The Teslascope is a radio transceiver that was alleged to have been invented by Serbian scientist Nikola Tesla for the purpose of communicating with life on other planets. Even though Tesla talked about "interplanetary communication" on many occasions, it has never been confirmed that he built such a device.
- The possibility of beckoning Martians was the extreme application of [my] principle of propagation of electric waves. The same principle may be employed with good effects for the transmission of news to all parts of the earth....Every city on the globe could be on an immense circuit. [Thus] a message sent from New York would be in England, Africa and Australia in an instant. What a grand thing it would be. - Nikola Tesla 
- Tesla's statement during an interview, explaining his electric wave propagation method for communicating with alleged Martians.
- Early in December [of 1900], we received from Lowell Observatory in Arizona a telegram that a shaft of light had been seen to project from Mars (the Lowell observatory makes a specialty of Mars) lasting seventy minutes. I wired these facts to Europe and sent out neostyle copies through. The observer there is a careful, reliable man and there is no reason to doubt that the light existed. It was given as from a well-known geographical point on Mars. That was all. Now the story has gone the world over. In Europe it is stated that I have been in communication with Mars, and all sorts of exaggerations have spring up. Whatever the light was, we have no means of knowing. Whether it had intelligence or not, no one can say. It is absolutely inexplicable. - Professor Pickering 
- Professor Pickering at Harvard College Observatory writes about the mysterious light that was received from Mars, from which he developed the idea of building mirrors in Texas to communicate with the alleged Martians. In 1909, Tesla denounced Pickering's idea of building mirrors, and instead introduced his own method of communicating with the alleged Martians.
- I can never forget the first sensations I experienced when it dawned upon me that I had observed something possibly of incalculable consequences to mankind. I felt as though I were present at the birth of a new knowledge or the revelation of a great truth. Even now, at times, I can vividly recall the incident, and see my apparatus as though it were actually before me. My first observations positively terrified me, as there was present in them something mysterious, not to say supernatural, and I was alone in my laboratory at night; but at that time the idea of these disturbances being intelligently controlled signals did not yet present itself to me. The changes I noted were taking place periodically, and with such a clear suggestion of number and order that they were not traceable to any cause then known to me. I was familiar, of course, with such electrical disturbances as are produced by the sun, Aurora Borealis and earth currents, and I was as sure as I could be of any fact that these variations were due to none of these causes. The nature of my experiments precluded the possibility of the changes being produced by atmospheric disturbances, as has been rashly asserted by some. It was some time afterward when the thought flashed upon my mind that the disturbances I had observed might be due to an intelligent control. Although I could not decipher their meaning, it was impossible for me to think of them as having been entirely accidental. The feeling is constantly growing on me that I had been the first to hear the greeting of one planet to another. A purpose was behind these electrical signals; and it was with this conviction that I announced to the Red Cross Society, when it asked me to indicate one of the great possible achievements of the next hundred years, that it would probably be the confirmation and interpretation of this planetary challenge to us. Since my return to New York more urgent work has consumed all my attention; but I have never ceased to think of those experiences and of the observations made in Colorado. I am constantly endeavoring to improve and perfect my apparatus, and just as soon as practicable I shall again take up the thread of my investigations at the point where I have been forced to lay it down for a time. -Nikola Tesla 
- Tesla explaining his experience with the mysterious signal he had received.
- The idea naturally presents itself that mirrors might be manufactured which will reflect sunlight in parallel beams. For the time being this is a task beyond human power, but no one can set a limit to the future achievement of man... But there is one method of putting ourselves in touch with other planets... This combination of apparatus is known as my wireless transmitter... It is evident, then, that in my experiments in 1899 and 1900, I have already produced disturbances on Mars incomparably more powerful than could be obtained by any light reflectors, however large. - Nikola Tesla 
- Tesla denouncing Professor Pickering's idea of creating a set of mirrors in Texas with the intention of signaling purported Martians, and also introducing his own idea on communicating with other planets.
- To be sure, we do not have no absolute proof that mars is inhabited [...] Personally, I have my faith on the feeble planetary electrical disturbances which I discovered in the summer of 1899, and which according to my investigations, could not have originated from the Sun, the Moon, of Venus. Further study since has satisfied me they must have emanated from Mars. - Nikola Tesla 
- Tesla recounting his experiences in 1899 with the electrical disturbances he had received.
- Others may scoff at this suggestion...[of] communicat[ing] with one of our heavenly neighbors, as Mars...or treat it as a practical joke, but I have been in deep earnest about it every since I made my first observations in Colorado Springs... At the time, there existed no wireless plant other than mine that could produce a disturbance perceptible in a radius of more than a few miles. Furthermore, the conditions under which I operated were ideal, and I was well trained for the work. The character of the disturbances recorded precluded the possibility of their being of terrestrial origin, and I also eliminated the influence of the sun, moon, and Venus. As I then announced, the signals consisted in a regular repetition of numbers, and subsequent study convinced me that they must have emanated from Mars, the planet having just then been close to the earth. - Nikola Tesla 
- Tesla writing about his experiences with what he believed were signals from Mars, ruling out his 1901 prediction that the signals he received could have come from Venus instead of Mars.
- [I have conceived] a means that will make it possible for man to transmit energy in large amounts, thousands of horsepower, from one planet to another, absolutely regardless of distance. I think that nothing can be more important than interplanetary communication. It will certainly come some day. and the certitude that there are other human beings in the universe, working, suffering, struggling, like ourselves, will produce a magic effect on mankind and will form the foundation of a universal brotherhood that will last as long as humanity itself. - Nikola Tesla 
- Carlson, W. Bernard (March 2005), "Inventor of Dreams", Scientific American: 85
- Aldrich, Lisa J. (May 31, 2005). Nikola Tesla and the Taming of Electricity. Greensboro, North Carolina: Morgan Reynolds Publishing. pp. 142-143. ISBN 978-1931798464. OCLC 56194706.
- Nelson, Robert A. (1997). Communicating with Mars: The Experiments of Tesla & Hodowanec. Borderland Sciences Research Foundation, Inc. Retrieved on 2007-05-28.
- "Is Tesla to Signal the Stars?". Electrical World. April 4, 1896. pp. 369.
- Seifer, Marc J. (1996). "Martian Fever (1895-1896)". Wizard : the life and times of Nikola Tesla : biography of a genius. Secaucus, New Jersey: Carol Pub.. pp. 157. ISBN 978-1-55-972329-9. OCLC 33865102.
- Professor Pickering (January 16, 1901). The Light Flash From Mars. The New York Times. Archived from the original on 2007-05-20. Retrieved on 2007-05-20.
- Seifer, Marc J. (1996). "Bladeless Turbines (1909-1910)". Wizard : the life and times of Nikola Tesla : biography of a genius. Secaucus, New Jersey: Carol Pub.. pp. 337. ISBN 978-1-55-972329-9. OCLC 33865102.
- Tesla, Nikola (February 19, 1901). Talking with the Planets. Collier's Weekly. Retrieved on 2007-05-04.
- Tesla, Nikola (May 23, 1909). How To Signal To Mars. The New York Times. Archived from the original on 2007-05-03. Retrieved on 2007-05-03.
- Nikola Tesla and Planetary radio signals
- Tesla, Nikola (September's 24, 1921). "Interplanetary Communication". Electrical World. pp. 620.
- Seifer, Marc J. (1996). "Martian Fever (1895-1896)". Wizard : the life and times of Nikola Tesla : biography of a genius. Secaucus, New Jersey: Carol Pub.. pp. 222-223. ISBN 978-1-55-972329-9. OCLC 33865102.
- July 20, 1931, "Tesla at 75", Time (magazine) 18 (3): 3 .