The Super Spyglass is a better version of the Spyglass with doubled map reveal range. It can be crafted using a Spyglass, an Eye of the Tiger Shark and a Gold Nugget. It requires a Science Machine to prototype and can be blown away by Strong Winds.
The range reduction while on a boat doesn't apply to it, but the range is still affected by the time of day.
The distance revealed by the Spyglass can be sailed in a short amount of time with boats, so it is recommended to use it to peek towards other directions that the player does not travel into.
On console editions, having a Boat Lantern equipped prevents the use of Spyglasses while at sea. Removing the lantern will allow normal use of the spyglass. This bug also affects other hand-held equipment that have a cursor (such as the Volcano Staff) from being used while on a boat.
The art for the Super Spyglass was changed in the Eye of the Tiger Shark update to reflect it being craftable with an Eye of the Tiger Shark.
Range Comparison (Normal Spyglass on the left and Super Spyglass on the right)
Wilson holding a Spyglass.
Wilson holding a Super Spyglass.
Wilson using a Spyglass.
Wilson using a Super Spyglass.
Walani using a Super Spyglass, as seen in the Shipwrecked trailer.