Light pollution id the enemy of astronomers, but it is possible to pick out some stars even in the largest cities
led by Dr Alejandro Sánchez de Miguel at the University of Exeter, UK suggests that a global rise in artificial lighting has substantially boosted light pollution levels over the past few decades – some regions have suffered as much as a fivefold increase! The problem is intrinsically linked to energy waste, so it would be reasonable to expect that efforts are underway to tackle it, but not all approaches are beneficial to our view of the sky.
Aside from the Sun and Moon, everything else in the sky can be regarded as a point source or a diffuse object . Stars are point sources, whereas deep sky objects such as nebulae and galaxies are diffuse. In our solar system, planets and satellites are point sources, and the comas and tails of comets are usually diffuse.
In the very brightest urban skies, the limiting magnitude is severely restricted to stars brighter than +4. The ideal limit of +6.5 is drastically better. From a dark rural site, you can see stars at least ten times fainter than the faintest visible in the city centre. There’s an easy way to visualize your sky darkness when planning your stargazing sessions. The open source, free to use home planetarium softwareis capable of simulating the appearance of light pollution, allow you to predict how the stars will really appear in urban skies. With the software launched, open up the Sky and Viewing Options window and change the light pollution value. In exceptional skies, you can leave it at zero. In extremely poor skies, set it to 9.
You can also ask Stellarium to automatically estimate your sky quality using a database of measured light pollution values. No matter how awash the sky becomes with artificial light, at least a few dozen bright stars will always stand out, and you may be surprised by just how many fainter ones can be found from urban sites you’d previously written off.
Norge Siste Nytt, Norge Overskrifter
Similar News:Du kan også lese nyheter som ligner på denne som vi har samlet inn fra andre nyhetskilder.
Swoon in Tech Stocks Puts Startup Valuations in Harsh New LightAfter a blowout year, venture investors have taken note of the downturn in publicly-traded tech stocks and are beginning to question prices for late-stage funding rounds.
Les mer »
Philips Hue’s new smart outdoor light fixture harkens back to a simpler timePhilips Hue outdoor lights add an old-timey vibe to your smart home
Les mer »
Michael Madsen Says Son Hudson’s “Memory and Light Will Be Remembered” Following His Death at 26The actor's family said they are 'heartbroken and overwhelmed' by the death.
Les mer »
Thailand gives green light to growing cannabis at homeThailand's narcotics board on Tuesday said it would remove cannabis from its drugs list, paving the way for households to grow the plant.
Les mer »
Fans Choose Charlie Puth’s ‘Light Switch’ as This Week’s Favorite New MusicThe singer-songwriter’s new track brought in nearly 46% of the week’s vote.
Les mer »