Final answer:
The term 'smaller FOV in phase direction' likely refers to the field of view along a specific orientation in optics, particularly in telescopic observations. Greater angular magnification is achieved with a long focal length objective and a short focal length eyepiece. Image inversion in telescopes is also an important factor to consider.
Step-by-step explanation:
The question mentions 'smaller FOV in phase direction' which is a term that could be related to the field of Physics, particularly in optics and the study of telescopes. When considering the phrase 'FOV' or 'field of view', it often refers to the extent of the observable world that can be seen at any given moment. In this context, a phase direction might hint at a specific axis or orientation in which the field of view is being considered or measured.
In the context of telescopes, the angular magnification is influenced by the focal lengths of the objective and the eyepiece. To achieve the greatest angular magnification, it is advised to have a telescope with a long focal length objective and a short focal length eyepiece. However, this discussion on telescopic magnification seems to be only tangentially related to the 'FOV in phase direction', potentially indicating that there might be some confusion or mix-up in the concepts being addressed.
The provided information also discusses issues related to the image inversion as indicated by a minus sign in magnification and how certain telescope arrangements correct this inversion. The concept of image inversion is essential in understanding telescope designs and how they impact the observed images.