BEGINNING OBSERVER TECHNIQUES: DRAWING WHAT YOU SEE WITH YOUR TELESCOPE

Sometimes the best way you can become a good OBSERVER is to draw what you see.

It's not hard to draw simple things that you see in your telescope, like the disk of a planet against dark space. You just use a soft pencil and "reverse" the black and white in your mind: thus, when you see something 'light' you draw it dark on the paper. This is the way telescope drawings have been done since the telescope was first invented, around four hundred years ago!

But, now most homes have a computer, and often a scanner. So now it's very easy to scan, "reverse" or "invert" what you are drawing with a computer program for editing graphics, and have it come out 'light on dark' as you see the sky at night with your telescope. The example below is Stephen's drawing of Comet Hyakutake: the original pencil sketch is on the left, and the computer processed version -- adjusted to resemble a "real view" of the sky -- is on the right.

Below is a drawing that Stephen made with the telescope shown at the top of this article: my own little inexpensive 4" Orion "Starblast" reflector scope. This is Comet Holmes, one of the brightest such objects ever seen, sketched from our driveway right in the middle of San Jose, California. The original pencil drawing (full scale size), scanned without alteration, is shown first, followed by the final computer "inversion", with enhanced and carefully adjusted contrast, processed to try to show something like the realistic view as seen in the eyepiece.

As you practice making drawings, your ability to observe will improve. At first, you can try to draw the stars you see, and to place them carefully in the shapes -- triangles, squares, or other forms -- that they seem to show. Draw the brightest stars with a firm, dark point. The faintest stars can be just a faint dot. Experiment with the sizes of the stars to indicate the differences in how bright they are: that's the way printed star charts are made.

The Moon is an easy subject. You can start with low magnification, and try to draw the largest crater that you see. If your telescope does not have a motor to point it at the Moon and keep it there as the Earth slowly rotates, you will have to adjust your telescope to keep looking at the same view. It will be hard at first, and easier and easier as you progress and learn from experience.

Most Moon drawings are intended to show specific details of the craters and "rilles" (fine markings of channels that may run for hundreds of miles.) Moon drawings are often best made when the Sun's light casts the longest possible shadows: see this webpage for more information about the time to draw the Moon. Here is a page showing the famous historic scientist Galileo's early moon watercolors (done soon after he built his first telescope and turned it on the sky, in the early 1600s.) The pictures are very beautiful, but they are simple and do not record much detail: there is no reason that you too -- if you like to draw, and enjoy using your telescope -- can do something like this, with practice! Start when you can see a low power view of the moon when it has a partial 'phase' and is not fully illuminated. Draw the outline, and then the shape of the most distinct markings; shade the differences of contrast with the side of your pencil point. Draw heavy lines to indicate the dark shadows. Your Moon picture will become a permanent record of what YOU saw!

DRAWING THE PLANETS

The planets will be a greater challenge, because their disks are small in diameter since they are so much further away than our Moon. You will have to use high magnification. That means employing an eyepiece that magnifies as much as, or more than, a hundred times. It is very difficult to keep a planet's image in the field of your eyepiece in a telescope with an "alt-az" mount at 100x. Most people who specialize in drawing planets use telescopes with equatorial mounts, and equip them with motor drives. Then the planet's image will stay steady, and one might magnify Jupiter about 160 to 200 times, Saturn as much as 300 times, and Mars even as high as 400 times (with an appropriate telescope; small beginner scopes won't do well with such high magnification.)

Here are some drawings that we made, years ago when producing our program "Eyepiece". The telescope used had a large mirror of 10 inches' diameter, so the view was crisp, bright, and sharp. But we had to wait until each planet was best sighted, since the distance of some planets -- like Mars -- varies greatly as both the planet, and the Earth, revolve around the sun in their distinct orbits. It is best to draw the planets when they are "at opposition", their disks being the largest possible diameter with the best view of details. This can be found out by consulting with astronomy magazines for a planet "ephemeris", or on websites -- such as Calsky -- that have information about the placement of the planets. Mars' apparent size from Earthly vantage, for instance, varies continuously and is "at opposition" every 780 days, and at most favorable periods (twice each 32 years, at 15 and 17 year intervals) will be as much as seven times closer to the Earth than at its maximum distance. But every two years or so, Mars is close enough to get a decent view, and that's the time you want to make your drawing. Jupiter and Saturn, having larger orbits, take much longer to move with respect to the Earth, so the changes of apparent diameter don't occur as rapidly and dramatically as that of Mars.

The picture below was drawn by Stephen, back in the late 1980's during a favorable Mars opposition. He used his 10" telescope at 400x magnification, and made a pencil sketch. I converted it to a scanned image file and colorized it using an old graphics editing program (created long before Microsoft Windows even existed!) called "Neopaint". As you can see, there is a lot of bright color on the disk of Mars, with darker markings as well as a very bright polar cap (made of ices that reflect the Sun's light brilliantly.) There may be less color seen by eye if you use a smaller telescope.

The website of the Northern Virginia Astronomy Club has a nice, illustrated, step-by-step tutorial all about observing and drawing Mars, by Bob Bunge.

The next drawing, of Saturn and some of its brightest moons, was done several years earlier, and has been scanned and computer-processed to resemble what was seen by eye. Saturn does have some subtle color as shown in a fairly large sized telescope, with a distinctly different shade for the rings than the body of the planet. This picture is scaled so that it resembles a lower magnification than the image of Mars, above. Perhaps Saturn might look like this at about 175x in your telescope, but the rings change their tilt and go through a full range of inclination every few years. Perhaps the best time to view, and sketch, the planet is when the rings are tilted toward the Earth, so that the dark band -- the "Cassini division" -- is widest and mostly easily seen. The ring divisions are quite visible in 2007, but by 2009 and 2010, the rings will be on-edge toward the Earth.

High school and age adult observers who wish to learn more advanced techniques of making 'standard' drawings of the planets, useful as scientific tools to record details of changes that are sometimes even hard to photograph or image, may consult with the information supplied by the British Astronomical Association, for over a century helping amateurs achieve a level of critical performance. Here are the direct links to their Mars, Jupiter, Saturn, and Lunar observing sections. The American Association of Lunar & Planetary Observers has a comparable program, with web pages broken down into each solar system object, containing instructions and standard forms for submitting observations, such as the Jupiter template shown below. You will learn, for instance, how to draw the details of the cloud bands, loops, ovals, and other Jupiter phenomena so that your observations will be comparable to other observers, and useful to planetary scientists. (Are you thinking, perhaps, "science fair project"? We hope so!)

DRAWING THE STARS

Making a drawing of star clusters is possibly even more challenging than sketching the details of the planets. You will see so many stars with your telescope that keeping the arrangements in mind will be very challenging. Our friend Jaakko Saloranta, a deep sky observer in Finland, loves to draw star clusters best of all. His website has many superb sketches that have remarkable realism; he explains how he does many of them on this page. Here's a technique he uses: comparing the arrangement of the stars with something familiar, such as an object or animal. On his webpage of Visual Deep Sky Impressions, Jaakko shows you how he visualizes some star clusters as a mushroom, a turtle, an umbrella, or a frog.

To show you how beautiful and accurate Jaakko's drawings can be, I took one of his recent ones -- of an open star cluster called NGC-1980 in the constellation of Orion -- and made up a comparison with a sky photograph of the same object. Now, Jaakko has been making astronomical drawings for a long time, and has done hundreds of them: by now he is a master!

Isn't that an amazing comparison? Notice how well Jaakko managed to draw the relative positions, and brightness, of the stars.

It is important, when you begin sketching the stars, to follow a plan. On the website of Jere Kahanpää, a Finnish amateur astronomer and friend of Jaakko, you will find out how to do it: read his Deep Sky Drawing Guide and learn about plotting the main stars, then adding the fainter field stars. After that, you will rough in the outline and then add pencil lead to increase the dark areas and improve contrast.. Finally, you will add in some of the faint outlying stars, improving detail as required. It's easy -- if you have a good plan and follow it.

SIMPLE SKETCHES TO HELP YOUR OBSERVING

Stephen often sketches the things he see at his telescope, just doing a very quick raw picture to record his impressions where he observes in the mountains, far from home. Then, at home he fires up the computer and gets pictures from the Internet, using a number of astronomical reference websites, in particular www.messier45.com, using its "Deep Sky Browser" pages for the objects in which he is interested. Often he will find details shown in his sketches that help him understand the photographs. Cameras and digital imagers, attached to telescopes, work much more efficiently than the human eye, and can record VERY faint images that the eyes don't perceive clearly. The eyepiece sketch may capture only a very vague notion of what a deep sky nebula or faint galaxy "looks like" to a giant observatory telescope. But, occasionally, Stephen is surprised to see how well his eyepiece impressions have worked out, compared to photos! You never know, until YOU try to record the sight you see, for later comparison.

Here are some random sketches that he's used in his "Faint Fuzzies" articles, scanned from Stephen's observing logbook.

These pictures are crude compared to those of masters like Jere or Jaakko... but Stephen only does them for himself as references to save some information of what he saw. He puts some of them in his web articles about observing to illustrate details that he spotted, not because they are "pretty pictures"!

It's always best, if possible, to make note of which direction the telescope is pointing at, and at least to indicate both north and one other direction 90 degrees opposite, east or west. You should also know what your telescope's image orientation is: for instance, standard Newtonian reflector telescopes have an upright, inverted image. Then, you can alter your drawing by scanning and rotating it to match a photograph done in the standard way, "pole up".

A SKETCHING CHALLENGE FOR ADVANCED OBSERVERS

Finally, here is a drawing that Stephen is especially proud of, but it's not the subject that we would recommend to beginners: THE SUN. For, it is dangerous to try to use a telescope for solar observing, and ALWAYS REQUIRES A SPECIAL SAFE SOLAR FILTER -- or you can be blinded! But, we have the necessary 'neutral density' and 'H-alpha' filters for the Sun, and carefully employ them following their safe-use directions. We suggest that beginning amateur astronomers should ONLY view the Sun with an experienced astronomer who has the appropriate solar filters, and NEVER to use their own telescope or binoculars. Under the proper supervision, BE SURE TO BE CAREFUL AND DO EXACTLY WHAT YOU ARE TOLD!

With those warnings out of the way, we present below a drawing that Stephen did back in the early 1990's using his "Lumicon Solar Prominence Filter" system, with which he could see the giant gas flares emitted in the solar corona; and when he found that it was almost impossible to register these fine details in a photograph, he made an eyepiece drawing instead, which I colorized so that we could include it in our "Eyepiece" program. I could not resist doing a little extra digital editing to make it look even better when I produced this webpage. (The deep red color of light is the wavelength of hydrogen alpha, which will show up -- in some specific types of filters -- prominences and even fine details on the photosphere of the sun, as in this fantastic picture.)

OTHER WEBSITES THAT HELP YOU LEARN HOW TO DO ASTRONOMICAL DRAWINGS:

There are many links on the web that will help you learn how to master the art of drawing what you see at your telescope. Here are some of our favorites:

• Astronomy Drawing by Michael Geldorp is a very nice and elegantly illustrated tutorial that takes beginners from the first stages to a finished drawing.

• Astronomy Sketches is a little web page by our friend Sue French, the "Deep Sky Wonders" editor and monthly columnist for Sky & Telescope magazine. Her drawings on this page were made with a 4" telescope, and show what may be seen even in a small, modest instrument.

Belt of Venus is an exceptionally beautiful website by Flagstaff, Arizona professional designer -- and amateur astronomer/artist -- Jeremy Perez. Being a superbly talented artist, he has put his exceptional eye to work, producing "photorealistic" drawings that are rendered white-on-black, wonderful replications of what the eye could see -- ideally -- under superb, dry, high desert skies. His special interest seems to be double stars, which he takes the trouble to measure carefully, and to render in their particular color differences. His deep-sky drawings, like this marvelous M-17, viewed in his 6" Newtonian at Anderson Mesa, are much closer to the true "eye experience" than you get from typical photos or CCD images. There are also very detailed tutorials that are invaluable. Jeremy is one of the authors of Astronomical Sketching: A Step-by-Step Introduction in Sir Patrick Moore's Practical Astronomy series, published by Springer.

• Bill Greer's Astronomy Site is a superb resource for learning how to do astronomical drawing. "To Sketch Is To See" is the motto, and Bill -- who is one of the most experienced and prolific contributors to the newsgroup sci.astro.amateur -- has been doing this for more than forty years. He has examples of excellent lunar, planetary, and deep sky sketches, often in color: and very useful descriptions of how to maximize one's technique.

• Visual Deep Sky Observing by Andreas Domenico of Breitenbuch, Unterfranken (Germany) is an interesting web page of drawings that have been reversed so that they are white-on-black like photos. Andreas has drawn many very obscure celestial objects, and has an excellent technique for showing nebulae and galaxies realistically.

• Suburban Deep Sky Observing & Sketching by Jay Michaels, written in 2003, covers much more than just making astronomical drawings (though the writing level is adult, and there is only one example of an object sketch: four stages of making an accurate drawing of the galaxy M81, which suggests that beginning observers with small aperture telescopes lacking motorized tracking aren't being addressed by the author.)



• Jaakko Saloranta's short tutorial illustrates how he makes, for instance, two raw sketches at different magnifications, and then "cleans up" the final result. This Finnish observer has posted hundreds of very useful sketches on his astro-website, most of them made with modest sized telescopes of 3 and 8 inches aperture, such as the small 80-mm Konus refractor telescope shown with Jaakko in this photo. We have one of those scopes -- in the "Orion" brand name model -- and can recommend it as a good starter instrument for youngsters and families.

RELATED RESOURCES ON OUR OWN WEBSITES:

• Regina's Article on the 2003 Mars Opposition, with two drawings of Mars done by Stephen.

• Telescope & Eyepiece View Simulations, from photos and drawings.

•  Christmas Present from Jaakko: Sketch Card for Cluster NGC 2420.

•  Inexpensive "starter" telescopes that we own and can recommend.