proud uncle
Carpal Tunnel
Reged: 01/22/07
Posts: 1576
Loc: Central Texas
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I recently read about this in Sue French's "Deep Sky Wonders" article in the July 2008 issue of S&T. Apparently, this is a triple star system. The A/BC is quite easy at low power (separation 35"); may even be doable with big binos. BC is reported to be a pair of red dwarfs with current separation 1.1", mags 10.2 and 10.7. I decided to try for this last night. The A/BC was, of course, very easy split at 39x. The BC was very faint at that power, almost at the limiting magnitude for my scope at that power. Increasing the power made the secondary appear brighter. I tried several powers between 100x and 400x, spending several minutes at the eyepiece, but could not detect a split of the B and C components. Has anyone successfully split this one? If yes, what aperture and power? Based on your observation, do you agree with the 1.1" separation? Thanks!
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Kenneth
Zhumell 10" Dobsonian (f/4.9)
2" 32mm WA eyepiece
9mm, 12.5mm, and 20mm Plossls
6mm TMB/BO Planetary
2" 2x ED Barlow
Nikon 10x50 binocular (6.5 deg FOV)
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Catapoman
scholastic sledgehammer
Reged: 06/06/03
Posts: 777
Loc: VA
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Hi Kenneth,
Here are notes on this system from 06-09-08:
Quote:
Mu Herculis BC (1.09”; 10.2, 10.7) – At the time of my observation, Mu Herc was only up about 45 degrees and the sky wasn’t as steady in that direction. Using the BO/TMB 3.2mm @ 875x, I was only able to get elongation on this pair. Part of the issue seems to be glaring from brighter “A” component and the dimness of the “BC” pair. Although I didn’t get a split on this one, I’m certain it will be conquered.
As difficult as this pair (B-C) I think it should be doable in your scope as well as my NX11 with the right conditions. BTW, I do agree with the separation value.
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Pernel
Nexstar 11 GPS
Takahashi TSA-102
Mewlon 210
GM-8
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proud uncle
Carpal Tunnel
Reged: 01/22/07
Posts: 1576
Loc: Central Texas
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Thanks, Pernel. I think your observation about glare from the primary A component is valid. Related to that, when I was observing, the BC sub-system was very near one of the diffraction spikes from component A. I'm sure that increased the difficulty. Is your 11" a SCT? That should not have a diffraction spike issue.
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Kenneth
Zhumell 10" Dobsonian (f/4.9)
2" 32mm WA eyepiece
9mm, 12.5mm, and 20mm Plossls
6mm TMB/BO Planetary
2" 2x ED Barlow
Nikon 10x50 binocular (6.5 deg FOV)
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Catapoman
scholastic sledgehammer
Reged: 06/06/03
Posts: 777
Loc: VA
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Yes, the 11" is a SCT. No diffraction spike issue, but as you know there are other things dealing with SCTs.
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Pernel
Nexstar 11 GPS
Takahashi TSA-102
Mewlon 210
GM-8
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Tom and Beth
scholastic sledgehammer
Reged: 01/08/07
Posts: 929
Loc: Tucson, AZ
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I tried this pair a few weeks ago (before our rainy season). I used a homemade 7 inch F10 Newt and SUSPECTED an elogation using an 11MM Nagler. Shorter EPs made the pair too dim to take advantage of them.
One very tough nut to crack!
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sgottlieb
sage
Reged: 07/22/07
Posts: 339
Loc: SF Bay area
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I took a look at Mu Herculis a few nights ago at the Sierra Buttes in good seeing at 7200 ft. The tight pair of red dwarfs was cleanly split at 280x in my 18" Starmaster. The separation appeared roughly 1" or perhaps slightly wider.
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Steve Gottlieb
18" f/4.3 Starmaster
Adventures In Deep Space
7500+ NGC/IC Visual Descriptions
NGC/IC Project
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Clive Gibbons
Mostly Harmless
Reged: 05/26/05
Posts: 13439
Loc: Oort Cloud
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Had a look at Mu using the Megrez 110ED (229x) last week.
The primary star was a lovely "textbook" image (sharp Airy disk surrounded by one diffraction ring).
The secondary was quite faint and twinkly in the seeing. I couldn't resolve the components. Using averted vision for splitting tight doubles doesn't seem to work. 
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A few telescopes of dubious value.
Understanding wife, two curious cats and one sadly departed.
"Semper ubi sub ubi"
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Clive Gibbons
Mostly Harmless
Reged: 05/26/05
Posts: 13439
Loc: Oort Cloud
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Had another look at Mu Herc a couple of nights ago with the Megrez 110ED.
This time, using more magnification.
At 308x, the secondary seemed to be elongated, but it was faint and the mediocre seeing didn't help. Still, it appeared that the elongation was oriented pretty much toward the direction of the bright primary.
Not an easy observation. 
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A few telescopes of dubious value.
Understanding wife, two curious cats and one sadly departed.
"Semper ubi sub ubi"
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dpwoos
sage
Reged: 10/18/06
Posts: 218
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I gave mu Hercules a go with my 10" f/6 dob this evening, and I successfully split the BC pair both at 250x and 312x. The sky transparency was excellent this evening from my back yard. I quickly checked out delta Cygnii, mu Draconis and zeta Aquarii to gauge the seeing, and they all split easily at 250x but the overall seeing wasn't great. Once I moved to mu Herculis, it only took a few moments to realize that the faint pair is aligned almost exactly with the primary. After a couple of minutes I started seeing clear separation in the periods of better seeing. I was using a BO/TMB 6mm at this point, but after 20 mins or so I switched to a 4.8mm Nagler. This opened up the pair a bit, and I again repeatedly confirmed a nice split when the seeing cooperated. I also believe that the star nearer the primary was the brighter of the two. This is a very challenging triple, and I really enjoyed the hour I spent. I am certainly going to check in on it from time to time, and am looking forward to observing it when the seeing is better.
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Bonco
Carpal Tunnel
Reged: 04/17/06
Posts: 2297
Loc: Florida
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dpwoos...Excellent report. My 4.8 Nagler is my high power eyepiece of choice for many different scopes. Sometimes I combine it with a barlow and get excellent results.
Cheers, Bill
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RV6
Meade 2045
6 inch f/4 RFT R. Fagin Optics
TV Genesis
2.4 inch Lafayette Equitorial
3 inch Polarex/Unitron Equitorial
10 inch Zhumell
PST 40mm Solar scope
4 inch F/15 Antares
2.4 inch Unitron Equitorial
Tasco 10K 80mm/1200mm
Towa 339 Restored
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Patricko
Carpal Tunnel
Reged: 01/30/07
Posts: 1533
Loc: SE New Mexico USA
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Got a new 9X50mm finder for my 87.5mm Mak and decided to track this system down with it for the first time. I didn't even know mu Herculis was a double until reading this thread the other day, man I like this forum! Anyways here's my notes from last night:
9/22/09 8PM LT Orange zone
Conditions: clear, cooling rapidly as a strong cold front passed through last night, no Moon seen due to local trees/buildings. Mag 4+ stars near the zenith could just barely be made out with direct vision
Seeing: 4/10 (Mak also was still acclimating)
Instrument: 87.5mm Mak (Starmax 90)
mu Herculis:
my first attempt at this complex binary system. A is @ mag 3.4 w/BC ~36" away at ~mag 10. A was of course easy to see while BC was seen with averted vision ~5 o'clock w/ 90° diagonal. BC was held with direct vision for a few seconds at a time. A star appears to be strong yellow while BC gives the impress that it more orange; however, this could be an illusion due to the fact that these stars are so much dimmer than A. 14mm Meade 5000 UWA was used to see BC the best @ ~90x while a 10.5mm ortho was used to confirm what was seen in the Meade @ ~119x. Given how dim and close BC are I highly doubt that the 87.5mm Mak could show them elongated under the sky conditions tonight.
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Clear skies,
Patrick
INTERNATIONAL DARK SKY ASSOCIATION
60MM TELESCOPE CLUB!
"You can always have better, but will you ever be happy with what you have?" - Me, myself, and I
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Achernar
Postmaster
Reged: 02/25/06
Posts: 5025
Loc: Mobile, Alabama, USA
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I separated it at over 250X with my 10-inch, but the seeing has to be very steady. Mu Herculis B and C seem to be closer together than 1.1-arc seconds. When I have split them, they were barely separated. That to me indicates they're more like .7 or .8 arc seconds apart right now. Not doubt they're in an elliptical orbit that results in them being more difficult to split at some times than others
Taras
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15-inch F/4.5 Dob under construction
10-inch F/4.5 Discovery Dob
6-inch F/8 Homebuilt Dob
4 1/4-inch F/4 Homebuilt reflector
A whole bunch of eyepieces, filters and other accessories....
Two curious cats
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Edwin Quiroga
professor emeritus
Reged: 01/31/08
Posts: 612
Loc: Miranda, Venezuela
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Why Mu Herculis is not labeled as a Multiple System in my Pocket Sky Atlas? 
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TeleVue 85 w/FeatherTouch
Televue Panoptic 35
Pentax XW (3.5, 5, 7, 10, 14, 20)
Pentax XO 2.58
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Bonco
Carpal Tunnel
Reged: 04/17/06
Posts: 2297
Loc: Florida
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Quote:
Why Mu Herculis is not labeled as a Multiple System in my Pocket Sky Atlas?
It's a pocket guide and a rather good one. But it's not all inclusive. Other aids and multiple star lists will show many additional multiple stars. I like Sissy Haas' book and Burnham's even tho its outdated.
Bill
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RV6
Meade 2045
6 inch f/4 RFT R. Fagin Optics
TV Genesis
2.4 inch Lafayette Equitorial
3 inch Polarex/Unitron Equitorial
10 inch Zhumell
PST 40mm Solar scope
4 inch F/15 Antares
2.4 inch Unitron Equitorial
Tasco 10K 80mm/1200mm
Towa 339 Restored
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Edwin Quiroga
professor emeritus
Reged: 01/31/08
Posts: 612
Loc: Miranda, Venezuela
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Thanks for the info. But it`s weird, 'cause in this guide apperars another doubles even fainter than mu Herculis. Maybe the separation grade is too short (about 1") for this guide?
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RAKing
Carpal Tunnel
Reged: 12/28/07
Posts: 2086
Loc: West of the D.C. Nebula
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Quote:
Thanks for the info. But it`s weird, 'cause in this guide apperars another doubles even fainter than mu Herculis. Maybe the separation grade is too short (about 1") for this guide?
I'm not sure. The close separation is only for the B/C pair. The 'A' star and the B/C pair are far enough apart - and actually look pretty good on their own.
I tried yet again to split B/C last night with no luck - but I'll keep trying and hope I get some cooperation from Mother Nature someday.
Ron
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Time spent looking at the stars is added to your life.
Tak FS-128, C925-CF, C6SE, other stray cats and refractors.
A-P Mach1 GTO
Zeiss orthos to Ethos - and some stuff in between.
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kevin M13
member
Reged: 03/07/09
Posts: 88
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I've tried a number of times with my 140mm refractor at mags to 357x and have been unable to split BC. It leaves me to believe it takes quite a bit of scope to split 10.7 mag stars less than 1" apart.
Regards,
Kevin
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lionel
member
Reged: 08/12/07
Posts: 68
Loc: Delaware
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Here is the ephemeris for mu Her BC from the 6th Catalog of Orbits:
Year Sep'n PA
2008 1.09" 235
2009 1.12" 240
2010 1.11" 245
2011 1.07" 250
2012 0.99" 256
Seeing has been poor in the mid-Atlantic and Hercules is now too low for a serious attempt. It's on my to do list for next summer 
Lionel
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Tak Mewlon 250
Powerstar C8
1960s Bushnell 60mm f12 refractor
Sphinx SXD
CG5-ASGT
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RAKing
Carpal Tunnel
Reged: 12/28/07
Posts: 2086
Loc: West of the D.C. Nebula
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Quote:
I've tried a number of times with my 140mm refractor at mags to 357x and have been unable to split BC. It leaves me to believe it takes quite a bit of scope to split 10.7 mag stars less than 1" apart.
Kevin,
I think the sky conditions are more to blame than your scope. Here in Virginia, we have lots of humidity and I have not been able to split the B/C pair with anything.
I've tried a 102 achro, 150 f/12 Mak Cas, 200 f/12 Mak Cas, and C925 SCT with no luck. Next up is my FS-128. Maybe someday.....
Ron
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Time spent looking at the stars is added to your life.
Tak FS-128, C925-CF, C6SE, other stray cats and refractors.
A-P Mach1 GTO
Zeiss orthos to Ethos - and some stuff in between.
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