Our article identifies the five planet models that can be seen in TOS in the order of their appearance, as well as a couple of other celestial objects, and contrasts these planets with the new ones created for TOS-R.
Planet 3 does not have recognizable continents. Much of its surface is covered by blurry clouds. We can imagine that the model stands for water planets when colored blue. Aside from blue, we can most often see Planet 3 in orange though. As already mentioned, it is absolutely possible that Planet 3 is identical to the Guardian of Forever planet, only that the latter was not so much blurred (was it done intentionally for Planet 3?).
The following composite image demonstrates how the differently colored planets, filmed from different angles, are still based on the same miniature of Planet 3. The cloud patterns are clearly identical.
Planet 3a - dark blue The planet appears for the first time in TOS: "Catspaw", here in a darker blue gray, as opposed to the clear blue of later episodes.
|Pyris VII (TOS: "Catspaw") Complying with the desolate impression of the planet's surface, Pyris VII became a rocky gray planet is TOS-R.|
Planet 3b - light blue This is the brighter blue version that appears in a total of four episodes.
|Argelius II (TOS: "Wolf in the Fold") The hedonistic Argelius is a Class-M world with clearly visible population centers in TOS-R.|
|Sigma Iotia II (TOS: "A Piece of the Action") This very Earth-like planet was given a standard Class-M look in TOS-R.|
|Troyius (TOS: "Elaan of Troyius") The remastered Troyius is another typical Class-M planet, although its atmosphere seems to be somewhat darker.|
|Scalos (TOS: "Wink of an Eye") Scalos is Class M. The planet is characterized by some unusual geological formations, which appear colorful from space. It is worth mentioning that the matte painting of the Scalosian city, which used to be bluish like the whole planet, was modified to gray for TOS-R.|
Planet 3c - orange Planet 3 can be seen with dirty orange to brown color variations in eight more TOS episodes.
It is possible that this ice age planet was created using the model of the Guardian of Forever planet or of Planet 3. Anyway, the way the globe looks in "Spock's Brain", it is unique in TOS. We can see that much of the northern hemisphere is covered with ice.
|Sigma Draconis VI (TOS: "Spock's Brain") In TOS-R the planet retained its partial snow cover. But unlike the original the rest of Sigma Draconis VI is brown (unless TOS showed only the ocean side and TOS-R only the land side).|
Excalbia is the last new planet created for TOS. We can see the small solidified spot on the magma surface of this highly active planet.
|Excalbia (TOS: "The Savage Curtain") Instead of a contiguous surface of molten rock the lava on the TOS-R planet pours out from various big fissures in its crust.|
The asteroid shots first appeared in "The Paradise Syndrome" and were later re-used for Yonada, only differently colored.
As already shown, the Medusan homeworld was dropped altogether and replaced by a starship. The other way round, some planetary bodies previously not seen were created for TOS-R.
|Sol system (TOS-R: "Tomorrow is Yesterday", "Assignment Earth") In TOS-R: "Tomorrow is Yesterday" we can see the Sun, Mercury, Moon and Pluto during the Enterprise's slingshot maneuver. In TOS-R: "Assignment Earth" the Moon is visible once more.|
|Beta VI (TOS-R: "The Squire of Gothos") This Class-M planet is the destination of the Enterprise in TOS-R: "The Squire of Gothos". The planet is a reuse of Sigma Iotia II as seen in the remastered "A Piece of the Action".|
|Ring planet near Starbase 11 (TOS-R: "Court Martial") The Starbase 11 planet has a ringed sibling visible from space only in TOS-R. The ring planet, however, appeared as early as on the original matte painting of the starbase in TOS: "The Menagerie, Part 1", and was only slightly revised on the new painting.|
The opening credits of TOS season 1 show the same brown Planet 1a (Delta Vega). For seasons 2 and 3 it was replaced with a red planet 2e (Vulcan).
Galactic Barrier The barrier naturally looks the same when the Enterprise crosses it in TOS: "Where No Man Has Gone Before" and once again in TOS: "By Any Other Name". For the ship inside an anomaly of the Great Barrier in TOS: "Is There in Truth No Beauty?" a new, very colorful effect was created.
Stars Rather than by models, stars were represented by light spots in TOS.
Various celestial objects These are the other celestial objects that changed from TOS to TOS-R.
|Icarus IV (TOS: "Balance of Terror") In TOS-R the comet was given more detail, and a wider coma with chunks of ice that break away.|
|Murasaki 312 (TOS: "The Galileo Seven") While the color of the remastered Murasaki 312 is close to the original, it was given the shape of a huge galactic spindle. Interestingly, it was made to look like a real space object called microquasar, so the verbal description of Murasaki as "quasar-like" makes sense. The anomaly also looks much more impressive because it now encompasses the planet in several closer shots.|
|L-370 debris (TOS: "The Doomsday Machine") The planet debris, which looked rather like ice chunks from a comet in TOS, was modified to generic pieces of rock in TOS-R. We can also see such debris floating around the USS Constellation.|
More about TOS-R Changes
Planet Surfaces in TOS and TOS Remastered - survey of the TOS matte paintings and how they were remastered
Starships in TOS and TOS Remastered - "before & after" comparison of all ships that appeared in the series
Special thanks to Matt Wright who did most of the TOS-R screen caps for Trekmovie.com. Some other screen caps are from TrekCore. Thanks also to Kevin Kozoriz for pointing us to the microquasars, to G2K for reminding us of the Tycho IV crater and to Ambassador/Ensign_Q for a hint about the sky on Planet Q.