Questions on Islamic Science

I have come across many websites on Islamic science that say something similar to:

• Abul Hasan is distinguished as the inventor of the Telescope, which he described to be a "Tube, to the extremities of which were attached diopters".
• Al Haytham used parabolic mirrors to observe the sky in more detail

Does anyone have more information on these topics? If you have, please leave a comment with the information.