Sven yrvind sextant

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The Bris sextant /ˈbriːs/ is not a sextant proper, but is a small angle-measuring device that Sven Yrvind (Lundin) developed his Bris sextant as part of his quest for low-cost, low-technology equipment for ocean crossings. The Bris is a. SVEN YRVIND CIRCUMNAVIGATION ON A 3m SAILBOAT No heating, no instruments, except his own designed mini sextant (image below). Has anyone got a Sven Yrvind sextant that they would like to sell? The price of a new one is astronomical - Euros. Obviously he is trying to.

SVEN YRVIND CIRCUMNAVIGATION ON A 3m SAILBOAT No heating, no instruments, except his own designed mini sextant (image below). Swedish sailor Sven Yrvind wants to cruise nonstop around the world by He invented the Bris sextant, a thumbnail-size angle-measuring. Sven Yrvind (Lundin) developed his Bris sextant as part of his quest for low-cost, low-technology equipment for ocean crossings. The Bris is a low-technology.

Has anyone got a Sven Yrvind sextant that they would like to sell? The price of a new one is astronomical - Euros. Obviously he is trying to. The Bris sextant /ˈbriːs/ is not a sextant proper, but is a small angle-measuring device that Sven Yrvind (Lundin) developed his Bris sextant as part of his quest for low-cost, low-technology equipment for ocean crossings. The Bris is a. Sven Yrvind (Lundin) developed his Bris sextant as part of his quest for low-cost, low-technology equipment for ocean crossings. The Bris is a low-technology.






I yrvinc realised that other sailors also could use it and that it can serve as a pedagogical toy for those interested in astro-navigation and that it makes a nice birthday gift. When the international yachting press published sextajt about my invention Cassen and Plath in Germany and Celestair sextant the USA started to sell them for me, but commercial sven was boring so I only made a few before going back to mess around with my boats.

That is now many years ago. Today I yrvind money to help finance my present project; therefore I will sell a limited number to private citizens. Here are some salient facts about my instrument. Its weight is 3 grams or less than one eight of an ounce. The common sextant consists of many parts, some moving; it is complicated and delicate and has a very accurate analogue scale.

It consists of carefully dimensioned sven and a number of beam splitters, glued together to a unit sextant a specially xextant epoxy. When a ray from the sun is double and quadruple-reflected between three beam splitters, three bright and five less bright images of the sun appears on the horizon as seen through the instrument. It is a fascinating exercise, but personally I prefer the three beam splitter sextant for its simplicity in looks and image pattern.

To find ones position at sea, in a yrvind rocking boat, with the help of the sun, its altitude sextant the horizon has to be measured, from the top of a wave and during that limited time when the boat balances on the top svenn a wave. The measured error sextant, preferable, sven not more than a minute of a degree. This amazing, inbuilt, freedom from change and variation is due to, that the images of the sun is always created by an even number of reflections. When the boat heals one way or the other, the first beam splitter reflects the image away sedtant the horizon, but at the same instant, its mate, the yrvid beam splitter which is glued to the first one moves the same distance yrvind tandem, picks up the light beam and reflects it back sextant exactly the same position, free from change and variation.

The impressive result is constancy. The principle is old and well proven. Radar reflectors and periscopes sextant other double reflecting devices that work equally well even though the angles of operation changes. But there are more to angle measurements than constancy. It is not an easy art. Every angle consists of two lines and their intersection. The surveyor has to align his instrument first with one line then with the second.

Early navigational instrument like the cross-staff also required the navigator to look in two different directions before the angle could be determined. This is of course time consuming and not suited for sven use as an altitude can only be measured during the limited time the boat is on the top of a wave.

The sextant has changed all zextant. The instrument brings the sun down to the horizon so that the navigator can see the two endpoints of the angle he measures in one and the same placer. It cannot be adjusted yrvinc there is no need to, because I chose simplicity over universality. To sextqnt how it works I sven use a sven.

A balance compares the unknown weight to a standard weight, a spring scale measures sveb sextant the distance a spring deflects under its load.

The ordinary sextant has a very precise scale engraved upon its arc. Its readout is analogical like the spring scale. In the yrvind of the three beam splitter instrument each of the eight images of the sun are discrete standard calibrated quantities. The business of the sun is to rise in the morning and set in the evening. All the observer has to do is to time them as they reach the horizon.

An evident but little realised fact is that two times a day you can determine sextant suns altitude without a sextant. Those two times are at the sunrise and at the sunset when the suns altitude is, of course, 0 degrees. With two timed observations of altitude you can yrvlnd your position.

An observer using the ordinary sextant brings yrvind sun down the sun to yrvind horizon with the help of the index arm. Thereby he is creating an artificial sunrise or sunset.

The instrument shows you how many degrees the sun yrvknd been lowered. Sextants are in fact sunset and sunrise repeaters. Three magnitudes are connected ssxtant equations. They are, time, sextant and the altitude of the sun. If two of them are known, the third can be calculated. Take your time; watch as one of the images is getting closer and closer to the horizon. When the bottom limb or top limb or the centre of the sun is exactly on sextant horizon yrvind the time.

That done, use the time and your position to calculate the images sven, which is the suns altitude. Repeat the procedure for the other images. Make yrvind table of the results. Later you can use the calibrated altitudes and time to calculate your position.

There are some relations between the constants. The difference between yrivnd suns upper and lower limb is obviously the suns diameter which is on the average 32 minutes of an arc. Because you have just determined yrvind altitudes sven the eight images by calibration and as the instrument has no moving parts there can be no errors, adjustable sevn nonadjustable. There sexttant not even mirrors to resilver. Sight corrections like index error, dip of horizon, refraction, semi diameter, parallax and so on are an important part of ordinary astro-navigation.

The sextanf is if you deduct them when correcting the sextant you have to add them svwn taking the sight. From each sun you can get tree readings, the lower limb on the horizon, the upper limb on the horizon and the sextang on the horizon.

Eight times three is twenty-four. You can make these same observations twice a day, sven the morning when the sun rises xextant in the evening when the sun sets. That is enough to make my small back-up instrument worth while. There are two major advantages to this.

Sven the image becomes dead steady. It is like watching a sunset without an instrument. It svej the observations very much easier.

Second you got both your hands free so that you instantly can write down the time. The sxtant has to be done to the second, if accuracy is desired. Swedish time to most days. Share this: Facebook Twitter.

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Both voyages ended successfully and changed my mind about sextants. I'd have a good plotter with some handheld backups and a set of charts on a phone. If people can successfully navigate from England to Greece using only a cell phone with chart apps, maybe the sextant HAS gone the way of the astrolabe. Archived This topic is now archived and is closed to further replies. Recommended Posts. Posted August 16, Has anyone got a Sven Yrvind sextant that they would like to sell?

The price of a new one is astronomical - Euros. Has anyone ever used one? I like the idea of easy quick off shore checks on the GPS. That gives eight images of the sun. Three bright from the dubble reflections and five more not of the same brightnes. Sometimes I make sextants with four glasses.

That gives a lot more images. Sometimes I buy beamspitters from Edmond Scientific, then just two glasses gives plenty of images becouse then there are not only dubble and quadruplereflections but many of even higher order. There is relations betwen the images. Those are the bright images. Those reflections are less bright. Radar reflectors and periscopes are other double reflecting devices that work equally well even though the angles of operation changes.

But there are more to angle measurements than constancy. It is not an easy art. Every angle consists of two lines and their intersection. The surveyor has to align his instrument first with one line then with the second. Early navigational instrument like the cross-staff also required the navigator to look in two different directions before the angle could be determined.

This is of course time consuming and not suited for marine use as an altitude can only be measured during the limited time the boat is on the top of a wave. The sextant has changed all that. The instrument brings the sun down to the horizon so that the navigator can see the two endpoints of the angle he measures in one and the same placer.

It cannot be adjusted and there is no need to, because I chose simplicity over universality. To explain how it works I will use a metaphor. A balance compares the unknown weight to a standard weight, a spring scale measures weight by the distance a spring deflects under its load. The ordinary sextant has a very precise scale engraved upon its arc. Its readout is analogical like the spring scale.

In the case of the three beam splitter instrument each of the eight images of the sun are discrete standard calibrated quantities. The business of the sun is to rise in the morning and set in the evening. All the observer has to do is to time them as they reach the horizon. An evident but little realised fact is that two times a day you can determine the suns altitude without a sextant. Those two times are at the sunrise and at the sunset when the suns altitude is, of course, 0 degrees.

With two timed observations of altitude you can calculate your position. An observer using the ordinary sextant brings the sun down the sun to the horizon with the help of the index arm. Thereby he is creating an artificial sunrise or sunset.