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And Sketching Primer. Astronomy Logs. By Jeffrey Fink. Logs for every need!. Why keep a log?. Keeping logs of your observations allows you (and others) to review and compare what you’ve seen at a later date, observe any possible changes, and to track your progress with the hobby.

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Why keep a log?

Keeping logs of your observations allows you (and others) to review and compare what you’ve seen at a later date, observe any possible changes, and to track your progress with the hobby.

Recording astronomical observations is something that has been done for thousands of years. From the first paintings on cave walls showing the stars and moon in the sky, to ancient Chinese pictographs showing comets in the sky. It’s records such as these that help us understand more of what we see today.

For example, Halley's comet has been observed by astronomers since at least 240 BC, and was recorded by the Chinese, Babylonian, and mediaeval Europeans, but it was not recognized as reappearances of the same object. The comet's periodicity was first determined in 1705 by English astronomer Edmond Halley, after whom it is now named. Looking back at the ancient records, we now know that this is the same comet observed throughout history.


What do I gain?

Your contribution may not be the big discovery as Halley, but there are still things that keeping logs will do for you.

At the very least, keeping logs will teach you patience. To accurately record your observations, you will be spending more time looking for those faint details that you would otherwise miss with casual observing.

As an added benefit, you’ll find that your observing skills will improve. Over time, you’ll train your eye to see more detail, and fainter objects that you may have not seen before. What once was only visible with averted vision, you may find you can see directly. And if you choose to sketch your observations, these skills can be honed even more.

Also, if you would like to participate in any of the Astronomical League’s observing clubs, you’ll need to submit your logs to earn the certificates.

So where do I begin?


Log files should contain at least the basic information, such as location, equipment used, conditions and of course, your target.

The Notes you make should be as detailed as you can make them, describing as much as you can about what you see.

Your log files can be something as simple as a basic spiral notebook…

Or a form you can print out, available from various sources.

You can also make your own.


If a simple log is what you prefer, then using a spiral notepad is perfect for a general log file.

However, for sketching, you may want to look into something without lines, such as a sketching pad.


If you choose to use a printed form, the forms you can use can be simple note style logs…

Or log sheets designed with areas for sketches.

what should i include
What should I include?

The Basics

Object Name

Object Type

Date / Time


Instrument (Aperture / Focal Length)

Eyepiece / Magnification

Transparency / Seeing

Other Conditions


Lets look at your Notes

You want your description in the notes section to include as much information as you can.

You should be able to review your notes at a later date and fully understand what you observed.

This means nothing, and can describe MOST of what we see!

Faint fuzzy oval.


Planetary Nebula

What is the overall shape, is it disk shaped or more stellar?

Are the edges sharp or diffuse?

Is it easy or difficult to identify in the field?

What is the color of the Planetary?

Is the center brighter, darker or uniform brightness as the edges?

Identify any other DSO in the field.


Did you use direct or averted vision? filters needed?

What is the overall shape?

Are the outer edges sharply defined?

Is any part of the nebula brighter or more concentrated?

Are there any voids or dark patches or lanes, bright filaments or streamers in the nebulosity?

Is there an open cluster nearby or involved or any obvious stars involved with the nebulosity?

Identify any other DSO in the field.

Open Cluster/ Nebulosity

Did you use direct or averted vision to view the cluster and nebulosity, are filters needed?

What is the overall shape?

Are the outer edges sharply defined?

Can both the cluster and nebulosity be seen with direct vision, or is averted vision or filters needed?

What is the overall shape?

Are the outer edges sharply defined?

Are the stars concentrated in any one area?

Is the cluster embedded in the nebulosity or is there a distinct separation?

Is any part of the nebula brighter or more concentrated?

Are there any voids, dark patches or lanes, bright filaments or streamers in the nebulosity?

Identify any other DSO in the field.

Open Clusters

Is it easily distinguished from the background stars, is it well defined?

Is there a overall shape?

How many stars can you count in the cluster?

Are the stars concentrated in any one area?

Is the cluster fully resolved or is background nebulosity noticed?

Are there areas where stars are absent in the cluster?

Are there any brighter stars in the cluster and do any stand out in color?

Identify any other DSO in the field.

Globular Clusters

Did you use direct or averted vision?

Is the core bright, compact, or not distinguishable?

Is it highly or loosely concentrated?

Is any part of it resolved into stars, averted vision or not,

or does it show mottling, or stars resolved at the edges?

Identify any other DSO in the field. 


Did you use direct or averted vision?

What is the overall shape?

Is the core noticeable, compact, stellar ?

Can structure be seen in the galaxy, mottling, bright or dark patches or lanes?

Are the outer edges sharp or diffuse?

Identify any other DSO in the field.

Notes for the Notes

This list is available as a handout after the presentation.


A new look at your Notes

Now that you have a better feel of what to include, lets see what your Notes should look like now.

Now THIS is something you can understand.

Very faint oval shape with direct vision, slightly brighter on the west. A.V. shows extended lobes to the east/west, and can just make out small dark patches near the southern edge. Slight hint of central star. Using OIII filter shows faint wisps on the northern edge.


A Log for Imaging?

So you’re asking yourself, “Why keep a log if I’ll have an image? Isn’t a picture worth a thousand words?”

What about ISO, exposure time, filters, conditions… There is plenty of information you should include in your imaging session logs.

Whether you’re shooting film or digital, you should keep a log of what you’re shooting in each frame. After all, one star field looks like most other star fields.


Feeling More Ambitious?

Try your hand at Sketching what you see!



You don’t want to be standing the whole session! So get yourself a nice chair or stool.

You want to be at a comfortable position to view in the eyepiece without a lot of work, as well as comfortably hold your clipboard for drawing. You can hold the clipboard on your knee if your stool has a footrest.

There are specialized observing chairs that have adjustable seat heights as well as an adjustable foot rests.

Those with better woodworking skills have even made customized “chairs” out of wood ladders.

You need to be able to SEE what you’re doing. And we all know that WHITE light is a big no-no.

Since you need to be able to draw you need your hands free, so a flashlight is out! You could look into a “Headlamp”, although it may be cumbersome when going back to the eyepiece.

A better option would be a small book light that you can clamp on to the clipboard. Just cover the light with red plastic wrap, or better yet, the red tape used for taillight repairs.


Pencils come in various levels of hardness, which can help in illustrating different brightness levels. But for starting out, a Standard No.2 pencil is perfect. If you’re sketching the planets, you can use colored pencils. Other sketching methods use charcoal sticks, or even white pencils when you use black paper.

Don’t forget the sharpeners! The difference between a sharp pencil and a dull one could make the difference between a magnitude 12 star and a magnitude 2 star!

This can be standard printer paper, or a spiral bound sketching pad. Start with white paper. As your skills improve, you can switch to black paper.

One tip is to use 100% cotton paper. This will help on those humid nights to keep your logs from getting soggy!

The online community recommends NOT using a plastic clipboard. The “cheap” fiberboard clipboards have a better feel.

They say the plastic ones tend to make your sketches to too harsh, and darker than you intended them to be.

They also attract dew quicker, which will soak the paper, ruining your logs.



RED light

Chair / Stool


Start SMALL!

On standard printer paper or a sketching pad, use the lid from a peanut butter jar to draw a circle.

For beginners, it would be less daunting to keep your sketching area somewhere between 2 to 3 inches in diameter.

Over time, as your skills improve, you can increase your “Canvas” size.

For full constellation, or even lunar sketching, you may want to use a large box.


Keep it simple!

You don’t need to be an artist.

Keeping a simple drawing of the field of view can give you the same results as your notes, and in some cases, can give MORE information than those same notes.

Over time, your drawing skills will improve, showing more and more detail.


Before you begin

Perhaps the hardest part of sketching is learning to draw in “negative”. This would be drawing DARKER on the paper to show the BRIGHTER areas you see. It will take some practice, but over time, this will become almost second nature. If you wish, You can try your hand at sketching white on black paper.

TIP: Try to avoid looking at images before your sketching session. Without you realizing it, your mind will remember the image, and will have a tendency to “fill in” areas that your eyes are NOT really seeing. You’ll find yourself adding details that you may never see under those same conditions.


Establish your starting point by adding the brightest stars in the field. Stars around the edges work to help you with your spacing.

Starting out

One by one, begin adding fainter and fainter stars in the field. Estimate brightness by varying the size of your dots. As your skills improve, you can use lighter shades of pencil darkness to show this.

Begin adding your main subject, slowly “darkening” the brighter areas.

Using your finger, eraser or blending tool, you can “smudge” the main subject to show very faint, or nebulous areas.

Adding features such as dust lanes may be tough is you didn’t plan ahead. Specialized gum erasers can be shaved into sharp points or wedges to help you in these cases. Also, molding erasers are great for “lifting” pencil marks to make them lighter.

Now add your finishing details such as fainter stars, and other DSO’s in the field.

Don’t forget to add your direction points. You only need to add North and West. For planets, the north (or south) POLE of the planet, and the direction of rotation are more important than the compass points.

If you know the scale of your field of view, you should add that as well.


Some Tips for Sketching

For sketching planets, there are ready made templates available for Jupiter that include faint “guidelines” for the banding, or Saturn with faint rings to help you with the size and position. You just need to file in the details that you see.

Note the time of your sketch for the major features you draw. A planet like Jupiter may look different from the start of your session to the end. It would also be useful to note both start and end times.

It may be wise to use a template for Jupiter. Since Jupiter turns so fast, having the band guidelines helps for you to insert all the details you see. Also, remember, Jupiter is NOT round. It has a slightly oval shape. The templates would also reflect this.

TIP: Erasing some mistakes are difficult to do in the field. For these, put a light ‘X’ through the item that needs correction, with a note on the side of your drawing. Once you’re back inside, you can made those corrections easier.


Once you’ve finished your session, you can save it to the computer. Simply scan in your drawing.

Once on the computer, you can use a paint or photo editing program to “invert” the drawing so it looks more realistic to the view you had at the telescope.


There are programs available to keep records as well. Some can be used as “Planners” that you can print out to use in the field then transfer your notes back to the program to save. Using these programs make it much easier to make corrections, as well as review your notes at later times.

Do More on the Computer

TSOL (The Simple Observing Log) is one such program. You can also scan in your sketches and insert them into the log.

The same person also makes log programs that are specialized for objects like the Messier 110, Caldwell, and the “Overlooked” objects. These come with finder charts built in.

Best of all, these programs are FREE!


Editing Planet Sketches

When sketching planets, let your features go beyond the template circle. Trying to stop at the edges will give your sketches an unnatural look.

Once scanned to the computer, you can use your image editing software to crop the planet circle.


Further Information

If you are interested in learning more, there is a wealth of information, tutorials, tips and people willing to assist on the internet.

If you prefer, there is also a book available for purchase that was compiled and written by several amateur astronomers.

Astronomical Sketching: A Step-by-Step Introduction - $24.65 on Amazon


Log Sheets

Jeremy Perez – The Belt of Venus - - Free - Printable

AstroCards - - Prices vary with quantity.

Logging and Planning software


- Freeware

AstroByte Logging software -

- Freeware

AstroPlanner -

- $45.00 (Download)

- $69.00 (Disc)


Image Credits (Sketches)

Plato - Uwe Pilz -

Copernicus Crater - Ferenc Lovró – Graphite Galaxy -

Jupiter – Jay Scheuerle

Jupiter - Uwe Pilz -

Tutorial Pics - Yann Pothier

M27 – Jeff young -

Special Thanks

I would like to extend a special THANK YOU to all my online friends at for their help and tips for this presentation, as well as lending their fantastic sketches to be included for the examples. You guys are the greatest! 