Additionally I find it strange the difference between seeming equal magnitude stars When I’m using my naked eye. I can see Albireo even though it’s faint but all but one star in is invisible Saggita and that star is extremely difficult. The coat hanger is invisible.
This is all as it should be -- relatively speaking. Albireo is magnitude 3.0 (including both components), while Gamma, the brightest star in Sagitta, is mag 3.5 -- just 2/3 as bright as Albireo. And second-brightest Delta is even fainter, at mag 3.8.
The Coat Hanger is definitely invisible to the unaided eye in badly light-polluted skies.
However, a limiting magnitude of 3.5 or worse hints that your sky is likely Bortle 9, not Bortle 8. Granted, the ability to see faint stars varies greatly depending both on visual acuity and experience. Nonetheless, part of the definition of Bortle 8 is a naked-eye limiting magnitude of 4.5, and one full magnitude is a pretty big discrepancy. How do you do on the two other criteria for Bortle 8: the naked-eye visibility of M31 and M44? Those would be affected by experience but not by acuity, since they are fuzzy as well as faint.
For what it's worth, from Danehy Park in Cambridge, Massachusetts, on a night of good transparency, I can see M31 but not M44, and stars down to magnitude 4.7 with about the same effort that it takes to see M31. I therefore rate it as Bortle 8/9, since it meets two of the three criteria for Bortle 8.
It's possible that your sky might be Bortle 8 at other times of year, but is Bortle 9 in the summer due to the haze that often accompanies high humidity.
Anyway, in skies where I cannot see stars fainter than mag 3.5, I would expect M71 to be a fairly difficult target through a 130-mm scope. But it will certainly be fun to try! Sagitta is a very cool constellation in its own right, as seen through binoculars and finderscopes.
Edited by Tony Flanders, 11 August 2020 - 05:58 AM.