The 2024 edition (5th edition) of the Imm Deep Sky Compendium is now finished and available for free download. The 36 MB download link is here.

The Compendium is a free, detailed Excel spreadsheet that provides the astrophotographer with a useful tool for finding interesting deep sky targets to image, specific to the current time and user location. The spreadsheet contains a database of 3145 deep sky objects and 26 cross-referenced catalogues. Each object has an image, a description, an imaging rating, a SIMBAD link, an ALADIN link, and 20 pieces of technical data. The spreadsheet runs on both Windows and Mac.

At this time, this update is only available for the English language version. If you are a new user looking to download one of the other 6 language versions, please see the previous 4th edition post here.

5th Edition Changes
This 5th edition contains the following changes:

As requested by a number of you, I have added an Azimuth column (column BJ), telling you the approximate object azimuth from your location at any time in degrees clockwise from north (0/360=N, 90=E, 180=S, 270=W).
240 more objects have been imaged and posted to Astrobin, with corresponding images and links in the spreadsheet, making for a total of 2450 posted objects (out of the 3145 total).
180 objects have had their images upgraded.
10 new objects have been added to the database.
Now that I have finished imaging the complete vdB catalog, those object images and data have been updated. The vdB catalog is shown in column BD.
I have added my new 109 object Faint Giants catalog to the spreadsheet in column BI.
A leap year related calculation which led to a one day error in using the “Sunset” button has been corrected.
Minor calculation errors with the object transit times and dates at certain longitudes have been corrected.
Numerous error corrections have been made to the 100,000+ object data entries.

Addressing Current Users
Many of you have adopted the Compendium spreadsheet for your own use, adding your data and notes in the My Section columns (Columns W to Y), or using the spreadsheet in other ways. To help you port data to this new 5th edition, a hidden column (Column BO) has been added to the spreadsheet. If you sort alphabetically by this column, the first 3135 data rows of the spreadsheet will be in the same order as the most recent previous version (edition 4g), assuming that it is also sorted alphabetically. You may then copy and paste your existing user data from the 4th to the 5th edition.

Before You Begin

Once you download the spreadsheet you must enable the macros, which are disabled by default in all downloaded Excel documents. To enable the macros in Windows, right click on the downloaded file in Windows File Explorer, select Properties, and select the Unblock checkbox on the bottom of the General tab. To enable the macros in Mac, simply click on Enable Macros when opening the file.
Depending upon your computer settings, you may see formula warnings (green triangles in cells) throughout the sheet which are visually annoying and which slow down the refresh time. Disable these warnings by clicking on one of those cells, then clicking on the exclamation point which appears, then clicking on Error Checking Options, then (under Error Checking Rules) deselecting the boxes for "Unlocked cells containing formulas" and "Formulas referring to empty cells".

Excel Access
The program requires Excel - it cannot be run on free spreadsheet programs. I have not found a free program which is able to run the 2300 lines of macros (VBA programming code) that is used for the calculations for each of the 3145 DSO objects (with 64 pieces of data for each object) together with sun and moon calculations. Similarly, because of the macros, the spreadsheet only runs on the desktop versions of Excel for Windows and MacOS. The use of macros is not supported on Excel for iPhone, iPad and Android phones, nor in the online (browser) version of Excel.

For those of you without Excel, I have published a750 Best Deep Sky Objects book on Amazon to assist you with imaging target selection.

Astronomy Scholarship Fund
The Compendium is provided free for your use. If you find it useful, I would appreciate a small donation to the Imm Astronomy Scholarship Fund, a tax-deductible donation account where 100% of the donations are used to provide scholarships to college students with an interest in astronomy. Scholarships are awarded each June.

Best regards and clear skies!
Gary