Questions tagged [observational-astronomy]
Questions about the techniques and practice of observing the night sky.
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questions with no upvoted or accepted answers
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What is the farthest reported distance from observer from which a solar system body has occulted a star?
I originally wrote "...farthest distance from Earth..." but changed to "observer" in case the occultation was observed from a space telescope. It may not matter much but I didn't want to over-...
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77 views
How do radio astronomers avoid having their receivers burned out by ground-imaging radar from satellites?
After about 34:00 in the 9th press conference of AAS 235, radio astronomer and NRAO's spectrum manager Harvey Liszt talks about Radio Astronomy in a New Era of ...
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91 views
How do magnetic fields mess with astronomers' observations?
Does anyone else watch 'Dr. Becky' on YouTube?
Her March 'Night Sky News' video, subtitled 'The biggest black hole burp, a wobbly Milky Way & Betelgeuse is brighter' says that...
"Dust and ...
4
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140 views
What's the highest frequency that's been imaged by a radio telescope?
In this answer to Should we update definitions and remove the 100 GHz hard limits on radio astronomy related tags? I wrote the following partial answer:
Yes, there are plenty of dishes that focus ...
4
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108 views
Is 486958 Arrokoth (2014 MU69 aka Ultima Thule) the only solar-system object determined to be binary by occultation?
The asteroid 486958 Arrokoth was discovered to be binary by astronomers lugging a bunch of telescopes around (I think) camping with them. The timing offered additional astrometry for the orbit ...
4
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125 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. ...
4
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36 views
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 ...
4
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67 views
What actually determines the angular uncertainty of the source of a detected gravitational wave?
This answer and comments got me thinking. Astrometry 101 tells us that while we can use $\lambda/D$ as an estimator of resolution, if we can assume a point source we can determine the centroid or ...
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40 views
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 ...
4
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80 views
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 ...
4
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1answer
244 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 ...
3
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Hello again, Barlow Lenses
I am debating if I should buy a 2x Barlow Lens. My telescope, a go-to Meade star navigator, has an aperture of 114mm, focal length of 1000mm and I currently have a 9 and 26mm eyepieces. I want to see ...
3
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51 views
Short term changes in celestial coordinates of stars
The right ascension and declination of stars change on a day to day basis. Some of the changes are quite large. The right ascension of Polaris, for example, changes by more than a degree over the ...
3
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151 views
Are Saros series separated by “40” in numbering related in any way?
Can anyone help with this question? My question arose from an eclipse related observation that I made while looking into lunar Saros series 129. It is the Saros series number for the lunar eclipse ...
3
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70 views
Creating planispheres from the perspective of nearby objects
I'm attempting to create a set of [reasonably] astronomically accurate planispheres from the perspective of observers positioned at the north or south poles of various nearby celestial objects. So ...
3
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56 views
Linear motion in the equatorial frame
I would like to calculate how the RA/Dec changes when an object has an apparent linear motionin the equatorial sphere. For example, more or less what an artificial satellite would do in a circular ...
2
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28 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 ...
2
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21 views
Software for simulating/calculating a known EMW pulse propagating in ISM, including dispersion, scattering, etc
Could you please let me know, if there is any software/code/tool for simulating/calculating the result of a short EMW pulse (waveform is exactly known) propagating in the ISM for long distance, ...
2
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74 views
How did we measure the mass of the universe?
In an wiki article, observable universe, it was mentioned that,
Mass (ordinary matter) 1.5×10^53 kg
I wonder how did we measure the mass of our observable universe?
2
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28 views
How thick are the intergalactic filaments?
Recently, in October, news came out about the faint intergalactic filaments finally being 'found'.
Then, in June, astronomers announced that these things had enough normal matter in them to solve the '...
2
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32 views
What observatories provide data similar to USNO?
USNO (the United States Naval Observatory) generates positions for the celestial bodies (planets, moons,stars) and provides them in the form of .bsp files and their ...
2
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52 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,...
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26 views
Detect sources near image edge with python photutils
As my question suggests, I 'm trying to use a python library photutils in order to detect sources from MUSE cube. MUSE (Multi Unit Spectroscopic Explorer) is an ...
2
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134 views
Betelgeuse problem
I've been given this problem:
(a) A telescope is required to image an area of the sky of angular size 1 arc second onto a 10 mm square CCD. What focal length must the telescope mirror have to fully ...
2
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48 views
Why do all the stars near this comet show up as four separate dots in a row?
After seeing this tweet about our not-so-new but at least newly-discovered "mini-moon" I scrolled down and saw the tweeted image below.
Since the object is the known short-period comet 114P/Wiseman–...
2
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61 views
Field rotation and observing the moon
For stars, field rotation can be accounted for with an equatorial mount aligned with the Earth's axis and turning at the correct rate.
Since the Moon's orbit is on a different axis then the Earth's ...
2
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1answer
160 views
Precision in the measurement of the distance to the Sun
How precisely can the distance to the Sun be measured? Wikipedia says the distance to the Moon can be measured upto millimeter precision. But Wikipedia article on distance to the Sun says only about ...
2
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28 views
Why does the star formation rate correlate with the total stellar mass in star forming galaxies?
The so-called "Main Sequence" of star-forming galaxies (e.g., Brinchmann et al. 2004; Noeske et al. 2007) clearly points to a linear relation between the stellar mass of galaxies and their star ...
2
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106 views
We should be seeing more than 59% of the Moon
It is said that we see about 59% part of the Moon due to libration. However we must be seeing more than that. My logic is as below.
Since the Moon's orbit is inclined to the plane of Sun-Earth by 5 1/...
2
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104 views
How are small objects automatically identified and their locations determined in digital images?
I have a large quantity of old digital images of low energy electron diffraction (LEED) patterns that I must process to identify and locate small, sometimes elongated gaussian-like blobs of a few ...
2
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42 views
Any night sky image databases
I was wondering if there were any available databases for photos of the night sky. It doesn't have to feature pictures of any particular star, just has to be a large collection of photos from the ...
2
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54 views
Can the patterns in the CMB be detected by off-the-shelf antennas/sensors?
I recently wrote a paper (will attach soon if feasible) for an astronomy class that analyzed the usefulness of the Cosmic Microwave Background as a static reference for attitude determination. The ...
2
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131 views
What is the meaning of ellipticity of a galaxy being more than 1?
I was recently doing a project on calculating ellipticities of galaxies using SDSS data. I downloaded the stokes parameter values (q and u) from data
$e = 1 - \frac{b}{a} = 1 - \frac{1 - \sqrt{Q^2 + ...
2
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47 views
Requirements for an amplifier and filter for a horn antenna-based 21 cm radio telescope?
We are looking into the possibility of building a low budget horn antenna for detecting 21 cm hydrogen line radiation (~1420 MHz) and and possibly measuring its spectrum.
What are the types of ...
2
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112 views
How was the astrometry of the famous 1919 solar eclipse confirmation of General Relativity calibrated and verified?
The new New York Times article The Eclipse That Made Einstein Famous describes several events and discussions on the hundred year anniversary of the the 1919 solar eclipse and verification of the ...
2
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25 views
Asteroid identification in fits image
I have a fits image, and I need to identify an asteroid. What characteristics do I look out for?
2
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61 views
How far away was the binary black hole that produced GW170729?
GW170729 was gravitational wave signal's detected by the Virgo and LIGO detectors. I read the following in a news report:
Known as GW170729, in accordance with the date of its discovery (in US
...
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35 views
Why do default coordinates from IR-optical observatories are usually not trustworthy, while from radio interferometers they usually are?
I have noticed in my experience that the coordinate solution within the headers of default reduced images from radio interferometers are commonly trustworthy to the arcsecond or less. From IR and ...
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40 views
How to compare the observation with the theoretically predicted result?
On the Wikipedia Article on “Geodesics in general relativity”, it says the following: “Thus, for example, the path of a planet orbiting a star is the projection of a geodesic of the curved 4-D ...
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60 views
What are the procedures and protocols to use with Gauss'method and personal observations?
I would like to use the Gauss' method to determine the orbit of planets of solar system.
I would like to calculate their orbits with personal observations.
What is the methodology/procedure/protocol ...
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76 views
Is there any formulae to calculate whether the sun will depress 18 degrees or more below the horizon on a certain day / location?
I'm trying to code a piece of software which will calculate some times for me that would greatly help me in my day to day but none of my formulae work if the sun doesn't go at least 18 degrees below ...
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54 views
What's the profound reason(s) why the star formation rate drives the scatter of the mass-metallicity relation in galaxies?
Since decades it's well known that a correlation between stellar mass and metallicity (Z; both stellar and gas-phase Z, but here I focus on the gas-phase Z) exists (e.g., Tremonti+04; analysis of >...
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74 views
Asteroseismology; recordings of star vibrations duration and data availability?
A short video titled "Why Tess is recording the "sounds of stars" at the bottom of the page of the BBC News article Planet-hunter launches from Florida gives a short description of Asteroseismology by ...
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150 views
How to trim CCD overscan and amplifier turn on/off regions
I have begun reducing images I collected with a telescope and CCD detector. I read in the the "Handbook of CCD Astronomy" by Howell that I need to trim overscan regions (as well as possible amplifier ...
2
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44 views
Finding individual band magnitudes: Why and how is the integration of individual flux values for each wavelength used?
What differentiates the distance modulus equation to find the difference between two apparent magnitudes? For example,
$$ m_1 = -2.5\cdot log_{10}\left(\frac{F_1}{F_2}\right) + m_2$$
leads to the ...
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50 views
How the observed deuterium abundance constrains big bang nucleosynthesis?
I know deuterium can be used as a good tracer to constrain the big bang nucleosynthesis. But can anyone tell me the in details how this is actually done?
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49 views
Any method to apply inverse TPoint model?
I have an automated telescope that I have written some software for. I am currently using TPoint to compensate for some of the irregularities of my system.
However with TPoint you apply an offset (...
2
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93 views
Was the Crab Nebula to the southeast of Zeta Tauri 1,000 years ago?
I've been reading about SN 1054 and how most professional investigators believe that it is the Crab Nebula today. But the wiki article has this to say:
The location of the guest star as "to the ...
2
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60 views
Visible Light Ground-Based Solar Observatory Data Archives?
I'm mainly searching for the best(or good/significant/important) solar data archives via ground-based telescopes. If I'm not being very straightforward...
Say if I wanted high quality/resolution ...
2
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82 views
Where can I find raw text, ascii, or binary data from the GALEX satellite?
I am looking for stars in the GALEX data through the GALEX data using GALEXview and plugging in their Henry Draper Numbers
http://galex.stsci.edu/galexview/
But the task is tedious by hand. Is there ...
