Step 1: Pick an Object.

Pick an object from the following list. Then go to the STSCI Digitized Sky Survey to see a photograph of your object. If you are having problems accessing the STSCI Digitized Sky Survey link, then try the European Southern Observatory (ESO) Digitized Sky Survey.
 

Step 2: Get a Photograph of your Object

This is the Digitized Sky Survey, a huge database of pictures from every part of the sky. Depending on which link you have chosen you will have slightly different directions. Below are two sets of instructions. In order to retreive an image of your object, follow the insructions that apply to the site you have chosen.

STSCI Digitized Sky Survey Instructions:

First, you enter the name of your object in the name resolver near the top, and click on Get Coordinates. The page will reload, and the coordinates (RA and DEC) will appear below.

Next, scroll down to where it says file format and select GIF.

Leave the rest as the default and click on Retrieve Image. After a few seconds, your object will appear! Pretty, isn't it?

Save the image to disk if you want, and print it. Next, we will find different kinds of pictures of this object.
 

ESO Digitized Sky Survey Instructions:

First, you enter the name of your object in the Object Name field of the Query Form.

Next, scroll down to where it says Output Format and select Display as GIF File.

Leave the rest as the default and click on Retrieve Image. After a few seconds, your object will appear! Pretty, isn't it?

Save the image to disk if you want, or just try to remember what it looks like. Next, we will find different kinds of pictures of this object.
 

Step 3: Images from other Wavelengths

As we learned in class, visible light is only a small part of the EM spectrum. A great place to find images of objects in other parts of the electromagnetic spectrum is the SkyView All-Sky Viewer. It contains images from every part of the sky in many different wavelengths: radio, infrared, visible, ultraviolet, X-ray, and Gamma-ray! Follow the above link to try to find some of these other images of your object.

Just type the name of your object (NGC **** is best) where it says coordiantes or source, and select all of the six wavelength regimes from the table below. You may want to make sure all of the images are shown at the same scale. To do this, select from the list of possible image sizes. Try 1o or 3o. Then click on Submit to retrieve the images.

A little while later (it takes a bit to process your request), six images will appear. They might look very different, but each is of the same object viewed in a different kind of EM radiation. One thing to keep in mind is that the pixel size is different for the different images; the x-ray image has 2o pixels, the optical image has 1.7 arcesond pixels.

Questions


 

Step 4: Hubble Space Telescope Images

Click here to go to the HST page. You know the drill by now: Type the name of your object (NGC **** is best) where it says Target Name, then press Resolve. De-select all options under Images and Spectra, except WFPC2. WFPC2 is the post-repair HST camera, and it gives the best images. Everything else can be left blank. Click on Search.

A little while later, it will give you a table of all the images of your object it found in the HST archive. There may be very many images, but lots of them are calibration images. Look under Target Name to see which images are actually interesting. For example, if you are doing M1, then look for "crab nebula" or "pulsar".

This archive exists for professional astronomers to download Hubble data, but you have to be registered with NASA to do this. We can preview the images, however. Click on the Target Name of the object you wish to preview. A new window comes up. Click on Get Preview, and the image will load.

Warning: Sometimes these images are empty, or bad quality. If this happens, try one of the other images. Especially try different wavelengths. You should be able to find a good image. Note especially the improved quality of the HST image over the DSS image.

Questions

Click here to go back to the main page.


waters@ucolick.org
Last modified: Thu Mar 5 17:22:19 1998