The Bahtinov mask is an extremely useful tool for verifying autofocus results in accuracy aid for astrophotography
Diffraction Spike Mask Slide is used for cool fun effects on bright stars. Simply slide it in, then watch as stars get cool spikes.
You recieve the MASK DELUXE Dust Cover, which allows you to protect the optics of the Seestar S50. And yes, you can even power down the Seestar with the Dust Cover installed!
A dew shield prevents your telescope optics fogging-up in the first place. It keeps the optics completely dew-free and lets you observe for hours with the optimal view.