Questions tagged [observational-astronomy]
Questions about the techniques and practice of observing the night sky.
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How to convert flux to flux density for a synthetic spectrum?
I have several model SEDs generated by the CLOUDY spectral synthesis code. The data is formatted with one wavelength column and one flux column. I wish to perform Hubble synthetic photometry on these ...
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Calculate change in spectral line intensity for a change in temperature
I am trying to do some simple modelling of spectral line emission. I am starting with some ALMA observations of a protoplanetary disk, where the emission from a particular molecule at frequency 344GHz ...
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Should you include aberration effects during low Earth orbit observations?
I am working on calibration of some observations of low Earth orbit satellites and I am wondering should I include aberration effects? My logic is that diurnal aberration would have neglegible ...
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Formula for rate of expansion of the universe vs distance?
How does the distance $r$ scale with the expansion of the universe?For example if $r_{o}$ is the distance between us and a galaxy and $V(r_{o})$ is the rate of expansion of the universe at that ...
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Population growth of black holes [duplicate]
As any population, the population of black holes is found by the population growth equation:
$\frac{dB(t)}{dt} = c(t)B(t)-d(t)B(t)$.Which are $c(t)$ and $d(t)$ for Black holes?
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Where can i find dark frames in the ESO archive?
I am doing an image reduction with data from ESO but I can't find dark frames when I download the zip-folder even though I downloaded the associated callibration files. The image reduction I am doing ...
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If 42000 Starlink satellites interfere with telescope observations from Earth would someone observing from another solar system detect them too?
SpaceX's Starlink constellation could place up to 42000 satellites around the Earth. Would aliens with their own telescopes notice them? They would be about 150 km apart and could reflect light of ...
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Why is the H-alpha line slightly shorter in wavelength (656.28 nm) in air than in vacuum (656.46 nm)? Shouldn't it be longer?
Perhaps this is a question better suited for Physics SE, but since the H-alpha line is so important in astronomy, I'm posting this here....
I would, naively, assume that wavelengths would be longer, ...
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Space-based radio telescope array
I’m wondering about the abilities of a technology: You may have heard of the Square Kilometer Array. The array is focused by adjusting the timing of the individual antennas.
Q: Could this array be ...
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Astro-filters for the solar system
I’m looking for set of filters for my telescope. Something for the solar system. Can you say me what is the best choice?
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How can the new moon set before the sun, as will happen in some locales on November 13, 2023?
I have somewhat of an interest in sighting the new moon. I recently heard a lecture by someone who had written a program to provide the conditions for the first new moon sighting for any location for ...
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Which place in the world should be best for astronomy with an optical telescope?
Would it be somewhere in a desert a long way from water and mist, or high on a mountain above the lower atmosphere? Where is the best location in theory or in practice?
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Are there plans to detect life on Earth from the outer solar system?
This has been kicking around in my head for a while. We've been detecting planets for decades by observing regular dips in starlight from many light years away as a planet transits its host star. I've ...
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Do the discs of observed solar systems have random orientations?
Is there any bias in the orientation of solar systems?
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How do eyepiece mm values equate to telescope tube extension mm values?
I'm trying out a DSLR on my Celestron 70EQ refractor telescope with a DSLR T-ring.
The first try didn't magnify very much, and I learned that I need to extend the focus length to magnify the image; I'...
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For what period of time can planets be viewed from the North Pole as just being there?
I would like details on observations (since North Pole is not possible, approximately around the North Pole) which tell us for how long are planets visible from the North Pole?
I understand that ...
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S0-2 (S2) Diameter/Radius
I'm a student, I am doing an investigation about S0-2. My idea was to take the wavelength that emanates from the star.
When I saw the data from Science magazine I found a problem that was that the ...
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Gas mass and velocity in galaxy
I was going through the SPARC data on galaxies (http://astroweb.cwru.edu/SPARC/)
The velocity of gas in the SPARC data is in http://astroweb.cwru.edu/SPARC/MassModels_Lelli2016c.mrt
The gas velocity ...
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Why is plasma used to deposit aluminum on the VLT's four large mirrors?
In Tim Scott's October 2, 2023 video "The largest telescope that will ever be built*" (note the asterisk, link below) there is a discussion of the "re-silvering" of the four main ...
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How to find the constellation in which the sun is located using the night sky map?
The following sky map was given as part of practice problems in my Astronomy course
The moon is in its first quarter phase. I am supposed to find the approximate date and time of the year in which ...
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is there any site with historical radiotelescope data about observations 21 cm line Hydrogen (1.42 GHz)?
I am looking for an open source that contain historical raw data or (meta)data about historical observations of the 21 cm line hydrogen made via radio telescopes.
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calculating mass of galaxy from luminosity
A very elementary question, just to make sure I got this thing right.
Suppose we are given that the mass to luminosity ratio of a galaxy is $2 \frac{M_{\odot}}{L_{\odot}}$.
Let us say, that the ...
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What effects you have to have in mind during LEO satellites observations?
I am attempting to calibrate my setup for conducting survey-like satellite observations similar. The idea is that I have a wide-field camera that takes images at 5FPS. The camera is equipped with a ...
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Orientation of the Dark Matter Halo in Andromeda Galaxy
In this paper: https://iopscience.iop.org/article/10.1088/0004-637X/789/1/62#apj496316t3
Refer to the Discussion and Concluding Remarks section. It says,
"This result also indicates that the ...
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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 ...
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What would evidence of stars and galaxies significantly older than 13.8 billion years old look like? In what parts of space has it not been found?
The September 19, 2023 podcast with transcript Why the earliest galaxies are sparking drama and controversy among astronomers includes the following:
An article published earlier this year in the ...
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What spectroscopic methods are there? [closed]
It was said in a comment on this site that there are different ways spectroscopy can be achieved. I am therefore asking: What methods are available when doing spectroscopy on the composition of ...
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How accurate is astronomical spectroscopy?
We all now that green is a mixture of blue and yellow, and that purple is a mixture of red and blue. In astronomical spectroscopy the chemical composition of a planet’s atmosphere is determined, by ...
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Formula to calculate time of day from shadow direction on Earth and latitude?
Web search found how to calculate shadow length and others but not my specific question. I have a photo. I found location on a map (so I know directions to objects: north/west/... and latitude). There ...
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Recurring flying object near the Big Dipper
This evening I was watching the Big Dipper when I noticed a bright-enough object (it looked either like a satellite or a really slow shooting star) a little above the line that connects Dubhe and ...
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Seen over 15 strange lights flying in a straight line [duplicate]
At about 9:30pm on 9/4/2023 in the Dayton Ohio area went out on the back porch and look in the sky and I noticed one light flying in a straight line across the sky and it was going at a fast speed and ...
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Help with simulating long-term orbital dynamics of exoplanetary systems using Rebound
I am a junior in high school working on an independent research project and I need help because I've reached the limits of my knowledge. My goal is to simulate the long-term orbital dynamics of ...
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Mauna Kea versus Mauna Loa: Astronomy ethical considerations
There have been controversies and conflicts related to telescopes/observatories developed on Mauna Kea, as described here. However, there does not seem to be controversies related to observatories on ...
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Gravitational-wave Angle?
As a train of gravitational waves generate from its source and passes through, is it stretch and compression of space-time with same angle all through the distance it is passing and damping over time, ...
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How do you calculate the position of the True Node
this is the code i am using for the "Mean Node" even tho even this one is off by a couple of minutes
...
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What are the differences between different types of flux density in radio astronomy?
I am new to radio astronomy and have started to analyze some radio observational data of pulsars recently. I am wondering about the differences between "peak flux density", "integrated ...
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How can I better align stamps from Hubble images?
I am trying to do difference imaging with Hubble ACS/WFC images and have been using TweakReg to align images and cutout stamps. The problem is that residuals haven't been great and I'm looking for ...
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ICRS to CIRS in sofa library
I'm new to astronomy and sofa lib. as you know sofa library give us some function to transform star coordinate between varies reference systems. I want to use iauAtci13() function to transform some ...
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How do we get -0.4 mJy/beam in the the 1.28 GHz MeerKAT Galactic Center Mosaic?
Dr. Becky's Feb. 11, 2022 video Move over JWST! 5 new telescopes to get excited for makes a quick mention of this image produced by the Meerkat array and published in Heywood et al. 2022 The 1.28 GHz ...
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Obtaining Transit Spectrum for Celestial Bodies Using JWST NIRSPEC
I've recently been tasked with obtaining transit spectrum data for some fascinating celestial bodies, including Ceres, Enceladus, Ganymede, Io, and Titan. The goal is to compare their transit spectra ...
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A question about the cosmic distance ladder
So I have a table of data for the following stars: Vega, $\alpha$ Crv, $\beta$ CVn and $\epsilon$ Eri. I have been given their parallax, luminosity, $m_{B}$ magnitude and the $m_{V}$ magnitude. Now I'...
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Do high power radar astronomers try to avoid beaming power at (at least some) artificial satellites as they pass overhead?
This answer to "Next Generation Arecibo Telescope (NGAT)... would combine a 314-metre-wide platform with a swarm of 9-metre dishes on top" What would that look like? links to an interesting ...
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"Next Generation Arecibo Telescope (NGAT)... would combine a 314-metre-wide platform with a swarm of 9-metre dishes on top" What would that look like?
In Nature News' August 11, 2023 Closing down an icon: will Arecibo Observatory ever do science again? found in The Observatory there is discussion of the Next Generation Arecibo Telescope (NGAT):
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How can I compute reasonable errors on my Gaussian fits to the observed strong optical lines of interest?
I'm fitting Gaussians to optical lines spanning from H-beta to Sulfur using Astropy's Gaussian (https://docs.astropy.org/en/latest/api/astropy.modeling.functional_models.Gaussian1D.html) model with a ...
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Public data for calculating equilibrium temperature of exoplanets
I am a high school student beginning a simple independent project to calculate the equilibrium temperature of exoplanets. I'm curious to see how many exoplanets have a similar equilibrium temperature ...
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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 ...
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How much of the celestial sphere can a naked eye observer see? [duplicate]
Yeah I know, 'Half'. But if you're in the middle of the pacific Pacific, where the surface curvature is greatest(?), with the sun and moon are at opposition, the nadir, on a cloudless night, even ...
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Has any astronomer/physicist used geometry and trigonometry to calculate where the center of the universe is? [duplicate]
Since we are pretty sure that the universe is expanding at a steady and accelerating rate wouldn’t it be possible to simultaneously observe 4 points (galaxies) that are all, as closely as we can tell, ...
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Differentiating supernova types with light curves
as an introductory activity for my work on transients, I am studying the light curves of different supernovae. It appears that Type-I supernovae have a more pronounced maximum than Type-II supernovae. ...
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Mismatch between Nasa Horizons Alt & Az data and theskylive and other star maps
I am trying to use NASA's Horizons systems to create a tracker for planets but I am running into a problem related to the returned ephemeris data, particularly with the altitude and azimuth. When ...
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