If you're looking to Download Messier Finder Charts on your Chromebook laptop Then read the following guideline.

These Messier finder charts contain maps for every Messier deep sky object. It's user interface has intentionally been made as simple as possible so you can use this app in the freezing cold while using your telescope in total darkness. The app uses only red on the map to preserve your night vision. This is best used by holding the iPhone or iPad next to your Telrad reflex sight while viewing both the bulls eye in your Telrad and the bulls eye on the map to quickly find targets.