[Weltevreden SA (Dana)]

I’m curious how many IIS observers have experienced clear resolution of M54 (NGC 6715) member stars. We’ve had several nights of better-than-average seeing over here in SA, and I’ve logged three observations on different nights of ~20 faint stars in M54 using a 200 mm Mak at up to 358x, and ~10 in a 150mm Mak mounted alongside at 269x. The cluster stars are evenly spread across the 8 arcmin face and all have nearly the same visual mag of about 15.5. The cluster stars possess a uniformity clearly distinct from seven adjacent field stars, which are irregularly half a mag to 2 mag brighter. A colleague with me on one night confirmed the above apparent resolutions.

M54 has a foreground reddening of only 0.15, so in our eyepieces its stars are little diminished from their actual magnitude. The brightest 10 red giants start at vm 15.5 and the effective limit for visual observers is the cluster’s considerable population of horizontal branch stars at vm 17.5. While red giants can differ visually over a couple of magnitudes, HB stars in a cluster are nearly uniform in apparent visual mag. While M54 is important to the professionals because it is likely the core of the tidally stripped Sagg Dwarf Gx, I am more interested in what we see from our backyards. Can anybody confirm this kind of resolution with these apertures? Thanks, Dana in SA