Practically everyone has seen a picture of the Horsehead Nebula. It is among the most photographed astronomical objects by amateurs and professionals alike. You know what I mean — that black profile of a horse’s head silhouetted against a streak of red, glowing gas.

My first experience of the Horsehead was on television, a tendency typical of my generation. Every Friday at 8:29 p.m., all my other teenage pursuits would grind to a halt as I dashed to the living room to watch the latest episode of the original “Star Trek” series.

Between battles with the Klingons, the Horsehead and other alluring gas clouds often appeared as a backdrop on the Enterprise viewscreen.

In 1998, NASA polled the astronerds of the nation to find out what astronomical object they would like to see the Hubble Space Telescope photograph next.

With over 5,000 votes, the Horsehead was the hands-down winner. The resulting poster later graced many a bedroom wall, including my own.

The Horsehead is the most famous example of a dark nebula, a cloud of dust and hydrogen gas unilluminated by stars in its interior. We only see it because of IC 434, the glowing nebula behind it.

Nebulas like IC 434 are called emission nebulae. They glow because they are stellar nurseries. The gas inside them is dense enough in places to condense into clumps of gas that eventually collapse into stars.

Those newborn stars ignite the gas in much the same way that a spark of electricity ignites the gas in a fluorescent light bulb.

The Horsehead is not dense enough with gas to form any significant new stars. However, its high dust content is sufficient to block the light from IC 434.

Long-exposure images show that what I wrote above isn’t entirely true. Dark nebulae like the Horsehead often contain a few low-mass, red-dwarf stars. Such stars usually don’t provide enough oomph to cause the gas to glow.

Those same images indicate that the Horsehead is indeed glowing a faint red. The nearby star Sigma Orionis is close enough to ignite the Horsehead’s gas, albeit very weakly.

As amateur telescopes increased their light-gathering power in the late 1970s, the Horsehead Nebula became the Holy Grail of visual astronomy. Many astronerds tried to see it in their telescopes, but few were successful.

Unless you have a VBT (Very Big Telescope) or know someone who does, you’ll have to settle for “Star Trek” reruns and Hubble Space Telescope images.

If you have access to a VBT, you’ll find it just below the left star in the belt of Orion. A detailed star chart helps. Of course, you’ll have to be out in the middle of nowhere. Even a trace of “skyglow” from city lights will erase the view.

It also takes one of those cold, clear winter nights to see it — one of those nights when it’s so frigid you wish you stayed home and binge-watched “Star Trek” reruns instead.

It will look like a notch of blackness cutting into an exceedingly faint streak of nebulous light.

Only the sharpest-eyed visual observers or the best amateur liars have ever claimed to see the structure of the Horse’s head.

Most of all, you need to lower your expectations. The Horsehead is tiny, only 3.5 light-years wide, and it’s 1,375 or so light-years away.

The first time I saw the Horsehead was one -16 degrees Fahrenheit night in southern Ohio, miles from the nearest heater.

The sky was utterly black because the nearest light-polluting town was miles away. Stars filled the sky. The winter Milky Way glowed like a glorious smear of diamond dust.

It was almost like some unknown force had blasted the atmosphere from Earth. Not a single star twinkled to reflect the usual atmospheric turbulence that plagues high-magnification visual observing. The stars shone steady and bright.

I first observed the Great Nebula in Orion, a nearby emission nebula easily visible in binoculars. I then turned my attention to finding the Horsehead. If I was ever going to see it, that night was the night.

With my heavily gloved hands, I pulled the eyepiece out of my telescope and awkwardly screwed on an expensive H-beta filter. It would block out any remaining skyglow from distant cities. Its creator had purposefully designed it to brighten the dim light of faint nebulae.

Okay, I admit it. I had spent $100 for a filter designed to observe the Horsehead visually.

Was I trembling with excitement? Or was it the cold? Or was it the possibility that my heavily gloved hand might drop a $160 combination of eyepiece and filter onto the frozen ground below?

I found Alnitak, the leftmost star of the three stars in Orion’s Belt. Again and again, for the next hour, I hopped from star to star on my way to the promised land. Again and again, I found my way to the Flame Nebula, another nearby emission nebula. Again and again, I had gone too far. Again and again, I had passed over the Horsehead without seeing it.

And then, finally, a faint streak of light that more than filled the field of view of my ‘scope. And, yes, a tiny black notch was all I could see of the Horsehead.

It was enough. It was more than enough. Like Sir Galahad, I had seen the glory of the Grail, even if imperfectly and from a great distance.

I bragged about it a few days later to Professor Tweed, a professional astronomer of my acquaintance.

“I saw it,” I said. “I saw the notch!”

He stared at me for a long moment and then dryly commented, “Tom, old buddy, if they ever discover the other end of the Horsehead, they’ll name it after you.”

These days, amateur telescopists rarely try to find the Horsehead visually. Instead, a new generation of high-tech imaging technology has enabled amateurs to capture the nebula digitally.

It’ll cost you an arm and a leg to purchase the telescope, digital camera, filters, and ancillary equipment like auto-guiders to help keep the telescope pointed precisely in the right direction.

Astro-imagers usually start with bright star clusters and nebulae like the Great Nebula in Orion before they inevitably move on to fainter objects like the Horsehead.

They sit comfortably in front of computer screens and take a series of digital exposures. They then “stack” the resulting images into stunning amalgamations that rival the pros and their mammoth telescopes.

It was not always so. My old observing buddy Biff Smooter was, for his time, an expert amateur astrophotographer. In other words, he took photos with old-fashioned film technology.

Film is not nearly as sensitive as today’s CCD chip. Exposures were long, and the telescope operator had to guide the ‘scope by hand.

I’ll ne’er forget the frigidly cold night that Biff decided to photograph the Horsehead Nebula.

At the time, he was a poor graduate student, but he had scrimped and saved to purchase an equatorially mounted telescope with a massive (for the time) mirror (gasp) 10 inches in diameter.

Like most “equatorials,” the telescope was tilted to match the observer’s latitude. It had a main motor that could roughly follow an astronomical object like the Horsehead as it moved across the sky. A second motor adjusted the up-and-down orientation.

However, the main motor did not operate at an exact enough rate to keep the telescope’s target reliably in the center of the field of view.

An astrophotographer was required to look continuously through a separate “guidescope” strapped to the primary telescope. Biff constantly had to adjust the telescope’s position with a paddle-style controller.

When he began his imaging session, the guidescope eyepiece was conveniently placed so that he could comfortably sit on his high observing stool.

As the Horsehead and telescope moved, he had to kick the stool out of the way and stand up. As the minutes and the motor ground on, he began arching his back so he could still look through the guidescope eyepiece.

A full 90 minutes passed before he completed his exposure of the all-too-faint Horsehead and its background nebula.

By that time, his back was so agonizingly rainbowed over the telescope that, to this day, I still marvel that he kept his balance. In those days, astrophotography was truly back-breaking labor.

The resulting photograph didn’t come close to what a typical astro-imager can do with about $2,000 worth of high-tech digital equipment these days. But it was beautiful nonetheless. I still have a fading print buried somewhere in my mountains of old papers.

That night, Biff got frostbite on three of his fingers. As far as I know, he never got back full use of those digits.

Whenever the subject of the Horsehead came up, Biff was fond of painfully flexing the fingers and muttering with a contented sigh, “Ah, but it was worth it.”