Introduction to astronomical drawing –

Introduction to astronomical drawing

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You are enough people that when seeing one of the drawings that in these pages are exposed you are interested in how they have been made, and you even consider trying it. I will start here what I intend to be a series of articles in which I will explain how I make my astronomical drawings, and offer some advice for those who encourage you to try.

Go ahead that the drawing and its techniques are something totally personal, that each one is developing according to their preferences with time and practice. There are other ways to do it, and of course you are all invited to expose and comment on these pages.

The drawings on these pages are made in negative , black on white, and then scanned, labeled and inverted for publication. Drawing in negative has several advantages: it looks better in the dark, the pencils are more precise and versatile, it is easier to correct, and it is much cheaper.

It’s just that I do not draw …

It is the phrase that I can hear most times when I encourage people to do it. Let’s not kid ourselves, nobody knows how to draw at the beginning. The keyword is practical , if you do not try, it sure does not come out.

Luckily, astronomical drawing does not require great means or complex techniques, nor great manual skill: almost everything that is seen by the eyepiece are dots and objects without much detail. We will talk about the Moon and the planets much later.

The main objective of amateur astronomical drawing is to support astronomical observation. They are natural notes, made with very simple techniques, and in short times.

To make learning easier, you can start by drawing naked eye constellations or asterisms. This avoids having to fight with the telescope in addition to the paper.

Basic tools

To start, you need some very simple tools: paper, pencil, red light, and a diffuser (optional).

The paper can be at first any, although I would recommend a white pad of acid-free paper, which is something consistent to resist moisture, and have some grain, but little. The size, according to the tastes; mine are A5, type field notebook .


The pencil , of ordinary graphite, can be of different hardnesses. Everyone has their preferences about it. I recommend having at least three pencils, one fairly soft (4B), one medium (B) and one somewhat hard (HB to 2H), although you might be more comfortable with something harder: do tests.

The pencils have to be sharpened. A pencil sharpener does not always offer the right sharpening we need, and a blade can be dangerous to handle in the dark. That’s why I use mechanical pencils, with a standard 2mm blade, and I sharpen them with a sharpener, with a metal body better than plastic, or with a scraper . Fine mechanical pencils, of 0.5 mm mines and the like, are not practical for these uses.

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The scraper is a tablet with a block of sandpaper stapled into it, and a sponge to clean the graphite powder from the tip of the pencil. It also serves to sharpen and clean the blurs. It allows to leave the tip of the mine more or less blunt, according to the need of the moment.

The red light flashlight is very important. It serves to see in the dark without harming the adaptation of our eyes to night vision. The view takes a half hour to adapt to optimal performance in the dark. However, in tenths of a second exposed to a bright light this adaptation is lost and you have to wait another half hour to recover it. The red light however does not harm this process; The rods, which are responsible for vision in low light conditions, are insensitive to the lights of these wave frequencies.

The light must be really red. If you are going to use a normal flashlight, you will have to put several layers of red acetate or similar until you get a totally red light and no cracks. However, today they are very common those that use LEDs instead of incandescent bulbs. In these, it is usually easy to replace the white LEDs with other bright red ones (the normal red ones are too dim). If you do not drive with the welder, surely you know someone who can do it.

Normally the light of the lanterns is very concentrated in certain points, creating areas brighter than others, or fences and halos. This can be very annoying to draw, and yet it is very easy to solve: just place a paper screen or Scotch Magic 3M adhesive tape.

If you are going to draw diffuse objects, you will need a medium thickness blur , although there are those who work with your finger. I do not recommend it for the simple reason that a dirty finger is unwise when handling eyepieces, filters, etc. The blur should be good, bought in a specialized stationery, better than in a school. Even so, as it comes from the factory, any blur is too rigid: you have to give it good hammering, placing it on a hard surface, until it is soft and flexible. Then you can sharpen or clean with the scraper.

As you can see, I have not spoken of deleting. Erase is not a simple matter and I will discuss it later in depth. For now, if you make a mistake, mark the error with a cross and keep drawing.

First exercises

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First, you should familiarize yourself with the material before going out to the field to draw.

To test the reaction of our pencils with the chosen paper, you have to make some test stars. Make several series of stars of different caliber, experiment with the different mine hardnesses, and with the tip more or less blunt.

To prevent stars from sticking out , you have to hold the pencil in a different way than usual. You have to keep it totally vertical, support it on the page and lift it. To give a little intensity to the star, turn the pencil a little; more spin, thicker. It is a mistake to tighten more to get more intensity. In the photo you can see how to pick up the pencil that I prefer.


It is also convenient to blur some paper with the difumino, to test how it reacts. For this, you start staining with the softest pencil in the margin of the sheet. Then the “fuzz” is “loaded” by rubbing it and turning on that spot. Also in the margin, they make strokes with the blur until they are very faint, and then it is applied in the area of ​​the drawing to be made. Soft circular strokes should be made, with very little pressure. Make tests with the more or less loaded diffuser and with different pressures.

To draw with the difumino one acts by applying very soft layers, one over another, until achieving the level of “brightness” (in our case darkness) desired. It is very common for things to remain larger than they are when drawing with the blur; the drawing tends to extend. As always, only practice solves this problem. If we have gone off tone, it can be clarified using the clean tip of the diffuser.

So far we have drawn in the comfort of a well-lit table. When you draw in the field with red light and weak, the thing changes. It is normal, in addition to tending to make things bigger than they are, to make a stronger mark with the pencil or with the blur of what is really necessary. You have to learn to control yourself, a strong brand is impossible to erase.

I said it at the beginning and here I repeat it, practice , blur many sheets, it is the only way.