-- edition of January 1, 2017 --
The Kickstarter campaign for this project ended May 23, 2016, but the site plays on: https://www.kickstarter.com/projects/1592946658/bright-eye-telescopes. We are accepting reservations but not new orders via eMail: firstname.lastname@example.org; or by snail-mail to: 2625 Alcatraz Avenue #235, Berkeley, California 94705 USA. Once we finish the first batch of telescopes, we will determine production processes for the next batch.
© Norman Sperling
co-designer and producer
2625 Alcatraz Ave. #235, Berkeley, CA 94705 USA
Congratulations! You just launched on the easiest and fastest route to the stars! Bright–Eye® sets up the fastest and lets you find targets the fastest of any newcomer’s telescope. It shows you the widest, richest, most contrasty view. Bright–Eye is compact, portable, rugged ... and cute.
DON’T LOOK AT THE SUN!
Even without magnifying, the Sun is painfully bright. Collecting more light makes it so intense that you can permanently burn out your retina in a fraction of a second – faster than you can flinch. That hole in your vision will be permanent; the retina never grows back. If you point your scope at the Sun, even if you aren’t looking through it, concentrated sunlight can melt plastic, and quickly set fire to whatever wanders into its line of sight, such as your shirt or your hair. For telescope users, the Sun is a “no-go zone”.
OUT OF THE BOX
Bright–Eye tubes are made of polyvinyl chloride (PVC). Bright–Eye spheres are made of acrylic. Each individual shell has its own distinctive color pattern.
The shell has 3 distinct zones:
• The sphere is the telescope’s mounting.
• The cylinder keeps the mirrors and eyepiece all in their proper positions.
• Poking out of the cylinder’s side is the eyepiece focuser.
The cylinder encloses the optical tube assembly. That contains the first 2 optical pieces that light encounters on its way from the sky to the eye.
Set the base on a table, with the base-ring facing up. Gently set the telescope’s ball in the bowl, with the top of the cylinder pointing pretty high.
The dust-cap keeps the window clean when you’re not observing. It’s way easier to keep crud away than to very delicately clean it out later. Cleaning tips are on page \\. The hemispheres that protect big telescopes are domes, so we make our little one that shape too. It’s a simple friction fit. Start your observing sessions the same way the big observatories do: open up the dome.
If there is a plug in the eyepiece hole, pluck it out (but save it to put back when the session is over). The eyepiece itself is probably in a small box. Gently open the box and (avoiding touching glass surfaces) unwrap the eyepiece. Slide it into the eyepiece hole.
RIDE A BEAM OF LIGHT
Light’s First Encounter: Light goes to the bottom of the tube, where it hits the main mirror. That’s lower in the middle, higher on the rim. The mirror is 41/4 inches (108 mm) in diameter.
To focus starlight, the mirror has a special “paraboloidal” curve: take a parabola, and spin it on its axis. The amount the mirror is curved puts the focus 17 inches (432 mm) up the axis. You could stick an eyepiece at that focus, but if you tried to look through it, your head would block light from entering the telescope at all, leaving nothing to see.
Light’s Second Encounter: Pondering this problem, the great scientist Isaac Newton figured that you could stick a diagonal mirror a little before the focus, and shunt the light out the side. Put your eyepiece there, and look through it without blocking the view.
Newton was a genius! His plan worked. He made the first successful reflecting telescope. For hundreds of years, Newtonian reflectors have been the world’s favorite form of telescope. They collect more light for less money than any other kind. Bright–Eye’s optical pattern is a Newtonian reflector. The diagonal mirror is attached to the “spider” that straddles the top of the tube.
Light’s Third Encounter: The eyepiece is a sophisticated magnifying glass for examining the focused light. Astronomical eyepieces now come in a great many optical patterns. Each has advantages and disadvantages. Bright–Eye’s eyepiece gives a wide view with minimal distortions and comfortable “eye-relief”. It has a standard 1¼-inch (31¾ mm)-wide tube, so any other standard eyepiece can slide in there too. Shorter eyepieces magnify the image more. That’s good for observing planets and the Moon, but it makes the field of view very small, so planets are hard to find, and hard to keep in view. Higher magnification also dilutes the feeble light of comets, nebulæ, and galaxies. Different eyepieces may show wider views (but they’re a lot more expensive), and have less eye-relief (hard to use if you wear glasses, and sometimes hard to find the image even if you don’t), or are cheaper (with a narrow view ... or poor quality). As newer types of optical glass are invented, different combinations of features will be optimized, with different trade-offs.
Magnification (“power”) is the best-known, but one of the least-important, telescope factors. Divide the “focal length” of the big mirror (432 mm) by the focal length of the eyepiece (25 mm). 17 power is our recommended magnification for newcomers. Get used to it to start with. Experienced observers who have many eyepieces will tell you they use low power eyepieces most of the time.
Light’s Fourth Encounter: Your eye. Human eyes are not identical to one another. When reading this description, adapt it to your personal eyesight.
Light enters the dark circle in the middle of your eye, the “pupil”. This may widen to 7 mm (¼ inch) in a young person who has adapted to darkness for at least 30 minutes. That’s how to collect the most light, and therefore see the faintest details. The following factors narrow the pupil and dim the view, depending on dose and time:
• consuming alcohol
• consuming nicotine
• adapting to darkness for less time
• observing from a place that isn’t very dark
If you don’t wear eyeglasses (contact lenses are OK): look straight down the center of the eyepiece. Stay just out of eyelash-distance from the eyepiece.
If you wear glasses but aren’t sure of the technical reasons, here are easy ways to tell.
• Hold your glasses just above something printed. If the lenses act like magnifying glasses, you’re farsighted.
• Hold your glasses at arm’s length in front of you and look through the lenses. If they make things look smaller, you’re nearsighted.
• If you rotate a lens around its middle, and stuff beyond seems to tilt left and right, you have astigmatism.
• If things look fuzzy, your lenses need cleaning, so meticulously follow the instructions on page \\.
If you wear eyeglasses to correct astigmatism: You’ll probably see sharper with your glasses on. Unfortunately, eyeglasses keep you farther from the eyepiece so you see a narrower field of view. Keep far enough from the eyepiece to avoid scratching your eyeglass lens on the eyepiece frame: the easiest way is to unroll the rubber rim on the eyepiece. Experiment with and without glasses, with each eye. You may prefer the way that gives the sharpest view, but if it’s not much different, you may prefer the way that gives the most comfortable view.
If you wear eyeglasses because you are farsighted: Take your glasses off and put them in a safe place, where you won’t lose them in the dark, nor drop them, nor step on them. A buttoned shirt pocket might work, or a zipped jacket pocket. Use the eyepiece just the same as a person without glasses. The only difference is in tweaking the focus knobs a tad one way or the other compared to standard 20/20 vision.
If you wear eyeglasses because you are nearsighted: Read the “farsighted” paragraph above, but there’s an added hassle: When your glasses are off, you can’t see the starry sky well. To point the scope in the right direction, put your glasses on. To see when you’ve got your target in view, leave your glasses on but tweak the focus knobs to sharpen the view. Once you acquire the target, take your glasses off so you can approach almost to eyelash range of the eyepiece, and re-tweak focus to sharpen the view.
BRIGHT–EYE ON DAY ONE
For your first look through your new telescope, go outside during daytime, as long as the weather won’t hurt yourself or your scope. Set your base on a table, gently set the sphere in the ring-stand, and point the window up, but nowhere near the Sun. Then gradually swivel the top end down to where the sky disappears behind a tree, building, mountain, or whatever ... the farther away, the better. Looking straight down through the eyepiece, gently turn the focus knobs till the image sharpens. Now notice 2 things about your scope:
• Lean down behind the sphere, and look at where the top of the sphere, and the top of the eyepiece, line up with what you’re seeing through the eyepiece. That’s your line of sight.
• Also, notice how far the eyepiece stands above the flat that it pokes into. The nearer the thing you focus on, the higher up the eyepiece must be. Don’t look at objects within about 10 meters (33 feet) because the eyepiece could literally fall out of the tube. The farther away the object you focus on, the farther down the eyepiece must be. Farther than a kilometer (½ mile) or so, all objects beyond that are simultaneously in focus. That’s nicknamed “infinity”. Start your nighttime explorations with the eyepiece sticking out just that amount, so you’ll be very close to true focus.
While it’s still daylight, scan your scope around and look at everything you can see. Each time, notice where the top of the sphere and the top of the eyepiece are, compared to the thing you’re observing. Notice how far in or out the eyepiece is, and relate that to the distance of the thing you’re observing.
Practically all astronomical telescopes “invert” the view. There’s no up or down in space so that doesn’t matter. For looking at things on the ground, it can matter a lot, so here’s a way to make things look upright.
• Stand behind the scope, with the scope right in front of you, and the thing you’re looking at much farther away in that same direction. When you bend down to look through the eyepiece, the image looks upside down.
• Now move to the side of the telescope and look through the eyepiece. From that angle, the image looks sideways.
• Now move again, till you’re almost in front of the scope, with your back to the thing you’re looking at. (If you get exactly in front, you block the view yourself.) Look through the eyepiece. From that angle, the scene looks upright.
Trees, bushes, and rocks often look very esthetic even at unaccustomed angles. Experiment. If you like the view, that makes it “right”.
FIRST NIGHT, FIRST LIGHT
The first time a telescope shows you an astronomical object (like the Moon or stars) is called that telescope’s “First Light”. We recommend that you use a marker to write “First Light” and the date somewhere on the cylinder, or on the sphere close to the cylinder, or on the base. \\illustrate\\
Start observing astronomical objects, guided by the accompanying book To Know the Stars. At first, most targets will take some searching. Start with bright and big objects. They’re easiest to find, and very rewarding to examine. They’ll catch your eye instantly as you scan by. 5 seconds to look over each field of view is plenty to notice bright objects.
Develop a scan pattern: up and down, or side to side, or spiraling out ... whatever you please. To spot fainter objects, scan slower – 10 or 15 seconds to examine each field of view. It’s not a race, so take your time and enjoy whatever swims into sight. Use a “star-hopping” reference to show you the route from a bright star, past nearby faint ones, to your goal. Even if you can’t find your target, enjoy examining the neighborhood ... and often the target will turn up in the process.
Objects are usually easier to find the second or third time than the first time. They haven’t grown bigger or brighter, of course, but now you know what to look for. As you gain experience, try for fainter and smaller challenges.
While you watch sky objects, Earth’s rotation is magnified by the same 17 times as the view, so objects “drift” out of view after a couple minutes. While watching through the eyepiece, gently tap the upper end of the scope to push it in the direction you want the image to move. Think of yourself as pushing the image rather than pushing the telescope. You’ll soon get enough experience to keep stars in view for as long as you want. \\illustrate\\
Using a high power eyepiece makes things move out of view much faster, and chasing them becomes frustrating. That’s why bigger telescopes have clock drives and electronic-driven finders. You can grow into handling those. But while you’re just beginning, stick to the low-power eyepiece we supply. It minimizes frustration while maximizing brightness, contrast, and field of view.
From suburbs, Bright–Eye can spot 8 planets and at least 7 moons (4 of Jupiter and 2 of Saturn, and of course Earth’s). It can show you the entire Messier catalog of the finest clusters, nebulæ, and galaxies. The farthest findable object is probably Messier 87, a giant elliptical galaxy roughly 55 million light years away.
Moving from suburbs to dark skies makes every one of those objects easier to find and better-looking, and allows glimpsing even farther galaxies. It’s worth going to the darkest place that’s safe and convenient.
• NEWCOMER MODEL: Everything you need to get started: complete telescope, base, dust-cap, dew shield, eyepiece, skywatching book, carrying strap.
• CHECK-OUT MODEL, for libraries, clubs, and classes to check out. Complete telescope and carrying strap. For people using it unsupervised, we make pieces harder to lose: we bolt the eyepiece in, and tether the base and dust-cap with wires. Such groups already have skywatching books so we don’t make them buy another.
• QUICK-GRAB MODEL: a “second” telescope for experienced observers, when the occasion doesn’t call for big equipment. Complete telescope, base, dust-cap, and carrying strap. Such people already have their own eyepieces and skywatching books so we don’t make them buy more.
• The OPTICAL TUBE ASSEMBLY (including eyepiece focuser) is a useful component to add to large telescopes as a finder, and for photographers to use as a “telephoto lens”. It can also be a long-distance microscope. For technically-advanced users who already have the fittings, mountings, eyepieces, and skywatching books they prefer, so we don’t make them buy more.
• YOUR CUSTOM MODEL, selected from our buffet of features and accessories. Tell us what you have in mind, so we can make suggestions.
Origins: Bright–Eye is assembled in USA from mostly-American-made parts. For the Newcomer model, 85% of the cost and 69% of the parts come from the USA. Tracing back further: 19% of the parts, costing 5% of the dollars, come from Earth’s Anthropocene Epoch. 42% of the parts, costing 20% of the dollars, came from Earth’s Carboniferous Period. Geological origins of the remainder could not be determined. Even further back: cosmically, roughly 5% of the mass originated in the Big Bang, 65% from Red Giants, and 30% from Supernova explosions. We post updates and details on our website.
Amateur astronomy is a hobby. A wonderful aspect of hobbies is that you do only the parts you like. If part of the subject doesn’t interest you, simply skip that. You can also do the interesting parts in the ways you prefer. You decide for yourself how to do things. We suggest how other people enjoy exploring the Universe, but those are never requirements (except the warning to NEVER POINT A TELESCOPE AT THE SUN. That’s a firm rule.) As in all science, and all specialties, you can dig into finer and finer technicalities. Later! Whenever you feel like it. Maybe years later. Maybe never.
Astronomy clubs serve every big city and lots of smaller places. Even if you’re not usually a “joiner”, this is where to find people who have already been through the awkwardness of beginning. They know the best observing locations. They know where to buy advanced equipment when you get to that. They are happy to advise you. Most clubs host star parties where everybody can look through everybody else’s telescopes. Every club has its own personality. Visit all the clubs that are easy enough to get to. Join the one that feels best. Astronomy clubs are listed online, and your nearest planetarium probably knows all of them.
RETURN VISITS SHOW MORE
Like other fine art, celestial objects reward return appearances. First, enjoy the brightest and most contrasty parts. On later returns, seek dimmer details – “supporting stars” – in clusters and the Milky Way. Watch for patches and filaments in nebulæ and galaxies. Scout around for wider context. Mercury, Venus, and the Moon are lit from different angles at different times. Jupiter’s and Saturn’s clouds are always churning.
Skywatching is one of the few activities that children and adults can pursue as near-equals. You can see the same things, and learn the same skills and science, at the same rate. Galaxies are just as stupendous and wondrous to jaded adults as to elementary kids.
Children under 9 or 10 simply haven’t developed enough yet to handle a scientific instrument, even an easy one like Bright–Eye. Of course, children vary immensely in behavior and intellect, and different aspects mature at wildly different rates and ages. If you wonder whether you should leave a child alone with Bright–Eye, don’t. Help them till they convince you they don’t need you. After that, drop by frequently and have them show you what they’re observing.
Most people set their Bright–Eye on a picnic table or card table. Car hoods are no longer horizontal, but some car trunk lids are horizontal enough. The eyepiece (when the scope is pointing straight up) should be a little lower than your eye, for whatever you’re sitting on. If you have to bend down awkwardly, you won’t be comfortable while searching for or observing objects. You may not even find certain objects, if looking in their direction is too awkward.
An alternative is to use a tray that hangs onto a car window. 1950s-style “car hop” trays are available from eBay, Etsy, and other sources. Considering our use, I think they’re “star hop” trays. If the tray shakes a little, damp that with a gentle finger. Get the “large” size from Meritt Tool & Die, 203 W. Third Street, Vermontville, MI 49096. I bought mine through their store on Etsy.com.
Those trays’ hooks only hang on the windows of some cars. Back in the heyday of car hops, almost all cars had windows that had straight horizontal tops. No longer. A lot of car window tops are now curved and sculpted in ways that these trays simply can’t hook onto. For these trays to work well, they have to hook onto windows, at positions 11½ inches (28 cm) apart, that are at the same height above the ground. Measure your car windows before ordering a tray!
SIT OR STAND
Bright–Eye is easy to cradle in your lap while you sit in a chair, on a bench, or on the ground. You can brace it with your lap, with an arm hugging it, and with the shoulder strap helping hold it tautly. That’s stable enough for personal enjoyment, especially a leisurely scan along the Milky Way.
You can even hold Bright–Eye stable enough while standing up, if you lean against a building or car. Hold steady using your strap, arms, chest, and abdomen.
The only color of flashlight to use while skywatching puts out red light. All other colors destroy your dark-adaptation. After using white light at night, it may take 10 minutes to re-adapt fairly well, and 30 minutes to adapt completely, to seeing the faintest objects.
Red lights are widely available in bicycle shops, outdoor outfitters, and elsewhere. You can also cover a white-light flashlight with red cellophane (available as gift-wrapping) or red nail polish.
Once you know your way among the stars, and know what you’re looking at, use your Bright–Eye to show other people what celestial objects look like. Tell them something about the objects you show. You could do this as part of an organized event like Astronomy Day or Sidewalk Astronomers, or as a Halloween treat, or for people from a school, or elder care, or friends, or anybody. It doesn’t matter who or when, but it matters a lot that you do some such thing.
ADVANCED SKY BOOKS
After you learn what you want from Guy Ottewell’s To Know the Stars, you’re ready for a higher level of sky guide. There are many, each with a different attitude. Examine all the ones your library has, and all the ones your astronomy club members have. Since the stars and constellations don’t change much, consider older editions from online listings.
Richard Berry: Discover the Stars
Guy Consolmagno: Turn Left at Orion
Terry Dickinson et al: NightWatch
Alan Dyer: Backyard Astronomy, also called Advanced Skywatching
Robert A. Garfinkle: Star-Hopping
Phil Harrington: Star Watch
David Levy: Skywatching
Alan MacRobert: Star-Hopping for Backyard Astronomers
Fred Schaaf: 40 Nights to Knowing the Sky
Smartphone and computer apps abound. We hear good things about Sky Safari.
The yearly Observer’s Handbook of the Royal Astronomical Society of Canada has an excellent list of wide-field sights in the sky.
Tourists adorn their cars with oval bumper-stickers proclaiming where they traveled. You’ve probably seen them. They’re part tally, part brag: “Been There, Done That”.
I supply a sheet of oval stickers, so you can show where you have traveled ... across the sky: “Looked There, Seen That”.
When you observe an object, especially if it’s part of a project, you can write its name or number on an oval. I couldn’t guess whether you’d want to call the prettiest star cluster the “Pleiades”, “7 Sisters”, “Subaru”, or “M 45”. All of those are correct. But I don’t have to guess. Do it any way you want.
The classic observing project is to find every Messier object. Charles Messier was a French comet-hunter in the late 1700s. He was annoyed by blotches in the sky that looked fuzzy, like comets, but never moved across the background of stars like comets do. Therefore they weren’t comets ... therefore they were a waste of time. He listed over 100 of them to alert astronomers to skip these distractions!
Later telescopes revealed details in each object. Many Messier objects are clusters of stars. Many others are gas clouds; the Latin word is “nebulæ”. Most the rest are galaxies like our entire Milky Way, but much farther.
Messier had charted the best “deep-sky” objects. Some astronomical groups award certificates to members who see them all. Bright–Eye shows every Messier object.
... and more! I plan to publish 2 new categories from very creative authors.
• An “asterism” is any star pattern that isn’t one of the 88 official constellations. Your Bright–Eye reveals hundreds of them. Some have geometric shapes, so find a line, triangle, square, circle, etc. Some look like letters, so spell your name with stars.
• “Birthday stars” lie farther and farther numbers of light-years away. Help 8-year-olds see light that left its star when they were born 8 years ago. The next year, see light that left a different star 9 years ago, and so on.
You can record every sight you see on an oval. Stick its oval on your telescope cylinder or base, or in an observing log, or a wall or appliance. Maybe arrange them in the order in which you saw them, or separately for the solar system, Messier objects, asterisms, birthday stars, and other projects.
If ovals aren’t your way of doing things, you’re perfectly free to ignore them.
Decorate your Bright–Eye any way you wish, as long as it doesn’t get in the way of using the scope. Brownish scope: a Steampunked version by Artist/Astronomer Richard Miles. He accepts commissions in several artistic styles. StarBaseOne@outlook.com . Bluish scope: one painted in the style of Piet Mondrian.
DETOURS AND DISAPPOINTMENTS
DO NOT TOUCH GLASS SURFACES
The eyepiece and all mirrors are sensitive to the slightest smudge. Cleaning optical glass is so finicky that you’d rather not need to.
IT GETS COLD
Dress as if it’s 15º colder than you expect. That’s because you’re mostly standing still, not exercising, while wind-chill blows away your body heat. Wear a warm head cover and warm socks. Dress in layers, so adding or subtracting is easy. Insulation comes from the air trapped between layers. Keep warmth handy if you’ll be out longer than half an hour – a warm car, hot beverage, or other source.
The famous astronomer Caroline Herschel complained that town lights veiled a good look at Halley’s Comet ... in 1835! Light pollution grew ferociously in the 1900s and remains ghastly in the 2000s. Some fancy filters help a bit. But since your Bright–Eye is extremely portable (even adding a card table), get out of town! Your astronomy club has already scouted surrounding areas and will recommend the best one for you. If you don’t get such advice, examine a regional map. Notice where all the towns are. Go as far from them as you can. Mass transit only goes where masses of people go, so you’ll need a car. Bring food, warmth, pest repellant, red light, and star maps. Experience and club members will help you build your own checklist.
THE FULL MOON
The brighter the phase, the worse it makes viewing clusters, nebulæ, and galaxies. But there’s definitely a lot to see: the Moon itself! It is by far the most detailed celestial sight. Many books, magazines, and websites tell you all about its features. Since it’s uncomfortably bright, dim the view by covering most of your scope’s top opening – taping cardboard across ¾ of the open area helps. If it’s not exactly Full Moon, you can see surface detail in the long shadows on the sunrise/sunset line. For several nights before and after Full Moon, “rays” from geologically-recent cratering impacts show up wonderfully. The lava-seas are dark, but notice that patches are different shades of grey. You can recognize many large craters even without shadows.
Forecasts help you plan your next clear evening. For hour-by-hour predictions for cloudiness and temperature, start at www.cleardarksky.com. Then you might watch the clouds on Venus, Mars, Jupiter, or Saturn, and the deep-space clouds called nebulæ. When Earth’s clouds block the sky, there’s still something to see, at least by daylight, no scope needed: Earth’s clouds themselves. There are several types. Which ones are left over from the last weather system that passed? Which are portents of the next one coming?
INSECTS AND OTHER WILDLIFE
They’ve used this habitat since long before humans arrived. Some ignore us, some avoid us. Some consider us as food, others treat us as rivals to expel or fight. Ask several local people how to minimize hassles.
Look at the sky to see if clouds or trees are impinging on your view. You can still see bright objects through thin clouds and trees.
Dew can collect on your window and eyepiece. Some people use an electric hair-drier to blast dew away. Don’t wipe dew off the optics directly! You could scratch the optics, and you can leave a film that demands delicate cleaning.
Dust can also collect. Blow that away with pressurized “canned air”, available at camera stores. Camel-hair brushes can softly nudge dust away. Don’t wipe dust off, because the particles are themselves grit that will scar the optics.
Examine each optical component. It may be time to clean them. Follow instructions on page \\
The best uses for high magnification include seeing detail on the Moon and planets, and splitting close double stars. High magnification demands many trade-offs, however. The entire mounting must be very stable, since every vibration is magnified too. The field of view is tiny, so the occasional tap — that works with Bright–Eye’s rich field — loses the target at high power. You need a clock drive or computer-driven scope. And it’s not rare for the computer to fail to find the object. See “Setup Time and Technicality” below.
DETOURS AND DISAPPOINTMENTS
WITH DIFFERENT TELESCOPES
Bright–Eye is deliberately made sturdy. Using it, you may develop habits that are too rough for delicate scopes. Watch carefully how other people use theirs.
SET-UP TIME AND TECHNICALITY
Big powerful multi-task telescopes can do a lot. But they typically need 15-20 minutes to set up, and the same to take down. Learn exactly how each doodad fits into its thingamabob. Watch the owners set up at a few star parties. Carry heavy parts very carefully! Then volunteer to help several times before trying it on your own.
Every fitting has a purpose. It’s adjustable because it needs to be adjusted. The more complicated the equipment, the more adjustments it needs. The results are superior, but you have to earn them.
Computerized mountings can usually find objects automatically. How good that is depends on your attitude (as well as how well the gizmo works). Hurrying right to the intended target is similar to a traveler jetting into a city. Watching the sky along the way, as with Bright–Eye, is like taking in the countryside until you get there.
If you’re a newcomer, we echo the advice of tens of thousands of experienced observers to delay the frustrating finicky technicalities of time-exposures for a few years. Yes, years, really! Anecdotes are available at all astronomy clubs.