Thursday, 13 August 2026

Photography and Filmmaking: Why Lighting Matters More Than the Camera

 


Photography and Filmmaking: Why Lighting Matters More Than the Camera

It is very easy to become obsessed with cameras.

Which camera has the largest sensor? Which lens is sharpest? Should I be recording in 4K, 6K or 8K? How many stops of dynamic range does the latest model offer? Do I need another lens?

All of these things have their place, but after many years of taking photographs and making videos, I increasingly come back to a much simpler conclusion:

A good camera cannot rescue bad lighting nearly as effectively as good lighting can improve an ordinary camera.

Get the lighting right and a surprising number of other things begin to fall into place. Faces look better. Colours become richer. Autofocus tends to work more reliably. Noise becomes less noticeable. Backgrounds gain depth. Products acquire shape and texture. Even relatively inexpensive cameras and phones can produce remarkably professional-looking results.

Lighting is therefore not merely something added after choosing the camera.

Lighting is part of the picture itself.

In this article, I want to explore some of the basic lighting principles and practical setups that work particularly well for photography, video production and filmmaking.


Start by Looking at the Light, Not the Camera

One of the most useful habits a photographer or filmmaker can develop is to walk into a room and look at the light before taking the camera out.

Ask:

  • Where is the light coming from?
  • Is it hard or soft?
  • What colour is it?
  • How bright is the subject compared with the background?
  • Are there unwanted shadows?
  • Is the subject separating clearly from the background?
  • Could I improve the scene simply by moving the subject?

Sometimes moving somebody by a metre can make more difference than changing a £1,000 lens.

That is the fascinating thing about lighting. Much of the improvement costs nothing at all.


The Four Things I Usually Look at First

Before discussing individual lighting arrangements, it helps to think about four basic properties.

1. Quantity of Light

The obvious question is simply:

Is there enough light?

Modern cameras can operate in remarkably poor conditions, but just because the camera can produce an image does not mean it will produce the best image.

If there is too little light, the camera may need:

  • a wider aperture;
  • a slower shutter speed;
  • a higher ISO;
  • or electronic amplification.

Higher ISO can mean additional noise and loss of detail.

Adding more light frequently gives the camera a much easier job.


2. Quality of Light

Light can be hard or soft.

A small light source produces relatively hard shadows.

A large light source produces softer shadows.

This is why a bare LED lamp can produce quite an unflattering face while the same lamp shining through a large softbox can look excellent.

Interestingly, the Sun is physically enormous, but because it is so far away it behaves like a relatively small light source in the sky.

That is why direct sunlight can produce very strong shadows.

An overcast sky effectively becomes one enormous diffuser, producing much softer illumination.

For portraits and interviews, soft light is often extremely useful.


3. Direction of the Light

Direction changes how we perceive shape.

Light coming directly from the camera tends to flatten the subject.

Light arriving from one side creates shadows that reveal form and texture.

Backlighting can separate a person from the background.

Lighting from underneath can make somebody look distinctly sinister—which is one reason it has been used so effectively in films.

Simply changing the direction of a lamp can completely change the emotional character of a scene.


4. Colour of the Light

Not all white light is actually the same colour.

A traditional tungsten lamp appears warmer than daylight. Daylight itself changes throughout the day.

Lighting equipment is commonly described using colour temperature.

Typical values are approximately:

  • Candlelight: around 1,800 K
  • Traditional tungsten lighting: around 3,200 K
  • Daylight: around 5,500-6,500 K

Many modern LED lights can be adjusted across a range of colour temperatures.

The important thing is consistency.

If one side of someone's face is illuminated by daylight through a window while the other is illuminated by a warm household lamp, the camera can struggle to make both look natural.

Sometimes mixed lighting is deliberate.

Frequently it is simply distracting.


Setup One: The Simplest Light of All — A Window

Before buying studio lights, try using a window.

A large window can make an excellent soft light source.

Place a person near the window, but rather than having them stare directly towards it, turn them slightly so that the light comes from approximately 30 to 45 degrees to one side.

Immediately you begin to see modelling across the face.

One side is brighter.

The other has a gentle shadow.

The face suddenly looks three-dimensional.

Move the person closer to the window and the light becomes stronger.

Move them further away and it becomes weaker.

Add a white board, sheet of foamboard or reflector on the opposite side and some of the window light can be bounced back into the shadows.

You have just created a surprisingly sophisticated portrait lighting arrangement without switching on a single studio lamp.


Setup Two: One Light Can Be Enough

If I could encourage somebody beginning video production to learn one lighting arrangement, it would be the single large soft light.

Place a softbox roughly:

  • 45 degrees to one side of the camera;
  • slightly above eye level;
  • angled down towards the subject.

Do not automatically place it directly in front of them.

The slight side angle produces natural shadows and gives the face shape.

The result can be extremely effective for:

  • YouTube videos;
  • online teaching;
  • interviews;
  • presentations;
  • corporate video;
  • portraits.

And there is an important practical lesson here.

Move the light before buying another light.

People often try to solve lighting problems by adding equipment when changing the position of one lamp would work better.


Setup Three: The Classic Three-Point Lighting System

One of the best-known arrangements in filmmaking and video production is three-point lighting.

It consists of:

  1. the key light;
  2. the fill light;
  3. the back light or hair light.

It remains useful because it demonstrates three separate jobs that lights can perform.


The Key Light

The key light is the principal source.

It normally provides most of the illumination on the subject.

A typical starting position is about 45 degrees to the side and slightly above the subject.

However, this is a starting point rather than a rule.

Move it around.

Watch what happens to the shadows.


The Fill Light

The key produces shadows.

Sometimes we want those shadows, but sometimes they are too strong.

The fill light is positioned on the opposite side and is normally less powerful.

Its job is not necessarily to remove the shadows completely.

It simply controls how dark they become.

This is an important distinction.

Completely eliminating every shadow can leave a face looking flat.

A little shadow usually creates shape.


The Back Light

The third light is positioned behind the subject and directed towards them.

It might illuminate:

  • the hair;
  • shoulders;
  • edge of the body.

This produces a subtle rim of light.

Its purpose is separation.

Without it, somebody wearing dark clothes against a dark background can almost merge into the background.

Switch on the back light and suddenly the outline becomes clear.

It is a small change that can make footage look considerably more polished.


You Don't Necessarily Need a Fill Light

There is another useful lesson here.

A lighting setup may be described as three-point lighting, but that does not necessarily mean you need three lamps.

The fill can simply be a reflector.

A piece of white foamboard can bounce some of the key light back towards the subject.

You can also use:

  • a photographic reflector;
  • a white wall;
  • white card;
  • a sheet;
  • even a large piece of paper for small objects.

Learning to control existing light is every bit as important as learning to add more lights.


Negative Fill: Sometimes We Want More Shadow

Here is an interesting technique that is often overlooked.

Suppose you are photographing someone in a bright white room.

Light is bouncing from every wall and filling all the shadows.

The resulting image may look rather flat.

Instead of adding light, place something black beside the subject.

A black curtain, photographic flag or sheet of black foamboard absorbs some of the reflected light.

The shadow side of the face becomes darker.

This is called negative fill.

It demonstrates an important principle:

Lighting is as much about removing light as adding it.


Setup Four: A Simple Interview

Imagine recording an interview.

Instead of placing your subject against the wall, move them several feet forward.

Already the picture improves because the background can fall slightly out of focus.

Now position:

Key light:
Large softbox approximately 45 degrees from the face.

Fill:
White reflector on the opposite side.

Back light:
Small LED above and behind the subject.

Background light:
If available, place a small additional lamp behind the subject aimed at something interesting in the room.

Perhaps illuminate:

  • a bookshelf;
  • scientific equipment;
  • a musical instrument;
  • a plant;
  • a piece of machinery.

The background now has several layers.

Suddenly the shot has depth.

That is often one of the differences between footage that looks like "someone sitting in a room" and footage that begins to look deliberately produced.


Lighting a Background Is Often Forgotten

People understandably concentrate on lighting the person.

But filmmaking is about the entire frame.

Consider the background separately.

Is there a dark corner?

Could you illuminate an object?

Could a practical lamp appear naturally in the shot?

Could coloured lighting subtly distinguish the background from the subject?

Even something as simple as putting a table lamp in the background can create a useful pool of warm light.

You are effectively creating layers:

Foreground — subject — background.

That creates visual depth.


Setup Five: Product Photography

Lighting becomes particularly interesting when photographing objects.

Consider something simple such as a camera, piece of scientific apparatus, watch or electronic device.

Put a light directly above the camera and the object may look surprisingly flat.

Move a large softbox to the side and suddenly:

  • edges become visible;
  • textures appear;
  • curves become clearer;
  • lettering gains definition;
  • the object appears more three-dimensional.

You can then introduce white cards to reflect light onto particular areas.

This is almost like painting with light.

Move a small reflector and watch a highlight move across the product.

It is remarkably instructive.


Shiny Objects Need Special Treatment

Highly reflective objects introduce another problem.

You are not really photographing just the object.

You are also photographing everything reflected in it.

Try photographing:

  • polished metal;
  • glass;
  • glossy plastic;
  • chrome;
  • jewellery.

A tiny lamp may create an ugly bright spot.

A large diffused panel, however, produces a broad attractive reflection.

This is why professional product photography can involve enormous diffusers surrounding surprisingly small objects.

The object is effectively reflecting the shape of the light source.


Setup Six: Macro Photography

Macro photography creates its own lighting problems.

Move extremely close to an insect, electronic component or small experiment and the camera itself can block the available light.

Depth of field also becomes extremely small.

You may therefore want to use a smaller aperture, which in turn requires more light.

Possible solutions include:

  • LED panels;
  • diffused flash;
  • ring lights;
  • small reflectors;
  • flexible LED lights;
  • translucent diffusers.

But again, diffusion matters.

A powerful flash very close to an insect can produce harsh reflections.

A diffuser spreads the apparent source and creates much gentler illumination.

For photographing insects, flowers and small scientific specimens, this can make an enormous difference.


Setup Seven: Dramatic Lighting

Not every scene should be evenly illuminated.

Sometimes shadow is part of the story.

Move a key light strongly to one side and leave the other side relatively dark.

Immediately the scene becomes more dramatic.

This can work for:

  • documentary sequences;
  • film scenes;
  • promotional photography;
  • musicians;
  • workshop footage;
  • engineering projects.

Place the light almost directly to the side and you create a striking split across the face.

Move it slightly further around and the result becomes even darker.

Lighting therefore becomes storytelling.


Lighting Can Change the Meaning of a Scene

Imagine photographing exactly the same person in exactly the same room.

Version A uses:

  • bright soft frontal lighting;
  • bright background;
  • very little shadow.

The result may look friendly, open and instructional.

Version B uses:

  • a strong side light;
  • dark background;
  • little fill;
  • perhaps a rim light.

The same person may now appear mysterious or dramatic.

Nothing about the camera has changed.

Nothing about the subject has changed.

Only the lighting has changed.

Yet the emotional message is different.

That is why cinematographers devote so much attention to light.


Outdoor Photography: You Still Control the Light

Outdoors, we cannot move the Sun.

But we can move ourselves.

One of the worst times for portraits can be around midday on a bright sunny day.

The Sun is high and creates deep shadows beneath:

  • eyes;
  • noses;
  • chins.

Move the subject into open shade and the result may immediately improve.

Alternatively, use a reflector to bounce sunlight back onto the face.

Or use flash to provide a little fill.

Photographers sometimes describe this as "fighting the Sun", but frequently the easier approach is to work with it.


Golden Hour

The period shortly after sunrise and shortly before sunset is popular with photographers for good reason.

The Sun is low.

Light travels through more atmosphere.

Shadows become longer.

The direction of the light becomes more obvious.

The landscape gains shape and texture.

Photograph exactly the same scene at midday and again near sunset and it can look like two completely different places.

Again, the camera did not change.

The light did.


Backlighting Outdoors

One of my favourite techniques is to place the Sun behind the subject.

At first that sounds wrong.

Surely the light should be shining onto them?

Not necessarily.

Backlighting can produce a beautiful rim around:

  • hair;
  • leaves;
  • insects;
  • flowers;
  • sails;
  • translucent materials.

The front of the subject may then need a reflector or some fill flash.

For plants and nature photography, backlighting can be particularly effective because light passes through leaves and petals.


Filming Science Experiments

Lighting science experiments presents some interesting challenges.

The lighting should not merely make the apparatus look attractive.

It must make the result visible.

For example, when filming:

A chemical reaction

We may need strong side lighting so that colour changes are obvious.

Smoke or vapour

A dark background with strong backlighting can make tiny particles dramatically more visible.

Water

Reflections can obscure what is happening, so changing the light angle may be essential.

Microscopy or small equipment

Close-up lighting needs to reveal details without producing overwhelming reflections.

Demonstrations involving screens

We need to balance the brightness of the screen against the person presenting it.

The scientific objective should therefore influence the lighting arrangement.


Don't Forget Eye Reflections

Look at a good portrait carefully and you may see a small white reflection in the eyes.

These are called catchlights.

They may seem insignificant, but they give the eyes brightness and life.

Move your softbox slightly and watch what happens to them.

The eyes tell you quite a lot about the lighting arrangement.

In some photographs you can virtually reconstruct the studio by looking at the reflections in somebody's eyes.


The Problem of Glasses

Anyone making educational or corporate video will eventually encounter another challenge:

glasses reflecting the lights.

There are several possible solutions.

Move the light higher.

Move it further sideways.

Angle the person's face slightly.

Move the camera position.

Often only a few degrees are required.

This is where experimentation beats theory.

Rather than accepting the reflection, move things around while watching the monitor.


The Most Useful Lighting Tool May Be a Monitor

When filming myself or somebody else, I want to see the actual image being recorded.

A monitor allows me to spot:

  • blown highlights;
  • unwanted reflections;
  • dark eyes;
  • harsh shadows;
  • distracting background lights;
  • mixed colour temperatures.

Sometimes the problem is obvious on the monitor but surprisingly difficult to notice while standing beside the camera.


Practicals Can Be Part of the Scene

In filmmaking, a light visible within the shot is often called a practical.

This might be:

  • a desk lamp;
  • workshop light;
  • table lamp;
  • computer monitor;
  • illuminated sign;
  • instrument panel.

These can help make the environment feel believable.

A workshop should look like a workshop.

A laboratory should look like a laboratory.

A music studio should have its own visual identity.

Lighting can help tell the viewer where they are before anybody says a word.


You Don't Need Twenty Lights

It is very easy to watch behind-the-scenes footage from a major film production and conclude that professional lighting requires an enormous truck full of equipment.

For many smaller productions, it doesn't.

A very capable basic kit might consist of:

  • one large soft LED key light;
  • one smaller LED light;
  • one reflector;
  • a couple of stands;
  • diffusion material;
  • black foamboard;
  • clamps.

From that, you can create an enormous number of arrangements.

The real skill is understanding what each light is doing.


A Useful Exercise: Switch Everything Off

One exercise I find particularly valuable is to build a lighting setup one light at a time.

Start with darkness.

Turn on the key light.

Look at the image.

Then add the fill.

Look again.

Then add the back light.

Look again.

Then illuminate the background.

Each time ask:

What did that light actually contribute?

If switching a light on does not improve the picture, perhaps it does not need to be there.

More lighting is not automatically better lighting.


Another Exercise: Use Only One Light

Try creating several completely different images using one lamp.

Move it:

  • directly in front;
  • 45 degrees sideways;
  • directly beside the subject;
  • behind the subject;
  • above;
  • below.

Then move it closer and further away.

Add diffusion.

Bounce it from a wall.

Reflect it using white card.

Block part of it using black card.

You will probably learn more about lighting from that exercise than from buying three more lamps.


Camera Technology Helps — But Light Still Comes First

Modern cameras are extraordinary.

We have:

  • extremely high ISO performance;
  • sophisticated autofocus;
  • high dynamic range;
  • powerful stabilisation;
  • excellent lenses;
  • computational photography.

But camera technology does not change the fundamental nature of light.

The camera can only record the light that reaches it.

That is why a carefully lit subject filmed with relatively modest equipment can look excellent, while an expensive cinema camera pointed at a badly lit scene can produce surprisingly ordinary results.


Lighting Is Part Science and Part Art

There is plenty of physics involved.

We can study:

  • reflection;
  • refraction;
  • scattering;
  • inverse square behaviour;
  • colour temperature;
  • spectral output;
  • polarisation.

But there is also artistic judgement.

How much shadow feels right?

Should the scene look warm or cold?

Should the background disappear or attract attention?

Should a face look natural, dramatic, mysterious or inviting?

There is rarely a single "correct" answer.

That is what makes lighting so interesting.


My Approach: Build the Picture Before Pressing Record

One of the temptations with digital photography and video is simply to start recording because recording costs almost nothing.

I think it is often worth resisting that temptation.

Spend another few minutes looking at the frame.

Move the light.

Move the subject.

Move the camera.

Remove something distracting from the background.

Add a little reflected light.

Turn one unnecessary lamp off.

Then look again.

A few minutes spent preparing the light can save considerably more time trying to rescue the picture during editing.

And there are some things that editing simply cannot completely repair.


Conclusion: Learn to See Light

Buying better equipment can certainly improve photography and filmmaking.

I enjoy good cameras and lenses as much as anyone.

But one of the most valuable upgrades costs nothing:

learning to notice light.

Look at how light falls across a face.

Look at how it reveals the texture of wood or metal.

Watch what happens to the garden as the Sun moves lower in the sky.

Notice reflections in glass.

Look at the difference between direct sunlight and an overcast afternoon.

Move a lamp six inches and watch a photograph change.

Once you begin thinking this way, lighting stops being something you simply switch on.

It becomes another creative tool.

And whether you are photographing wildlife, recording a science experiment, making a YouTube video, filming an interview or creating a dramatic short film, the same principle keeps returning:

Get the lighting right, and much of everything else becomes easier.

The camera matters.

The lens matters.

The sound certainly matters for video.

But before pressing the shutter button or pressing record, there is one question worth asking:

What is the light doing?

Wednesday, 12 August 2026

Watching Wednesday’s Partial Solar Eclipse Safely: Turning an Astronomical Event into a Practical Science Experiment

 


Watching Wednesday’s Partial Solar Eclipse Safely: Turning an Astronomical Event into a Practical Science Experiment

On Wednesday 12 August 2026, the UK will be treated to an unusually deep partial eclipse of the Sun. Depending on where you are, roughly 90–96% of the Sun will be covered by the Moon at maximum eclipse. It will be the greatest solar eclipse coverage visible from the UK and Ireland since 1999.

For London and much of southern England, the eclipse begins at about 6.17 pm, reaches maximum at around 7.12 pm, and finishes at about 8.06 pm. Because the Sun will be quite low in the western sky, a clear western horizon will be particularly valuable.

But there is one subject that matters more than timings, photographs or even whether the weather cooperates:

How do we watch it safely?

And that presents an opportunity for some excellent practical science.


First Rule: Never Look Directly at the Sun

This sounds obvious, but during an eclipse there is a temptation to think that because most of the Sun has disappeared behind the Moon, the remaining part must somehow be safe to look at.

It isn't.

Even with most of the solar disc obscured, the remaining crescent is intensely bright and can damage the retina. Ordinary sunglasses are not sufficient protection either. UK Health Security Agency guidance recommends either genuine solar viewers meeting ISO 12312-2:2015(E) or an indirect projection method.

That means:

Do not stare at the Sun.

Do not look at it through ordinary sunglasses.

Do not look through binoculars, a camera lens or a telescope unless the instrument has a correctly fitted, purpose-made solar filter over its front aperture.

An unfiltered telescope or pair of binoculars concentrates the Sun's energy and makes the danger considerably greater.

Fortunately, we do not actually have to look at the Sun to observe an eclipse.

We can let physics do the work for us.


Project the Sun Instead

One of my favourite ways of observing solar phenomena is to project an image of the Sun onto a screen.

Instead of placing your eye where the image is formed, you allow the optical system to form its image on a piece of white card or paper.

You then watch the paper.

The result can be surprisingly impressive.

A bright circular image of the Sun appears on the screen. As the eclipse progresses, you can watch the dark silhouette of the Moon gradually move across it.

You are effectively turning the telescope into a solar projector.

The Royal Astronomical Society has described projection using a small telescope or binoculars as a method that can produce a sharp solar image, but stresses that it must be done with great care. The American Astronomical Society goes further and recommends optical projection only for experienced observers using their own equipment and supervising it continuously, because of both eye-safety and equipment-damage risks.

So this is very much an experienced-user experiment, rather than something I would suggest an unsupervised child tries with a pair of binoculars.


My Eclipse Experiment

My plan is fairly simple.

I can set up a small telescope so that it points towards the Sun, but importantly I do not look through it to find the Sun.

Instead, the shadow of the telescope itself can be used for alignment. When the telescope is pointing directly towards the Sun, its shadow becomes small and symmetrical.

Behind the eyepiece I can position a sheet of stiff white card.

When everything is correctly aligned, a bright image of the solar disc should appear on the card.

By moving the screen backwards and forwards I can change the size of the projected image. The telescope can then be focused until the edge of the Sun becomes reasonably sharp.

And then the experiment becomes really interesting.

At the start, there should be an almost complete circle.

A small indentation will appear.

Then the indentation grows.

Eventually, close to maximum eclipse, only a thin curved portion of the Sun will remain visible from much of Britain.

Then the whole process reverses.


A Very Important Warning About Telescope Projection

There is a second danger here that is easily overlooked.

The telescope itself can become damaged.

Sunlight is concentrated inside the optical system. If the solar image moves away from the correct position, concentrated sunlight can fall on internal components. Modern eyepieces frequently contain plastic parts that may overheat or be damaged.

Therefore, if I use projection, I will use a small, simple instrument, supervise it constantly and keep other people away from the eyepiece.

I would not leave a solar-projection telescope unattended even for a moment.

For a public demonstration, I would also physically arrange the equipment so that nobody can casually walk up and put their eye to the eyepiece.

That is particularly important when children are present.


Binocular Projection Can Work Too — But With the Same Caution

Binoculars can also produce a projected solar image.

Again, nobody looks through them.

They are secured firmly, pointed towards the Sun using their shadow, and their projected image is allowed to fall onto a white screen.

For binoculars, only one optical tube would normally be used for projection while the other objective is completely covered.

However, because binoculars were designed for visual observation rather than prolonged solar projection, heat can damage internal components. There is also the obvious risk of somebody instinctively looking through them.

For those reasons, although the demonstration is fascinating, I would regard binocular or telescope projection as something for an experienced experimenter rather than the simplest method for a family watching the eclipse.


The Simpler Alternative: Make a Pinhole Projector

There is a much easier experiment that almost anyone can try.

Take two pieces of card.

Make a small, clean hole in one.

Stand with your back towards the Sun.

Allow sunlight to pass through the hole onto the second card.

The bright spot you see isn't simply a blob of sunlight.

It is actually an image of the Sun.

During an eclipse it will gradually change from a circle into a crescent.

This is pinhole projection, and it requires no lenses at all. The American Astronomical Society specifically recommends keeping the Sun behind you and observing the projected image rather than looking through the hole.

It is a wonderfully simple demonstration of geometrical optics.


Try a Colander

There is an even more entertaining version.

Take an ordinary kitchen colander outside.

Hold it so that sunlight passes through the holes and falls onto the ground or a large piece of white card.

Normally you see dozens of roughly circular bright spots.

During the partial eclipse those spots should become dozens of tiny crescents.

Every hole in the colander has effectively become a small pinhole camera.

UKHSA specifically lists a colander as one of the simple indirect ways of observing the eclipse safely.

This could make a particularly good photograph.


Then Look Under a Tree

Nature may provide an even bigger pinhole projector.

Look at sunlight passing through the leaves of a tree.

Normally the patches of light beneath a tree are approximately circular.

That may seem strange. The gaps between the leaves aren't circular.

The explanation is that many of those tiny gaps are acting as pinhole projectors.

The circles on the ground are actually crude images of the Sun.

During Wednesday's eclipse, many of them should become crescents.

It is one of those occasions where something we normally walk past without thinking suddenly reveals a beautiful piece of physics.

I will certainly be looking at the shadows as well as at my projected telescope image.


Why Does Projection Produce an Image?

The experiment illustrates one of the fundamental ideas in optics.

Light approximately travels in straight lines.

Imagine rays leaving the top, bottom, left and right sides of the Sun.

A small aperture restricts which rays can reach a particular point on the screen.

Consequently, an image is produced.

With a telescope, lenses gather and focus considerably more light, so the image can be much larger and sharper.

That makes the eclipse an excellent opportunity to connect several topics:

  • straight-line propagation of light;
  • lenses and focusing;
  • image formation;
  • angular size;
  • shadows;
  • the motion of the Moon;
  • the scale of the Solar System.

It turns watching an eclipse into a genuine science investigation.


Why Can the Moon Cover the Sun?

There is also an extraordinary coincidence of scale.

The Sun is enormously larger than the Moon.

The Sun's diameter is about 400 times greater than the Moon's.

But the Sun is also roughly 400 times farther away.

Consequently their angular sizes in our sky are surprisingly similar.

That is why the comparatively tiny Moon can appear large enough to cover the enormous Sun.

On Wednesday the alignment will be almost perfect from Britain, but not quite. We will remain outside the narrow path of totality, so a thin part of the Sun will remain visible.

Parts of Greenland, Iceland and Spain lie within the path of totality; Britain and Ireland will experience the large partial eclipse instead.


We Can Turn the Eclipse into a Measurement Experiment

Rather than simply watching, I want to record what happens.

For example, I could photograph the projected image every five minutes.

Then I could compare the photographs.

I could measure:

Time

Record the exact time of each photograph.

Percentage coverage

Estimate how much of the solar disc is obscured.

Solar image diameter

Measure the projected diameter on the paper.

Temperature

Record the air temperature before, during and after maximum eclipse.

Light level

A light sensor could record how illumination changes.

This would create a surprisingly useful dataset from something lasting less than two hours.


Will It Actually Get Dark?

Not completely.

In southern Britain approximately 90% of the Sun will be obscured, but that still leaves part of the intensely bright solar surface exposed. Royal Observatory Greenwich says observers should notice a change in light and possibly temperature around maximum eclipse, but it will not become dark in the way it does during a total eclipse.

That itself makes an interesting observation.

Ask people beforehand:

How dark do you think it will become when 90% of the Sun is covered?

Then compare expectation with reality.

Human perception of brightness is not particularly good at making absolute measurements, which is another reason why using a light sensor could be revealing.


Watch the Environment as Well as the Sun

One of the mistakes we can make with astronomical events is concentrating so hard on the telescope that we forget to look around us.

During the eclipse I want to observe:

the changing quality of the daylight;

the shadows;

the temperature;

cloud behaviour;

wildlife;

and, particularly, those crescent images beneath trees.

The eclipse isn't just happening on a piece of white card.

For a short period, the whole landscape is being illuminated by a very strangely shaped light source.


Photography Needs the Same Safety Rules

There will naturally be a temptation to photograph the Sun directly.

A camera does not make an unfiltered view safe.

A long telephoto lens behaves rather like a small telescope and concentrates solar radiation. Cameras and optical equipment therefore require correctly designed solar filtration if they are going to be pointed directly at the Sun.

For most people, the easier photograph may actually be the better photograph:

photograph the projected eclipse image.

You can include the telescope, the white screen and the crescent Sun in the same frame.

That tells a much more interesting story than simply producing another picture of a crescent against a black sky.


The Weather Is the One Thing We Cannot Control

Of course, after preparing telescopes, cameras, sensors, projection screens and experiments, British weather could reduce the entire exercise to:

"There appears to be a slightly darker patch of cloud."

Astronomy teaches patience.

The eclipse takes place during the early evening with the Sun getting progressively lower towards the western horizon, so trees, houses and hills may be as important as cloud cover. A location with a clear western view will be particularly useful.

But even if clouds interfere with some of the observation, preparing the experiment is worthwhile.

Science frequently involves getting everything ready and then discovering that nature has other plans.


Conclusion: Don't Just Watch the Eclipse — Investigate It

Wednesday's eclipse is one of those occasions when a major astronomical event becomes accessible from our own gardens.

No observatory is necessary.

With something as simple as two pieces of card, we can observe the motion of the Moon across the face of a star approximately 150 million kilometres away.

With more carefully controlled equipment, we can project a larger image, photograph its progress, measure changes in illumination and temperature, and turn the evening into a real experiment.

I'll be particularly interested in seeing that first small "bite" appear in the projected image of the Sun and then watching it grow until only a narrow solar crescent remains.

But the most important message is also the simplest:

Never look directly at the Sun.

Project it.

Measure it.

Photograph the projection.

Look at the strange crescent shadows beneath the trees.

And use the eclipse as an opportunity to turn a spectacular astronomical event into practical science.

Wednesday evening could give us one of the best solar eclipses visible from Britain for decades.

Let's hope the clouds cooperate.