06-20-2014, 06:01 PM
Eigoya - as ever with projects like the TMT and ELT, the answers are complex. Both telescopes will have similar capabilities and both are designed to work in the same wavelength regime, i.e., visual and infrared light. The ELT will be slightly larger than the TMT resulting in a much larger collecting area for light. Usually that means the telescope will result in more sensitive observations and being able to detect fainter objects, although it isn't as simple as that. Despite being smaller, the TMT will win out on looking at single objects because of its optics whereas the ELT will win out looking at several objects in one go. So it depends on what science project is actually being done and that makes saying which is better very complicated.
The ELT will be built on a site that has slightly better seeing in visual light compared to Mauna Kea. Seeing is a measure of the detail you can resolve or see in images so it should win out there. On the other hand, the ELT will be at a lower altitude than the TMT, which means there will be more water in the atmosphere above the TMT and water makes infrared observations harder. In that case the TMT should win out - Mauna Kea is probably the second best currently used astronomical site for infrared observing. Only Antarctica is better.
ELT will be in the southern hemisphere, TMT in the north, so they will have access to different parts of the sky although there will be some overlap. The southern hemisphere is better for Galactic observations, the northern for extra-galactic. The telescopes will also only have access to their use to certain countries although there will be, no doubt, collaborations set up that will use both telescopes.
In summary, they are similar telescopes, with pros and cons for each if you're talking about competing, but will also complement each other because although they will be concentrating on some different areas of science, they will be doing slightly different ways of doing the same science. Unfortunately it will take time to build them, remember these are enormous instruments yet have to be built with a precision of microns on remote sites in difficult environmental conditions.
Personally I'm glad we will have two large telescopes, one in the south and one in the north. Imagine only one being built, say in Chile, and then some remarkable astronomical event happens in the northern sky, e.g., a Galactic supernova (we've been waiting for one of those for a long time now). Although we have several telescopes in the north, a large telescope like the TMT or ELT would be able to observe it like no other telescope has before (we're talking 15 times better resolution than the Hubble Space Telescope). It'd be a shame to miss that opportunity to understand our Universe just a little better.
The ELT will be built on a site that has slightly better seeing in visual light compared to Mauna Kea. Seeing is a measure of the detail you can resolve or see in images so it should win out there. On the other hand, the ELT will be at a lower altitude than the TMT, which means there will be more water in the atmosphere above the TMT and water makes infrared observations harder. In that case the TMT should win out - Mauna Kea is probably the second best currently used astronomical site for infrared observing. Only Antarctica is better.
ELT will be in the southern hemisphere, TMT in the north, so they will have access to different parts of the sky although there will be some overlap. The southern hemisphere is better for Galactic observations, the northern for extra-galactic. The telescopes will also only have access to their use to certain countries although there will be, no doubt, collaborations set up that will use both telescopes.
In summary, they are similar telescopes, with pros and cons for each if you're talking about competing, but will also complement each other because although they will be concentrating on some different areas of science, they will be doing slightly different ways of doing the same science. Unfortunately it will take time to build them, remember these are enormous instruments yet have to be built with a precision of microns on remote sites in difficult environmental conditions.
Personally I'm glad we will have two large telescopes, one in the south and one in the north. Imagine only one being built, say in Chile, and then some remarkable astronomical event happens in the northern sky, e.g., a Galactic supernova (we've been waiting for one of those for a long time now). Although we have several telescopes in the north, a large telescope like the TMT or ELT would be able to observe it like no other telescope has before (we're talking 15 times better resolution than the Hubble Space Telescope). It'd be a shame to miss that opportunity to understand our Universe just a little better.