It facilitates smooth and error-free tracking for prolonged viewing and astrophotography. A Barlow lens placed before the eyepiece increases the focal length of the telescope and thereby increases the magnification of the telescope. No. 3 about equatorial mounts, right ascension is the apparent movement of the object being viewed across the sky during a given time period. At the equator, the declination is represented as 0 degrees. Like latitude, declination is measured from 0 - 90 degrees starting at the celestial equator and ending at the pole.
Higher magnification decreases field of view making locating objects difficult.
Also, image brightness is decreased.