Questions tagged [dispersion]

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The preferred way of binning (classifying) data for galaxy snapshots in Python

Let's say I have a galaxy snapshot that I load with some package (pynbody etc) and I store my spatial coordinates of stars in the galaxy in x, y, z arrays and also velocity in array vz. Now I want to ...
  • 155
2 votes
1 answer
35 views

When measuring the spectrum of an object at the zenith, is it better to orient the spectroscopic slit N-S of E-W?

If you were to measure the spectrum of an object while it's exactly at the zenith, how should you orient the slit of the spectrograph to minimise atmospheric dispersion? Is North-South or East-West ...
  • 23
21 votes
2 answers
3k views

How hard is it to find the Sun's "sisters?"

As @ProfRob stated in his excellent answer regarding the ejection of the Solar System's fifth gas giant, It is for similar reasons that, even though the Sun was probably born in a cluster of $\sim 10^...
3 votes
2 answers
98 views

Understanding energy loss in a telescope aperture due to atmospheric dispersion

I'm trying to understand energy losses due to atmospheric dispersion, given the plot below from the Keck telescope. For a typical seeing I'm told that there's 80% encircled energy in 1". The ...
3 votes
2 answers
168 views

Do ASKAP and ALMA have "fast dump" interferometric modes? Can they see and perhaps report Fast Radio Bursts in real time?

Chatterjee et al 2017 The direct localization of a fast radio burst and its host nicely shows a VLA detection of a repeating FRB in 5 millisecond steps nicely demonstrating the dispersion slope ...
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