Enjoy Cosmic Triplets

By: The Editors of Sky & Telescope May 18, 2022 0

If you've just read Jerry Oltion's article "Seeing Triple" in the September 2022 issue of Sky & Telescope magazine and are wondering where to find a table of data and charts, you've come to the right place. Below are the accompanying finder charts that will give you an overview of where to find the targets in the sky, in addition to a table that reports coordinates of each of the targets, as well as other data such as magnitudes and apparent sizes and separations.

Table of Data

Object	Designation	Type	Mag(v)	Size/Sep	RA	Dec
—	Iota Cassiopeiae	Triple star	4.6, 6.9, 9.0	3.0″, 6.7″	02^h 29.1^m	+67° 24′
Triangle in Pleiades	24 Tau	Star	6.3	—	03^h 47.4^m	+24° 07′
	HD 23607	Star	8.3	—	03^h 47.3^m	+24° 07′
	HD 23608	Star	8.7	—	03^h 47.3^m	+24° 08′
Triangle in Gemini	HD 51502	Lucida of triangle	7.3, 7.4, 8.4	124.1″, 106.8″, 81.2″	06^h 58.1^m	+14° 14′
Triangle in Monoceros	HD 46867	Lucida of triangle	8.4, 9.2, 9.4	30.3″, 33.6″, 39.6″	06^h 35.9^m	+05° 19′
Triangle below M11	S Scuti	Carbon star	6.8	—	18^h 50.3^m	–07° 54′
37 Cluster	NGC 2169	Open cluster	5.9	6′	06^h 08.4^m	+13° 58′
—	Yield Sign	Triplet of double stars	—	—	04^h 30.0^m	+15° 55′
The Stargate	Σ1659	Asterism	7.9, 8.3	28.1″	12^h 35.7^m	–12° 01′
Cluster triplet	NGC 663	Open cluster	7.1	15′	01^h 46.3^m	+61° 13′
	NGC 654	Open cluster	6.5	6′	01^h 44.0^m	+61° 53′
	NGC 659	Open cluster	7.9	6′	01^h 44.4^m	+60° 40′
Cluster triplet	M46	Open cluster	6.1	20′	07^h 41.8^m	–14° 49′
	M47	Open cluster	4.4	25′	07^h 36.6^m	–14° 29′
	NGC 2423	Open cluster	6.7	12′	07^h 37.1^m	–13° 52′
Great Hercules Cluster	M13	Globular cluster	5.8	20′	16^h 41.7^m	+36° 28′
Trifid Nebula	M20	Nebulae	—	20′ × 20′	18^h 02.3^m	–23° 02′
Barnard’s E Nebula	B142	Dark nebula	—	40′ × 40′	19^h 39.7^m	+10° 31′
	B143	Dark nebula	—	60′ × 60′	19^h 41.4^m	+11° 00′
Leo Triplet	M65	Spiral galaxy	9.3	9.8′ × 2.9′	11^h 18.9^m	+13° 06′
	M66	Spiral galaxy	8.9	9.1′ × 4.2′	11^h 20.3^m	+12° 59′
	NGC 3628	Spiral galaxy	9.5	14.8′ × 3.0′	11^h 20.3^m	+13° 35′
Other Leo Triplet	M95	Barred spiral galaxy	9.7	7.4′ × 5.0′	10^h 44.0^m	+11° 42′
	M96	Spiral galaxy	9.3	7.6′ × 5.2′	10^h 46.8^m	+11° 49′
	M105	Elliptical galaxy	9.3	5.4′ × 4.8′	10^h 47.8^m	+12° 35′
Bonus triplet (with M105)	NGC 3384	Elliptical galaxy	9.9	5.5′ × 2.5′	10^h 48.3^m	+12° 38′
	NGC 3389	Spiral galaxy	11.9	2.8′ × 1.3′	10^h 48.5^m	+12° 32′
Andromeda Galaxy	M31	Barred spiral galaxy	3.4	190.5′ × 61.7′	00^h 42.6^m	+41° 15′
Pinwheel Galaxy	M33	Spiral galaxy	5.7	70.8′ × 41.7′	01^h 33.9^m	+30° 40′
Draco Triplet	NGC 5981	Spiral galaxy	13.0	2.8′ × 0.5′	15^h 37.9^m	+59° 24′
	NGC 5982	Elliptical galaxy	11.1	2.6′ × 1.9′	15^h 38.7^m	+59° 21′
	NGC 5985	Spiral galaxy	11.1	5.5′ × 3.0′	15^h 39.6^m	+59° 20′

Angular sizes and separations are from recent catalogs. Visually, an object’s size is often smaller than the cataloged value and varies according to the aperture and magnification of the viewing instrument. Right ascension and declination are for equinox 2000.0.