Messier 92 (M 92)

Introduction | Map | Find/Identify | Sketch | My Best Own Photos | My Own Observations | References || Appendix: My Own Photos

On this page I collect my observations of the globular star cluster M 92 (NGC 6341) in the constellation Hercules.

Introduction

The globular star cluster M 92 in the Hercules constellation is somewhat smaller (depending on the author, it is 7 'or 8' in size) than its more familiar "brethren" M 13. It is located above the Keystone asterism, the most prominent part of the constellation and more difficult to find than M 13. I was able to clearly see the bright nucleus (M 92 appears somewhat more concentrated at the center than M 13), but not dissolve single stars - until August 23, 2019, on which I suceeded using averted vision (and maybe also with direct vision...) for the first time. In my binoculars, M 92 appears also very small.

M 92 (NGC 6341)
Size: 14' (Wikipedia)
Distance: 25,000 light years (Stoyan)
Rating: *** (Stoyan)

Map

The globular star cluster M 92 is located above the Keystone asterism and a little more difficult to find than M 13. First find the Keystone asterism! (Image Courtesy of SkySafari Astronomy, www.simulationcurriculum.com)

Find/Identify

Find: The globular star cluster M 92 in the constellation Hercules is located above the Keystone asterism and hard to find for me because there are no stars that can be used for orientation:

I therefore try to start from the two upper Keystone stars and form a kind of triangle with them to find M 92, which is generally quite tedious. Another approach is, to go up again about the height of the keystone trapezoid and then go 1/3 of the upper side to the right.

Find (2):In September 2024, I found somewhat brighter stars in the vicinity of M 92, which helped me to clearly "approach" and identify M 92 with binoculars. While SkySafari does not show any stars in the vicinity of M 92, this is the case with Stellarium. And these actually help to locate M 92, because they match what you see with binoculars. M 92 forms the eastern corner of a triangle (as a somewhat "fuzzy star"), while two stars, one above and one below M 92 to the west of M 92, form the other two corners of the triangle. Other stars further to the west help to identify the triangle as such. The star below the triangle is particularly bright. Here is an image of the position of M 92 created with Stellarium:

Identify: If you found a globular cluster in this way, then M 92 is already identified! (Image Courtesy of SkySafari Astronomy, www.simulationcurriculum.com)

Sketch

The sketch by Michael Vlasov (DeepSkyWatch.com) provides a rough impression of what I observed in Summer/Autumn 2016 (my impression was much fainter and smaller than the sketch):

Sketch of the M 92 globular star cluster by Michael Vlasov (Copyright © Michael Vlasov 2016) - presented with the author's permission

My Best Own Photos

eVscope

M 92 - May 16, 2020		M 92 -May 16, 2020, processed		M 92 - May 16, 2020, processed and sharpened
M 92 - Jun 11, 2020, Sky somewhat bright		M 92 - Jun 11, 2020, processed		M 92 - Jun 11, 2020, processed and sharpened
M 92 - Aug 25, 2020, manual exposure		M 92 - Aug 25, 2020, processed		M 92 - Aug 25, 2020, processed and sharpened
M 92 - Sep 15, 2020, manual exposure		M 92 - Sep 15, 2020, processed		M 92 - Sep 15, 2020, processed and sharpened
M 92 - Jul 18, 2021		M 92 - Jul 18, 2021, processed		M 92 - Jul 18, 2021, processed and sharpened
M 92 - Aug 20, 2021		M 92 - Aug 20, 2021, processed		M 92 - Aug 20, 2021, processed and sharpened

eVscope 2

M 92 - Aug 21, 2023		M 92 - Oct 10, 2023, 5 min		M 92 - Dec 18, 2023, 3 min
M 92 - Aug 21, 2023, photo on top processed		M 92 - Oct 10, 2023, photo on top processed		M 92 - Dec 18, 2023, photo on top processed

Vespera

M 92, Jul 29, 2022 - original (29 frames = 290 seconds)

Vespera Pro

M 92, Jun 4, 2024 - 2000p (90 frames = 900s)		M 92, Jun 4, 2024 - 2000p (92 frames = 900s), processed
M 92, Jun 4, 2024 - 1800p (90 Frames = 900s), 1:1 section		M 92, Jun 4, 2024 - 1800p (90 Frames = 900s), 1:1 section, processed

My Own Observations

Observations Summer to Autumn 2016

• End of August 2016 (Mühlhausen/Kraichgau: Heritage 100P, Heritage P130, and GSD 680): Observed M 92 many times at various magnifications.
• September 1, 2016 (ditto: Heritage 100P), September 7, 2016 (dito: Skymax-102 on GoTo mount), September 99, 2016 (dito: Heritage P130 on GoTo mount): Observed M 92 with various telescopes.
• End of September, beginning of October 2016 (Sumène, Haute Loire, France: Heritage 100P, LT binoculars): Observed M 92 at various magnifications and with binoculars.

Observations May 2017

• May 12, 2017 (Mühlhausen/Kraichgau: Explorer 150PDS on GoTo mount): M 92 not found, but M 13...
• May 14, 15, 2017 (ditto): M 92 (gap in balcony) and further globular star clusters seen well (7 mm; 24/16 mm on May 15), all somewhat "resolved"; M 13 was the largest cluster
• May 16, 2017 (ditto): M 92 and further globular star clusters seen well (24/4 mm), all somewhat "resolved"; M 13 was the largest cluster. Probably never seen them that well and large (4 mm) before …

Observations October 2017

• Oct 2017 (Mühlhausen/Kraichgau: TS binoculars): M 92 observed with binoculars.

Observations September/October 2018

• Sep 27, 2018 (Sumène, France: PS 72/432, AZ Pronto Mount): M 92 seen well with PS72 and 4 mm, bright and small; M 13 ditto, but larger
• Oct 5, 2018 (Betz, France: diverse telescopes of the Orion43 group): M 13 und M 92 in Betz (Orion43) seen very good, stars partly resolved

Observations August 2019

• Aug 22-30, 2019 (Mühlhausen/Kraichgau: TS binoculars, LT binoculars, Skymax-127 and PS 72/432 both on AZ Pronto Mount; Explorer 150PDS on GoTo mount): M 92 observed with SM-127 on Aug 23 with magnifications of up to 150 x. When using the 16 mm and 10 mm eyepieces, we were able to detect fine stars, particularly with "averted vision". All in all, M 92 seen very nicely. Much harder to find than M 13, smaller and probably brighter at the center than M 13.
  M 92 observed with PS 72/432 on Aug 24 with magnifications of up to 108 x (4 mm). We were not able to detect fine stars, because the vision was worse (cloud veils).
  M 92 observed with Explorer 150PDS on Aug 25-26 with magnifications of up to 190 x (4 mm). Large (not as large as M 13), but we were only able to detect a few fine stars on Aug 25; more fine stars on Aug 26; bright center.
  M 92 and M 13 (Explorer 150PDS on GoTo mount; Aug 30): large in 10 mm eyepiece, but still not seen fine stars; saw fine stars in 7 mm eyepiece (more or less well...); M 92 clearly smaller than M 13, but also nice.
  M 92 also observed with both binoculars for several times (Aug 22), or only with the LT binoculars (Aug 23-24); with binoculars also much harder to find than M 13, but not quite as hard.

Observations September/October 2019

• Oct 3, 2019 (Sumène, France: StarTravel 120/600 on AZ Pronto Mount): M 92 (and M 13) seen well ; M 92 from 7 mm on resolved into fine stars.

Observations April to October 2020

• April 15, 2020 (Mühlhausen/Kraichgau: eVscope): M 92 photographed, but the morning sky was already to bright...
• May 16, 2020 (Mühlhausen/Kraichgau: eVscope): M 92 photographed in the new rectangular format without overlay
• June 11, 2020 (Mühlhausen/Kraichgau: eVscope): M 92 photographed (n.o., r.f.), somewhat bright
• July 3, 2020 (Mühlhausen/Kraichgau: eVscope): M 92 photographed (n.o., r.f.), sky too bright
• September 4, 2020 (Mühlhausen/Kraichgau: eVscope): M 92 photographed (n.o., r.f.), not usable...
• September 15, 2020 (Mühlhausen/Kraichgau: eVscope): M 92 photographed (n.o., r.f.)
• September 28, 2020 (Mühlhausen/Kraichgau: eVscope): M 92 photographed (n.o., r.f.), disturbed by clouds
• October 10, 2020 (Mühlhausen/Kraichgau: PS72 on AZ Pronto; TLAPO1027 on AZ4): M 92 observed, nice, brighter in the APO
• October 11, 2020 (Mühlhausen/Kraichgau: C8 on AZ4): M 92 observed, relatively large and good to see

Observations July to Oktober 2021

• July 18, 2021 (Mühlhausen/Kraichgau: eVscope): M 92 photographed (n.o., r.f.), new image size and processing, poor collimation despite new collimation
• August 14, 2021 (Mühlhausen/Kraichgau: C8 on Star Discovery): M 92 observed; also nice, smaller (compared with M 13), also resolved into stars
• August 20, 2021 (Mühlhausen/Kraichgau: eVscope): M 92 photographed (n.o., r.f.), new image size and processing, better new collimation
• September 2, 2021 (Mühlhausen/Kraichgau: PS72 on AZ-GTi mount, ASI224): M 13 photographed
• September 3, 2021 (Mühlhausen/Kraichgau: C5 on AZ-GTi mount, ASI224): M 13 photographed
• September 4, 2021 (Mühlhausen/Kraichgau: TLAPO1027 on Star Discovery mount, ASI224 ): M 13 photographed
• September 8, 2021 (Mühlhausen/Kraichgau: eVscope): M 92 photographed (n.o., r.f.), new image size and processing
• Oktober 16, 2021 (Mühlhausen/Kraichgau: eVscope): M 92 photographed (n.o., r.f.), new image size and processing; more than half moon
• Oktober 19, 2021 (Mühlhausen/Kraichgau: eVscope): M 92 photographed (n.o., r.f.), new image size and processing; nearly full moon

Observations July 2022

• July 21, 2022 (Mühlhausen/Kraichgau: PS 72/432 on AZ-GTi): M 92 and further globular star clusters observed (did not find the comet C/2017 K2)
• July 24, 2022 (Mühlhausen/Kraichgau: C5R on AZ-GTi): M 92 and further globular star clusters observed (did not find the comet)
• July 29, 2022 (Mühlhausen/Kraichgau: Vespera): M 92 photographed

Observations August to December 2023

• August 21, 2023 (Mühlhausen/Kraichgau: eVscope2): M 92 photographed, new image processing (DDT)
• October 10, 2023 (Mühlhausen/Kraichgau: eVscope2): M 92 photographed, new image processing (DDT app version 2.5)
• December 18, 2023 (Mühlhausen/Kraichgau: eVscope2): M 92 photographed, new image processing (DDT app version 2.5)

Observations June 2024

• June 4, 2024 (Mühlhausen/Kraichgau: Vespera): M 92 photographed

References

• Messier Catalogue - Messier 92: messier.seds.org/m/m092.html
• Messier 92 (Wikipedia): en.wikipedia.org/wiki/Messier_92

On this Site

• Sky-Watcher Heritage P130 Information (5" Dobson)
• Sky-Watcher Heritage 100P Information (4" Dobson)
• GSO GSD 680 Information (8" Dobson)
• Sky-Watcher Explorer 150PDS Information (6" Newton)
• Sky-Watcher Skymax-102 OTA Information (4" Maksutov-Cassegrain)
• Sky-Watcher Skymax-127 OTA Information (5" Maksutov-Cassegrain)
• Omegon Photography Scope 72/432 ED OTA Information (2.8" Refractor)
• Sky-Watcher StarTravel 120/600 OTA Information (4.7" Refractor, Borrowed)
• Celestron C8 OTA Information (8" Schmidt-Cassegrain)
• TS Optics Photoline 102/715 Information (4" Refractor)
• Unistellar eVscope Information
• Unistellar eVscope 2 - Information
• Vaonis Vespera - Information
• Vaonis Vespera Pro - Information
• Sky-Watcher AZ-GTi AZ GoTo Mount Information
• Sky-Watcher Star Discovery AZ GoTo Mount Information
• Sky-Watcher AZ Pronto Mount Information
• Sky-Watcher AZ4 Mount Information
• ZWO ASI224 Color Camera - Information
• My Binoculars

Appendix: My Own Photos

ZWO ASI224

M 92 - Sep 2, 2021, PS 72/432, stacked from single frames		M 92 - Sep 3, 2021, C5, 60frames, 5sec, gain300		M 92- Sep 4, 2021, TLAPO1027, 60frames, 5sec, gain300
M 92 - Sep 2, 2021, PS 72/432, stacked from single frames, processed		M 92 - Sep 3, 2021, C5, 60frames, 5sec, gain300, processed		M 92- Sep 4, 2021, TLAPO1027, 60frames, 5sec, gain300, processed

eVscope

M 92 - Apr 15, 2020		M 92 - Apr 15, 2020, processed		M 56 - 92 15, 2020, processed and sharpened
M 92 - Apr 15, 2020		M 92 - Apr 15, 2020, processed		M 92 - Apr 15, 2020, processed and sharpened
M 92 - May 16, 2020		M 92 - May 16, 2020, processed		M 92 - May 16, 2020, processed and sharpened
M 92 - May 16, 2020		M 92 -May 16, 2020, processed		M 92 - May 16, 2020, processed and sharpened
M 92 - May 16, 2020		M 92 - May 16, 2020, processed		M 92 - May 16, 2020, processed and sharpened
M 92 - Jun 11, 2020, somewhat bright		M 92 - Jun 11, 2020, processed		M 92 - Jun 11, 2020, processed and sharpened
M 92 - Jul 3, 2020, sky too bright		M 92 - Jul 3, 2020, processed		M 92 - Jul 3, 2020, processed and sharpened
M 92 - Aug 19, 2020, manual exposure		M 92 - Aug 19, 2020, processed		M 92 - Aug 19, 2020, processed and sharpened
M 92 - Aug 19, 2020, manual exposure		M 92 - Aug 19, 2020, processed		M 92 - Aug 19, 2020, processed and sharpened
M 92 - Aug 25, 2020, manual exposure		M 92 - Aug 25, 2020, processed		M 92 - Aug 25, 2020, processed and sharpened
M 92 - Sep 15, 2020, manual exposure		M 92 - Sep 15, 2020, processed		M 92 - Sep 15, 2020, processed and sharpened
M 92 - Sep 15, 2020, manual exposure		M 92 - Sep 15, 2020, processed		M 92 - Sep 15, 2020, processed and sharpened
M 92 - Sep 15, 2020, manual exposure		M 92 - Sep 15, 2020, processed		M 92 - Sep 15, 2020, processed and sharpened
M 92 - Sep 28, 2020, disturbed by clouds		M 92 - Sep 28, 2020, processed		M 92 - Sep 28, 2020, processed and sharpened
M 92 - Sep 28, 2020, disturbed by clouds		M 92 - Sep 28, 2020, processed		M 92 - Sep 28, 2020, processed and sharpened
M 92 - Jul 18, 2021		M 92 - Jul 18, 2021, processed		M 92 - Jul 18, 2021, processed and sharpened
M 92 - Aug 20, 2021		M 92 - Aug 20, 2021, processed		M 92 - Aug 20, 2021, processed and sharpened
M 92 - Aug 20, 2021		M 92 - Aug 20, 2021, processed		M 92 - Aug 20, 2021, processed and sharpened
M 92 - Oct 16, 2021		M 92 - Oct 16, 2021, processed		M 92 - Oct 16, 2021, processed and sharpened
M 92 - Oct 19, 2021		M 92 - Oct 19, 2021, processed

eVscope 2

M 92 - Aug 21, 2023		M 92 - Oct 10, 2023, 5 min		M 92 - Dec 18, 2023, 3 min
M 92 - Aug 21, 2023, photo on top processed		M 92 - Oct 10, 2023, photo on top processed		M 92 - Dec 18, 2023, photo on top processed

Vespera

M 92, Jul 29, 2022 - original (29 frames = 290s)

Vespera Pro

M 92, Jun 4, 2024 - 2000p (90 frames = 900s)		M 92, Jun 4, 2024 - 2000p (92 frames = 900s), processed
M 92, Jun 4, 2024 - 1800p (90 Frames = 900s), 1:1 section		M 92, Jun 4, 2024 - 1800p (90 Frames = 900s), 1:1 section, processed