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A brief biography of David (1564-1617) and Johannes (1587-1616) Fabricius.

David Fabricius was a Lutheran pastor and astronomer in the little town of Osteel, East Frisia (northwestGermany). He was a correspondent of Johannes Kepler and the discoverer of the first known variable star (1596). Early in 1611, his son Johannes,a university student, returned from the Netherlands with one or more telescopes, and he and his father turned these instruments tothe heavens. On 9 March, at dawn, Johannes directed the telescope at the rising sun and saw several dark spots on it. He called hisfather, and together the two investigated this new phenomenon. They directed their instruments to the edge of theSun, and when their eyes adjusted to the brightness slowly moved toward the Sun's center. This method was, of course, very painful,and the two quickly switched to the projection method by means of a camera obscura    .

Over the next several months they tracked spots as they moved across the Sun's face and found that a dozen or so daysafter they had disappeared from the western edge of the Sun they reappeared on the eastern edge. Johannes wrote a tract on sunspots , De Maculis in Sole Observatis, et Apparente earum cum Sole ConversioneNarratio ("Narration on Spots Observed on the Sun and their Apparent Rotation with the Sun"), the dedication of which wasdated 13 June 1611. It was printed in Wittenberg (the site of the premier Lutheran university, where Johannes was apparentlycontinuing his studies) in time for the autumn book fair in Frankfurt. In the tract Johannes rehearsed the observations madeby him and his father, without giving times or dates or showing a picture of the spots, and then stated his opinion that they wereon the Sun and that the Sun therefore probably rotated on its axis (an notion already suggested by Giordano Bruno and Johannes Kepler .

Johannes's style was florid, and only a small part of the tract actually dealt with hisobservations and diffidently stated conclusions. Because of the lack of a powerful patron interested in scientific matters whomight have called the little book to the attention of influential people, it drew very little attention, and by the time e.g.,Kepler had become aware of its existence the book was eclipsed by Christoph Scheiner's first publication on sunspots (January 1612). Johannes's diffidence mayhave been caused by a disagreement with his father about the nature of sunspots. In December 1611, David Fabricius wrote toMichael Maestlin (Kepler's old teacher) that he did not believe the spots were on the Sun's body, although the center of theirmotions clearly lay in the Sun. Neither father nor son were important participants in the 1612/13 debate on the nature ofsunspots.

Little else is known about Johannes Fabricius, except that he died in 1616, at the young ageof 29. A year later the father was killed when an irate peasant, whom he had accused of stealing a goose, hit him over the headwith a shovel.

Questions & Answers

what is math number
Tric Reply
x-2y+3z=-3 2x-y+z=7 -x+3y-z=6
Sidiki Reply
Need help solving this problem (2/7)^-2
Simone Reply
what is the coefficient of -4×
Mehri Reply
the operation * is x * y =x + y/ 1+(x × y) show if the operation is commutative if x × y is not equal to -1
Alfred Reply
An investment account was opened with an initial deposit of $9,600 and earns 7.4% interest, compounded continuously. How much will the account be worth after 15 years?
Kala Reply
lim x to infinity e^1-e^-1/log(1+x)
given eccentricity and a point find the equiation
Moses Reply
12, 17, 22.... 25th term
Alexandra Reply
12, 17, 22.... 25th term
College algebra is really hard?
Shirleen Reply
Absolutely, for me. My problems with math started in First grade...involving a nun Sister Anastasia, bad vision, talking & getting expelled from Catholic school. When it comes to math I just can't focus and all I can hear is our family silverware banging and clanging on the pink Formica table.
I'm 13 and I understand it great
I am 1 year old but I can do it! 1+1=2 proof very hard for me though.
Not really they are just easy concepts which can be understood if you have great basics. I am 14 I understood them easily.
find the 15th term of the geometric sequince whose first is 18 and last term of 387
Jerwin Reply
I know this work
The given of f(x=x-2. then what is the value of this f(3) 5f(x+1)
virgelyn Reply
hmm well what is the answer
If f(x) = x-2 then, f(3) when 5f(x+1) 5((3-2)+1) 5(1+1) 5(2) 10
how do they get the third part x = (32)5/4
kinnecy Reply
make 5/4 into a mixed number, make that a decimal, and then multiply 32 by the decimal 5/4 turns out to be
can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
I'm not sure why it wrote it the other way
I got X =-6
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
is it a question of log
I rally confuse this number And equations too I need exactly help
But this is not salma it's Faiza live in lousvile Ky I garbage this so I am going collage with JCTC that the of the collage thank you my friends
Commplementary angles
Idrissa Reply
im all ears I need to learn
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greetings from Iran
salut. from Algeria
A soccer field is a rectangle 130 meters wide and 110 meters long. The coach asks players to run from one corner to the other corner diagonally across. What is that distance, to the nearest tenths place.
Kimberly Reply
Jeannette has $5 and $10 bills in her wallet. The number of fives is three more than six times the number of tens. Let t represent the number of tens. Write an expression for the number of fives.
August Reply
What is the expressiin for seven less than four times the number of nickels
Leonardo Reply
How do i figure this problem out.
how do you translate this in Algebraic Expressions
linda Reply
why surface tension is zero at critical temperature
I think if critical temperature denote high temperature then a liquid stats boils that time the water stats to evaporate so some moles of h2o to up and due to high temp the bonding break they have low density so it can be a reason
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
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Source:  OpenStax, Galileo project. OpenStax CNX. Jul 07, 2004 Download for free at http://cnx.org/content/col10234/1.1
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