Welcome to the University of Michigan – Dearborn

Observatory

Founded 2007

Our Telescope

Housed inside its 12.5 ft diameter dome, our primary instrument is a 0.4 m diameter reflecting telescope.

A reflecting telescope works by using curved mirrors to form the image. Most modern telescopes are reflectors.

Our telescope has Ritchey–Chrétien optics – both mirrors have a hyperbolic shape.

The light is first focused by the primary mirror, then focused again by the secondary mirror. The light reaches the CCD camera through a hole in the primary mirror.

Light Path in a Ritchey-Chretien Telescope

Another famous Ritchey-Chretien Telescope – the Hubble Space Telescope

We also have a number of smaller telescopes that can be mounted on our observing deck. We use these telescope to teach students how to use a telescope, and for public observing sessions.

Observation Deck

Visitors enjoy the view

When using our 0.4 m telescope we use a camera to record what the telescope sees.

Cameras have several advantages over using our eyes.

1)By taking a longer exposure we can see much fainter objects.

2)We can save our images for later analysis.

Our camera works like the camera in your cell phone - it uses a light sensitive chip called a CCD.

Image Processing improves the quality of our images. We use different types of exposures to remove different errors.

Bias frames compensate for systematic noise in the CCD chip.

Raw Image of spiral galaxy M51

Dark frames compensate for random electronic noise.

Flat frames correct for defects in the optics.

Processed Image of spiral galaxy M51

The 0.4 m telescope has a small field of view – the piece of the sky the telescope sees – it is much smaller than the size of the full Moon.

To make a picture of the entire moon we have to fit together multiple smaller pictures.

Using a filter wheel attached to the camera, we take images through three filters, then combine them to create colour images.

Planetary Nebula M 27 - The Dumbbell Nebula

Planetary Nebula M 57 - The Ring Nebula

Jupiter

Comet Holmes Our first astronomical image, 25 October 2007