It’s hard to miss a flashlight beam pointed straight at you. But that beam viewed from the side appears significantly dimmer. The same holds true for some cosmic objects: Like a flashlight, they radiate primarily in one direction, and they look dramatically different depending on whether the beam points away from Earth (and nearby space telescopes) or straight at it.
Click here for original story, Seeing some cosmic X-ray emitters might be a matter of perspective
Source: Phys.org