When is the best time to observe 39 Draconis?

39 Draconis is best observed from May through July, with peak visibility during June when it transits around midnight in the Northern Hemisphere.

Where is 39 Draconis located in the sky?

39 Draconis lies in the constellation Draco at right ascension 18h 24m and declination +58° 48′.

What telescope do I need to split 39 Draconis?

Splitting 39 Draconis requires an aperture of roughly 100 mm or larger — the components are separated by about 3.8″ at magnitudes near 5.0. The companion is about 3.1 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

39 Draconis — Double Star in Draco

Observable Double Star Good (58/100)

Sep: 3.8", Companion: mag 8.1

Magnitude 5.0^m DoubleStar Draco (Dra) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.98

Spectral Type A1V

Star Color White (B-V 0.08)

Distance 93 ly

2Position & Identifiers

RA 18h 23m 54.5s

Dec +58° 48' 02.0"

Constellation Draco (Dra)

HR 6923

HIP 90156

HD 170073

SAO 30949

Flamsteed 39 Dra

Double Cat 11336

SIMBAD

3How easy to split?

Primary 5.0 mag Companion 8.1 mag Separation 3.8″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Hard+	Hard+	Hard+
150 mm Newton 150mm Newt.	Easy	Easy	Easy
Celestron C8 (203 mm SCT) C8 203mm	Easy	Easy	Easy

Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

4Visibility

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Best season May – Jul (peak: Jun)

5Multiple Star System 8 components F,G: optical

Components 8

Component IDs AB

Separation 3.8″

Companion Mag 8.1

Position Angle 347°

Star Colors A: White B: Yellow

Discoverer STF2323

Notes

AB binary with slow orbital motion. Combined mag., colors. B is A5p, vsini 80k/s. C, 7.1v F6V at 90" CPM. Some | discordance whether B or C is the brighter.