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LDN 1791

Set a site to see tonight's sky

When LDN 1791 is up, how long it stays usable and when it is in season all depend on where you observe from. Set your site and this page adds tonight's answer and its year.

Set it on Tonight

The science

What you are looking at

In one sentence

Cold dust dense enough to block the light of whatever lies behind it.

Class explainer for dark nebula (SIMBAD classification).

The facts

LDN 1791 is a reflection / dark nebula in Ophiuchus. SIMBAD gives no distance for it, so its true size and light-travel time can't be worked out here. On the sky it covers about 8.8′, estimated from the cloud's catalogued area — 28% of the full Moon's width.

Sources: AstroBrain catalogue; Lynds B.T. 1962, ApJS 7, 1, via CDS/VizieR VII/7A; CDS/SIMBAD astronomical database, Strasbourg (SIMBAD record LDN 1791). Contains information from SIMBAD, which is made available here under the Open Database License (ODbL). Download the SIMBAD-derived data.

For scale

Angular size, as it would sit on your sky.

The same patch of sky in visible light

Sky image
Observatory photos and open-licence sky surveys.
Credits on each image.

Neighbours in the sky

Sky maths: apparent positions with refraction, one-minute steps; usable = full astronomical dark, at least 30° up and clear of your skyline. Survey images: CDS, Strasbourg (DSS2 and other surveys). Science: SIMBAD. The hours, heights and Moon on this page use no weather forecast; the rank is this target’s place in the Targets list, whose score also counts the cloud forecast when there is one.

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LDN 1791

Set a site to see tonight's sky

When LDN 1791 is up, how long it stays usable and when it is in season all depend on where you observe from. Set your site and this page adds tonight's answer and its year.

Set it on Tonight

The science

What you are looking at

In one sentence

Cold dust dense enough to block the light of whatever lies behind it.

Class explainer for dark nebula (SIMBAD classification).

The facts

LDN 1791 is a reflection / dark nebula in Ophiuchus. SIMBAD gives no distance for it, so its true size and light-travel time can't be worked out here. On the sky it covers about 8.8′, estimated from the cloud's catalogued area — 28% of the full Moon's width.

Sources: AstroBrain catalogue; Lynds B.T. 1962, ApJS 7, 1, via CDS/VizieR VII/7A; CDS/SIMBAD astronomical database, Strasbourg (SIMBAD record LDN 1791). Contains information from SIMBAD, which is made available here under the Open Database License (ODbL). Download the SIMBAD-derived data.

For scale

Angular size, as it would sit on your sky.

The same patch of sky in visible light

Sky image
Observatory photos and open-licence sky surveys.
Credits on each image.

Neighbours in the sky

Sky maths: apparent positions with refraction, one-minute steps; usable = full astronomical dark, at least 30° up and clear of your skyline. Survey images: CDS, Strasbourg (DSS2 and other surveys). Science: SIMBAD. The hours, heights and Moon on this page use no weather forecast; the rank is this target’s place in the Targets list, whose score also counts the cloud forecast when there is one.

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