If you bestow more than a cursory glance on your Christmas cards you will know that stars have points. Some stars have five points, some only four. Some have as many as eight, or even more. But is that really what you see when you look up at the night sky?

Going outside at night these days and looking up at the sky is a disappointing experience for most of us. Light pollution from streetlights ensures that you don’t see many stars, and those few you do see are just feebly glowing dots. If Christmas cards were representational art, the simplest way of representing stars would be as needle pricks in a piece of black card held up to the light. If they want to avoid a boring product, greetings card designers need to rely more on imagination than observation.

When you launch your internet browser it shows a startup screen, which you can select for yourself. For me this used to be the BBC News website, which I gulped down with my unsweetened black coffee: hardly a restful experience. Later I began to see the benefit of something more relaxing, which however would change daily to avoid getting stale. I discovered the excellent NASA website: Astronomy Picture Of The Day (APOD), which feeds me an endless stream of beautiful starry pictures with my breakfast.

The first few pictures I saw took me by surprise. The stars had points – at least the brighter ones did. They were all four-pointed stars (which somehow seemed to vindicate the Christmas card designers), each a spiky cross which sometimes lay aslant, its size varying with the brightness of the star. Even more amazing was the fact that the crosses lined up across the whole picture, offering a sort of reassurance that there was fundamental order in the universe after all, in spite of the disorderly mess that most star fields manifest.

My first glimpse of this phenomenon gave rise to feelings of sadness rather than gladness. The sort of sadness I feel when I see on TV “science” programmes which show a giant asteroid hitting the Earth with an almighty BOOM! – which you hear instantly across 40,000 miles of empty space. If you’ve ever seen a gun fired from a ship at sea, perhaps only a mere mile away, you don’t hear the sound immediately after the flash, but a second or two later. So just how much science can that TV programme really contain? Like Christmas card designers, programme producers feel they must rely more on imagination than observation. The reasoning runs like this: when two celestial bodies collide, the viewers expect them to go BOOM! – and they must not be disappointed.

Nature is often difficult, messy and unpredictable, and occasionally the results are boring. Why shouldn’t the producers of TV programmes pander to the expectations of the viewer and embellish Nature with a little Art? As a result, time-lapse sequences of growing plants show flowers opening with a crackle (…is that a vastly speeded-up sound recording from a nearby microphone?), tiny insects munch plant fibres to the sound of a dog eating dog biscuits, and slugs mate with noises that the neighbours would complain about if they heard them coming through the bedroom walls.

This doctrine of Augmented Reality extends to the visual domain. Sir David Attenborough revealed the tricks of the trade when he exposed the celebrated sequence of lemmings tumbling over a cliff and bobbing lifeless in the water below. Everybody knows that swarming lemmings commit mass suicide, so when you watch a film about the fluffy little darlings, that’s what you’re waiting for them to do. Now lemmings, even en-masse, turn out to have little taste for grand gestures, and to get their shot the Disney film makers were obliged to herd the poor wee beasties over a cliff edge to their death.

The expectations of audiences can be cruel (as every Roman gladiator knew).

Which was how I viewed those pointed stars in the otherwise magnificent NASA pictures. The spikes must have been photoshopped on, because that’s what viewers expect to see. Imagine my surprise on learning that spiky stars are what the camera records, even before any touching-up gets done.

However could it be? Do stars really have points?

My scientific training leads me to believe that each of those glowing dots is a whole sun, maybe even a whole Milky Way. I’ve watched a lot of sunrises and sunsets in my time, even solar eclipses (through smoked glass of course) and I’ve never seen points on the sun. Although it must be said that a good solar eclipse reveals that the sun has hair – which seems further to vindicate the greetings card designers. But if the sun has to share the same sort of pointed cross, magnified by brilliance, that you see on the brighter stars in a typical astronomical picture, I feel sure it would not have escaped my notice.

But all this does lead me to suspect the evidence of my own eyes, and even to doubt the veracity of my own scientific training. I was told a lot of things in my science classes that I had neither the time nor the energy to verify for myself. Was it all therefore nothing but a systematised indoctrination, like one of the weightier world religions, whereby boys are sent to school to read and memorise one single holy book, nothing else?

Well, to be sure, in Science there was more than one holy book. And they kept on coming, and still do. Some people derive reassurance from the life of Jesus being recorded in not just one, but four, holy books, which differ in significant details when describing what are clearly the same events. Likewise I too am reassured by my scientific training having benefited from more than one source of knowledge – and continuing to do so. Moreover the story changes over the years: but does that guarantee the veracity of the overall programme, or merely expose the falsity of the older stories? The final word has yet to be said on that topic. But when it is, I want to be there to hear it.

But if the brighter nearer stars really are suns, it follows that stars don’t have points because the sun doesn’t. The points we see in NASA photographs must be instrumental artifacts: which is a fancy way of saying that the telescope itself must have accidentally originated them.

However does it do that? Astronomical telescopes, even ones that are satellites like Hubble, are large empty tubes with mirrors inside. Those mirrors have to be fixed firmly inside the tube, which demands a minimum of scaffolding. No matter how thin the rods holding the mirrors in place, some starlight cannot avoid having to diffract around them, which mutilates the anticipated image of a celestial sphere shrunken to a tiny dot.

It’s a theory I can well appreciate, and for once I can do so from my personal experience. Before I had my cataracts removed, I couldn’t see stars any more. But going out in the dark I could see distant streetlights, which I knew from memory would once have looked like brilliant coloured stars. If I covered my left eye, my right eye used to diffract each point of light into an emoji – a carnival mask – a little lopsided skull. As a consequence my visual field, whether by night or day, was a welter of skulls of varying colour and brightness but all the same size and orientation. It was entertaining, and I often went out at night just to relish the effect.

But deep down inside me something craved to see the world as it really was. And in the fullness of time our wonderful NHS removed my cataracts and enabled me to see the stars once more, and to see them as focused points of light, not skulls.

If you have never been through this experience yourself, you will find it hard to believe that the resulting gift of clearsightedness didn’t just stop at the back of the eyeball, but seeped through to the core of my mind and being.

I am not the man I was two years ago: wallowing in the mire of my illusions, knowing full well that they were illusions yet enjoying the entertainment they afforded. In place of a sort of consumerised contentment there is now a long bright needle of discontent: a yearning to reach out into the depths of space, straining to see back across billions of years to the furthest star. The stars may be many, but they are finite in number, therefore there must be a furthest star. And modern astronomy tells me that it must be the first star to have ever condensed from the nebulous clouds which fill the universe.

When at last I see it, I can but hope that the internal scaffolding of my upbringing, and the crystallised cataracts of my prejudices, will not distort my sight of it into an emoji, a carnival mask… or a skull.