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Questions tagged [observational-astronomy]

Questions about the techniques and practice of observing the night sky.

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Spatial wind speed distribution on Mars using dune shapes?

As a fan of exometeorology (the study of atmospheres of other planets), I scanned through a whitepaper Measuring Mars Atmospheric Winds from Orbit which says Measurements of Mars atmospheric winds ...
B--rian's user avatar
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8 votes
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217 views

Is there a standard deconvolution procedure to remove JWST's diffraction pattern yet? If so, would Arp 220 be a good candidate on which to try it?

Source: Webb captures the spectacular galactic merger Arp 220 Shining like a brilliant beacon amidst a sea of galaxies, Arp 220 lights up the night sky in this view from the NASA/ESA/CSA James Webb ...
uhoh's user avatar
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7 votes
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Can terrestrial infrared telescopes see through clouds or haze, sometimes at least?

My answer to Could UV-A imaging sensor reasonably see a total eclipse in progress through clouds? suggests that while clouds blocking visible light observation of the (partially) eclipsed solar disk ...
uhoh's user avatar
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7 votes
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157 views

Angular resolution of naked eye at night; type of vision used

It appears that most sources quote the angular resolution of the eye as 1', regardless of day and night. For instance, Naked eye Seconds of Arc and the Unaided Eye However, the following websites give ...
Cheng's user avatar
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What's the largest angle that light has been "seen to bend" by gravity? (of one object by a separate object)

Gravitational lensing is everywhere! because it falls off so slowly with $r$: $$\Delta \phi \approx \frac{4GM}{c^2r_0}.$$ That's the first order term. For a nice derivation see Viktor Toth's The ...
uhoh's user avatar
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6 votes
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153 views

How was the axial tilt of planets measured?

https://en.wikipedia.org/wiki/Axial_tilt#Solar_System_bodies gives the axial tilt of all planets with two decimal precision, but how and when were they measured so precisely ? I guess it's "easy&...
Dr. Goulu's user avatar
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202 views

How far have stars been seen beyond the center of the Milky Way?

What lies near the center of the galaxy is of great interest and in recent times the motion of dozen(s) of stars at the center of our galaxy orbiting around Sgr A* have been measured in great detail. ...
uhoh's user avatar
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6 votes
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488 views

Could non-supernova carbon, oxygen, or silicon flashes be observed?

I was reading about the helium flash, the short but sudden onset of helium fusion in certain red giant stars. As I understand, the upper (nondegenerate) layers of the star absorb the energy as they ...
HDE 226868's user avatar
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5 votes
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88 views

Is there a noob-friendly website/app for tracking a astronomical body's apparent movement over time?

As I walk home along my road most nights in winter, I see the Moon and one-or-more planets. Unsurprisingly, over the last 2 months, if it's been the same planet and it (and the Moon) has been in ...
Brondahl's user avatar
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How far away must galaxies be before current telescopes can no longer measure how quickly they are rotating around one another or internally?

What is the distance limit and does it depend on the size of the galaxy and on noise and interference from gas clouds and our own Milky Way?
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Positional astronomy - Speed of the sun in sky

Let $\vec{r}$ be the position of the Sun in the sky, from Earth. How could I estimate the magnitude of $d\vec{r}/dt$, to measure the rate of change in time of the arc it traces? I suppose it would be ...
nuwe's user avatar
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A new (radio) neutrino telescope in Greenland?

I just stumbled upon ScienceMag news from July 14th, 2021 which says: By placing hundreds of radio antennas on the ice surface and dozens of meters below it, they hope to trap elusive particles known ...
B--rian's user avatar
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What about the U planet?

In 2014 and 15, an object called U has been detected by the ALMA in Chile, considered likely to be a super-Earth at 300 AU, among other options. Is it located where the hypothetical super-Earth ...
John's user avatar
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Explain as simply as possible how the Sunyaev-Zeldovich (SZ) effect is used to estimate the Hubble constant

The Sunyaev–Zeldovich effect (SZ effect) is useful in determining the Hubble constant because it is independent of the cosmic distance ladder. This effect occurs when CMB (cosmic microwave background) ...
Astroturf's user avatar
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86 views

Significantly blueshifted Lyman-$\alpha$

Lyman-$\alpha$ line in galaxies is notably known to show a double peaked profile, mainly due to its scattering in a moving medium, see e.g., the very recent Matthee et al. 2021, The X-SHOOTER Lyman-α ...
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236 views

What are the deciding optical factors between a refractive and reflective space telescope optics as a function of aperture? (visible light)

Reading Yale News' Lighting a path to Planet Nine: To detect objects that are otherwise undetectable, Rice and Laughlin employ a method called “shifting and stacking.” They “shift” images from a ...
uhoh's user avatar
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5 votes
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Are occultation observations used/useful for orbit determination?

The IAU Minor Planet Center lists $(486958)\space 2014 \space MU_{69}$ "Ultima Thule" as having an uncertainty parameter of 2, based on the observation arc of 851 days, from its discovery in 2014, to ...
costrom's user avatar
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In the JPL small body browser, why is uncertainty on absolute magnitude "N/A"?

In the JPL small body browser, orbital elements are all provided with uncertainties and even a covariance matrix, such as for 2013 LA2. Very good. But underneath, the absolute magnitude is reported ...
gerrit's user avatar
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Infrared telescopes, magnitude and observations

Currently 22-23 magnitude could be the limit to make a spectrum for ground based 10m class telescopes, 21-22 magnitude may be easy for them. 4m class telescopes could possibly handle 20 magnitude, I ...
questionhang's user avatar
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Basics of Tracklet-less Heliocentric Orbit Recovery (THOR) - simple breakdown of how it works?

The New York Times's April 30, 2024 Killer Asteroid Hunters Spot 27,500 Overlooked Space Rocks begins: With the help of Google Cloud, scientists churned through hundreds of thousands of images of the ...
uhoh's user avatar
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4 votes
0 answers
144 views

Just how resonant is the "resonant sextuplet of sub-Neptunes transiting the bright star HD 110067"?

The November 29, 2023 arXiv preprint A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067 constructs a resonant chain of orbital periods based on mean motion resonances (MMRs) and ...
uhoh's user avatar
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4 votes
0 answers
120 views

Do the discs of observed solar systems have random orientations?

Is there any bias in the orientation of solar systems?
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44 views

What special auxiliary equipment / modeling are needed for ground-based sub-milliarcsecond astronomy?

I'm not asking about the astronomical equipment itself. I'm asking about the auxiliary equipment and modeling needed to enable the primary astronomical equipment to work properly at the sub-...
David Hammen's user avatar
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4 votes
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519 views

How to measure the latitude of the moon?

In the geocentric solar ecliptic (GSE) system of coordinates, the position of the Moon is described by its longitude and latitude. The former is, with great accuracy, the angular distance between the ...
WordP's user avatar
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82 views

Keyerror: 0 while using astropy SkyCoord

I am facing a problem while using SkyCoord from astropy library. The scenario is as below, I have read the data from a fits file into a pandas dataframe. I have applied several quality cuts to the ...
CTZenScientist's user avatar
4 votes
0 answers
52 views

Are magnetic vortices capable of providing magnetic lensing when observed away from the poles

Magnetic vortices-(ESA cluster mission from observations November 2018)(article, ESA, science & exploration: 'Magnetic Vortices explain mysterious auroral beads'. An observer during Saturn's ...
Butch's user avatar
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0 answers
203 views

What is the large dim feature near the center of the first James Webb image (of SMACS 0723)?

I was intrigued by the large dim feature (highlighted below) in the center of the first James Webb image of SMACS 0723. Is anything known about it?
MVTC's user avatar
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If you could get up close to them, what nebulae would be the most visually impressive to your naked eye?

Pop cult sci-fi movies like to show nebulae as they appear in photographs, but to a live, real-time viewer: these dazzling, snazzy and amazing backdrops to spaceship flying in front of them in real-...
The_Sympathizer's user avatar
4 votes
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59 views

How are plage regions related to the density of medium and velocity FeII ions?

During a literature review (abstract), I found that the intensity of FeII (298.5 nm) ions in the last solar minimum was higher than the two previous solar minima 21 & 22. The velocity of FeII ions ...
Autodidact's user avatar
4 votes
0 answers
106 views

What exactly would the resolution of an exoplanet hypothetically imaged by using the Sun as a gravitational lens be?

This video talks about how by sending a spacecraft to around 600 AU and beyond, we would could use the Sun as a gravitational lens and take clear detailed images of exoplanets light-years away. What ...
user177107's user avatar
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4 votes
0 answers
80 views

From what distance could the Sun's planetary nebula be seen entirely with free eye?

When collapsing to a white dwarf, a red giant Sun would emit a planetary nebula. How far from the Sun would that nebula stretch at most? Also: At about what distance could you see the planetary nebula ...
Plutos Loyer's user avatar
4 votes
0 answers
67 views

Is it possible to use something besides emulsion to directly record the image of a nighttime object using a telescope?

The following questions have got me thinking. Is it possible to use Photolithography for telescope image sensor? Fresnel lenses for a makeshift Galilei telescope? Has anyone ever tried to make a ...
uhoh's user avatar
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4 votes
0 answers
70 views

K-correction vs resizing photometric bands

Is there a difference between a K-correction (see Wiki https://en.wikipedia.org/wiki/K_correction) and simply "resizing" the bands, e.g. the 2-10 keV x-ray band, with the redshift? I've read ...
theWrongAlice's user avatar
4 votes
0 answers
134 views

How did Michelson measure the diameters of jupiter's moons using optical interferometry?

In Betelgeuse: How its Diameter was measured (Chant, C. A., Journal of the Royal Astronomical Society of Canada, Vol. 15, p.133, Bibliographic Code: 1921JRASC..15..133C) the author says: The paper in ...
uhoh's user avatar
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4 votes
0 answers
56 views

How is the roll of the Hubble telescope around its axis and the dispersive direction(s) of it's spectrometer(s) managed?

Reading Dupree et al. 2020 Spatially Resolved Ultraviolet Spectroscopy of the Great Dimming of Betelgeuse (also in arXiv and summarized in Phys.org's Hubble finds that Betelgeuse's mysterious dimming ...
uhoh's user avatar
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4 votes
0 answers
127 views

Longest time after an image was taken when a new solar system body was discovered from it?

This answer to If there's nothing special about Pluto, why was it discovered so early? says: In fact, often objects are discovered to be in pictures from long ago, such as Orcus, discovered in 2004, ...
uhoh's user avatar
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3 votes
0 answers
29 views

What are the technologies needed to make deep space LIDAR competitive with RADAR? Any plans for tests, prototypes or "pathfinder" systems?

ProfRob's answer to Would it be practical to map out the Kuiper Belt and Oort Cloud via Radar? gives us a "sobriety check" on the idea. Citing an example of a 1 million watt transmitter at ...
uhoh's user avatar
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3 votes
0 answers
36 views

Can a meteor streak exhibit different colors denoting presence of more than1 element?

A meteoroid's elemental composition can be determined by the color it exhibits while burning in the earth's atmosphere which we also call a "meteor". However, is it possible that a meteor ...
Dhruv Nayak's user avatar
3 votes
0 answers
50 views

How do you calculate the reddening corrections for photometry?

I have photometric data from Gaia for a star and am trying to de-redden the colors. I need to find the reddening corrections for the photometry. I have photometry for G, BP, and RP. To start I am ...
anna's user avatar
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3 votes
0 answers
98 views

SExtractor parameters for identifying Star Forming regions

I am using SExtractor (Source Extractor) to identify Star-Forming regions in a galaxy. The problem is I am unable to choose the parameters required for it. SExtractor is just a tool to identify the ...
Abhinna Sundar's user avatar
3 votes
0 answers
81 views

Why would nitrogen or hydrogen outgassing from 'Oumuamua not be detected?

Some of the theories put forward to explain 'Oumuamuas behavior include it being a hydrogen or nitrogen iceberg. This could explain 'Oumuamua's non-gravitational accelleration as outgassing of ...
JanKanis's user avatar
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3 votes
0 answers
97 views

How will China's Xuntian space telescope use its Terahertz capability? THz Spectroscopy? Imaging? Something else?

An Update on the Chinese Space Station Telescope Project Hu Zhan, National Astronomical Observatories, CAS, KIAA, Peking University, On behalf of the CSST Team, ISSI-BJ Workshop: Weak gravitational ...
uhoh's user avatar
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3 votes
0 answers
79 views

Mega Telescope using gravitational lensing and interferometry

I have been thinking about this crazy telescope idea, but I am not smart enough to understand if it's technically possible. I understand from an engineering and practical point of view it's a long way ...
Adrian's user avatar
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3 votes
0 answers
90 views

How do you keep your astronomy computer precisely on time?

I have two laptops running astronomy projects but the clocks are imprecise. I set the specialpollinterval to update the time to windows time once a day 86400s. This eventually worked after I set the ...
user36093's user avatar
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3 votes
0 answers
45 views

What does "Secondary reflection from Didymos may allow imaging of the night side of Dimorphos" mean? Why useful? Imaged from where?

@ConnorGarcia's "impactful" answer to Why did they decide to hit Dimorphos in the retrograde direction rather than prograde; was it a "coin-toss" or were there implications for ...
uhoh's user avatar
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3 votes
0 answers
93 views

Source flux in Jy + noise computation, radio astronomy

I have an image of an extended source obtained with an interferometer (after imaging the uv-data). The image consist of a certain number of pixels, with unit of Jy/beam. Somewhere on the image is a ...
Jylu's user avatar
  • 61
3 votes
0 answers
60 views

Metric to estimate measuring accuracy

I need help/suggestions on which metric/approach to use. I am trying to estimate pointing precision by measuring the offset of the experimentally measured values from the real, theoretical values, ...
Falco Peregrinus's user avatar
3 votes
0 answers
78 views

S/N binning of 2D spectral galactic data

I have the 2D spectrum of the ellipical galaxy NGC 4697 taken by a long slit spectrograph. The x-direction (horizontal) corresponds to wavelength and the y-direction (vertical) corresponds to distance ...
trynerror's user avatar
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3 votes
0 answers
60 views

Is the Arid meteor shower the first to be discovered photographically?

@planetmaker's answer to How can Mercury's sodium tail be imaged? links to Ciel et Espace (Sky and Space) and browsing through I found this tantalizing beginning of an article (reading the rest ...
uhoh's user avatar
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3 votes
0 answers
30 views

How to find x-values of fourier-transformed correlation functions in velocity space?

I am trying to extract the kinematic parameters (rotation velocity, velocity dispersion, ...) of an elliptical galaxy by extracting the kinematical broadening function using the FCQ-Algortihm first ...
trynerror's user avatar
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