astronomy

NGC 753

NGC 753 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 753 rather than just read about it. In short: NGC 753 is a spiral galaxy located 220 million light-years away in the constellation Andromeda. The galaxy was discovered by astronomer by Heinrich d'Arrest on September 16, 1865 and is a member of Abell 262.

Key takeaways

NGC 753 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 753 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 753 from memory before moving on to harder problems.

Reference excerpt

NGC 753 is a spiral galaxy located 220 million light-years away in the constellation Andromeda. The galaxy was discovered by astronomer by Heinrich d'Arrest on September 16, 1865 and is a member of Abell 262. NGC 753 has roughly 2-3 times more mass than the Milky Way and is classified as a radio galaxy.

Physical characteristics NGC 753 contains two main arms that extend to 180° on either side of the galaxy. From the two main arms, there are three larger and weaker arms that sub-divide into several branches. This open structure of the arms may be due to the influence of NGC 759 which is a close companion of NGC 753 that lies 1.4 Mly (0.44 Mpc) away.

Supermassive black hole NGC 753 has a supermassive black hole with an estimated mass of (2.2 ± 0.4) × 107 M☉.

Supernovae NGC 753 has hosted two supernovae:

SN 1954E (type unknown, mag. 18.5) was discovered by Fritz Zwicky on 26 September 1954. SN 2025mbr (Type Ia, mag. 17.3695) was discovered by the Automatic Learning for the Rapid Classification of Events (ALeRCE) on 25 May 2025.

Illustrations

Worked examples

Example 1 — a first encounter with NGC 753

Start with the simplest possible case. Write down what NGC 753 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 753 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 753 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 753

In research: NGC 753 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 753 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 753 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Abell 262, Andromeda (constellation), Astronomical objects discovered in 1865, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 753 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 753 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 753 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 753 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 753 in simple terms?

Why does NGC 753 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 753?

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 753.