astrokido
super member
Reged: 06/09/08
Posts: 154
Loc: Phoenix, AZ
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Star clusters yes, but individual stars by amateurs or the Hubble or anything from Earth?
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- Gill C. - All opinions subject to a speed limit of 299,792,458 m/s.
Nikon D40 - Bushnell 10x25 - Zhumell 20x80 - Celestron Cometron CO-100
skyatlas.rgbstore.com - cool sky charts, photo overlays, and data tables
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star drop
Guilty as Charged
Reged: 02/02/08
Posts: 751
Loc: Cattaraugus Co., NY
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Hi Gill,
Pictures from the major observatory telescopes and Hubble show individual stars in nearby galaxies. Observers with large amateur scopes might be able to resolve stars in the Magellanic clouds although I have not heard of it being done.
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Ted
635mm F/4.964 Grab and Tow
old Naglers, Meade UWA 30
observing site extras: astro cats on ladder surrounded by bug eating mammals in flight
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 6475
Loc: Beatrice, Nebraska
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Well, in the two large satellite galaxies the large and small Magellanic clouds, stars are easily resolvable in amateur telescopes. In M31, 20 to 30 inch telescopes can bring out at least a few of the galaxy's most luminous stars, but by in large, much of that galaxy's stars remain unresolved. When there is a supernova in another galaxy, it can often be seen in many modest apertures, but otherwise, visual observations of the stars in most other galaxies is beyond the ability of the human eye. Clear skies to you.
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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
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sgottlieb
sage
Reged: 07/22/07
Posts: 217
Loc: SF Bay area
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I believe this question or thread has come up before but there's no problem resolving individual stars in the Magellanic Clouds at the eyepiece.
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Steve Gottlieb
18" f/4.3 Starmaster
Adventures In Deep Space - New article on MASH planetaries
7500+ NGC/IC Visual Descriptions
NGC/IC Project
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sgottlieb
sage
Reged: 07/22/07
Posts: 217
Loc: SF Bay area
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Quote:
Hi Gill,
Pictures from the major observatory telescopes and Hubble show individual stars in nearby galaxies. Observers with large amateur scopes might be able to resolve stars in the Magellanic clouds although I have not heard of it being done.
See this recent thread on observing the LMC from Australia in April.
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Steve Gottlieb
18" f/4.3 Starmaster
Adventures In Deep Space - New article on MASH planetaries
7500+ NGC/IC Visual Descriptions
NGC/IC Project
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timokarhula
member
Reged: 01/30/06
Posts: 36
Loc: Sweden
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The brightest star in the Large Magellanic Cloud, the variable star S Doradus, can normally be seen already with binoculars. The star's absolute magnitude is about -9! The first time I identified it with binoculars was in February 1999, when I estimated S Doradus to be of magnitude 9.5-10.0.
/Timo Karhula
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PeterSurma
member
Reged: 08/24/06
Posts: 60
Loc: Heidelberg, Germany
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Hi,
it's petty easy to calculate this on your own. You have to know how luminous the object is M (absolute magnitude), that you wanna detect and you have to know the distance, even better know the so-called distance modulus (m-M) (which is just another measure for distance than pure miles and lyrs).
Your object has M = -8mag of absolute luminosity. Your galaxy has a distance modulus of (m-M)=+25mag (corresponding to 1 million pc = 3.2 million ly). So this object looks to us like a faint thing of apparent magnitude m = M + (m-M) = -8 + 25 = +17mag. This is the example calculated for M31 now. 17mag are reachable with a 20" scope under good conditions. So the VERY brightest M31 stars can be seen with a 20".
The most luminous stars typically have visual absolute magnitude of M=-8. So at a given distance they shine with apparent magnitude m, that you can calculate now.
Of, course, you can also turn it around and calculate the maximum distance modulus (--> distance) where you can still see some object of absolute magnitude M, if you know your limiting magnitude m.
As another example of such calculations you may checkout an observing report of mine on M13. [Edit: shortened the hyperlink]
There are some arguments around seeing faint stars in there.
Best wishes,
Peter
Some links, but they are partly hard to understand:
http://en.wikipedia.org/wiki/List_of_most_luminous_stars
- note here that M_v = M_bol +4mag for hot stars!!!
http://www.peripatus.gen.nz/Astronomy/SteMag.html
http://en.wikipedia.org/wiki/Distance_modulus
Edited by Olivier Biot (07/13/08 07:40 AM)
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astrokido
super member
Reged: 06/09/08
Posts: 154
Loc: Phoenix, AZ
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That's very impressive, I'll read about it while longing for aperture.
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- Gill C. - All opinions subject to a speed limit of 299,792,458 m/s.
Nikon D40 - Bushnell 10x25 - Zhumell 20x80 - Celestron Cometron CO-100
skyatlas.rgbstore.com - cool sky charts, photo overlays, and data tables
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Dave Mitsky
Postmaster
Reged: 04/08/02
Posts: 5538
Loc: Pennsylvania, USA
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Quote:
The brightest star in the Large Magellanic Cloud, the variable star S Doradus, can normally be seen already with binoculars. The star's absolute magnitude is about -9! The first time I identified it with binoculars was in February 1999, when I estimated S Doradus to be of magnitude 9.5-10.0.
/Timo Karhula
Yes, S Doradus is a rather easy binocular target.
I spent hours observing HII regions and star clusters in both Magellanic Clouds with a 22" Starmaster four years ago.
Dave Mitsky
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Chance favors the prepared mind.
De gustibus non est disputandum.
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stevecoe
"The Astronomical Tourist"
Reged: 04/24/04
Posts: 2018
Loc: Arizona, USA
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Interresting that this would come up now. I am just starting to put together the "What's Up--Dorado" article for later in the year. Several of the star clusters that Steve Gottlieb mentioned are in the article and, to cut to the chase, I resolved them in modest aperture scopes with no trouble. More details later;-)
Clear skies;
Steve Coe
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150mm 6" f/8 Celestron Refractor on Sirius Mount
80mmED 3" f/7.5 Orion Refractor
Author "Deep Sky Observing" Springer-Verlag
Author "Nebulae and How to Observe Them" Springer
New Canon Xt astrocamera with Hutech modification
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PeterSurma
member
Reged: 08/24/06
Posts: 60
Loc: Heidelberg, Germany
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Well, kind of sorry, didn't realize you were asking the question with a 'binocular background'. I wouldn't choose single stars as object with binoculars, of course, there are different things to enjoy then. Finally aperture does not matter, it's always too little... So, the right choice of objects is the crucial thing, I'd say.
Good luck,
Peter
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Web: http://www.eyes4skies.de/home_EnglishVersion.htm
Edited by PeterSurma (07/11/08 06:28 AM)
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RRaubach
AstroCowboy
Reged: 01/26/05
Posts: 2172
Loc: Douglas (Converse County),WY
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FWIW-
CN regular, Don Pensack, has reported resolution of the brightest blue-white supergiants in NGC 206 within M31. I have the original professional lit papers at home that list the magnitudes, and some of the brighter ones are within reach of moderately large amateur telescopes. i.e. 12.5" or larger.
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Rodger
Meade SN-10 (UHTC) on Tak EM-200 mount/Antares rotating rings. Moonlite focuser.
Parallax 14.5" Newtonian on HD 200 mount (arriving soon!) w/ conical Royce mirror.
TMB 203 f/7 APO refractor on Tak NJP-160 mount.
Discovery 12.5" PDHQ
Schneider 18x80 "Flakfernrohr" binoculars/tripod mounted. Canon 15x50 IS binoculars
Unihedron Sky Quality Meter
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astrokido
super member
Reged: 06/09/08
Posts: 154
Loc: Phoenix, AZ
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After a little searching on NGC 206, I found a link to a very detailed photo of it on APOD here. Good info, thanks.
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- Gill C. - All opinions subject to a speed limit of 299,792,458 m/s.
Nikon D40 - Bushnell 10x25 - Zhumell 20x80 - Celestron Cometron CO-100
skyatlas.rgbstore.com - cool sky charts, photo overlays, and data tables
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scopethis
super member
Reged: 05/30/08
Posts: 187
Loc: Kingman, Ks
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This probably doesn't belong here but I'll toss it in anyway. I've never looked for it, but I read about a Quasar (in the constellation Virgo) that is visible in amatuer scopes. It's appox. two billion light years away.
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Dave Mitsky
Postmaster
Reged: 04/08/02
Posts: 5538
Loc: Pennsylvania, USA
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Quote:
This probably doesn't belong here but I'll toss it in anyway. I've never looked for it, but I read about a Quasar (in the constellation Virgo) that is visible in amatuer scopes. It's appox. two billion light years away.
You're probably referring to 3C 273.
http://www.cs.cmu.edu/~zhuxj/astro/html/quasar3c273.html
http://www.astrosurf.com/jwisn/3c273.htm
http://www.lsw.uni-heidelberg.de/projects/extragalactic/charts/1226+023.html
http://schmidling.com/3c273.htm
http://seds.org/~spider/spider/misc/3c273.html
I've been able to see this bright quasar with my 101mm Tele Vue refractor under the dark skies of Cherry Springs State Park.
Dave Mitsky
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Chance favors the prepared mind.
De gustibus non est disputandum.
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Starman1
Postmaster
Reged: 06/24/03
Posts: 10684
Loc: Los Angeles
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Quote:
After a little searching on NGC 206, I found a link to a very detailed photo of it on APOD here. Good info, thanks.
Caution! There are 3-5 superimposed Milky Way stars on NGC 206 that make certainty more difficult. I was seeing at least a dozen stars in the star cloud and seeing the rest of the center part as "grainy". The average star is magnitude 20-21, which is well below the visible level, but there are about a dozen members from magnitude 16.5 to 17.5 which are reachable.
Other than quasars and supernovae, other galaxies are just too far away for visual sighting of component stars.
Oh, if you want to try for stars in NGC206, have at least a 12.5" aperture, very good to superb seeing, high magnifications. For a test, if you can see stars scattered across the front of M14 in Ophiuchus, the supergiants in NGC206 will probably be in reach.
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Don Pensack
12.5" Truss Dob, 5" Maksutov
Sustaining Lifetime IDA member, TeleVue junkie
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Steven Aggas
sage
Reged: 04/15/08
Posts: 266
Loc: Arizona
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Quote:
After a little searching on NGC 206, I found a link to a very detailed photo of it on APOD here. Good info, thanks.
This picture, while its color is way too saturated, is very representative of the view in the 36" with the black dust trails surrounding the star cloud with resolution very close to what that picture shows and the brightest blue was NGC 206 in the scope.
I'm going to be working my way further out than M31 to see what else is resolvable. One challenge object which is really at the limit of the 36" scope, on the best of nights, having drunk nothing but carrot juice all day, is detecting the brightest Supergiants of M51 with a distance modulus of 29.6, putting the Supers at ~21.6 mag. Other, less strenuous, target Supergiants would be found in galaxies shown HERE that have significant OB clusters.
Interstellar reddening is another thing to consider when looking over considerable distances due to scattering of the light.
Steven
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Mr. Wizard
Elements in Harmony I, an 8"f6 German Equatorial - Stellafane Winner,
II a 20"f4.2 Newt-Dob - Astrofest Winner,
III a 6"f3.5 Finder/Newt-Dob, and
IV a 36"f4.5 Newt-Dob - "If it's up there, it's in here."
www.DarkSkyObserving.com
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RRaubach
AstroCowboy
Reged: 01/26/05
Posts: 2172
Loc: Douglas (Converse County),WY
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I forgot to mention Barnard's Galaxy. There are several supergiants within reach of larger amateur instruments. I regret that I'm currently travelling on business, hence cannot retrieve any of my database. I seem to recall that there are definitely some mag 16 stars as possibilities.
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Rodger
Meade SN-10 (UHTC) on Tak EM-200 mount/Antares rotating rings. Moonlite focuser.
Parallax 14.5" Newtonian on HD 200 mount (arriving soon!) w/ conical Royce mirror.
TMB 203 f/7 APO refractor on Tak NJP-160 mount.
Discovery 12.5" PDHQ
Schneider 18x80 "Flakfernrohr" binoculars/tripod mounted. Canon 15x50 IS binoculars
Unihedron Sky Quality Meter
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Starman1
Postmaster
Reged: 06/24/03
Posts: 10684
Loc: Los Angeles
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A study of the photometry of the brightest stars in N6822 shows only a few brighter than magnitude 18 in V magnitude.
Lots between 18 and 19, though.
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Don Pensack
12.5" Truss Dob, 5" Maksutov
Sustaining Lifetime IDA member, TeleVue junkie
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