Questions tagged [observational-astronomy]
Questions about the techniques and practice of observing the night sky.
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Light or neutrinos graze or pass through the Sun and arrive at Earth - need an expression for Sun's gravitational effect on observation direction/time
Skyfield's Github has discussion Jupiter hiccup #815 which then links back to to Non-physical gravitational deflection corrections for Solar System bodies #734.
The script and plot from #815 are shown ...
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iphone & remote control tripod & stellarium
I am curious if anyone has success using one of those (relatively) inexpensive remote controlled (motored) tripods designed for iphones, and astrophotography.
These little iphone tripods and motorized ...
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What is the horizon-ecliptic angle formula?
For an observer in a city with latitude 35°, at what sidereal time is the angle that the ecliptic makes with the horizon equal to the angle that the equator makes with the horizon? What is the angular ...
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How does one convert between Modified Julian Date (MJD) and a standard (mm/dd/yr, hr:mm:ss)
I looked online and couldn't see an actual formula or anything, so I figured I'd ask here.
If I had an MJD like the following: 59145.6678
How would I convert that to a month, day, and year with the ...
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How would a person know if a planet is orbiting a binary star?
I read in Neil deGrasse Tyson's book Astrophysics for People in a Hurry that scientists can tell if a star has a planet orbiting it because the light appears to shake.
So if in the case of a binary ...
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Natural line width from absorption lines
Emission lines have a certain natural width. Due to the uncertainty principle systems that spontaneously decay or produce radiation have a fundamental energy blur, and their radiation has a ...
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Calculating background photons from flux levels
For a project, I'm trying to calculate the photon flux from the zenith galactic background that a sensor would see. From ScienceDirect I get a value of $2.6 \times 10^{12}$ photons sr$^{−1}$ s $^{−1}$ ...
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What is the mathematical condition for the statement: "gravitationally bound"?
When talking about galaxy clusters there is the frequently used phrase "gravitationally bound", f.e. we are gravitationally bound to our neighbor galaxy the Andromeda Galaxy. But how is this ...
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How do astronomical spectrometers measure spectra from single stars separately, without contamination from all of the nearby stars?
I am currently looking into light spectrometers, and I noticed that the ones I found had a similar problem; when the light reaches the spectrometer, it mixes giving a broad range of light wavelengths.
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Different types of line broadening in stellar and galactic spectra
When analyzing stellar and galactic spectra with spectrographs, the spectral lines get broadened from the instrument. Why do the spectral lines get broadened after the light moves through the ...
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Has "crescent-twinkling" even been demonstrated or at least calculated/predicted? Any "twinkleometer" data for Venus out there?
My new answer to Why does Venus flicker? addresses something that I find particularly interesting; Venus can be an incredibly thin crescent at times, and even a 1 arcminute large thin ring with an ...
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How does the James Webb Space Telescope achieve a focal length of 131.4m?
How does the James Webb Space Telescope achieve a focal length of 131.4m ?
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Time and space travel as applied to expanding space and the ratio of/between time and distance
If a place is 500 light years away, then I set out to this place, then is it true to say that, the place which I set out from, will be 750 light years away from my destination, once I have reached it?
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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-...
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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 ...
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"To date we have covered 624 square degrees of sky near to and interior to the orbit of Venus" meaning wrt Asteroid survey Interior to Earth and Venus
CNN's October 31, 2022 ‘Planet killer’ asteroid spotted hiding in the sun’s glare links to Sheppard et al. (2022) A Deep and Wide Twilight Survey for Asteroids Interior to Earth and Venus. The ...
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How do astronomers calibrate the intensity scale of their spectrometers?
Discussion on Strange bump in solar spectrum taken with home-made spectrograph made me wonder: How do astronomers calibrate the intensity scale of their spectrometers? I mean, how to take in ...
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Strange bump in solar spectrum taken with home-made spectrograph
I am an astronomy teacher, and made some kind of spectrograph with a difraction grating, a 3D printed slit, water pipes and a reflex camera. With a group of students we got this picture of the solar ...
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Does JWST have the largest bandwidth of any telescope?
If the longest and shortest wavelengths that JWST can focus are 28.3 and 0.6 microns respectively, then it has a bandwidth (max/min) of a factor of about 47.
That's a lot, and of course it needs ...
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Is pointing a telescope at a random place a viable astronomical strategy?
Recently I happened to be on the MAST portal, looking at jwst data. I happened to come across 2 interesting targets, “random place” and “another random place”
This got me thinking. It’s almost ...
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Why are most cosmic rays positively charged? Has anyone figured this out yet?
It is by now very common knowledge that the vast majority of (known) cosmic rays are protons, alpha particles and such, yet I cannot find in my recent reading any discussion of why this might be, or ...
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Can astronomy determine the days of the week [closed]
Can any day of the week be identified by only observing the stellar bodies without calendars nor satellite?
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Which are some little known catalogues whose objects can be observed during the night sky?
We all know about the Messier catalogue. Little know or have heard about the Melotte catalogue. I am in search of those rare catalogues apart from Messier, NGC and IC with objects/sources that aren't ...
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Which citizen science occultation experiences were done in the late 80's in the US? With what results?
The news story "A star eclipsed by an asteroid in France this week-end: how and why scientists ask you to observe it" (in French) relates how people were are asked to look at the occultation ...
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Is there any method that enables us to observe the 3D large-scale spatial distribution of the dark matter?
Can we get the three-dimensional spatial distribution of dark matter through gravitational lensing?
If not, is there any other way?
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How do I calculate my desired distance of mirror from screen?
I plan on using flat mirror projection, among other methods, to view Tuesday's partial eclipse.
How do I calculate the distance my flat mirror has to be from my screen in order for it to cast a sharp, ...
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How tall are the pillars of creation? (angular and physical) How bright are they? [duplicate]
NASA's October 19, 2022 NASA’s Webb Takes Star-Filled Portrait of Pillars of Creation shows a sparkly and beautiful infrared image of the Astronomical elephant trunks known as the Pillars of Creation.
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Time of comet at perihelion query
In Practical Astronomy With Your Calculator Or Spreadsheet by Duffett-Smith and Zwart, the authors write (in relation to calculating cometary positions):
The longitude of the comet is not usually ...
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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 ...
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First satellite of an asteroid (or double asteroid) ever imaged by delay-Doppler radar?
In comments about my previous bounty on the Space SE question Which deep-space spacecraft flew closest by Earth during a gravitational assist?, I started to look at the Galileo mission and ran across ...
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Why did they decide to hit Dimorphos in the retrograde direction rather than prograde; was it a "coin-toss" or were there implications for observing?
CNN Space and Defense Correspondent Kristin Fisher does a really good job of summarizing the current state of the Double Asteroid Redirection Test early observational results for general public ...
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Other than Lomb-Scargle Periodograms and String Length Minimization, what other methods can be used to find the period of unevenly spaced data?
I'm doing some research into how different methods of finding the period with unevenly spaced data compare with each other. So far, I've looked at the Lomb-Scargle and String-Length Minimization. I ...
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moving light with a fading pulse, very bizarre
October 9th southeast of Denver about 6 miles, looking northwest in the sky approximately 10 inches to the left of Alkaid, a bright light, what at first glance might have been a star, began moving ...
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Do these results mean that I have found this exoplanet?
Yesterday I was going through the TESS mission data on mast portal and after applying some filters I found some data. I started analyzing that data using the lightkurve library.
plot without using the ...
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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 ...
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How to find a direction given the sunset
If one is situated at 50° latitude (meaning north hemisphere) and looks at sunset in the evening, by how many degrees you need to turn leftwards to find the meridian that goes through the point you ...
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Recommendation for green laser pointer for 6" Orion SkyQuest; one integrated with finder or a separate laser added to current configuration?
I would like to replace the default finder scope on my 6" Orion SkyQuest with one that incorporates a green laser.
Do such things exist, and if so, what should I look for in the laser ...
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Are apparent magnitudes corrected for extinction at zenith?
For example, according to Google, the apparent magnitude of the sun is $-26.74^m$.
Is this the apparent magnitude viewed through Earth's atmosphere when the object is at zenith?
(Assuming most ...
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Satellites or UFOs? [closed]
Last night in Greenville MI at around 9:15pm-9:25pm (I don't know the exact time) I saw what appeared to be a satellite appear and disappear and then a few seconds later another possible satellite ...
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The Interpretation of Uncertainty Map of NEO in Minor Planet Center page
I am an observational astronomer. I have just started with the observations. If any of you use MinorPlanetCenter website to get the ephemeris of a possible NEO in the NEO confirmation page, there is ...
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Has NASA released any JWST images of Trappist-1? If not, why?
According to JWST weekly schedules (found here), the Trappist-1 system was among the telescope's targets during early July.
The only JWST image of an exoplanet in the Trappist-1 system that I've ...
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SDSS and DESI - How much variation in sky location?
I am trying to cross match a catalog derived from SDSS-MaNGA(self) with a catalog derived from DESI (Yang+2021). I am using TOPCATs Sky Algorithm, based on RA and Dec similarities to perform the ...
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Fitting isochrone on color magnitude diagram obtained from growth india telescope for M67
I was doing a project where I had to cross-match Panstarrs1 data (I took green data from there), with growth India telescope data (it is providing data red band) for NGC2682(Messier 67). After gaining ...
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How often and for what reasons does Hubble use two different instruments at the same time?
A comment under this answer to ** links to Hubblesite.org's Hubble Shoots the Moon The image, its description and credits are shown below.
As explained, the purpose of the observation was to record a ...
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Can we see atomic positronium lines in space? What could be learned from it and what are current challenges to doing so?
This answer to Have we detected spectra of exotic atoms in stars?1 currently ends:
Estimates for observing lines corresponding to transitions between different bound states of positronium are not ...
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How did this artefact end up in the SIMBAD sky map?
I was randomly looking through the SIMBAD sky map when I came across this artefact. It looks like the projection of a telescopes secondary mirror mount to me but I am wondering how that would end up ...
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What is the v sin i parameter?
In the August 2021 preprint by WeiJia Sun et al. Exploring the stellar rotation of early-type stars in the LAMOST Medium-Resolution Survey. II. Statistics there is histogram plot with the caption:
v ...
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Which (if any) space telescope would have worked longer if it hadn't simply run out of helium?
In this answer to Why is the hot part of Webb's MIRI cryocooler in the 300K area? and comments below discusses the helium refrigerator used for cooling JWST's Mid-Infrared Instrument or MIRI.
A ...
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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 ...
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Have we detected spectra of exotic atoms in stars?
I was reading this wikipedia article on positronium (a type of exotic atom) and noticed it mentioned that positronium has a spectra (of course).
So naturally this makes me wonder, have we looked at ...
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