Questions tagged [instruments]

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6
votes
1answer
208 views

How does ALMA produce stable, mutually coherent ~THz local oscillators for all of their dishes?

The ALMA (Atacama Large Millimetre/submillimetre Array) radio telescope's band-10 capabaility is now operational, per this answer. That's confirmed by NRAO's First Science with ALMA’s Highest-...
5
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4answers
238 views

How can Mercury's sodium tail be imaged?

I recently learned that Mercury has a sodium tail. Can this sodium tail be imaged with a ground based telescope? Is so, what is the minimum setup required to be able to take a picture of it? Do you ...
2
votes
1answer
242 views

What is the large astronomical instrument shown in this 1918 eclipse expedition photo?

This nice video musing about (among other things) the US Naval Observatory's $3,500 expedition to Baker City or at least Baker County Oregon to observe the June 18, 1918 solar eclipse, there is a ...
2
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2answers
157 views

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

I just learned the term "third generation gravitational wave detector" in answers to What would a kHz gravitational wave detector look like? (mountains on millisecond magnetars) How would it ...
8
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1answer
492 views

Was GRAVITY built to look at one star?

GRAVITY (shown below) is a interferometric combiner of near infrared light from four very large telescopes called The Very Large Telescope in order to make careful astrometric measurements near the ...
4
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2answers
194 views

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

The abstract of Gravitational waves from mountains in newly born millisecond magnetars says: In this paper we study the spin-evolution and gravitational-wave luminosity of a newly born millisecond ...
3
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1answer
89 views

Time domain astronomy and fastest eclipsing binary ZTF J1539+5027 (+20 mag, 6.91 minutes): How to measure its minimum brightness?

Per Wikipedia's ZTF J153932.16+502738.8 ZTF J153932.16+502738.8 is a double binary white dwarf with an orbital period of just 6.91 minutes. [...] The light curve shows eclipses. One dip in the light ...
3
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0answers
64 views

How were "microshutters" or other multiplexed or multi-object techniques first used in Astronomical spectroscopy?

This answer to How will microshutter arrays be used in the James Webb and future space telescopes? explains how multiple objects can be selected so that the throughput of a spectrometer can be ...
2
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1answer
67 views

Are the dispersion directions of the prism and the grating in Hubble WFC3 UVIS G280 perpendicular? Can we call this a "grism"? With cross-disparsion?

Prologue From Into the UV: A precise transmission spectrum of HAT-P-41b using Hubble's WFC3/UVIS G280 grism: The UVIS grism, however, comes with several quirks that make it difficult to observe with ...
2
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0answers
41 views

Why does X-shooter use double passes through prisms for Echelle cross-dispersion instead of gratings?

The catchy title Down-the-barrel observations of a multiphase quasar outflow at high redshift: VLT/X-shooter spectroscopy of the proximate molecular absorber at z=2.631 towards SDSS J001514+184212 ...
2
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0answers
357 views

How does the ESPRESSO Echelle spectrograph fold the spectrum so nicely?

The CBC News Technology and Science Q&A This ESPRESSO machine doesn't make coffee but scans the skies for habitable planets includes a nice description of ESPRESSO (Echelle SPectrograph for Rocky ...
0
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1answer
52 views

Did astronomers ever use photographic plate rotation along with alt-az mounts?

The video Earth's Rotation Visualized in a Timelapse of the Milky Way Galaxy - 4K (linked below) and discussion below this answer to Why does a timelapse video of a stationary Milky Way make the ...
4
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2answers
384 views

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

This answer to Why does the Gaia space telescope have two main mirrors says: According to the GAIA FAQs which does an excellent job: http://www.cosmos.esa.int/web/gaia/faqs: Why is there an angle of ...
8
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2answers
237 views

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

This is somewhat a follow up question to this one. This article indicates that the binaries detected have a distance between 320 and 2840 Mpc. With the current technology, is there a limit to the ...
7
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1answer
459 views

How could a 20 inch space telescope "be able to make out Earth-size planets" orbiting Alpha Centauri?

The NY Times article Telescope to Seek Earthlike Planet in Alpha Centauri System describes a proposed effort to put a telescope into orbit fairly quickly with a narrowly defined purpose - to look for ...
7
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1answer
226 views

Has Hubble photographed Venus in near IR? If so how does it compare to the new and exciting Parker Solar Probe image?

Phys.org's Parker Solar Probe offers stunning view of Venus includes the image below taken by the Parker Solar Probe during it's most recent gravitational assist flyby of Venus as it continues to rid ...
2
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0answers
66 views

Are astronomers still using photomultiplier tubes for optical photometry?

In Time domain astronomy and fastest eclipsing binary ZTF J1539+5027 (+20 mag, 6.91 minutes) How to measure it's minimum brightness? I've written A logarithmic magnitude scale might tend to show ...
2
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1answer
57 views

What was the first use of time-delay integration in Astronomy? Are there instances before GAIA?

In the context of GAIA, time-delay integration is the clocking of a CCD's charge shift register at a frequency such that it matches the linear speed across the focal plane of the actual image. So even ...
2
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1answer
60 views

What telescopes used 1000+ pixel Microwave Kinetic Inductance Detectors (MKIDs) for multispectral, single photon counting (time + energy of photons)?

This excellent answer to What would “the next GAIA”-like instrument be like? Could it simply be a 3 to 5x scaled-up version of the same beautiful system? is worth a thorough read-through, but it and ...
2
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0answers
38 views

What are the pros and cons of different types of echelle spectrograph cross-dispersers?

Echelle spectrographs, operating at high resolving power, typically consist of an echelle grating with a low numbers of lines/mm, used with high diffraction orders (often $n=$50-100). To separate the ...
1
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0answers
35 views

Astrophysical particle spectroscopy; narrow-line particle sources (charged or uncharged) for things other than photons? Have any been detected?

Is Cosmic Ray Astronomy a thing? Is there an equivalent of the red shift effect for cosmic rays? have got me thinking and under this answer I've commented: That's a good point; there aren't as many ...
0
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0answers
20 views

Have avalanche photodiodes been used successfully for precision photometry? If so, in analog (charge integration) mode or just in photon counting?

This excellent answer to What would “the next GAIA”-like instrument be like? Could it simply be a 3 to 5x scaled-up version of the same beautiful system? is worth a thorough read-through, but it and ...