<p>Water vapour in the atmosphere emits microwave radiation, which interferes with the observation of the microwave background. For this reason, space telescopes such as COBE or WMAP are best placed to study the very slight variations in the background.</p>
<p>However it is possible to use ground-based telescopes in exceptionally dry locations, such as the <a href="https://act.princeton.edu/" rel="noreferrer">Atacama Cosmology Telescope</a> which is capable of making arcminute-resolution measurements of the CMB.</p>

CC BY-SA 4.0
2023-10-21T02:38:43.543Z
There's been several modest resolution but really interesting microwave instruments at the south pole, which is not only at 9,300ft (2835m) but the super c-c-c-cold air even at the surface means very little [column-integrated precipitable water vapor](https://astronomy.stackexchange.com/q/18791/7982).
uhoh
CC BY-SA 4.0
2023-10-19T05:15:29.810Z
2023-10-19T05:15:29.810Z
James K
<p>With CMB peaking at roughly 158GHz would it be possible to create a more precise map of CMB just by sampling 'points' using existing Earth-based radio telescopes? I understand that large dish parabolas should provide a much sharper angular resolution. Why is this not being done?</p>

<telescope><radio-astronomy><cosmic-microwave-background><radio-telescope><angular-resolution>
Would it be possible to use existing radio-telescopes to do spot measurements of CMB?
user2820052
# Would it be possible to use existing radio-telescopes to do spot measurements of CMB?

(Asked by: username_0 on 2023-10-19)

With CMB peaking at roughly 158GHz would it be possible to create a more precise map of CMB just by sampling 'points' using existing Earth-based radio telescopes? I understand that large dish parabolas should provide a much sharper angular resolution. Why is this not being done?

**Tags:** telescope, radio-astronomy, cosmic-microwave-background, radio-telescope, angular-resolution

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## 1 answers

### Answer by username_1 on 2023-10-19. Score: 10

Water vapour in the atmosphere emits microwave radiation, which interferes with the observation of the microwave background. For this reason, space telescopes such as COBE or WMAP are best placed to study the very slight variations in the background.

However it is possible to use ground-based telescopes in exceptionally dry locations, such as the [Atacama Cosmology Telescope](https://act.princeton.edu/) which is capable of making arcminute-resolution measurements of the CMB.

> **Comments:**
> **username_2**: There's been several modest resolution but really interesting microwave instruments at the south pole, which is not only at 9,300ft (2835m) but the super c-c-c-cold air even at the surface means very little [column-integrated precipitable water vapor](https://astronomy.stackexchange.com/q/18791/7982).  

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