Managing Your Deep-Sky References

Amateur astronomer Phillip Kane gives some advice on organizing "your" observing experts to assist you at the eyepiece.

Dumbbell Nebula

M27, the Dumbbell Nebula
Westview Observatory, Ohio

Like many amateur astronomers who visually observe deep-sky objects, I have a shelf of favorite references whose authors write about their compiled observations. The books I most use are:

  • Burnham, Robert Jr. Burnham’s Celestial Handbook (3 volumes), Dover Publications, 1978.
  • Dyer, Alan. “The Finest NGC Objects.” In: Observer’s Handbook 2006, 275-277. Royal Astronomical Society of Canada, 2005.
  • French, Sue. Deep-Sky Wonders. Buffalo: Firefly Books, 2011.
  • Houston, Walter Scott: Deep-Sky Wonders. Edited by Stephen J. O’Meara. Cambridge, MA: Sky Publishing, 1999.
  • Jones, Kenneth Glyn, Ed. Webb Society Deep-Sky Observer’s Handbook (5 volumes). Enslow Publishers (USA) and Lutterworth Press (UK), 1978-1981.
  • Luginbuhl, Christian B. and Brian A. Skiff. Observing Handbook and Catalogue of Deep-Sky Objects. Cambridge: Cambridge University Press, 1990.
  • O’Meara, Stephen James. Deep-Sky Companions: The Messier Objects. Cambridge, MA: Sky Publishing, 1988.
  • O’Meara, Stephen James. Deep-Sky Companions: The Caldwell Objects. Cambridge, MA: Sky Publishing, 2002.
  • Mallas, John H. and Evered Kreimer. Cambridge, MA: Sky Publishing, 1978.
  • Newton, Jack and Philip Teece. Cambridge Deep-Sky Album. Cambridge: Cambridge University Press, 1983.
  • Vehrenberg, Hans. Atlas of Deep-Sky Splendors. 4th Ed. Cambridge, MA: Sky Publishing , 1983.
  • Webb, T. W. Celestial Objects for Common Telescopes. Reprint Ed. Dover Publications, 1962.

Anyone reading this has, no doubt, a different shelf of favorites, but one’s favored books are not the focus here. Rather, it’s the frustration and time-robbing inefficiency of shuffling through them — and their imaginative indexing systems — to gather observing clues while observing. Why did I invest in all these great resources to not use them “at the eyepiece?” Why do I put up with inefficient habits like this? (1) Book juggling and page flipping while holding an uncooperative red flashlight; (2) finding out the deep-sky object I’m observing isn’t even in the book I’m searching; or (3) finding out the object is in the book but only with comments for scopes with double the aperture of mine. And (4) why do I go through this process as some sort of ritual — often for the same object?

These frustrations have induced me to get moving on a plan of consolidation. Presented below is my attempt to diminish this waste of eyepiece time (and investment). While this observing muddle is not the biggest problem many amateur astronomers face — getting a larger, better telescope is — finding a way to utilize those great observing handbooks in “real time” is a worthwhile pursuit.

So, to help speed things up while observing, I embarked a while ago on a project of “doing my homework first ” — once and for all — and in the light of day! I took a list of my deep-sky favorites (about 260 targets) and checked each one in my stack of references. If an object was in a source, its page number was noted. I also noted if small-scope comments were even included in the text (I now observe with 4- and 6-inch refractors). If I found notes for small scopes, I abstracted them to what I deemed most useful for at-the-eyepiece help. I held each comment to about 50 words, usually less. I always included the page number, making it easy to seek the context of my summary. Although a very time-consuming effort, I found this abstracting work rewarding and educational because it caused me to think about what might be important while actually looking through the eyepiece.

I chose an Excel spreadsheet for the format because these notes are part of a larger layout that includes several data-columns for each object. Here are three examples of how my entries look:

Setting up your spreadsheet

Sample of my spreadsheet. The header row contains information for the deep-sky object, including primary and alternate catalog designations, type of object, visual magnitude, size, distance, and position (RA and Dec.). Information from the various reference books is positioned beneath the header row. Click on image to make larger.
Philip Kane

Above the abstracts of the reference books, I inserted a row for each deep-sky object with additional information, some traditional and some not so much. Besides catalog numbers, object type, magnitude, and size (from Luginbuhl/Skiff), distance (from SEDS), and RA and Dec., I’ve added a few columns of my own.

Add a rating column

It’s a simple matter to add or delete columns to a spreadsheet. My spreadsheet includes a “rating” column to give me an indication of how many references describe a particular object. Click on image to make larger.
Philip Kane

The first column, “Rating,” is a count, for each object, of how many reference books have useful small-scope notes. This is an arbitrary rating, obviously, but it gives some guidance and priority. In my setup, the maximum rating can be 9 (there are more than nine references, but some of them are mutually exclusive, like the Messier and Caldwell books.) I always include Webb, whether he has comments or not, for historical interest. If Webb has comments (based mostly on observations from the 1850s), it’s interesting to realize that he did not know the nature of what he was observing.

A matter of personal preference

I’ve added several columns based on my own interests and observing habits, including “light-year diameter of a 1° field-of-view eyepiece,” “apparent light-year size,” and comparative magnitude and size information. Click on image to make larger.
Philip Kane

Other columns I’ve added for my enjoyment include: 1) The light-year diameter of a 1° field-of-view eyepiece; 2) the object’s light year size; 3) the Sun’s apparent magnitude if it were part of the object (not included for galaxies); and 4) the apparent size of the object if it were “brought alongside” the 1° extent of the well-known “dipper” of the Pleiades cluster, M45 (also not included for galaxies).

There are, of course, numerous photographs available for any popular deep-sky object, but my “Photos” citations rely mainly on the two albums of Verhenberg and Newton & Teece. These two on-my-shelf sources have fairly “realistic looking” and appropriately scaled pictures for a small telescope. (At the eyepiece, great Hubble shots don’t help much!)

My layout, the choices of objects, and the publications I’ve used are, of course, personal. Although my compilation of 260 deep-sky objects might be of general interest, I suspect everyone reading this would have a different way of doing it. However done, you’ll feel “homework free,” create more eyepiece time, and gaze upon the celestial targets you cherish with a little more attention to the details “your expert observers” see. My file of deep-sky objects has increased the amount of time I spend viewing any particular target because all the hints offered by diverse observers have been brought together in one place — available in the dark, next to the scope, on a computer screen. These gathered observing suggestions do not, obviously, preclude using other appropriate sources, like current magazines, or even adding other references. But it certainly saves a lot of page flipping in poor lighting.

— Phillip Kane, Cassel, California, September 21, 2015,

4 thoughts on “Managing Your Deep-Sky References

  1. BillB

    I love Phil’s advice!

    Many of us have invested deeply in an extensive astronomical reference library. Each volume has something unique to offer, and read at leisure provides an almost inexhaustible source of learning and discovery. Yet, the whole library is of little use under the dark sky, behind an eyepiece, while attempting to acquire an object.

    What Phil discusses makes common sense; a relaxing, enjoyable hour with the reference volumes under daylight will save hours of time under the night sky. I have done something similar, usually at the beginning of an observing year or season. Constellation, by constellation, I compile the pertinent facts from each resource to generate a succinct and personally tailored observing list. It saves loads of time and frustration. The greatest benefit of all is more time looking at objects. And after all, looking is what it’s all about!

    Thanks Phil, for taking the time to suggest an enjoyable way to get more productivity out of our precious observing hours.

    Clear skies, ~ Bill Boublitz

  2. Joe-Timmerman


    Your list of reference books are classics that many of us also own. Would you be willing to share your spreadsheet with others?

    Thank you,

    Joe Timmerman

    1. Phillip

      Thanks for your comment, Joe. I would like to publish my 260 targets as an Observing Handbook, so I am not willing to send out the whole spreadsheet yet. What I would like to do is send you two constellations “of your choice” to try out and see if they add to your observing experience. I need some feedback. Send me your email address at my icycomet email above. Thanks for your interest, Phil

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