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vdB 4

Set a site to see tonight's sky

When vdB 4 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

Dust grains scattering the light of nearby stars rather than emitting their own.

Class explainer for reflection nebula (catalogue type).

The facts

vdB 4 is a reflection / dark nebula in Cassiopeia. SIMBAD gives its distance as 558.005 pc (−4.2657 pc / +4.2657 pc) — ≈ 1,819.97 ly, measured by parallax from 4 measurements. The light reaching us from it now left it around the year 206 CE. On the sky it spans 8.4′ — 27% of the full Moon's width. At that distance, that angle means it is roughly 4 light-years across.

Sources: AstroBrain catalogue; van den Bergh S. 1966, AJ 71, 990, via CDS/VizieR VII/21; CDS/SIMBAD astronomical database, Strasbourg (SIMBAD record BD+61 154 · distance from 2020yCat.1350....0G). 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.

4 ly

across — 1× the distance from the Sun to its nearest neighbour star (4.37 ly).

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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vdB 4

Set a site to see tonight's sky

When vdB 4 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

Dust grains scattering the light of nearby stars rather than emitting their own.

Class explainer for reflection nebula (catalogue type).

The facts

vdB 4 is a reflection / dark nebula in Cassiopeia. SIMBAD gives its distance as 558.005 pc (−4.2657 pc / +4.2657 pc) — ≈ 1,819.97 ly, measured by parallax from 4 measurements. The light reaching us from it now left it around the year 206 CE. On the sky it spans 8.4′ — 27% of the full Moon's width. At that distance, that angle means it is roughly 4 light-years across.

Sources: AstroBrain catalogue; van den Bergh S. 1966, AJ 71, 990, via CDS/VizieR VII/21; CDS/SIMBAD astronomical database, Strasbourg (SIMBAD record BD+61 154 · distance from 2020yCat.1350....0G). 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.

4 ly

across — 1× the distance from the Sun to its nearest neighbour star (4.37 ly).

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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