Observational Mishaps


Compiled by Kaspar von Braun, Kristin Chiboucas, Denise Hurley-Keller
Department of Astronomy, University of Michigan
Last revision: March 3, 2006


This webpage contains an image database of astronomical observations (as of this revision: only photometry) which exhibit problems one might encounter during observing runs. These problems include everything from common occurences, such as bad seeing and dust grains on the dewar window or filters, to somewhat more eccentric issues, such as the failure of primary mirror support or insects in the lightpath.

The purpose of this database is to enable observers to compare unusual symptoms they might be experiencing to the images here, and discover the cause of (and perhaps even the solution to) their trouble, thus saving telescope time.

The way this database is structured is as follows: the main division is between commonly occuring problems and the more obscure ones. Within these two categories, we have attempted to organize the database according to general symptoms. The basic motivation for this is that when an observer encounters some inexplicable feature in the image, all he or she will have as a basis for a search for the cause of the problem are the symptoms. We have, however, also provided the option of accessing the entire collection of images from one location.

We would greatly appreciate receiving input on this database from the astronomical community. In addition, we would like to add any images with similar problems as the ones presented here in order to increase the usefulness of this database. If you have any such images, please read the instructions on how to submit them. For a list of astronomers who have contributed to this project, see the acknowledgments. References are listed here.

The publication which refers to this site is: von Braun, Chiboucas, & Hurley-Keller 1999, I.A.P.P.P Communications No 75, 62. A pdf version of this paper can be downloaded here.



  • Common Problems:
  • "Advanced" Cases - by Symptoms:
  • You may also check out a list of all the compiled images. This list includes a brief description of the symptoms for every image.

    For any correspondence, please refer to the addresses below (replace _AT_ with @).

    kaspar_AT_ipac.caltech.edu (KvB)

    chib_AT_umich.edu (KC)

    denise_AT_smaug.astr.cwru.edu (DHK)


    University of Michigan Astronomy Department