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... М16 < М17 > М18 ...

Emission nebula and open star cluster M17

Die offener Sternhaufen M17 or Omega, Swan, Horseshoe, or Lobster Nebula Emission nebula and open star cluster is in the constellation Sagittarius (Sgr).

M17

Equatorial coordinates (epoch J2000):
Ra (α):18h20.8m, Dec (δ):-16° 11'

Visual magnitude: 7,0m
Distance from the nebula M17 to the Sun is 5910 light years
Angular size: 46'x37'

Discoverer: Jean-Philippe Loys de Chéseaux, 1745 year.

The designation M17 in other catalogs: NGC 6618

Optimum magnification for a telescope with observations of M17, depending on the aperture of the telescope (D), is about D/6-D/3. Higher magnifications of course add details, but lead to a strong drop in the brightness of the image, making it difficult to observe.

The best month for observing M17 is July. At this time, the object is at midnight near its highest point in the sky, that is, it is less affected by light from the lanterns and atmospheric distortions.

For observers in the northern latitudes:The nights in July are still quite light, so it makes sense to try to observe M17 also in August.
The first half of August is also not very dark, in addition the object will be at midnight not at its highest point,which provides the least exposure and atmospheric distortion. But, the difference is not so noticeable. And already in the second half of August the night sky becomes quite dark for observations (although in September it will more darker).The farther south the place of your observation is located, the earlier the sky will darken - both in time on the clock and on the calendar.

The parameters of the open star cluster M17

or Omega, Swan, Horseshoe, or Lobster Nebula The parameters of the open star cluster

Equatorial coordinates (epoch J2000):
Ra (α):18h20.8m, Dec (δ):-16° 11'


Distance from the star clusters M17 to the Sun is 5910 light years
Angular size: 5'
External dimensions the star clusters M17 are about 10 light years.
Number of stars: 2200
Age of the object M17 is 1x106 years

The best month for observing M17 is July. At this time, the object is at midnight near its highest point in the sky, that is, it is less affected by light from the lanterns and atmospheric distortions.

For observers in the northern latitudes:The nights in July are still quite light, so it makes sense to try to observe M17 also in August.
The first half of August is also not very dark, in addition the object will be at midnight not at its highest point,which provides the least exposure and atmospheric distortion. But, the difference is not so noticeable. And already in the second half of August the night sky becomes quite dark for observations (although in September it will more darker).The farther south the place of your observation is located, the earlier the sky will darken - both in time on the clock and on the calendar.


Мessier 16

Мessier 18

Nikolay Kurdyapin, astro-map.com  
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