![In a reflecting telescope (Cassegrain), is there a difference between using a concave or convex secondary mirror? - Astronomy Stack Exchange In a reflecting telescope (Cassegrain), is there a difference between using a concave or convex secondary mirror? - Astronomy Stack Exchange](https://i.stack.imgur.com/j0i4Y.jpg)
In a reflecting telescope (Cassegrain), is there a difference between using a concave or convex secondary mirror? - Astronomy Stack Exchange
![A Cassegrain telescope uses two mirrors as shown in above figure. Such a telescope is built with the mirrors 20 mm apart. If the radius of curvature of the large mirror is A Cassegrain telescope uses two mirrors as shown in above figure. Such a telescope is built with the mirrors 20 mm apart. If the radius of curvature of the large mirror is](https://haygot.s3.amazonaws.com/questions/421595_3dd363e6ca254d3182d8b1cafaea23f9.png)
A Cassegrain telescope uses two mirrors as shown in above figure. Such a telescope is built with the mirrors 20 mm apart. If the radius of curvature of the large mirror is
![Amazon.com : Maksutov-Cassegrain Telescope, Mak70 Telescopes for Adults Kids 1000mm Focal Length 70mm Objective Lens, Beginners Astronomy Telescope with Slow Motion Gimbal Tripod : Electronics Amazon.com : Maksutov-Cassegrain Telescope, Mak70 Telescopes for Adults Kids 1000mm Focal Length 70mm Objective Lens, Beginners Astronomy Telescope with Slow Motion Gimbal Tripod : Electronics](https://m.media-amazon.com/images/I/6181U-bM8EL.jpg)