Eyepiece Book (eyepiece book) is an application that displays how the moon, planets, and typical nebula star clusters look like by combining an astronomical telescope and an eyepiece.

Select the telescope and eyepiece respectively and select the object you want to see, and it will show how it looks in that combination. The planets can be selected from Mercury, Venus, Mars, Jupiter, Saturn, and Nebula clusters: Andromeda Galaxy, Orion Nebula, and Pleiades. The phases of the moon, the positions of Jupiter's satellites and large red spots, etc. are calculated and displayed at the current time.

In addition to displaying the moon, planets, and nebula stars in the center of the screen, you can also see how fast the celestial body moves in the field of view when using the glacial bench.

There are two astronomical display windows, so you can simultaneously view, compare, and confirm combinations of astronomical telescopes and eyepieces.
In order to compare the apparent visibility of the eyepieces, the smaller view is narrowed and displayed according to the larger apparent visibility selected in the two windows.