What you want to look at. The name of the star or planet or galaxy or nebula.
What detector on the Hubble Space Telescope you want to use.Do you want to collect an image, or a spectrum? Do you care about fast changes in the light? Do you want to look in visible light or ultraviolet or infrared light? Also, think about whether what you’re proposing to observe can be resolved within 0.05 arc seconds!
It is better to come up with a definite plan of how to use the telescope to measure something interesting or to test a definite hypothesis,Remember all the things that can be learned from light: the temperature of a star or planet (blackbody), the elements that make it up (spectral lines), motion towards or away from us (the Doppler shift of the spectral lines.)
Here are some sites that can be used for the project:
Public and professional sites from the Space Telescope Science Institute
An overview for the public on how the Hubble works
Some of Hubble’s most inspiring photos
A public-level summary of Hubble’s discoveries.
Some example Hubble observing projects are listed on the HubbleObserver Corner, updated monthly
You can check whether Hubble has looked at something before from this page. For example, type “betelgeuse” into object name, click “get coordinates”, then “search” lower down. You’ll be given a list of proposal numbers that have also targetted Betelgeuse; clicking on the number will give you the abstract of the proposal, for example, this one. You can certainly look at something that’s been looked at before, but it’s better if you mention that it was looked at before and mention anything special about the way you want to look at it.
Try to cite reputable sources (preferably books and .edu sites, or Wikipedia, or published research papers.)