Questions tagged [observational-astronomy]

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

74 questions with no upvoted or accepted answers
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83 views

Anecdote of an astronomer looking for correlations in antipodal pairings of stars; what am I remembering?

The question Are the stars distributed in uniform distribution, on the celestial dome, with respect to brightness? brings to mind a different study that I vaguely remember hearing about a while ago, ...
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105 views

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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67 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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101 views

Which astronomer set his beard on fire because he left the cap off his telescopes finder?

There is a famous story of an experienced astronomer setting his beard on fire because he left the cap off his telescopes finder. I know it's said to be true of Galileo, but I thing it's relatively ...
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33 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 ...
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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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1answer
225 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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49 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 ...
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167 views

Are quasars simply AGNs that are viewed from a particular angle?

I found the picture below in an answer to the post "Was the Milky Way ever a quasar". The picture is published on a website belonging to "NASA/IPAC Extragalactic Database". In the answer that has 16 "...
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140 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 ...
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71 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 ...
3
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1answer
133 views

How long do hot X-ray sources last?

Some X-ray sources in nebulae are caused by hot materials in the millions of degrees that formed in supernovae. What's the cooling rate of this stuff? How long does it stay this hot? If we would take ...
3
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54 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 ...
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37 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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98 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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2answers
73 views

Position of a star on the HR diagram

Does the position of a star on a HR diagram depend on the magnitude system/color index used? I made a CMD of a particular cluster using HST WFC3/UVIS data, and when I plotted $F275W vs F275W - F606W$...
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59 views
+100

Will the Magdalena Ridge Optical Interferometer be able to image extended objects like the surface of the Moon?

Inspired by several questions: When will a moon landing site be visible via telescope? Could the E.H.T. produce an image of the human artifacts on the moon? Picture of equipment left on the Moon? ...
2
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35 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 ...
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52 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 ...
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106 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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0answers
42 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 ...
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97 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 ...
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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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59 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 ...
2
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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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39 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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58 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 ...
2
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50 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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0answers
66 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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111 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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0answers
63 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 ...
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41 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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47 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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0answers
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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79 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 ...
2
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0answers
30 views

How to find out which Messier objects are in the Kepler/K2 fields?

I am interested in figuring out which Messier globular clusters (plus 47 Tuc and Omega Cen) are in the Kepler/K2 fields, both fields that have already been observed and any that will be observed. ...
2
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0answers
43 views

In SETI has anyone calculated an estimate of the mean time between observations?

So the Drake Equation, proposed by Frank Drake, is often cited as a means to estimate the number of intelligent civilizations that exist in the observable universe. Initial calculations by Drake ...
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103 views

Given a collection of pixels, how to deduce the flux from them?

I've obtained the coordinates of brightest pixels from different images (.fits files) using Python. I want to get the flux of each pixel. How do I go about finding out the flux?
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63 views

About bias in sidereal time (used by astronomers)

I came up on this stanza in various websites when looking up on experimenter bias. It says "If the signal being measured is actually smaller than the rounding error and the data are over-averaged, a ...
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0answers
130 views

Uncertainty in the FWHM (IRAF)

I measured the FWHM (Full Width at Half Maximum) of several emission lines using SPLOT in IRAF, and now need to calculate the uncertainty. How can I do that?
2
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1answer
72 views

How well can the Sun's surface be resolved by an observatory?

There's no lack of photons, how well could a telescope resolve Sun spots and other surface features of the Sun? How would a high resolution Solar (space) telescope differ from for example Hubble which ...
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25 views

What was the field of view of the Ohio State University Radio Observatory of Wow! signal fame?

This answer to Did comets 266P/Christensen or P/2008 Y2 (Gibbs) cause the Wow! signal? points out that the comets in question were nowhere near where the radio telescope was pointed. Wikipedia says ...
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1answer
68 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 ...
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0answers
15 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 ...
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48 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 ...
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50 views

How can I get the exact time of each zodiac every year?

I want to make a calculator for Chinese New Year calendar. There is a rule that a leap year happens if the eclipse happens before each zongqi (equivalent to the middle of zodiac sign, ie. 15º, 45º, ...
1
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1answer
76 views

How to calculate parallactic angle from a fixed alt-az position?

Say we have an observer at a specified latitude and longitude on Earth who would like to observer a specific fixed alt-az sky position (rather than RA and dec), for example to look at geosynchronous ...
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20 views

How to determine Az-El pointing of a telescope spiral scan?

I am writing a simulation of an automated telescope observation program. One part of this is to run a spiral scan pattern on and around objects of interest. I would like to tile this scan pattern so ...
1
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1answer
36 views

How can I check if we can observe a certain star (given its equatorial coordinates) from a certain location on Earth (given its DMS coordinates)?

I am given the equatorial coordinates of a star (e.g. Sirius has RA: 6h45m8.9s and Dec = -16°42'52.1"). Now my question is: can we observe this star from a specific location on Earth (e.g. from ...