astronomy

NGC 1566

NGC 1566 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 1566 rather than just read about it. In short: NGC 1566, sometimes known as the Spanish Dancer, is an intermediate spiral galaxy located around 69 million light years away in the constellation of Dorado. The exact distance of this galaxy remains elusive with measurements ranging from 6 Mpc up to 21 Mpc.

Key takeaways

NGC 1566 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 1566 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 1566 from memory before moving on to harder problems.

Reference excerpt

NGC 1566, sometimes known as the Spanish Dancer, is an intermediate spiral galaxy located around 69 million light years away in the constellation of Dorado. The exact distance of this galaxy remains elusive with measurements ranging from 6 Mpc up to 21 Mpc. It was discovered on May 28, 1826 by Scottish astronomer James Dunlop. At 10th magnitude, it requires a telescope to view.

Neighborhood This galaxy forms a member of the NGC 1566 subgroup of the Dorado Group, of which it is dominant and brightest member, although Kilborn and colleagues (2005) listed it as second brightest member of the NGC 1566 group after NGC 1553. The X-ray emission from the group is dominated by the hot gas halo of this galaxy, which extends out to 29 kpc before merging with the background radiation. The galaxy appears to be interacting with smaller members of its subgroup. Radio emissions suggest the disk is asymmetrical and the neutral hydrogen gas shows a mild warp.

Characteristics The morphological classification of NGC 1566 is SAB(rs)bc, which indicates a spiral galaxy with a weak bar structure around the nucleus (SAB), an incomplete ring around the bar (rs), and showing wound arms (bc). The spiral arms are strong and symmetrical. The galactic plane is inclined at an angle of 31°±7° to the line of sight to the Earth and the long axis is oriented along a position angle of 219°±4°. The northwest side of the galaxy is more strongly obscured by dust, suggesting it is the near side. The mass ratio of neutral hydrogen gas to the mass of the stars is 0.29, which is on the high side for a galaxy of this mass. Absolute luminosity is 3.7×1010 L☉, and is calculated to contain 1.4×1010 M☉ of H I. NGC 1566 is an active galaxy with many features of a Seyfert type I, although the exact type remains uncertain. It is one of the closest and brightest Seyfert galaxies. The mass of the supermassive black hole at the center is estimated at (1.3±0.6)×107 M☉. The proximity of the galaxy, along with strong spiral arms and an active nucleus, have made it the subject of much scientific study in the astronomy community. It is the nearest known CL AGN galaxy.

Supernovae Three supernovae have been observed in NGC 1566:

SN 2010el (Type Iax, mag. 16.8) was discovered by Berto Monard of South Africa on 19 June 2010. It was located 13″ west and 22″ south of the center of the galaxy. ASASSN-14ha (Type II, mag. 14.6) was discovered by All Sky Automated Survey for SuperNovae (ASAS-SN) on 10 September 2014. SN 2021aefx (Type Ia, mag 17.24) was discovered by the Distance Less Than 40 Mpc Survey (DLT40) on 11 November 2021. It reached magnitude 12, making it the brightest supernova of 2021.

Gallery

References

External links

Spitzer Space Telescope page on NGC 1566 Discovery image of SN 2010el (2010-06-19; The star to the left of the core of the galaxy is magnitude 12.3)

NGC 1566 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Illustrations

Worked examples

Example 1 — a first encounter with NGC 1566

Start with the simplest possible case. Write down what NGC 1566 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 1566 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 1566 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 1566

In research: NGC 1566 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 1566 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 1566 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1826, Discoveries by James Dunlop, Dorado, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 1566 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 1566 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 1566 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 1566 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 1566 in simple terms?

Why does NGC 1566 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 1566?

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 1566.