Sample interview questions: How do you ensure accurate sky background subtraction and noise reduction during observations?
Sample answer:
- Use dark frames: Dark frames are taken with the telescope shutter closed, which records the thermal noise of the detector. By subtracting the dark frame from the observed image, the thermal noise can be effectively removed.
- Use bias frames: Bias frames are taken with the telescope shutter open but without any exposure, which records the electronic offset of the detector. By subtracting the bias frame from the observed image, the electronic offset can be removed.
- Use flat frames: Flat frames are taken with the telescope shutter open and illuminated by a uniform light source, which records the pixel-to-pixel variations of the … Read full answer