Linked Questions

19 votes
4 answers
5k views

What are "non-Keplerian" orbits? What are some familiar examples in our solar system, and can some still be closed?

This excellent answer to Forms of stellar orbits around the galactic center invokes the following concepts: non-Keplerian orbits closed orbits I have a fairly good idea what these mean and so might ...
uhoh's user avatar
  • 30.7k
17 votes
2 answers
877 views

Is Optical VLBI theoretically feasible? If not why not?

There are plenty of optical interferometers in use with baselines of up to maybe 1km. As far as I can find out, they all work by directly collecting the light at all the telescopes, using mirrors to ...
Steve Linton's user avatar
  • 10.3k
5 votes
2 answers
755 views

How does the Event Horizon Telescope implement the interferometry?

The BBC article Event Horizon Telescope ready to image black hole describes the Event Horizon Telescope, a coordinated observing technique with several radio telescope arrays across the globe forming ...
uhoh's user avatar
  • 30.7k
8 votes
1 answer
432 views

Highest frequency that's been imaged by a radio telescope?

In this answer to Should we update definitions and remove the 100 GHz hard limits on radio astronomy related tags? I wrote the following partial answer: Yes, there are plenty of dishes that focus ...
uhoh's user avatar
  • 30.7k
3 votes
1 answer
201 views

How, precisely, do radio astronomers detect (and record) the phases of waves for interferometry?

Interferometry is always in the news, and at radio frequencies it has been for a long time... The popular press always talks about directly 'interfering' two waves as they come in, but can they tell ...
Kurt Hikes's user avatar
  • 5,307
3 votes
2 answers
195 views

Would "layered" radio interferometry work?

tl;dr - Is splitting up the process of interferometry as shown in the diagram possible, and if so, is it more efficient and/or easier than traditional methods? I have been doing some research into ...
sforsingh's user avatar
  • 1,443
6 votes
1 answer
145 views

Do circa 1 THz radio telescope front end amplifiers actually down convert before amplifying? At what frequency does amplification become untenable?

A discussion of how astronomers view where "radio" ends and "infrared" begins under What does the celestial sphere look like in thermal IR? led me to wonder just how high of a ...
uhoh's user avatar
  • 30.7k
6 votes
1 answer
156 views

Reference request (explaining) how optical correlators combine light from multiple telescopes to produce ultra-high resolution interferometric images?

This is a reference or resource-request because it may be too challenging to explain in an answer post, but if you'd like to attempt a short summary as well, that will be great! I have a basic ...
uhoh's user avatar
  • 30.7k
7 votes
1 answer
143 views

Is there any work underway to push the long baseline capabilities of the Event Horizon Telescope to sub-millimeter wavelengths?

The Max Planck Institute for Radio Astronomy's press release Something is Lurking in the Heart of Quasar 3C 279; First Event Horizon Telescope Images of a Black-Hole Powered Jet shows a stunning ...
uhoh's user avatar
  • 30.7k
0 votes
1 answer
116 views

How often do they move most/all of ALMA's dishes?

The Phys.org article Unknown treasure trove of planets found hiding in dust reports on recently published radio measurements (~1.3mm) of planetary systems forming around stars in Taurus: Scientists ...
uhoh's user avatar
  • 30.7k
3 votes
0 answers
104 views

How will China's Xuntian space telescope use its Terahertz capability? THz Spectroscopy? Imaging? Something else?

An Update on the Chinese Space Station Telescope Project Hu Zhan, National Astronomical Observatories, CAS, KIAA, Peking University, On behalf of the CSST Team, ISSI-BJ Workshop: Weak gravitational ...
uhoh's user avatar
  • 30.7k
2 votes
1 answer
83 views

Do we have the technology to create a satellite telescope constellation that uses interferometry?

Apologies for putting the bulk of the question in the description. I'm honestly not sure how to ask this properly. The idea for this question came from a Vsauce video from several year ago I can't ...
Gryphon's user avatar
  • 23