This course brings together all the relevant information required for an observational high energy astrophysicist. We will start with an introduction where we will go into physics subjects which are frequently used in high energy astrophysics such as the electromagnetic spectrum, photoelectric effect, and shock waves. Afterwards, we will look into some very “famous” types of objects that are most active in High Energies such as X-rays and Gamma rays. And then, we will be discovering the space telescopes that are being used today. We will also briefly talk about the engineering and the instrumentation of these sources. Finally, I will show you the very basics of spectral analysis by using public archival data of Chandra X-ray Observatory.