Marking up sky atlases

February 4, 2017

I’m a book lover. Any space I’m in for long will have books on every available surface and piles of extras on the floor. Because of this love of books, for a long time I wouldn’t mark them up. This hands-off reverence extended to my sky atlases. But eventually I realized that sky atlases are tools, not heirloom pieces, and anything that makes them more useful when I’m observing is justified.


Here’s a representative page from my working copy of the Pocket Sky Atlas (I also have a second copy, autographed by John Dobson, that actually is an heirloom piece now). The circles and polygons flag objects from various Astronomical League observing projects. Triangles are double and multiple stars, rectangles are Herschel 400 objects, big circles are for the Binocular Deep Sky objects, and an open letter C designates Caldwell objects. I also drew in the position of Almach, which is just off the edge of this chart, wrote in the number for the multiple star 57 Persei, and wrote down the magnitudes of Algol and some of the useful reference stars, including Almach. Arrows in the margins are left over from my Caldwell tour.

I’ve finished all of those projects except the Herschel 400. You’ll see that some of the little rectangles have a diagonal slash across one corner – that’s how I flag which ones I’ve already observed. I’ve actually seen all of the H400s on this chart, I just got lazy about marking them off in the atlas. But I did write ‘CLEAR’ in the corner of the page so I know not to waste my time looking for unobserved H400s here. Other pages have the numbers of the H400s I still need written in the margins, for quick sorting and bookkeeping at the eyepiece.

These marks are very helpful while I am working on a project, because I have an instant visual reminder of what’s available to see in any given stretch of sky. And once I’m done with a particular project, the marks still point me to a lot of ‘best in class’ objects that I might otherwise overlook or forget.

Oh, I also sketch in the positions of comets from time to time, with the dates of observation.

This method has worked so well for me that I have thought about picking up extra copies of the PSA (for $13!) just so I could mark them up with objects from other observing projects. I’ve done that with a couple of my other atlases. My copy of the Cambridge Double Star Atlas has all of the AL Binocular Double Star targets marked, and I use my Jumbo PSA (which is ridiculously useful) to keep track of targets from the last several years of Sky & Telescope’s Binocular Highlight column, to help me avoid repeats. Of course I have other lists for all of these things, both physical and digital, but it’s nice to have an easy reminder when I am out observing or doing desk research.

Do you mark up your atlases? If so, what system do you use? Let me know in the comments.


  1. Yeeah. I have been “highlighting” and putting pointers in the margins of my only copy of PSA for more than 2 years, Carbon stars particularly get the yellow highlight. Took more than 10 years to mark anything in “Nortons”-the PA of Porrima when it just became splittable in my celelestron ED 80 a couple of years ago. Got it wrong by exactly 180 degrees. Took wrong star as the primary. Made no change to my comment -that is how i saw it.
    Many thanks for your gr8 blog. Clear skies, rich.

  2. I mark up the pages printed out from the online Tri-Star Atlas to identify target objects. My Interstellarum Atlas I don’t feel a need to mark up, although some of the introductory pages have already come off the spiral.

  3. A relative newcomer, I’m working on the AL Messier program. I’ve circled just about every Messier in my Pocket Sky Atlas, and noted the date of my first observation of each object. I also love my books and have the aforementioned piles of them…but I have no problem with making marginal notes or underlining or highlighting.

  4. Right there with you, Bill. I used to work in a used bookstore so I had an almost visceral horror of marking up books. But then I realized that if I was reluctant to mark up a book, it was because I was worried about the resale value or what the next owner would think – it was an admission that I might not keep the book for life. Now I’m very free about marking up my ‘keepers’. Although they all look like keepers when it’s time to make space on the shelf.

  5. I’ve been marking my atlases for few years. For me it’s a sort of diary of my observations, so don’t have any problem with making notes in my atlases. Clear skies, Stan

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: