Note - the 4th edition of the Compendium was released on November 6, 2023, including both Mac and Windows versions. Please go to this link for the latest edition.
Also, on Sunday, Dec. 3, 2023, at 8:30 pm CST, I will be giving an overview of the new edition of the Compendium on the free Youtube Astro Imaging Channel.********************************************************************************************
The 2nd edition of the Compendium is now finished. This work is to further my goal of providing the astrophotographer with free and useful tools for finding interesting deep sky targets to image.
Most of the 2nd edition work has been on the spreadsheet, which includes the following changes:
- Spreadsheet utilizes user-specific data such as user location and time of day.
- Sun rise and set times (including nautical darkness onset) are included, as well as a bar to indicate sun elevation.
- Moon phase, rise and set times, age and illumination percentage are included.
- Object parameters such as transit time, transit date, moon separation, and impact of moon phase are shown for every object.
- For each object, the altitude profile for the next 6 hours from the selected time is shown, color-coded to indicate the best imaging time.
- Five filter buttons have been added to more easily filter subsets of the total sheet.
These features require the use of many macros for the detailed object calculations. Starting in 2022, for security reasons, Microsoft is blocking macros by default in all downloaded spreadsheets. To enable the macros in this (or any other) spreadsheet, simply select the Unblock checkbox on the General tab of the Properties dialog for the downloaded file in Windows File Explorer. If you are uncomfortable running these macros on your computer, you may download the
1st edition which does not have these macros (or the associated features). Acknowledgements to Keith Burnett, Simon Dawes, Jean Meeus, Peter Duffett-Smith and Jonathan Zwart for their past work on detailed equations which formed the basis for many of the calculations.
The overhead of the above calculations for so many objects is significant, so I had to make a few changes to reduce the recalculation times. I have removed the mouseover images from all columns except the first one (the Object Name column), and I have reduced the number of objects to 3000 by removing the smallest and most obscure objects. When sorting the data, or changing the location or time, the spreadsheet takes about 3 seconds on my computer to complete the refresh.
For those of you who added your own entries to the first edition, I apologize for the work which will be required to move those to this sheet. I am hopeful that future revisions will not be as significant.
The eBook remains largely the same but has been modified to include a more comprehensive user’s guide to the spreadsheet.
The 2nd edition of the Compendium is available for free download at these links:
As a reminder, the Compendium provides technical data on 3000 unique deep sky objects from 27 object types for declinations down to -50 degrees. These objects are cross-referenced to 28 catalogues. Object images are provided for 1922 of these objects in 96 compilation posters. Hyperlinks and thumbnail mouseovers are used for each of the 1922 imaged objects, including a link to each object's Astrobin image posting.
Please let me know if you have any questions or corrections. The long term home for the Compendium will be at my new web site (
www.garyimm.com), which I am still developing.
Note - For those of you who do not have access to Excel, I have tried to get the spreadsheet running on programs other than Excel but I have not been successful. I will keep looking for a solution but I have none at this time. The spreadsheet macros appear to be too complex for other programs to access it. I will keep looking for an answer. However, if you don't have Excel, you should still be able to run version 1 of the spreadsheet on most non-Excel programs - see the download in this
Astrobin post. Version 1 has no macros and so cannot do the complicated sun, moon and object calculations. But there are still plenty of useful features - all of the object data for 3000 objects, mouseover images of each object, links of each object to my Astrobin image, and cross-references to 100 catalogs and compilations.
Also, for those of you who use a Mac, I have received feedback that this spreadsheet (version 2) works by using Parallels, installing Microsoft Office, and then using Excel.
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I gave a YouTube talk on this Compendium in November, 2022 on The Astro Imaging Channel, shown in its entirety at
this link.
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