In the telescope magnification formula M = -Doc/Dobj, what does the negative sign indicate?

In the telescope magnification formula M = -Doc/Dobj, what does the negative sign indicate?

• A. Image inversion
• B. Upright image
• C. No inversion
• D. Magnification magnitude negative

Answer: (A)

The negative sign reflects the image orientation. In a simple telescope, the objective forms a real image that is inverted, and the eyepiece magnifies that inverted image without correcting its orientation. Therefore the overall magnification is negative, indicating an inverted (upside-down) final image relative to the object. The magnitude tells you how large the image is compared to the object, while the sign tells you whether it’s inverted or upright. If you wanted an upright view, you’d need additional optics (like prisms) to re-invert the image.

The negative sign reflects the image orientation. In a simple telescope, the objective forms a real image that is inverted, and the eyepiece magnifies that inverted image without correcting its orientation. Therefore the overall magnification is negative, indicating an inverted (upside-down) final image relative to the object. The magnitude tells you how large the image is compared to the object, while the sign tells you whether it’s inverted or upright. If you wanted an upright view, you’d need additional optics (like prisms) to re-invert the image.