Go Observing Help

Downloading and Displaying Image Data


Image from professional telescopes are not just pictures, but Image Data. To look at and study such data, you will need to do a little bit more than you would to look at a picture on a web page, but you can find out a lot more as well.

This page contains the answers to some of the questions you may have. You may want to print this page to look at later.


Frequently Asked Questions
Click on the question number to see the answer

Q. 1 How do I download my observation Image Data?
Q. 2 Do I need any special software?
Q. 3 How do I load my data into LTImage?
Q. 4 I have loaded my image, but it is just black with some small white dots. What do I do now?
Q. 5 I have adjusted the display of my image, but there is not much there. Is there anything else I should check?
Q. 6 My image looks basically good, but there is something wierd in there as well. What is it?


Q. 1: How do I download my observation Image Data?

Use the Observation Archive to find your observation.

  • When you have got the correct page, move your mouse button over the "download" link near the bottom and press and hold the right mouse button.
  • You will then get a little menu. Select "Save Target As..." or "Save Link Target As..." and use the window that appears to save your Image Data file.
  • It is important to remember which folder you put the file in as you will need to find it later.
 
Q. 2: Do I need any special software?

Yes, you will need to have LTImage installed on your computer or network. Ask your Teacher if it is available. If not, they can download it from here.

 
Q. 3: How do I load my data into LTImage?

Start up LTImage (ask your teacher how to do this) and:

  • Go to the File menu and select Open Data Image.
  • Use the new window to find the folder you downloaded the Data file to.
  • Select the file from the list by clicking on it and click Open.
  • Your image data should now be loaded in.
 
Q. 4: I have loaded my image, but it is just black with some small white dots. What do I do now?

Astronomical Image Data has a lot more detail in it than the computer can display at one time. This means that if there are bright stars in the image, you may not see the object you really want to see at first.

Display Scale Tool However, LTImage lets you change the way the computer displays the image to see the fainter parts. It does this with the Display Scaling tool:

  • Go to the Display menu and select Scaling.
  • You should have a new Tool like the one in the picture on the right.
  • In the Tool window, move the right-hand slider (labelled "Maximum") down nearly to the bottom.
  • Watch the small image as you do this. When you see something interesting, click on the Use New Values button.
  • Keep experimenting until you have found a picture that you like.
 
Q. 5: I have adjusted the display of my image, but there is not much there. Is there anything else I should check?

Observation Conditions page Although professional telescopes like the Liverpool Telescope are put on the best Observing Sites, the weather is not always perfect.

If you have experimented with the scaling (see question 4) and you still cannot see your object, it may be because of poor weather.

You can see if there was some cloud blocking out your object by checking the Observation Conditions (such as the example shown on the right). You do this by clicking on the link at the bottom of the Download page for your observation.

Look at the Sky Image in the bottom right of the page. Does it look cloudy?

Astronomers have had to get used to their observations being spoilt by bad weather. The only solution is to be patient and try again!

 
Q. 6: My image looks basically good, but there is something wierd in there as well. What is it?

There are a number of things that can make astronomical images look a little odd - we've put some examples together here.