Messier 7
From DeepSkyPedia
| M 6 << Messier 7 >> M 8 Cr 353 << Collinder 354 >> Cr 355 Mel 182 << Melotte 183 >> Mel 184 | |
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| Position (epoch J2000) [1] | |
| Constellation | Scorpius |
| Position | Ra 17:53:51.1 Dec -34:47:34 |
| DSS images | |
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Appearance [1] | |
| Apparent mag. | 3.3 |
| Size | 80' |
| Class | I 3 r |
| Stars | |
| Dreyer's description | Cl vB pRi lC st 7...12 |
| Other | |
| Other designations | Ptolemy Cluster, M 7, NGC 6475, Collinder 354, Cr 354, Melotte 183, Mel 183, Lund 791, OCL 1028 and ESO 394-SC009 |
| Notes | |
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Messier 7 is an open cluster in Scorpius.
[edit] How to find it
[edit] Appearance
[edit] Naked eye
Using naked eye and direct vision, under 6.5- to 6.7-mag skies, Messier 7 is easily seen as a patch of light, with up to 4 or 5 individual stars[2][3].
Under even darker skies (LM=7.1), it might seem to "glitter", making impression of many stars just on the edge of being resolved.[4]
It is quite brighter then nearby Messier 6[3].
[edit] Telescopes up to 70mm, binoculars up to 50 mm, and finders
In 7x35 binoculars, M7 appears large and scattered, unmistakably seen as an open cluster, unlike nearby M 6 (in the same 8° FOV), which is more diffuse. Between 15 and 20 stars can be seen scattered in front of the hazy background.[5]
In 10x50 binoculars, M 7 and M 6 just barely fit together in the same 6.5° FOV, centered just SW of the fainter open cluster NGC 6416[4]. At least 20 stars are visible in M 7, even under 4.0-mag skies[6].
Under much darker skies (LM ~ 7), 10x50 binos will provide a view of much more stars and clouds of light that hints to hundreds of stars beyond limits of resolution. Some darker areas can be seen in those clouds, especially in the NW and SE parts.[4]
A 60-mm refractor will also show about 20 stars.[7]
More reports:
- Scorpius by Steve Coe - Messier 7 with 10x50 binos, 11x80 finder, 6" f/6, 13.1" f/5.6, 17.5" f/4.5, 36" f/5 [include this report]
[edit] Telescopes 71mm - 100mm (2.8" - 3.9"), binoculars 51mm - 70mm
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Messier 7 observation and sketch by Jaakko Saloranta with naked eye AND3" Konus @ 24x [include this report] - Messier 7 observation by Jeff Burton (x.astrogeek.org) with Oberwerk FMC Mini-Giant 12x60mm Binoculars [include this report]
- Messier 7 observation by Jeff Burton (x.astrogeek.org) with Meade ETX-90EC 90mm Maksutov [include this report]
- Messier 7 observation and sketch by Rony De Laet with TS Marine 15x70 binoculars [include this report]
[edit] Telescopes 101mm - 141mm (4" - 5.5"), binoculars 71mm - 100mm
- Messier 7 observation and sketch by Rony De Laet with Meade ETX 105 [include this report]
- Messier 7 observation and sketch by Iiro Sairanen with Newton 110/805mm [include this report]
- (IAAC) Obj: M7 (Ptolemy's Cluster, Mel 183, Cr 354) - Inst: 120mm KONUS refractor, f/8.33, equatorial [include this report]
- M 7 with 120mm f/8.33 refractor, eq. mount (Konus, Lukrica) by Ante Perković (SEEN, Jul 17 2004) [include this report]
- (IAAC) Obj: M 7 - Inst: 120mm KONUS refractor, f/8.33, equatorial by Natko Bajić [include this report]
- (IAAC) Obj: M7 - Inst: Meade ETX125 [include this report]
[edit] Telescopes 141mm - 177mm (5.6" - 6.9")
- (IAAC) Obj: M7 - Inst: 6" Orion Dobsonian [include this report]
- (IAAC) Obj: M7 Butterfly cluster - Inst: Orion 6" Dob [include this report]
- (IAAC) Obj: M7 (NGC 6475) - Inst: Orion 6" dobsonian [include this report]
- Messier 7 observation by Tom Polakis with 6" and 13" [include this report]
[edit] Telescopes 178mm - 234mm (7" - 9.2")
- Messier 7 observation by Sjoerd Dufoer @ deepskylog.be (with Orion UK 20cm) [include this report]
- M 7 with 8" (203mm) f/10 SCT (Šime) by Ante Perković (SEEN, Jul 10 2004) [include this report]
- (IAAC) Obj: M7 - Inst: SCT 8", F/10 (Meade) [include this report]
- Messier 7 observation by Jeff Burton (x.astrogeek.org) with Meade LX200GPS 203mm SCT [include this report]
[edit] Telescopes 235mm - 305mm (9.25" - 12")
- Messier 7 observation by David Erzeel @ deepskylog.be (with Sky-Watcher 10" dobson (250 mm)) [include this report]
[edit] Telescopes 306mm - 381mm (12.1" - 15")
- Messier 7 observation by Jeff Burton (x.astrogeek.org) with AstroSystems TeleKit 14.5" Reflector [include this report]
- Messier 7 observation by Jeff Burton (x.astrogeek.org) with AstroSystems TeleKit 14.5" Reflector [include this report]
[edit] Telescopes above 15"
[edit] Notes
[edit] References
- ↑ 1.0 1.1 Historic NGC and IC by Wolfgang Steinicke (version Nov. 20, 2006.)
- ↑ (IAAC) Obj: M 16, M17, M 24, M 25 , M 20, M8, M22, M6, M 7, M 21 - Inst: naked eye
- ↑ 3.0 3.1 Messier 7 observation and sketch by Jaakko Saloranta with naked eye AND 3" Konus @ 24x
- ↑ 4.0 4.1 4.2 (IAAC) M6, M7, NGC 6416 , Lew Gramer , 7x50 , 1997-07-4/5 , Savoy, MA, USA (42N) , LM: 7.1 , seeing: 5/10 (mediocre, increasing cumulus)
- ↑ x.astrogeek.org , Jeff Burton , Bushnell Falcon 7x35mm Binoculars, Orion Little Giant II 20x70mm Binoculars , May 15, 2001 , Paducah, KY, USA , LM: 4.0 - 4.5 , seeing: 8/10
- ↑ (IAAC) M7 , Brian Reasor , Nikon 10x50 , 7/8/2005 , Jordan Lake, NC, USA (Lat 35.7) , LM: 4.0 , seeing: 8/10
- ↑ (IAAC) Messier 7 , William L. Schart , ETX-60 , d=60mm , f=350mm , 14x, 39x , 9/16/01 , Killeen, TX , LM: 3 , seeing: 7/10
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