Scheetz Family Web

Astronomical League's page for the Globular Cluster Program
Astronomical League YouTube video on the Globular Cluster Program
Globular Clusters that defined the class (click on the image to get full size pic of object)
Messier Globular Clusters (click on the image to get full size pic of object)

Shapley-Sawyer Concentration Class Descriptions

Class	Description
I	High concentration of stars towards the center (M80)
II	Dense central concentration of core stars (M2)
III	Strong inner concentration of core stars (M54)
IV	Intermediately rich concentration of core stars (M15)
V	Intermediate concentration of core stars (M13)
VI	Intermediately mild concentration of core stars (M3)
VII	Intermediately loose concentration of core stars (M22)
VIII	Rather loose concentration of core stars (M14)
IX	Loose concentration of core stars (M12)
X	Very loose concentration of core stars (M68)
XI	Almost no concentration of core stars (M55)
XII	No concentration of core stars (Palomar 12)

Challenge Objects

A sketch of the star field where the cluster is located and another sketch showing the cluster you see in the eyepiece is required.

Summary in Astronomical League Program Order

Completed 34 of the required 50 Globular Cluster Observations

Recorded observations in the order they were observed

Hopefully observation quality and class concentrtion estimates improve over time

Transparency is rated as the truncated magnitude of the dimmest star I can see.
Seeing is rated from 1 to 5 with 1 being perfect.
I rarely attempt making observations unless conditions are pretty good.

AL#49 (M79) NGC1904

AL#67 M3 (NGC5272)

Challenge Object - AL#59 NGC 4147

This is a challenge object where the AL program guide says magnitude 9.9, SkySafari says magnitude 10.3 and Wikipedia says magnitude 10.7.

At 85x I can barely see the cluster as a dim fuzzy patch and made a sketch showing the cluster in its star field. At 145x and the view was pretty much the same with no new detail noted. At 203x the fuzzy patch seemed to be elongated and I made a detailed sketch. There was some brightness near the bottom (South West) of the cluster - which seemed to come and go due to seeing. Overall, the cluster was fairly nebulous almost like an elliptical galaxy - I could not resolve any individual stars. The brightness I observed seemed to be about a third of the width of the fuzzy patch. Based on the comparison pictures of the program guide and descriptions I thought it matched "Class IV - Intermediately rich concentration of core stars" and I estimated this to be a class IV cluster since the brightness appeared to be pretty concentrated.

Starfield sketch at 85x (using my 24mm ES68 eyepiece) showing where the cluster is located

0060_20240504_1123_AL59 NGC4147 85x Sketch.jpg

Cluster detail sketch at 203x (using my Delos 10mm eyepiece)

0070_20240504_1124_AL59 NGC4147 203x Sketch.jpg

AL#64 M53 (NGC5024)

AL#77 NGC5904 M5

AL#92 M13 (NGC6205)

AL#106 M92 (NGC 6341)

Observed from Chippokes State Park during the Back Bay Amateur Astronomer's Spring East Coast Star Party.
M92 although smaller than M13 it is pretty close in apperance to M13 so I spent some time going back and forth between the two. At 85x the cluster is located in a very nice field of stars and is quite beautiful with many stars resolved. I can resolve stars across the face of the cluster except at the very center. Appears uniformly round, no noticable dark lanes.
At 203x it is still beautiful although tonight I am not getting that 3D sensation I sometimes get from it and M13.

AL#94 M12 (NGC 6218)