NEW! Astronomy Projects for Amateurs, Educators & Students

Project 02: Visual Photometry Project
Charts, Stars & Magnitudes

M67: Nigel Sharp, Mark Hanna/NOAO/AURA/NSF

Visual photometry is the process of determining the brightnesses of an unknown star by comparing its brightnesses to nearby standard stars of known brightness.  This comparison is made by eye. The standard stars that match the unknown closest in brightness set limits on what the visual magnitude of the unknown star can be; if the unknown is fainter than standard A but is brighter than standard B, then its visual magnitude is somewhere between those of A and B.

This project uses an image of the star cluster M67 (Its name indicates that it is the 67th object in the catalog compiled by Messier.) projected on the computer screen.  The image for M67 is HERE. More images and information on M67 is HERE. The image is in color, which makes the project even more interesting as color can affect the magnitude estimation. Using the finding chart (in the project) to identify the standards and unknown stars in the image on the computer screen, compare standard stars to unknown stars to estimate the magnitudes of the unknown stars.

Enjoy, and we solicit your comments/suggetions/critique at

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