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20 votes

What on-site equipment is installed with radio telescopes?

Though it will vary by telescope, some of those computers are likely used to control and monitor the telescope. The operator, who may be the astronomer but is usually an observatory staff member, ...
HDE 226868's user avatar
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12 votes
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Was GRAVITY built to look at one star?

No, the GRAVITY instrument is multi-purpose. This link gives you all the papers that have cited the instrument description paper. The list of papers shows that it has been used for studying: the ...
ProfRob's user avatar
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12 votes
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At the intersection of engineering and astronomy in its structure as a scientific discipline

Yes, there is an intersection between astronomy and engineering. In my experience, it will mostly be astronomers who have a flair for technology and instrumentation who at some point, either from the ...
pela's user avatar
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11 votes

Which JWST instrument modes are compatible with observations of the bright trans-Earth planets Mars, Jupiter, and Saturn? Which aren't?

There are approved proposals for Cycle 1 to point the JWST at The Jovian system Jupiter's great red spot Mars Saturn and its moons and rings In those PDFs, they describe exactly what instruments ...
Gavin S. Yancey's user avatar
10 votes
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Has Hubble photographed Venus in near IR? If so how does it compare to the new and exciting Parker Solar Probe image?

This web page -- "Here is why the Hubble Space Telescope only looked a few times at Venus (and why it looked at the Moon instead)" -- seems like a pretty good answer to your main question (...
Peter Erwin's user avatar
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10 votes
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Is there a limit to the distance of detectable gravitational wave events?

Several factors influence whether a source of gravitational waves at a certain distance is observable by a certain instrument. One way to compute the limit to the distance is explained in Abadie et al ...
Sextus Empiricus's user avatar
9 votes
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Did they ever figure out why Parker's WISPR cameras were able to see the surface of Venus? Mischaracterized filter, or unexpected atmospheric window?

There's actually a paper by Wood et al. (2022) that came out focused on this. It discusses the expected detection given the expected emission (using a model that combines the surface emission and the ...
Peter Erwin's user avatar
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8 votes
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How could a 20 inch space telescope "be able to make out Earth-size planets" orbiting Alpha Centauri?

I'm not familiar with the design of the ProjectBlue telescope, but I think you have answered your own question. The habitable zones for Alpha Cen A and B, are approximately centred at 1.25au and 0....
ProfRob's user avatar
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8 votes

At the intersection of engineering and astronomy in its structure as a scientific discipline

Yes, this intersection exists, in the instrumentation, and somewhat in mission design. When it gets to designing instruments, it needs knowledge of both worlds: what does science want, how and in what ...
planetmaker's user avatar
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7 votes
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Why (the heck) is the basic angle of GAIA 106.5°?

The choice of basic angle in Hipparcos and Gaia is related to the "rigidity" of the stellar reference system that can be constructed when connecting accurate positional measurements across ...
MichaelP's user avatar
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7 votes

What would a kHz gravitational wave detector look like? (mountains on millisecond magnetars) How would it differ from LIGO/Virgo?

In principle, not much different to LIGO, since LIGO is sensitive to kHz gravitational waves. But you need to find ways to increase the sensitivity at kHz frequencies, without compromising response at ...
ProfRob's user avatar
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7 votes

How do radio astronomers avoid having their receivers burned out by ground-imaging radar from satellites?

There are a number of approaches to avoid the impact of radio frequency (RF) emitters in radio astronomy. This interference can impact performance even if it is not at level that is significant to ...
GrapefruitIsAwesome's user avatar
7 votes

Which JWST instrument modes are compatible with observations of the bright trans-Earth planets Mars, Jupiter, and Saturn? Which aren't?

All modes can be used. But for bright targets, observations are limited to specific filters, subarrays, regions of the target planet, or spectral intervals. James Norwood and colleagues wrote a paper ...
giardia's user avatar
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7 votes

What on-site equipment is installed with radio telescopes?

Radio telescopes are a composite technical complex, the decomposition of which can be done as follows: The main one is an antenna device, an irradiator, a calibrator and a very sensitive receiving ...
ayr's user avatar
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6 votes
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What is the detection threshold of gravitational waves for LIGO?

I'm afraid this is not straightforward The amplitude of the gravitational wave strain signal from a merging compact binary (neutron star or black hole) is $$h \sim 10^{-22} \left(\frac{M}{2.8M_{\odot}}...
ProfRob's user avatar
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6 votes
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How exactly did JWST take a "selfie" of its own primary mirror, and what is the real purpose of this capability?

Let us just ask Lee Feinberg, the Webb Optical Telescope Element Manager: How exactly did JWST take a "selfie" of its own primary mirror? In this video at 2:09: There's actually a special ...
User123's user avatar
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5 votes

How can Mercury's sodium tail be imaged?

Yes, it is possible; see https://twitter.com/sevospace/status/1328082050889490433 However, M. Voltmer used a “custom-made sodium filter,” without giving any details…
Pierre Paquette's user avatar
5 votes
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How does ALMA produce stable, mutually coherent ~THz local oscillators for all of their dishes?

ALMA produces stable, mutually coherent ~THz LO (Local Oscillators) for all the antennas by... Using a single central LO and piping it to every antenna via fiberoptic cable! The fiber expands and ...
Connor Garcia's user avatar
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5 votes

How do astronomical spectrometers measure spectra from single stars separately, without contamination from all of the nearby stars?

I imagine it's done differently based on the goals. Anything wanting to study just one object could simply mask out everything else. But the Sloan Digital Sky Survey studies numerous objects at once....
Greg Miller's user avatar
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5 votes
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Is "monochromatic source" different than "monochromator" in astronomical instrumentation?

Is "monochromatic source" different than "monochromator" in astronomical instrumentation? Sure! "Monochromatic source" is a very general term for any source of radiation ...
uhoh's user avatar
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4 votes

Number of lenslets in wavefront sensor array

Generally speaking as many as possible because the number of lenslets determines the lateral wavefront resolution. But in reality there are a few factors to be considered. Wavefront sensor Say your ...
WDC's user avatar
  • 484
4 votes

Is there a limit to the distance of detectable gravitational wave events?

As an addendum to Sexti Empirici answer note that LIGO and Virgo have not yet reached their full "design" sensitivity. Each run their sensitivity is further improved. The current observation run (O3) ...
TimRias's user avatar
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4 votes

How to calculate luminosity in g-band from absolute AB magnitude and luminosity distance?

Here is my attempt to reconcile your calculations. If the AB g-band apparent magnitude is 22.5, then the flux density in the g-band is given by $$f_{\nu} = 10^{(-48.6-22.5)/2.5} = 3.63 \times 10^{-29}...
ProfRob's user avatar
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4 votes

What is the detection threshold of gravitational waves for LIGO?

Figure 1 of this paper shows the horizon distance (distance to which a circularly polarised overhead signal would be detected at SNR 8) for larger mass systems up to total mass of 1000 solar masses, ...
Matt Pitkin's user avatar
4 votes

What leads an observer to choose a narrow slit over a wide one (and vice-versa) when observing?

You seem to have all the ingredients apart from the variables of what size your detector pixels are (either physically or binned in software/hardware) and the angular extent of the object you are ...
ProfRob's user avatar
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4 votes

Why (the heck) is the basic angle of GAIA 106.5°?

I did not find anything conclusive on the web, and I am yet waiting to receive feedback from ESA's contact page. In a German speaking IT forum there is something a bit less vague than the FAQ cited in ...
B--rian's user avatar
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4 votes

Is the difference between LIGO & Virgo and their "Advanced" versions really generational, or were these just planned incremental upgrades?

I think this is largely a matter of what you decide is incremental as opposed to a generational change. The basic location and overall size and detection principle of the interferometers did not ...
ProfRob's user avatar
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4 votes
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What would a kHz gravitational wave detector look like? (mountains on millisecond magnetars) How would it differ from LIGO/Virgo?

To briefly supplement Rob's answer, there is at least one concept being floated for a gravitational-wave detector which is explicitly targeting kilohertz gravitational waves and sacrificing ...
liam's user avatar
  • 76
4 votes
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Do circa 1 THz radio telescope front end amplifiers actually down convert before amplifying? At what frequency does amplification become untenable?

An article in Astronomy & Astrophysics 1 (A. M. Baryshev et al., A&A 577, A129 (2015)) titled “The ALMA Band 9 receiver Design, construction, characterization, first light” covers this. The ...
Jon Custer's user avatar
4 votes
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Formation of spacecraft instrumentation

Science spacecraft are custom-built, instruments tailored for the specific mission (and the mission custom-tailored to the available instruments - it's a inter-dependent process), taking into account ...
planetmaker's user avatar
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