

New editions

• Struve-Straka Nebulae
• Dorschner-Gürtler Nebulae
• Van den Bergh Reflection Nebulae
• Rojkovskij-Kurchakov Nebulae
• Bernes Bright Nebulae
• Neckel-Staude Nebulae
• Merrill Planetary Nebulae
• Peimbert-Bátiz & Peimbert-Costero Planetary Nebulae
• Herschel Regions

To note what editions are part of this interim update, it's easier to list the 16 editions that were not updated: The KTS and Grus Chain galaxy editions, the Dolidze-Dzimselejsvili, Roslund, Lyngå, Hogg, Harvard, Haffner and Pfleiderer star cluster editions, the LMC Regions edition, the Messier and Lacaille binocular editions, the double star editions and the observing aids.
Every other edition was updated.

The total number of files that were added or updated on 22 September 2025 is 26200:

• 22353 pdf's, including 652 index files
• 374 AstroPlanner planfiles
• 837 Argo Navis User Catalogs
• 874 NexTours
• 875 EQTours
• 887 Autostar tours

New editions February - September 2025

From February to September 2025, 20 new editions were added:

• All Deep Sky Forum's Objects of the Week for the year 2020 - 14 February 2025
• Haro Galaxies - 21 March 2025
• Texas Star Party 2025 - Advanced Observing Program - 9 April 2025
• Lacaille binocular edition - 12 April 2025
• Texas Star Party 2025 - Regular Observing Program - 12 April 2025
• Texas Star Party - Binocular Observing Program - 12 April 2025
• Texas Star Party - Advanced Binocular Program - 12 April 2025
• Texas Star Party - Binocular Program from "Hell" - 12 April 2025
• All the Webb Deep-Sky Society's Objects of the Month for the year 2020 - 19 April 2025
• All the Astrotreff Objects of the Month for the year 2020 - 19 April 2025
• The Double Stars in Burnham's Celestial Handbook - 18 May 2025
• Stellafane 2025 - Observing Olympics - 27 June 2025
• Stellafane 2025 - Binocular Observing Olympics VII - 27 June 2025
• Astronomy Magazine's 101 Cosmic Objects You Must See - 12 July 2025
• Astronomy Magazine's 101 Weirdest Cosmic Objects - 12 July 2025
• Starnights 2025 - Observing Program - 25 July 2025
• Starnights 2025 - Challenge Observing Program - 25 July 2025
• Starnights 2025 - Binocular Observing Program - 25 July 2025
• All Deep Sky Forum's Objects of the Week for the year 2019 - 16 August 2025
• All Deep Sky Forum's Objects of the Week for the year 2018 - 13 September 2025

CSOG 3.0

With the publication of CSOG 3.0 on 29 November 2024, 20 new editions were added. Where applicable, new objects and new or updated information was incorporated into existing content.

The new CSOG 3.0 nebula editions bring further unique content to CSOG. These editions will appeals to both observers and astrophotographers alike. For these catalogs, the objects they contain and for their proper "historically first" designations, the record is finally set straight, after many decades. This information - as goes for most CSOG content - is not available in any other publication.

Updated Content

• CSOG 3.0 was in essence a complete rewrite: there was not a single file that was not edited. A lot of changes were also made 'behind the scenes', allowing for much easier updates from here on;
• For every galaxy in "by object" guides that is within the SDSS footprint, an SDSS image was added in addition to the DSS images that were already part of every observing guide. These images add a lot of useful detail, especially to the many galaxies in the Herschel edition and the Herschel 400, Herschel II, Herschel 3 and the new Herschel Sprint observing programs filtered from it;
• "By object" guides (one object, one guide) were added to the Melotte, Raab, Trumpler and Collinder star clusters editions. Other star cluster editions will follow;
• Countless updates to and corrections of existing content, along with lots of cosmetic tweaks;
• Many objects added, for example, in addition to the new editions: 295 objects added to the Named Objects edition, 798 objects added to the 12-14" Constellation edition... and much more;
• For every download, the number of included observing guides & the number of pages, the index files, planfiles and tourfiles is now displayed.

CSOG Statistics

updated: 15 November 2025

• 105 Editions, 2 observing aids and 22 "Periodicals" (Objects of the Week / Month / Season) for complete years;
• >1.4 terabytes of content;
• 16251 unique observing guides & observing aids (47690 pages) and 726 index files (3256 pages), excluding the "Periodicals" for the current year;
• 693 unique AstroPlanner planfiles;
• 4741 unique Autostar Tours, NexTours and EQTours;
• 5236 unique Argo Navis User Catalogs.

The size of CSOG

CSOG is a digital publication, intended to be used on a computer (for planning and logging) and on a properly filtered and dimmed tablet at the eyepiece of the telescope. CSOG will not exist in print, unless a publisher wishes to create books for specific editions; that, of course, only with my permission and appropriate compensation.

The following analogy gives a good impression of the size of CSOG:

Say, one was to in fact print CSOG. All editions as of 15 November 2025, including all index files. No mirrored editions, only the unmirrored ones. Printed once, double-sided (duplex). Some guides and index files have an odd number of pages, which would leave blank pages at the end, but for the sake of argument let's say every page were to be filled.

Given that, per the image to the left, a pack of 500 pages is 5.3 centimeters (2.09 inches) in height... how high would the stack of paper be for all CSOG editions printed (every edition and every index only printed once, double sided, no mirrored editions)?

47690 pages of observing guides & observing aids + 3256 pages in the index files = 50946 pages. Printed double-sided that would fill 25473 pages front and back. Divided by 500, that is 50.9 packs of paper. Multiplying that by 5.3 centimeters (2.09) inches tells us the height of the stack for all of CSOG (unmirrored) printed once, including all index files, is 2.70 meters (8.86 feet).

Were one to print all mirrored content, too, again double sided and making sure to print the index files and the unmirrored binocular editions, double star editions and observing aids only once (amounting to almost 6 times the total number of double-sided pages in the last printed edition of the Encyclopaedia Britannica), the height of the stack would be 9.87 meters (32.4 feet).

That is the size of CSOG and that is why it does not exist in print.

Due to the sheer size of the publication, CSOG 3.0 was the last release in which every edition was updated simultaneously. From here on, there will be interim updates to existing content in addition to publication of new editions.

How does CSOG compare to other astronomy publications?

You can best make a comparison yourself, but here are a few pointers.

Registration & Support

To download the Clear Skies Observing Guides, registration and a support donation is required: a modest fee to support the creation and publication of CSOG.

CSOG is a one-man-show, created, hosted and self-funded by Victor van Wulfen. It cannot exist without support.

Support donations will offset only a fraction of the time, effort and costs that have gone into creating CSOG, since the year 2001 and in its current form, since the year 2008. There is no profit and unless literally thousands of support registration will pour in, there never will be a profit.

As of the publication of CSOG 3.0 on 29 November 2024, registration and a support donation gains access to all CSOG downloads and any new editions and updated content for the duration of one year (365 days) after the day of the support donation. That ought to be plenty of time to download all CSOG editions and any new content published within that one year, in all image orientation options. Once the year has expired, a new support donation will be required to continue to have access to the downloads for another year.

Registrations for CSOG 2.4 were deleted and a new registration and yearly support donation is required for CSOG 3.0.

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