Hi!

 Looking at the star charts, M4 should have been a very easy target. Massive globular, very close to the Antares...but my 8" Dob fails to reveal even hints of this glob. I have tried it a number of ways, printed detailed charts, still no luck.  On the other hand, M80 is revealed very clearly and it is a sight to see.

Am I missing something? Or it is just the Plano / Dallas skies, and the glow from Antares?

Please let me know if there is an easier method to locating this gem.

Thanks and Regards

It's the skyglow.

You are observing from almost due north of me. I can't see it through the skyglow whenever the humidity is high enough, or there is enough dust in the air, to obscure it. The spread of light from Dallas is just too great.

On a very clear night (think September-ish), when the nights start to cool off just after sunset, we can see it from the park where we hold the SpringPark Star Party on the First Saturday of the month.

You have no cause for concern.  M4 is a difficult object for two reasons.  The first has already been hit upon.  It is quite low from your latitude and this causes it to be hidden by light pollution, humdity, and just plain more atmosphere to look through.  The second reason is that while the star chart may list M4 at Mag. 7.12 the actual brightness of most of the stars that make up this globular are in the 10th and 11th magnitude range.  As with many large objects, M4 is 36' across, the combined brightness of 7.12 is a bit of a misnomer.  M80 is has a denser core that combines the available light into a smaller area which your telescope can pick out from the background glow easier than the large diffuse glow of M4.

I live at just a tad over 33 degrees north and M4 can be impossible to see if the conditions are not right in either my 6" SCT or my 8" Newt.  Wait for a low humidity night with transparent skies and no Moon and you should be able to catch it.  Personally there are a number of much better globules to be explored north in Ophiuchus that are much grander than M4.

L

I can get M4 in my 15X75 binoculars easily. But I'm having the same issue with my 4.5'' reflector. I can't get it in. Sometimes I wonder if I'm not as good with my scope as I thought I was. In my area, the light pollution is more nortward. The southern sky is great. Don't feel bad....you're not the only one who can't find it in the scope.

witt3696:

Sometimes I wonder if I'm not as good with my scope as I thought I was

Don't be so hard on yourself!   M-4 is a low surface brightness object spread over a large apparent area.  Your scope's 114mm mirror is not that great a leap in size from your binocular 75mm lenses.  Your brain also is able to discern faint objects much better when using both eyes as well.  For viewing extended objects both eyes, low power, and steady skies will beat a narrow view cyclops of a telescope every time.  There is a whole list of objects that binoculars will show far better than a telescope.  Don't believe me, check out Phil Harrington's binocular essays at this site or elsewhere.

L 

Believe it or not, M4 is a naked-eye object from a truly dark site at an appropriate latitude.

http://www.visualdeepsky.org/chat/msg01732.html

Dave Mitsky

DaveMitsky:

Believe it or not, M4 is a naked-eye object from a truly dark site

Yep, I was equally surprised when I saw M4 naked eye on 23 June 08 under very clear skies fom a place a few miles from my home town at +14 deg. The same evening I had no trouble seeing a few other clusters naked eye as well: M6, M7, M22.

 When I was living back east in MA, I was able to detect this GC easily with 10x50s and could resolve many of its outer stars with a 10" newt. The transparency there was fairly bad on most summer nights with M4 being low in the sky (I was at 42 degrees latitude) with moderate haze and humidity.

  Out here in NM, the GC is very bright and easily seen in 10x50s and the view is much better in my 10" than back east (here I'm at 34 degrees).

  So I'm wondering if your sky transparency is a lot worse than you think, keeping you from detecting it? The only way I know of to answer this question is for you to see what visual limiting magnitude you have near M4. This info may help us determine if it is a transparency problem or not (most likely it is, since the GC is within a moderate power f.o.v. of Antares, making locating it extremely easy)

  Mr Q