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Purchasing CSOG

Below are all CSOG editions and prices, in US dollars.

Customers outside of the EU are exempt from VAT (sales tax).
VAT (21%) is added for customers in the European Union euro zone only.

Payments go through PayPal, as it is safe and available worldwide. You do not need a PayPal account to complete a purchase.

Click the PayPal button or shopping cart to select your CSOG content. You will not be asked for any payment information until you are on PayPal's website.
When the payment is complete you will receive the download link(s) by e-mail. CSOG Download links expire after a short while: Please make sure you start downloading soon after your purchase.

If you instead prefer to pay by different means, such as a transfer by bank account, please send an inquiry.

CSOG as a gift

When purchasing CSOG as a gift for friend or family, complete the purchase as you normally would. Send an e-mail to (or use the contact form) with the e-mail address of the recipient to whom future updates can be sent.
A "gift option" will be added to the payment system in the near future that will allow a personal message to be included.

Catalog Editions

Messier $5.95
Lacaille $3.95
Dunlop $14.95
Herschel $34.95
Herschel 400 $14.95
Herschel II $14.95
Caldwell $5.95
Bennett $7.95
Palomar Globular Clusters $1.95
Terzan Globular Clusters $1.95
Hickson Compact Galaxy Groups $9.95

Object Editions

  All Sky Northern Southern
5-6" Carbon Stars  $6.95  $4.95  $4.95
8-10" Carbon Stars  $7.95  $5.95  $5.95
12" Carbon Stars  $9.95  $7.95  $7.95
5-6" Globular Clusters $6.95 $4.95 -
8-10" Globular Clusters $7.95 $5.95 -
12" Globular Clusters $8.95 $6.95 -
5-6" Planetary Nebulae $6.95 $4.95 $4.95
8-10" Planetary Nebulae $7.95 $5.95 $5.95
12" Planetary Nebulae $9.95 $7.95 $7.95

The Catalog & Object editions as listed above include tours depending on the edition, but always include an AstroPlanner planfile:

  • the Messier catalogue is available sequentially (no tours), by constellation (with tours) or sorted for a Messier marathon (no tours)
  • the Lacaille catalogue is available sequentially (no tours) or by constellation (with tours)
  • the Dunlop catalogue, by constellation, tours included
  • all Herschel objects, by constellation, tours and index for Herschel 400 and Herschel II included
  • Herschel 400, by constellation, tours included
  • Herschel II, by constellation, tours included
  • the Caldwell list is available sequentially (no tours) or by constellation (with tours)
  • the Bennett list is available sequentially (no tours) or by constellation (with tours)
  • Palomar Globular Clusters, sequentially (no tours) or by constellation (with tours)
  • Terzan Globular Clusters, sequentially (no tours) or by constellation (with tours)
  • Hickson Compact Galaxy Groups, one guide for each of the Hickson groups, tours included
  • Carbon Stars, Globular Clusters or Planetary Nebulae are available by constellation, by telescope aperture (5-6", 8-10" or 12") and in either the All Sky or hemisphere editions, tours included. There is no separate southern edition for globular clusters.

Constellation Editions by telescope aperture

5-6" All Sky $39.95
5-6" Northern $29.95
5-6" Southern $29.95
8-10" All Sky $59.95
8-10" Northern $44.95
8-10" Southern $44.95
12" All Sky $94.95
12" Northern $69.95
12" Southern $69.95

Choosing your edition(s)

Image orientation

All of the CSOG editions are available in four image orientation editions:

  • True - unmirrored: North up, east to the left
  • Mirrored horizontally - MH : North up, west to the left
  • Mirrored vertically - MV : South up, east to the left
  • Mirrored horizontally & vertically - MHV : South up, west to the left

When selecting your edition(s) you will be asked to choose the image orientation of the content you selected. Please give this some thought before finalizing your order.
If you are in doubt whether or not your telescope mirrors, observe a fixed object in daytime and compare the naked eye view to that in your eyepiece.

Upgrades & Discounts

If you previously puchased a CSOG edition, you can purchase the same edition in a different image orientation at 25% of the original price, a 75% discount.

If you purchased a Northern or Southern hemisphere Constelllation Edition and wish to upgrade to "All Sky", you can do so by just paying the price difference.

Customers who wish to upgrade from a 5-6" or 8-10" Constellation Edition to an 8-10" or 12" Constellation Edition can do so at a 33% discount.

Customers who purchased a 12" Constellation Edition and who would like to purchase an 8-10" Constellation Edition, will receive a 50% discount. The same discount applies to existing 8-10" Constellation Edition customers wishing to purchase a 5-6" Constellation Edition.

Please submit your request by e-mail.

Downloading CSOG

After completing the purchasing process with PayPal, you will receive a download link by e-mail. Click on this link to download purchased content. Please make sure the e-mail did not end up in your spam folder.
To prevent piracy CSOG download links expire after a while.

All CSOG editions come in zipfiles. Please ensure the download proceeds uninterrupted. If you have a relatively slow internet connection (<5 Mbit) you may want to let it run overnight.
Once a zipfile is extracted you will find a folder containing all of the edition's content. It is up to you how to sort and store the files. Keeping them organized in constellation folders or a separate Specials folder is recommended.

If you have a slow or intermittent internet connection, please take note of the following:

  • Use a wired (ethernet) connection to ensure an uninterrupted signal.
  • When downloading an edition with multiple files, download the files one at a time.
  • Use a browser that automatically resumes an interrupted download. Use of Google's Chrome is recommended: The CSOG server supports resuming downloads, some browsers may not.
  • MS Windows users are encouraged to use Free Download Manager, a free application that will automatically resume an interrupted download.
  • If your connection is very, very slow and/or intermittent, please try using a faster connection at a different location.