The Mayasiar Shrine is one of many shrines in The Legend of Zelda: Tears of the Kingdom that require players to solve a puzzle hidden somewhere in the overworld, rather than in the shrine space. Using their understanding of reflection and light, players must venture to Starview Island and unravel its mystery to gain access to the shrine. Here's how Link can gain this shrine's Light of Blessing.
Mayasiar Shrine Location in TotK
In Tears of the Kingdom, the Mayasiar Shrine can be found at the coordinates -3545, -0320, 1965 high in the western skies of Hyrule. More specifically, it can be found in the North Gerudo Sky Archipelago above the Gerudo Highlands.
Players can use the Gerudo Highlands Skyview Tower to reach the skies and glide in the direction of the large floating sphere. As they enter the airspace of the archipelago, players will find themselves in a low-gravity field. The nearest floating island players will be able to reach will have some floating platforms and 
Rockets they can use to their advantage. Be forewarned as this area of the sky is quite cold, so Link will need to pack cold resistance food/elixirs or dress accordingly.
By attaching the rockets to the platforms, Link can ascend higher into the sky to better reach the sphere. The low gravity will allow the platform to maintain some momentum after the rockets dissipate, so it's recommended to wait until it comes to a full stop before attaching another rocket.
After roughly two rockets' worth of height, players should be able to jump and glide to the sphere. The low gravity in effect will allow Link to travel further than normal and descend at a much slower pace. Players also have the option to build a flying machine of their own and navigate their way to the shrine's coordinates.
Mayasiar Shrine Walkthrough
Players will find a large opening on the upper hemisphere of the structure. They can then glide down to a platform in the center and be greeted by the Starview Island location discovery. Starview Island is populated with numerous 
Mirror on rotating wheels and four large lamps on a wheel in the middle.
The goal is to illuminate the hexagonal switch near the top of the structure by reflecting light off each of the mirrors. Players should begin by pushing the turnstile in the middle of the room to rotate the lamps toward the mirror at the same height.
In doing so, the light of the lamp will reflect off it, then off a mirror on the ceiling, and finally to another mirror on a platform floating above. Players can use the many updrafts in the structure to reach this higher platform.
Once there, players can rotate this mirror to hit yet another mirror on a similarly-sized platform across the way.
Again, players should follow the light to the next mirror and rotate it toward a mirror on a lower platform on the opposite side of the structure.
At this next mirror, players can direct the light toward the switch located on the right to open a small chamber containing a Sage's Will.
Next, direct the light to the mirror in the center of the room.
Players can then rotate this final mirror and illuminate the switch in front of it. Players may have chosen to do this as they rotated the central platform at the beginning, but doing so now will not mess up their progress.
When all the mirrors are aligned, the reflected light will trigger the switch and reveal the Mayasiar Shrine.
Players can now enter the shrine to find Rauru's Blessing and receive both its Light of Blessing and a Star-Fragment Staff from the chest. It's not very strong, but can help Link illuminate the darker areas of Hyrule.
The Legend of Zelda: Tears of the Kingdom is available for the Nintendo Switch.