astronomy

John Caldecott

John Caldecott is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand John Caldecott rather than just read about it. In short: John Caldecott (16 September 1801 – 16 December 1849, Trivandrum) was an East India Company commercial agent, meteorologist and astronomer who worked in the court of the Raja of Travancore at the Trivandrum Observatory. Biography Caldecott was born in Finsbury in London where his father, also John, and mother Susannah lived.

Key takeaways

John Caldecott belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect John Caldecott to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of John Caldecott from memory before moving on to harder problems.

Reference excerpt

John Caldecott (16 September 1801 – 16 December 1849, Trivandrum) was an East India Company commercial agent, meteorologist and astronomer who worked in the court of the Raja of Travancore at the Trivandrum Observatory.

Biography Caldecott was born in Finsbury in London where his father, also John, and mother Susannah lived. He was christened on 1 November 1801 at St Luke's Church. John Caldecott (junior) went to India in 1820 on the Mulgrave Castle and reached Bombay in May 1821. He worked at Apollo Cotton as an assistant to Daniel West who was a family friend. A relative, William West had an interest in telescopes and microscopes as an evening amusement and this sparked off a scientific interest in John Caldecott. In 1832 he was posted as a commercial agent at the Indian port of Allepey (now Alappuzha) and he saw the need for an astronomical observatory there. This idea was aired in 1836, supported by the Resident Colonel James Stuart Fraser and approved by Raja Swathi Thirunal Rama Varma of Travancore. An observatory was constructed at Trivandrum. The building was constructed by Captain Horsley of the Madras Engineers. Opened in 1837, Caldecott was appointed as director. Two mural circles, a transit and equatorial telescopes were installed at the observatory. In April 1841, he also brought in instruments to measure the magnetic field of the Earth. He was interested in examining the magnetic field of the Earth at various parts, a scheme inspired by Alexander von Humboldt. He was also very interested in matters of the temperature of the core of the Earth. He published his observations extensively and pursued these ideas until his death. His measurements of the temperature of the ground at different depths in Trivandrum allowed him (and J.D. Forbes who commented on his observations) to point out errors in the assertions of Professor A. Kupffer, of the Imperial Academy of St. Petersburg who said that the Earth is about 6 degrees cooler than the air (based on measurements in Russia) and pointed out that Bossingault was wrong in assuming that the temperature underground below a depth of one foot was constant. He made observations on the solar eclipse of 21 December 1843 at Parrat near the origin of the Mahé river and noticed Baily's beads. He made observations of several comets. He also collaborated with Thomas Glanville Taylor of Madras and examined the magnetic field variations in southern India. Caldecott married Selina, daughter of James Somerville Darby of Dublin on 8 November 1825 at Bombay. This however did not work out well and she returned to England in 1827. He married again in 1835 to Sophia Rodgers at Allepey. Caldecott was elected to the Royal Society as well as the Royal Astronomical Society in 1840. Caldecott died in 1849 at Trivandrum and his work was continued by Reverend Josiah Sperschneider until his position was succeeded by John Allan Broun at the Trivandrum observatory.

References

External links Will of John Caldecott Biography of John Caldecott

Illustrations

Worked examples

Example 1 — a first encounter with John Caldecott

Start with the simplest possible case. Write down what John Caldecott claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to John Caldecott before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about John Caldecott ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of John Caldecott

In research: John Caldecott appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses John Caldecott in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: John Caldecott is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1801 births, 1849 deaths, British East India Company civil servants, so understanding it makes those chapters shorter.
In everyday life: Look for John Caldecott outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “John Caldecott” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study John Caldecott in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what John Caldecott means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain John Caldecott out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is John Caldecott in simple terms?

Why does John Caldecott matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study John Caldecott?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on John Caldecott.