Questions tagged [observational-astronomy]

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

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What is a photoelectric scanner?

I am reading this article by Wing, Peimbert and Spinrad, where they mention the use of a photoelectric scanner. By searching online, I find that photoelectric scanners are used to scan punchcards, ...
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Weird object seen moving through space binoculars (irregular pattern) [duplicate]

I was looking up to the western sky with some very high powered binoculars. I am just grooming the sky looking at things I cannot see with my naked eye. I then run into this box like constellation ...
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Why would radio astronomers choose ¹³CO and C¹⁸O spectral lines instead of the most isotopically common combination?

Wikipedia's T Tauri explains that this system is an atypical example of T Tauri stars. It says: As typical for the young stars, all three stars of T Tauri system are surrounded by a compact disks ...
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How do we know that objects that appear in duplicate or triplicate, etc. due to strong gravitational lensing aren't actually multiple objects?

If we are looking at faraway objects, there is no parallax view, correct? So isn't there a chance that an object that appears multiple due to strong foreground gravitational lensing is actually ...
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How big would a telescope have to be to get a good look at the nearest neutron star?

It's my understanding of observational astronomy that the size of a telescope limits its effective angular resolution, which is why scientists needed to use radio telescopes all over the globe to look ...
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How does one think about optical depth in the context of gravitational microlensing? Is it measured or deduced from observations? Used for planning?

This excellent answer to Which studies prior to 2018 "claimed to find evidence of extragalactic planets in the Andromeda galaxy"? Which instrument was used? introduces the technique of "...
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Have interference effects (in space) ever been observed by a single instrument, as opposed to interferometry?

Not asking about: Interferometry can be done with multiple instruments who's light paths or signals are combined interferometrically, or even between different parts of a single aperture, e.g. What ...
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Looking for an interactive star chart

First, apologies; I understand this is like a software request over at Stack Overflow. I'm looking for a star chart for a friend that likes to stargaze while in his outdoors hot tub. He is at latitude ...
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When will Alpha Centauri A and B overtake Proxima Centauri as the closest stars to us?

There are 3 stars in the Alpha Centauri system: 2 large stars orbting around each other (A & B) and a distant Proxima Centauri (C) orbiting around both. Right now it just happens that Proxima ...
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Which studies prior to 2018 "claimed to find evidence of extragalactic planets in the Andromeda galaxy"? Which instrument was used?

After the first round of popular news items about the "first extragalactic exoplanet" discovery, CNET's Did astronomers find the first planet outside of the Milky Way? It's complicated ...
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Which University of Oklahoma research purported to "detect thousands of extragalactic planets back in 2018"? Which instrument was used?

After the first round of popular news items about the "first extragalactic exoplanet" discovery, CNET's Did astronomers find the first planet outside of the Milky Way? It's complicated ...
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After only one eclipse of its X-ray bright primary, how can astronomers estimate the first extragalactic exoplanet's period to be about 70 years?

Phys.org's Astronomers may have discovered the first planet outside of our galaxy links to Di Stefano et al. 2021 A possible planet candidate in an external galaxy detected through X-ray transit (...
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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 ...
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balmer alpha , beta line intensity [closed]

In different temperature environments, the intensity of the Balmer lines is determined by the Saha equation and the Boltzmann equation. What I'm curious about is as follows. How can we measure the ...
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Telescope/s functioning from underground mines

Theoretically and Practically, Can a Telescope function for the astronomer observed from underground mines? By "telescope" I mean the instrument used by astronomers to observe stars, planets ...
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By type, how far out do we have good star maps?

First off, these questions asked by others seem related, but each asks a slightly different question and neither have very good answers: How well have we mapped our local neighborhood of stars? ...
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What is the 'AT' astronomical catalogue? And the 'TXS' one? As in AT2019dsg and AT2019fdr?

I cannot find a site stating what the AT or TXS star/astronomy catalogues are, even though some AT and TXS 'events' have been in the news lately....
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What is Hubbles WFC3 "UVIS 47 G200" filter? What is it used for? How to find an example?

Extensive reading for 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? led me to ...
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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 ...
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Sudden spikes on the light curve of a Quasar from K2 mission

I obtained the optical light curve of 3C 273 QSO from the MAST repository off the K2 mission and plotted it by making the FITS into a CSV file through Pandas dataframe and plotting the obtained ...
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Which Venus scientists discovered the hole in the ozone layer?

After 21:00 in Venus: Earth’s Evil Twin or Just Misunderstood? (live public talk) from the JPL YouTube channel the person being interviewed "Sue Smrekar, Rocky ...
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Why is the Nancy Grace Roman Space Telescope's field of view shaped like a PacMan "ghost"?

The Curious Droid YouTube video NASA's Mega Hubble - The Roman Space Telescope illustrates the shape of the telescope's field of view and the outline has a smile or frown shape. For whatever reason it ...
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Farthest observed protoplanetary disk observed at radio frequencies? Catalog

This could be a naive question or maybe too easy to solve (I do not really know!). Brief context: I'm interested in a certain planetary system at $d \sim 300 \, \mathrm{pc}$. It would be really nice ...
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Why Nyquist Sampling Rate depends on Bandwidth and not max frequency?

Is the Nyquist sampling rate same for different bands if those bands have same bandwith? E.g. Would the Nyquist Sampling rate be same for 1000-1400 MHz band as for 100-500 MHz band because both the ...
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Shortest and longest wavelengths at which exoplanets have been resolved from their primaries?

Phys.org's Radio signals from distant stars suggest hidden planets summarizes the Nature Astronomy paper The population of M dwarfs observed at low radio frequencies (also in arXiv) but this is an ...
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Obtaining the Flux-Time plot for a Quasar

As a follow up question to Obtaining the Light curve of a a Quasar, I wish to know how to obtain a Light curve for a quasar observation like this data set over here. Is there an archival repository ...
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rms noise, confusion and dynamic range in radio images

I have been trying to understand imaging in radio astronomy. Below are some of my questions related to it and my understanding of their answers. I am not very confident about my understanding of them ...
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How exactly was Giovanni Cassini able to measure the distance to Mars?

Recently learned that Cassini was able to calculate the distance to Mars quite well using parallax in 1671. I was surprised, since even at opposition of Mars, the parallax (with respect to the Earth's ...
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Why was there a gap in exoplanet detection in 2015?

The question How has the number of known TNOs evolved over time? contains a link to this image: Number of extrasolar planet discoveries per year through April 2018, with colors indicating method of ...
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Can Mercury be seen from the 60th parallel north on Earth? Shetland, Faroe, Norway, St Petersburg, Alaska

I'm originally from a city in Spain which is 40 degrees north, and I used to watch Mercury (naked eye and telescope) every time I had the opportunity, that is, when Mercury was at maximum elongation ...
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How exactly does NEOSTEL's fly's eye telescope's secondary mirror array split the primary beam among sixteen cameras?

Wikipedia's NEOSTEL says: The Near Earth Object Survey TELescope (NEOSTEL - also known as "Flyeye") is an astronomical survey and early-warning system for detecting near-Earth objects sized ...
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6 votes
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How does the Hubble Space Telescope measure the speed of the wind inside Jupiter's Great Red Spot?

Space.com's Jupiter's winds of change show increased storm speeds in Great Red Spot and Hubblesite.org's Hubble Shows Winds in Jupiter's Great Red Spot are Speeding Up both link to the recent open ...
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2 votes
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Query Gaia by star name

I am attempting to query Gaia programmatically in python to get certain properties for specific stars. I can write a query which obtains some properties, but only for all stars, not a set of stars or ...
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How to calculate S/N in galaxy absorption spectra?

I want to calculate the S/N of an galaxy absorption spectrum. I therefore chose a part of the spectrum which contains very little to none absorption features and should be only made up of noise and ...
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How was the recently publicized Hubble image of a distant galaxy showing clearly resolved lensed in an Einstein ring produced? When was it produced?

The 24-Sep-2021 NASA Goddard video Einstein Ring Spotted by Hubble and it's Goddard Media Studio's page Einstein Ring Spotted By Hubble discuss the image, but don't really give credit to how it was ...
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Was the Nobel prize for gravitational waves handed out based on a hand-drawn theoretical curve? Has the data been fit more rigorously now?

In Sabine Hossenfelder's November 2019 video "Have we really measured gravitational waves?" (transcript, video), Sabine mentions the now famous image of the generally agreed-upon-to-be-very-...
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8 votes
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Is Carl Sagan's famous "snowflake" quote correct?

“The total amount of energy from outside the solar system ever received by all the radio telescopes on the planet Earth is less than the energy of a single snowflake striking the ground.” ― Carl Sagan,...
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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 ...
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What kind of space telescope could best take advantage of orbiting far from the Sun?

While Hubble has provided an astounding amount of science from low Earth orbit, one of the reasons it was put in LEO was to be readily accessible for service and upgrades by the Space Shuttle. JWST ...
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How can we know if a star which is visible in our night sky goes supernova?

Let's say there is a star about 3000 light-years away from earth visible in our night sky. If this star were to go supernova tomorrow(not relative to earth's night sky), we would know about it 3000 ...
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23 votes
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Why can't observatories just stop capturing for a few seconds when Starlink satellites pass though their field of view?

Given that the positions and trajectories of the Starlink satellites are public, why can't the telescopes just ignore the photons they receive when the satellites pass through the field of view? It ...
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1 vote
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Curated dataset of labelled images for NEO detection

I am looking for a dataset of images. Some images should contain NEO's (1 or more), others should not. With the dataset, there should also be an accompanying file, of which should contain 'labels'. ...
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How, precisely, do radio astronomers detect (and record) the phases of waves for interferometry?

Interferometry is always in the news, and at radio frequencies it has been for a long time... The popular press always talks about directly 'interfering' two waves as they come in, but can they tell ...
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2 votes
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Why would a quantity like the 'Hubble contrast' be squared, then have its square root taken?

From Sabine Hossenfelder's recent video, New Evidence AGAINST Standard Cosmology: And her source.... Figure 2. The variation with increasing void radius of the variance of the Hubble parameter, the ...
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How to remove redshift from galaxy spectra in Python?

Hello I extracted a spectrum from the central region of the 2D spectrum of the major axis from NGC 4697 (I just took a central row in the 2D data set, see this question for more information: How to ...
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How to calculate an infrared SED from the specific intensities?

I have values of total infrared fluxes (SED) in literature expressed in Jy (Jansky) for galaxies. I want to assure that my infrared radial profiles of the same galaxies in MJy/sr (and other in Jy/...
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Optical Observation Calls: How and Where to apply for optical observations?

How and Where to apply for optical observations to support a research project? I'm involved with research in multifrequency astrophysics and my next project will demand optical (spectroscopy) ...
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What two "little observatories" run by a university in Chile and "by Germans" are near the future site of the Extremely Large Observatory?

Brady Haran is known for the Numberphile and Periodic Table of Videos YouTube channels but also does Deep Sky Videos. In the video for the Extremely Large Telescope Haran stands at the site of the ...
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Determining masses from radial velocity curves of eclipsing binaries

Is the statement From radial velocities or astrometry for eclipsing binaries, one obtains masses. wrong, because only minimal masses can be obtained?
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What does lowercase 'beta' mean in this graph of radio-emitting galaxies?

Correlation between the mass of the galaxies (X-axis) and the difference of their radio emissions at different radio frequencies (Y-axis). Each symbol represents an individual galaxy. The image of an ...
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