astronomy

NGC 6845

NGC 6845 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 NGC 6845 rather than just read about it. In short: NGC 6845 (also known as Klemola 30) is an interacting system of four galaxies in the constellation Telescopium. The cluster has certain similarities with Stephan's Quintet.

Key takeaways

NGC 6845 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect NGC 6845 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 6845 from memory before moving on to harder problems.

Reference excerpt

NGC 6845 (also known as Klemola 30) is an interacting system of four galaxies in the constellation Telescopium. The cluster has certain similarities with Stephan's Quintet. Its distance is estimated to be about 90 Mpc. The components of the galaxy cluster are the two spiral galaxies NGC 6845A and NGC 6845B as well as the two lenticular galaxies NGC 6845C and NGC 6845D. The four galaxies occupy an area of about 4' x 2' in the sky. The largest galaxy in this compact galaxy cluster is NGC 6845A, a barred spiral galaxy. SN 2008DA was a Type II supernova observed in NGC 6845A in June 2008. The dwarf galaxy ATCA J2001-4659, which is found around 4.4' northeast of NGC 6845B, was identified as a companion of NGC 6845. NGC 6845 was discovered on July 7, 1834 by John Herschel.

References

External links Media related to NGC 6845 at Wikimedia Commons Capella Observatory

Illustrations

Worked examples

Example 1 — a first encounter with NGC 6845

Start with the simplest possible case. Write down what NGC 6845 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 NGC 6845 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 NGC 6845 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 NGC 6845

In research: NGC 6845 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 NGC 6845 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: NGC 6845 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1834, Interacting galaxies, NGC objects, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 6845 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.

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How to study NGC 6845 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 6845 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 NGC 6845 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 6845 in simple terms?

NGC 6845 (also known as Klemola 30) is an interacting system of four galaxies in the constellation Telescopium. The cluster has certain similarities with Stephan's Quintet.

Why does NGC 6845 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 NGC 6845?

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 NGC 6845.