Messier 26

From DeepSkyPedia

open cluster M 25 <<  Messier 26  >> M 27  Cr 388 <<  Collinder 389  >> Cr 390  Mel 211 <<  Melotte 212  >> Mel 213
Sketch by Vedran Vrhovac
Position (epoch J2000) [1]
Constellation	Scutum
Position	Ra 18:45:18.6 Dec -09:23:01
DSS images	10' · 20' · 30' · 45' · 1°
Appearance [1]
Apparent mag.	8
Size	14'
Class	II 3 m
Stars
Dreyer's description	Cl cL pRi pC st 12...15
Other
Other designations	M 26, NGC 6694, Collinder 389, Cr 389, Melotte 212, Mel 212, Lund 858 and OCL 67
Notes
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Messier 26 is an open cluster in Scutum.

Contents 1 How to find it 2 Appearance 2.1 Telescopes up to 70mm, binoculars up to 50 mm, and finders 2.2 Telescopes 71mm - 100mm (2.8" - 3.9"), binoculars 51mm - 70mm 2.3 Telescopes 101mm - 141mm (4" - 5.5"), binoculars 71mm - 100mm 2.4 Telescopes 141mm - 177mm (5.6" - 6.9") 2.5 Telescopes 178mm - 305mm (7" - 12") 2.6 Telescopes above 12" 3 Notes 4 References 5 Links

[edit] How to find it

Find a 3.95-mag Alpha Scuti^{see map:[2]}, the brightest in the constellation of Scutum. To the east, there are two more bright stars: 4.88-mag Epsilon Scuti and variable (4.6- to 4.8-mag), triple star Delta Scuti ^{see also wikipedia article}. Those 3 stars make right triangle, with right angle in Delta Scuti. Go from Alpha towards Delta, pass Delta, and continue for 40' in the same direction to reach M 26.

[edit] Appearance

This is a small cluster, and its brightest part is less then 5' in diameter. The most brightest star shines at m=9.2, two more stars are at m=10.3 and fourth brightest is actually a close 11-mag pair. Those 4 stars form the shape of kite. Total number of stars in the entire cluster (having 15' in diameter) is somewhere around 90. Except the 4 main stars, all other are dimmer than m=11.7. The cluster is unique for having a well-defined zone of low star density in a 3' diameter region, immediately surrounding the nucleus, inside the "diamond", propably due to dark interstellar matter obscuring this region.^[3]

[edit] Telescopes up to 70mm, binoculars up to 50 mm, and finders

• M 26 with 12x45 binoculars by Ante Perković (SEEN, Jul 22 2004) [include this report]
• Scutum by Steve Coe - Messier 26 with 8x50 finder, 10x50 binox, 6" f/6, and 13" f/5.6 [include this report]

[edit] Telescopes 71mm - 100mm (2.8" - 3.9"), binoculars 51mm - 70mm

At 12x (12x60 binos), the cluster is very small, faint fuzzy ball with no structure.^[4]

At 20x (20x70 binos), fuzzy ball only grows a little, and 9-mag central star might pop out of the fuzzy ball's center.^[4][5]

[edit] Telescopes 101mm - 141mm (4" - 5.5"), binoculars 71mm - 100mm

At lower power (21x), 4" telescope will give more-less the same view as 20x70 binoculars - small faint fuzzy ball^[6], maybe with a single star in the center.

In 4.5" telescope, you will need to raise power to somewhere between 25x and 30x for bringing another 3 stars out of the fuzzy ball. Those 4 main stars form 3'-long kite, while fainter stars still make the faint patch in the background. In good conditions, raising power to 90x can help you see up to 8 stars in the cluster, with no nebulosity left. Most of the stars are outside the "kite" but very close to it, so cluster doesn't grow to much. In bad conditions, you might, even at higher power, see only 4 stars and nebulosity.^[7][8]

More reports:

• Messier 26 observation and sketch by Rony De Laet with Meade ETX 105 [include this report]
• M 26 with 4.5" (114mm) f/8 homemade dobson (babydob) by Ante Perković (SEEN, Aug 17 2004) [include this report]
• M 26 with 4.5" (114mm) f/8 homemade dobson (babydob) by Ante Perković (SEEN, Nov 18 2003) [include this report]
• M 26 with 25x100 binoculars by Ante Perković (SEEN, May 01 2005) [include this report]

[edit] Telescopes 141mm - 177mm (5.6" - 6.9")

In 6" telescope, at higher power (120x), at least 15 stars are visible (under 4.0-mag skies), most of them linked in chains.^[9][10]

[edit] Telescopes 178mm - 305mm (7" - 12")

Depending on sky darkness and other factors, a telescope with aperture between 8"^[11][12][13] and 10"^[14] will show M 26 as either just a diamond-shaped group of 4 bright stars with a few fainter stars around, or, in good conditions (like LM=7.2!), as a rich cluster, somewhat concentrated and pretty well detached, with up to 30 stars (possible with some more, but unresolved, in fuzzy background), mostly outside the central "diamond". Some stars are arranged in chains. Power higher of 100x is needed to see this cluster at its best. Averted vision might also help.

[edit] Telescopes above 12"

Using even higher-apurture telescopes might actually makes this cluster less atractive, since number of visible stars in cluster will probably not go much over 30 or 35, while background stars will grow in number, making this cluster less detached. ^[15][16][17]

More reports:

• M 26 (@ Scutum) observation by Tom Polakis with 13" [include this report]

• M 26 (@ Sagittarius) observation by Tom Polakis with 20" [include this report]

[edit] Notes

The closest DSO is^{see map:[18]} 12-mag planetary nebula Min 1-59, with diameter of some 4" (30' NW), and stellar planetary K 3-11 (1° NW). Further NW are open clusters Trumpler 34 (1.5°) and NGC 6664 (2.5°, near Alpha Scuti).

Globular cluster NGC 6712 and large but dimm (d > 1', m=12.7) planetary IC 1295 are cca 2.5° to the ENE.

[edit] References

[edit] Links

ikipedia has an article on Messier 26

• SEDS: Messier 26

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