Has a Deep Field Picture of the Sky Been Captured with a Radio Telescope?

  • Context: Stargazing 
  • Thread starter Thread starter zuz
  • Start date Start date
  • Tags Tags
    Picture Sky
Click For Summary

Discussion Overview

The discussion centers around the possibility of capturing a "deep field" image of the sky using radio telescopes, akin to those taken by the Hubble Space Telescope. Participants explore the methods, technologies, and challenges associated with deep sky observations in radio astronomy.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants note that early radio astronomical surveys were conducted using telescopes like "Big Ear" and the Mills Cross, but achieving deeper images requires Very Long Baseline Interferometry (VLBI) and international collaboration.
  • It is mentioned that constructing detailed radio images from VLBI data necessitates intensive numerical processing, contrasting with the faster accumulation of optical images using sensor arrays.
  • Concerns are raised regarding the Five-hundred-meter Aperture Spherical Telescope (FAST), which primarily publishes data on pulsars and fast radio bursts (FRBs), suggesting a potential limitation in capturing deep sky images due to its focus on bright sources.
  • Participants discuss the limitations of FAST, including its single-location operation and sensitivity issues caused by man-made interference and nearby bright sources, which affect the quality of synthesized images.
  • The Square Kilometre Array (SKA) is proposed as a more suitable option for deep sky observations due to its distributed aperture and higher resolution capabilities, although funding and computational resources are noted as potential barriers.
  • FAST's geographic limitations are highlighted, as it is restricted to observing the northern sky and is less steerable compared to the SKA, which has elements positioned in Africa and Australia for better southern sky observations.

Areas of Agreement / Disagreement

Participants express varying views on the capabilities of current radio telescopes for deep sky imaging, with no consensus reached on the feasibility or effectiveness of existing technologies like FAST versus the SKA.

Contextual Notes

Limitations include the dependence on international collaboration for VLBI, the challenges posed by man-made interference, and the specific operational constraints of telescopes like FAST and SKA.

zuz
Messages
100
Reaction score
36
Has anyone ever taken a "deep field" picture of the sky, like Hubble, but with a radio telescope?
 
Astronomy news on Phys.org
Some of the early radio astronomical survey mapping was done by telescopes like "Big Ear" in the North, or by the Mills Cross in the South.
https://en.wikipedia.org/wiki/Ohio_State_University_Radio_Observatory
https://en.wikipedia.org/wiki/Mills_Cross_Telescope

To get deeper detailed images of smaller areas, requires VLBI, with international collaboration. The construction of detailed radio images, from the VLBI time data, requires intensive numerical processing. An optical image can be accumulated, on an image sensor array, which is a faster parallel process.
 
  • Informative
Likes   Reactions: berkeman
Baluncore said:
To get deeper detailed images of smaller areas, requires VLBI, with international collaboration. The construction of detailed radio images, from the VLBI time data, requires intensive numerical processing. An optical image can be accumulated, on an image sensor array, which is a faster parallel process.
All that exists at FAST but all publications I could find from them were pulsars and FRB and again pulsars, i.e. only the sources that were very bright for the telescope. I wonder whether this is for a reason or due to the relatively young age of FAST.
 
fresh_42 said:
All that exists at FAST but all publications I could find from them were pulsars and FRB and again pulsars, i.e. only the sources that were very bright for the telescope.
Deep sky observations require high sensitivity and high resolution. Unfortunately, man-made interference, and nearby bright sources, raise the noise floor of the synthesised images.

The Five-hundred-meter Aperture Spherical radio Telescope (FAST), operating alone, is a single location observatory. Resolution is limited by the 500 metre diameter. FAST finds more pulsars because it has a larger aperture area, and therefore has higher sensitivity than earlier observatories. It can make point measurements, where the signal is the sum of all the beam energy. That is suited to strong signals, or pulsar observations, not deep sky.
https://en.wikipedia.org/wiki/Five-hundred-meter_Aperture_Spherical_Telescope

The Square Kilometre Array (SKA) has a distributed aperture, so should have over 1000 times the resolution of FAR, since SKA is designed to operate as a long baseline interferometer. That would be more suited to deep sky observations, if you can find and fund the computer time.
https://en.wikipedia.org/wiki/Square_Kilometre_Array

FAST is located at about 26° North, and zenith limited, so is restricted to the northern sky. It is not as steerable as the elements of the SKA.
The SKA is based in Africa and Australia, with many more steerable elements. It is better positioned to observe the southern sky with the best view of the Milky Way.
 
  • Informative
Likes   Reactions: fresh_42
Thank you. That is just what I was looking for.
 
  • Like
Likes   Reactions: pinball1970 and berkeman

Similar threads

  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 19 ·
Replies
19
Views
3K
  • · Replies 5 ·
Replies
5
Views
959
  • · Replies 17 ·
Replies
17
Views
2K
  • · Replies 7 ·
Replies
7
Views
4K
  • · Replies 17 ·
Replies
17
Views
4K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 13 ·
Replies
13
Views
5K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 6 ·
Replies
6
Views
5K