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... М19 < М20 > М21 ...

Emission nebula and open star cluster M20

Emission nebula and open star cluster M20 or Trifid nebula is in the constellation Sagittarius (Sgr).

M20

Equatorial coordinates (epoch J2000):
Ra (α):18h02.3m, Dec (δ):-23° 02'

Visual magnitude: 5,0m - this object can be seen with the naked eye on a black sky, in the absence of illumination from street lighting.
Distance from the nebula M20 to the Sun is 2660 light years
Angular size: 29'х27'

Discoverer: Charles Messier, 1764 year.

The designation M20 in other catalogs: NGC 6514

M20 in the middle latitudes is located quite low above the horizon, so observation is difficult due to atmospheric distortions.
In the northern latitudes is not visible. Optimum magnification for a telescope with observations of M20, depending on the aperture of the telescope (D), is about D/6-D/4. 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 M20 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 M20 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 M20

or Trifid nebula

Equatorial coordinates (epoch J2000):
Ra (α):18h02.3m, Dec (δ):-23° 02'


Distance from the star clusters M20 to the Sun is 2660 light years
Angular size: 20'
External dimensions the star clusters M20 are about 15 light years.
Number of stars: 120+
Age of the object M20 is 0,3—0,4x106 years

Discoverer: Charles Messier, 1764 year.

M20 in the middle latitudes is located quite low above the horizon, so observation is difficult due to atmospheric distortions.
In the northern latitudes is not visible.

The best month for observing M20 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 M20 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.

M19
Мessier 19
M21
Мessier 21

Nikolay Kurdyapin, astro-map.com  
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