Review: Patek Philippe Grand Complications Sky Moon Celestial 5102PR
When the world went into lockdown in 2019, me and many thousands of others did something we’d never done before. We looked up. Scores of people took the opportunity to begin a study of the night sky, to discover what wondrous, beautiful and terrifying objects there are looming above us. With the James Webb Space Telescope primed to take some of the best pictures we’ve ever seen of our universe, we decided to give you a little bit of a tour of the night sky, courtesy of the Patek Philippe Grand Complications Sky Moon Celestial 5102PR—and a few photos I’ve taken along the way.
The Moon
As an astro photographer, there’s little out there as annoying as the moon. It hangs there big and bright, obscuring the dim nebulae we try and photograph, so when’s it’s out full, may as well grab the chance to take a look at it instead. And it is impressive. With a diameter of 3,500km—it would barely fit between Chicago and San Francisco—it is the fifth largest natural satellite in our solar system, composed of oxides of silicon, aluminium, iron, magnesium, titanium and sodium that give it its silvery-grey sheen. Inside is a sold iron core, surrounded by liquid iron that is still molten today.
It's the closest alien world to Earth, pockmarked with impact craters thanks to the thin atmosphere offering little protection, some as old as the moon itself, which has been hanging around in Earth’s orbit for over 4.5 billion years.
It’s easy enough to find in the night sky, so you don’t really need the Sky Moon Celestial to locate it, however there’s a bit more going on to the moon’s trajectory than you might think. It orbits the Earth with steadfast regularity—once every 27.3 days, known as a sidereal month—but the Earth isn’t stationary, it’s orbiting the sun, and so from new moon to new moon actually takes a little longer, 29.5 days—known as a synodic month.
The Sky Moon Celestial shows both the orbit and phase, despite the idiosyncrasies between the two, using a clever system of layered sapphire disks that provide incredible accuracy to just 0.05 seconds per day. As the moon cycles the dial every 27.3 days, completing a full orbit of the Earth, the phases cycle every 29.5, so the 5102PR can be used not only to determine whether the moon will be waxing, waning, full or new, but in which direction you should look to see it.
The Nebulae
But what we’re really outside for isn’t our nearest neighbour, it’s for the deeper dive into our galaxy—for the nebulae. Nebulae are giants clouds of dust and gas in space, places where stars are born and the legacy of stars that have died, remnants of the past and visions of what’s to come in an order of magnitude that spans billions of years.
What you see here on the Sky Moon Celestial is a representation of the all the stars in our galaxy, from near to far. All the individual dots, those are stars nearer to us, and this band in the middle, that’s not a dust cloud—that’s us looking through the core of our home galaxy, the Milky Way, to the densely packed 400 billion stars that make up the rest of it. We actually live between the two major spiral arms of the Milky Way, in a structure called the Local Arm. Don’t panic, but it seems that The Hitchhiker’s Guide To The Galaxy was wrong.
The stars in the night sky are actually fixed in place relative to Earth, but the orbit and axial tilt of our planet mean they refuse to stay still. All but two stars that is, Polaris in the Northern hemisphere and Polaris Australis in the Southern hemisphere. Everything else rotates about them as we spin around and around. So how exactly are you supposed to find the incredibly dim, almost invisible nebulae in a sky that’s constantly moving?
The trick is to use those very stars, the things you can see, to isolate your target, and the Sky Moon Celestial helps with exactly that. Above the moon phase are more layers of crystal, one with all the stars applied to it and another with compass headings to tell you in which direction to look. And right in the centre, through the hand stack, is Polaris, that stationary point around which all else rotates.
From there you can follow the constellations to find Orion, home of the Orion nebula, a stellar nursery where new stars are born, and the Horsehead and Flame nebula, blasted by ultraviolet light from the nearby star, Alnitak. Scoot across to Perseus and there you’ll find the California nebula, which fluoresces from the energy of the star Xi Persei. Or perhaps to Cepheus and the Elephant’s Trunk nebula, a column of dense dust silhouetted against glowing gas clouds. The Sky Moon Celestial will get you there in a flash.
The Galaxies
What’s really impressive about the Sky Moon Celestial is that it doesn’t just tell you in which direction to look to find things in the night sky, it tells what you can see and what you can’t. Because of the tilt in Earth’s axis, from Summer to Winter we don’t get to see the same night sky, and dealing with that irregularity is the Patek Philippe’s trump card.
By bolstering up the base calibre 240 from 161 parts to 315 for the upgraded 240 LU CL T, Patek Philippe has been able to add a horizon indication with a view from Geneva—and any other location on the same latitude. This meanders independently of the starry scene to ringfence the sky you’ll see that very night from the horizon up. By equipping the sapphire celestial disk with 356 teeth, it’s accurate to 0.08 seconds per day.
Setting this watch is no mean feat. The 44mm platinum and rose gold case has two crowns, one for setting the time as normal and a whole extra one for setting the moon and sky—winding one way for the moon and the other for the sky. There’s even a complex calculator on the Patek Philippe website to help you work out exactly what you need to do to get the display perfectly aligned with real time. But when you do, there’s nothing else quite like. A fully functioning planetarium on the wrist!
And not only can it be used to locate the visible and invisible wonders of our own galaxy but those of our neighbouring galaxies as well, such as the Andromeda galaxy, which, were it visible to the naked eye, would be five times wider than the moon in the night sky. Or the Triangulum galaxy, with its many loose spiral arms. And even the Whirlpool galaxy, actually two galaxies in the midst of a collision that spans 76,000 lightyears across.
The study of time and space have long been linked together, and the masterful command of the Grand Complications Sky Moon Celestial 5102PR demonstrates why Patek Philippe has risen to become one of the greatest manufacturers of luxury watches of all time. To have a mechanical display of such scale and majesty in such a small device that operates to such high precision says everything. Given an unlimited budget, this watch would be the ideal companion to anyone who, when faced with a clear, crisp night, can’t help but turn their head skyward. And if that’s what $250,000 gets you, imagine what we’ll see from the $10 billion James Webb Space Telescope!
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