Starship Asterisk*

What are the three vertical lines? I don't think they could be satalite tracks due to the position of the STEREO A spacecraft that took the picture. Are they artifacts from the camera?

APOD frequently states how many lightyears away an object is, which translates into looking that many years into the past. How are objects at different distances imaged by a large, observatory sized telescope? Is the magnification changed? How? Does the focus have to be adjusted dramatically? Aren’t...