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M1, the Crab Nebula in Taurus

TargetTypeR. A.Dec.ConstellationMagnitudeSize
M1 (NGC 1952)Bright Nebula05h 34m 00s+22° 01′ 00″Taurus8.46.0×4.0 arcmins

Overview

The Crab Nebula is the remains of a supernova (star explosion) in the constellation Taurus. It’s believed to be the one documented in China nearly 1000 years ago, in 1054. At that time, it bright enough to be seen during the day but, now, M1 shines at magnitude 8.4, so it’s not visible to the naked eye even on the darkest night, but it is within easy reach of smaller telescopes.

What we’re seeing is the remains of a supernova, one of the most cataclysmic events known in the universe. It was naked for a crab following one of the earliest telescope-based drawings done of it, by William Parsons in 1843 using a 36″ telescope. Although actually first seen (we think) in 1054, the English astronomer John Bevis is credited with its modern day discovery in 1731. Messier saw it in September 1758.

The Crab Nebula is located in the Perseus Arm of our Milky Way galaxy, roughly 6,500 light-years away from our solar system. It is about 11 light-years wide, which tells us that the exploding star material is travelling with enough velocity to cover 5.5 light-years in about 1,000 years. To give some perspective to that, our solar system is about 0.002 light-years wide. The Crab is still growing today, at a rate of 930 miles per second (1,500 km/s), which is 0.5% of the speed of light.

What remains of the exploded star at the center of this nebula is a neutron star spinning 30 times per second and known as a pulsar. It’s no more that 20 miles wide – putting it far out of reach of our backyard telescopes – and is one of the brightest sources of gamma radiation that we know of. It is also the densest matter we know of, with one teaspoon having the equivalent mass of a mountain.

M1, The Crab Nebula, imaged by NASA’s Hubble Space Telescope (source)

Finder Charts

This first sky chart, from SkySafari 6, shows the sky looking south at 9:00 p.m. in mid-February.

M1 is above the ‘head’ of Orion (circled orange), perhaps the most famous and easily recognized of all the constellations after the Big Dipper (Plough). More precisely, it is between the ‘horns’ of Taurus the bull as they face towards the twins of Gemini, Castor and Pollux.

Stars on this chart are shown to magnitude 5.0 and the moon and planets are not shown.

[M1-1] It’s easiest to find Orion and then the Y-shaped horns of Taurus. Click for full-screen.

In the zoomed-in image below, we can see that a line traced from Meissa, at the top of Orion, to Elnath, the brighter of Taurus’s two horns, practically passes through M1, which is just over one degree northwest from the other horn, Zeta Tauri.

[M1-2] The Crab Nebula is on the Zeta Tauri side of the line connecting Meissa to Elnath. Click for full-screen.

In this final star chart, with stars now shown to magnitude 7, you can see a blue circle representing that 1° field of view. Note how M1 and Zeta Tauri on on its rim at the same time. Use a slightly wider field of view to see both star and nebula at the same time.

[M1-3] With Elnath still visible, you can see M1 and Zeta Tauri almost inside a 1° field of view. Click for full-screen or download the pdf below.

Now you have this beautiful nebula in your eyepiece, what should you expect to see?

Individual Telescope Views

The following views will help you find M1 in different telescope types by presenting the images as your telescope will show them. The first image is with a black sky and white stars, the second picture is the same image but presented in inverse monochrome. Black stars on a white background is often easier to use at the telescope. Stars are shown to magnitude 10.0 and the larger circle is a 1° field of view, as shown in the third star chart above. You can also see the star Zeta Tauri in each image.

Each image can be clicked on for a full-screen version.

Upright View – This is what your eyes see unaided and through a reflex or red-dot finderscope

[M1-4]
[M1-5]

Upside-down view – This is what reflectors and magnifying finders show, and refractors / Cassegrains without a star diagonal

[M1-6]
[M1-7]

Mirrored View – Refractors and Cassegrain models with a star diagonal show this view

[M1-8]
[M1-9]

Observation

The Crab Nebula’s magnitude 8.4 glow puts it on a par with Titan, the largest moon of Saturn, so comfortably in reach of most telescopes, and even binoculars under a dark sky. However, what’s equally important is a clear sky with high transparency. Any wisps of cloud or haziness severely deplete the amount of outer structure we can see.

Despite being relatively ‘bright’ this can be a tricky creature to track down if you don’t have great conditions to work with. Ideally, begin with a large field of view and use averted vision to draw your attention to this ghostly apparition. Its faint circle of light is accompanied by two brighter stars, one to the south and one to the east.

As with all nebulas, a larger telescope letting in more light reveals more detail than a smaller model. At lower magnification we can see a definite mid section that looks like its narrower than the expanded extremities. Higher magnification reveals a patchier consistency to the nebula.


PDFs for Printing

Each of the star maps above is reproduced as a pdf below. Each star map has a number in [square brackets] beneath it which corresponds to the file number below. If you want image [M1-1], for example, click the ‘download’ button next to it below and you’ll be able to open it as a printable pdf.

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