(IAAC) Obj: NGC6520 - Inst: 4.5" Homemade Dobson reflector, f/8

  Observer: Ante Perkovic
Your skills: Intermediate (some years)
Date/time of observation: July 18th, 2004. 0:10h
Location of site: Konjevrate, near Sibenik, Croatia (Lat. 43.6 N, Elev. 
Site classification: Rural
Sky darkness: 6.5 <Limiting magnitude>
Seeing: 9.5 <1-10 Seeing Scale (10 best)>
Moon presence: None - moon not in sky
Instrument: 4.5" Homemade Dobson reflector, f/8 ("babydob")
Magnification: 28x, 53x, 87x, 154x
Filter(s): None
Object(s): NGC6520
Category: Open cluster
Constellation: Sgr
Data: mag 7.6  size 6'
28x: Very small, with 2 chains of 3 stars each inside 3'.
  The background is slightly granular.
53x: Few more faint stars in the center and faint nebulosity
  in the background.
87x: I clearly see 6 stars in the center, 3 to 4 star slightly to
  the N and nebulosity, that can be due to either poor eyepiece or
  some more stars in the background.
154x: I see nothing new compared to 87x.
I checked this object in the computer later and found out that there is
around 20 stars between mags 11 and 12, so that explains background
nebulosity. I must check this object with bigger scope!