Globular Clusters

Personal Information:

Steve Boerner

sboerner@charter.net

All objects were located personally with no additional assistance.

Telescope used for all objects:

Celestron 14 modified to GOTO

Date started: 5/21/2012

Date completed: 6/16/2012

Certificate Number: 212

Location for all observations:

Brommelsiek Park
(click for more information)

Bortle Sky: Longitude: Latitude: Elevation:

orange 90.815o W 38.723o N 644 ft.

Seeing Scale:

1 :: Chaotic: lowest power stellar images unsteady

2-3 :: Severely disturbed: low power planetary/nebulae images unsteady

4-5 :: Poor: medium powers unsteady

6-7 :: Good: only high powers unsteady

8-9 :: Excellent: only highest powers soft

10 :: Superb: all powers steady

Transparency Scale:

1 :: Mostly Cloudy

2-3 :: Hazy; 1 or 2 Little Dipper stars visible

4 :: 3-4 Little Dipper stars; Milky Way not visible

5 :: 4 Little Dipper stars; Bright parts of Milky Way visible (Scutum star cloud)

6 :: 5 Little Dipper stars; Milky Way visible with averted vision

7 :: 6 Little Dipper stars; Milky Way visible

8-9 :: Excellent: 7 Little Dipper stars; M-31 visible

10 :: Superb: M-33 and/or M-81 vis

Requirements:

The goal of this Observing Program is for you to observe or image and compare the structures of globular clusters, and to that end, you can use manual (finder scopes and star hopping techniques), digital setting circles or any other computer aided Go-To systems. Remote telescopes are allowed.

Observers select a minimum of any 50 globular clusters from the list of 190 cataloged in the Program's Guide. This allows for customization of an observing list suitable to the individual observer's interests, skies and equipment.

However, this program is more than just observing 50 globular clusters and recording your observations. This program requires both visual and imaging observers to determine the Shapley-Sawyer concentration class of each globular cluster observed. The Guide explains this classification system and provides reference images of globular clusters and their concentration classes, along with an explanation of how to determine the concentration class of each globular you observe by using these images.

For reference I mention Chesterfield a few times below. It is a suburb of St. Louis with population of about 48,000 that is about 15 miles due east of Broemmelsiek Park. I live in Chesterfield.

Required sketches for the two challenge objects may be found at the bottom of the page.

Observations for fifty-one globular clusters have been recorded including two challenge objects. Viewing conditions associated with the site make seeing detail in other challenge objects virtually impossible. Globular clusters with a magnitude less than 9.8 are very difficult from Broemmelsiek Park.

Click for information about Shapley-Sawyer Concentration Class

Observation Log:

Sketches for challenge object(s):

Object Starfield View Eyepiece View

NGC 5466

NGC 4147

I tried to see detail in NGC 4147 on three separate nights. Very difficult!

Astronomical League Globular Cluster list--completed but more to do