Astronaut Starry Sky Star Projector:A well-made novelty star projector that every kid, or space fan, will love to have in their bedroom. It isn't quite on par with other star projectors performance-wise, but it does everything we'd expect of it, given its reasonable price. ★★★★

Though the Crab Nebula’s fluffy red-orange filamentary dust cage surrounds three sides of its milky centre, in certain areas the synchrotron emission extends beyond. Despite being outpaced by the synchrotron-emitting gas at times, clumps of dust are accelerating away from the pulsar centre as the gas bubble rapidly expands. However, because the gas is low in density, some of the dust creates sinking spindly fingers, leaving a small trace behind. Notice how the filaments tend to be longer toward the right side of the nebula, in the direction the pulsar is moving. Slipher and Edwin Hubble continued to collect the spectra from many different nebulae, finding 29 that showed emission spectra and 33 that had the continuous spectra of star light. [18] In 1922, Hubble announced that nearly all nebulae are associated with stars and that their illumination comes from star light. He also discovered that the emission spectrum nebulae are nearly always associated with stars having spectral classifications of B or hotter (including all O-type main sequence stars), while nebulae with continuous spectra appear with cooler stars. [20] Both Hubble and Henry Norris Russell concluded that the nebulae surrounding the hotter stars are transformed in some manner. [18] Formation [ edit ] NGC 604, a nebula in the Triangulum Galaxy Stars form when clumps of hydrogen and other gases in an H II region contract under their own gravity. As the gas collapses, the central clump grows stronger and the gas heats to extreme temperatures by converting gravitational potential energy to thermal energy. If the temperature gets high enough, nuclear fusion will ignite and form a protostar. The protostar is 'born' when it begins to emit enough radiative energy to balance out its gravity and halt gravitational collapse. The Orion Nebula contains a very young open cluster, known as the Trapezium Cluster due to the asterism of its primary four stars within a diameter of 1.5 light years. Two of these can be resolved into their component binary systems on nights with good seeing, giving a total of six stars. The stars of the Trapezium Cluster, along with many other stars, are still in their early years. The Trapezium Cluster is a component of the much larger Orion Nebula, an association of about 2,800 stars within a diameter of 20 light years. [10] The Orion Nebula is in turn surrounded by the much larger Orion molecular cloud complex which is hundreds of light years across, spanning the whole Orion Constellation. Two million years ago the Orion Nebula cluster may have been the home of the runaway stars AE Aurigae, 53 Arietis, and Mu Columbae, which are currently moving away from the nebula at speeds greater than 100km/s (62mi/s). [11] Coloration [ edit ] In 1902, Vogel and Eberhard discovered differing velocities within the nebula, and by 1914 astronomers at Marseilles had used the interferometer to detect rotation and irregular motions. Campbell and Moore confirmed these results using the spectrograph, demonstrating turbulence within the nebula. [28]nebula, (Latin: “mist” or “cloud”) any of the various tenuous clouds of gas and dust that occur in interstellar space. The term was formerly applied to any object outside the solar system that had a diffuse appearance rather than a pointlike image, as in the case of a star. This definition, adopted at a time when very distant objects could not be resolved into great detail, unfortunately includes two unrelated classes of objects: the extragalactic nebulae, now called galaxies, which are enormous collections of stars and gas, and the galactic nebulae, which are composed of the interstellar medium (the gas between the stars, with its accompanying small solid particles) within a single galaxy. Today the term nebula generally refers exclusively to the interstellar medium. Chaisson, E.; McMillan, S. (1995). Astronomy: a beginner's guide to the universe (2nded.). Upper Saddle River, New Jersey: Prentice-Hall. ISBN 0-13-733916-X. This particular projector is aimed at children, and the stars it projects aren't scientific like you'd find on the more 'adult' Sega Homestar Flux. But it still features a slide projector and three easy-to-handle discs containing 24 color images taken by the Hubble Telescope. Each disc has a different theme; Nebulas, Spacecraft & Astronauts and Planets & the Moon.

Kuhn, M. A.; etal. (2015). "The Spatial Structure of Young Stellar Clusters. II. Total Young Stellar Populations". Astrophysical Journal. 802 (1): 60. arXiv: 1501.05300. Bibcode: 2015ApJ...802...60K. doi: 10.1088/0004-637X/802/1/60. S2CID 119309858. Operation is manual rather than digital, but you can access additional informative descriptions of the pictures on the slides online using a provided 'secret code.' This allows children to learn more about the objects in space and adds a bit of fun and mystery to learning. Beginning in 1864, William Huggins examined the spectra of about 70 nebulae. He found that roughly a third of them had the emission spectrum of a gas. The rest showed a continuous spectrum and were thus thought to consist of a mass of stars. [17] [18] A third category was added in 1912 when Vesto Slipher showed that the spectrum of the nebula that surrounded the star Merope matched the spectra of the Pleiades open cluster. Thus, the nebula radiates by reflected star light. [19] Although small and discreet, this USB-powered projector has the capability to turn any room into a celestial wonderland. When connected to a USB power source, it projects hundreds of laser stars, providing a truly immersive and atmospheric experience. Whether you're a gamer aiming to elevate your gaming space, a parent wanting to create a magical bedtime atmosphere for your child (ensuring they don't look directly into the beam) or just someone who enjoys the beauty of the cosmos on a dark and dreary night, this star projector is sure to bring joy.Bowen, Ira Sprague (1927). "The Origin of the Nebulium Spectrum". Nature. 120 (3022): 473. Bibcode: 1927Natur.120..473B. doi: 10.1038/120473a0.

The region takes on a different appearance when viewed in the longer infrared wavelengths detected by Webb’s Mid-infrared Instrument (MIRI). The hot stars fade, and the cooler gas and dust glow. Within the stellar nursery clouds, points of light indicate embedded protostars, still gaining mass. While shorter wavelengths of light are absorbed or scattered by dust grains in the nebula, and therefore never reach Webb to be detected, longer mid-infrared wavelengths penetrate that dust, ultimately revealing a previously unseen cosmic environment. There are a variety of formation mechanisms for the different types of nebulae. Some nebulae form from gas that is already in the interstellar medium while others are produced by stars. Examples of the former case are giant molecular clouds, the coldest, densest phase of interstellar gas, which can form by the cooling and condensation of more diffuse gas. Examples of the latter case are planetary nebulae formed from material shed by a star in late stages of its stellar evolution. Observers have long noted a distinctive greenish tint to the nebula, in addition to regions of red and of blue-violet. The red hue is a result of the Hα recombination line radiation at a wavelength of 656.3 nm. The blue-violet coloration is the reflected radiation from the massive O-class stars at the core of the nebula.Ever wondered how to make a star projector? Sold as the 4M Night Sky Projection Kit, (or in the U.K. as the Science Museum Create A Night Sky) this cardboard cut-out might not seem at first to be a worthy addition to our list of the best star projectors. After all, what's on offer here is merely some tiny holes in cardboard positioned over a lamp. The resulting image is pretty basic, of course, but how you get there is the clever part. With Webb’s NIRCam ( Near-Infrared Camera) and MIRI ( Mid-Infrared Instrument), the game is afoot as new details are uncovered–including the first complete map of dust distribution –in the search for answers about the Crab Nebula’s origins. Watts, William Marshall; Huggins, Sir William; Lady Huggins (1904). An introduction to the study of spectrum analysis. Longmans, Green, and Co. pp. 84–85 . Retrieved 2009-10-31. Clark, Roger (March 28, 2004). "Surface Brightness of Deep Sky Objects" . Retrieved June 29, 2013. . The conversion to nits is based on 0 magnitude being 2.08 microlux. The Orion Nebula is an example of a stellar nursery where new stars are being born. Observations of the nebula have revealed approximately 700 stars in various stages of formation within the nebula.

The 2.0 version of this projector comes with the BlissLights smartphone app, connecting via Bluetooth. Using the app, you can select from seven effects modes, modify the projector's intensity, adjust laser brightness, and even set the rotation speed. Additionally, you can create your own custom color blend through the app. Just keep in mind that the stars will always appear either green or blue, depending on which model you get. The answer to this question depends on the type of star projector you're considering. Some FDA-approved laser star projectors are safe for brief and accidental exposure to eyes, but they are not recommended for children, and you should never look directly into a laser beam. The hardware is simple and straightforward. It includes a small lamp that runs on 4 x AA batteries (not included) and a square base. The assembled night sky dome, positioned over the lamp, has support fixed at each of its four corners. Once the lights are off, the stars on the globe light up, casting their projections onto the walls and ceiling.

Hearnshaw, J.B. (1996). The Measurement of Starlight: Two Centuries Of Astronomical Photometry. New York: Cambridge University Press. p. 122. ISBN 9780521403931 . Retrieved March 4, 2016. Some of these collapsing stars can be particularly massive, and can emit large quantities of ionizing ultraviolet radiation. An example of this is seen with the Trapezium cluster. Over time the ultraviolet light from the massive stars at the center of the nebula will push away the surrounding gas and dust in a process called photo evaporation. This process is responsible for creating the interior cavity of the nebula, allowing the stars at the core to be viewed from Earth. [8] The largest of these stars have short life spans and will evolve to become supernovae.