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A secret society of inventors has been hiding for years. Finally, they have designed their Mars base in the year 2019! Unfortunately, they "borrowed" most of their supplies. If they were to build a glass survival dome say, 200 meters in length, would NASA or any of the other space agencies be able to find it in the next few years?

Assuming that no Martian rovers or anything come across the dome, would satellites or telescopes notice the domes, and how long until they do?

The rover Curiosity, way smaller than 200 m, can be seen from Martian orbit:

So, for a martian satellite in polar orbit it would be just a matter of days before capturing visual proof of the presence of "something" that big on the surface. If instead its orbit wasn't polar, and the dome was built in a suitable location, it could go unnoticed.

For Earth based telescopes the task is harder, and they cannot spot anything of that size.

So, maybe an "incident" can take care of the martian satellites before the building work starts...

it would be easier to provide radiation-shielding if the enclosure were built sub-surface. also easier to camouflage the installation. best of all to make an excavation large enough to facilitate sub-surface mining, especially for water-drilling.

some facility would have to be devised to excavate & distribute any mineral debris in a non-detectable way. but that would be the case wherever the enclosure is located.

there is going to be a need for access to sub-surface water in any case.

A good answer by L.Dutch regarding sensor resolution, but remember that people knew where to look for the rover.

There are good chances that pictures would be taken and fed to an automated analysis system, which would not be programmed to spot domes. Scientists might not look at the data as it comes in, until some grad student tries to analyse weathering patterns or whatever years later.

Perhaps the data would be fed into a public database. Some random guy running a flight simulator on Mars might spot it.