Pleiades

On the left, cataloged as NGC 1499, the California Nebula does have a familiar shape, though its coastline is actually over 60 light-years long and lies about 1,500 light-years away. The nebula's pronounced reddish glow is from hydrogen atoms ionized by luminous blue star Xi Persei seen just to its right. At the far right, the famous Pleiades star cluster is some 400 light-years distant and around 15 light-years across. Its spectacular blue color is due to the reflection of starlight by interstellar dust. In between are hot stars of the Perseus OB2 association and dusty, dark nebulae along the edge of the nearby, massive Perseus molecular cloud.
The photo covers 12 degrees or it would take 25 full moons. This type of photo take very,very dark skies which is getting harder and harder to do
This why nowday they place telescope in middle of no where. Like the telescope on Hawaii are place on top of a extinct volcano and there are law that forbids build of anything around the area. The whole area is classified as national park ,so no one can be build in the park,its keep as clean as they can
In the past they just place a telescope close to the college that support the telescope this why they place the 200 inch Hale telescope-Palomar Observatory in California on a mountain by LA,plus they didn't think LA would grow so fast.At the time it was build it was the biggest on the Earth this last for some time but now days 200 inch telescope is consider on the small size. But the light pollution is effecting the 200 inch plus 100 inch telescopes at Palomar Observatory in California
.They update the telescope now they used electric camera instead of film. They now build the new telescope elsewhere but these telescope are name part of the Palomar Observatory. They have a 60 inch in its good time this telescope took the first full sky maps,theese map are still being used today,they did it again using electric camera but nowday its being used as a teaching telescope people can look through it or buy time and used it all night....
There was talk of moving both the telescope,the 100 inch and the 200inch,but so far I don't know,it might be cheaper to try to limit the type of light people used outside.they like LED lights and low pressure mercury light.High pressure light block out the light wave astronomer used