Questions tagged [observational-astronomy]
Questions about the techniques and practice of observing the night sky.
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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?
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?
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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Space telescope spectroscopic data for stellar classification using Wien's law
My goal is to make a simple project which consists of classifying stars by applying Wien's displacement law.
I need public spectroscopic data about different stars from a space telescope, so that I ...
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Acetylene at Uranus? What's JWST's evidence and current thinking of how it's possible?
After about 03:22 in PBS Newshour's July 13, 2023 James Webb Space Telescope prompts scientists to rethink understanding of the universe JWST Interdisciplinary Scientist Heidi Hammel talks about ...
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Understanding PSF models and PFSEx output
I understand that PSFs are models for spreading of light. When I visit Hubble website (https://www.stsci.edu/hst/instrumentation/wfc3/data-analysis/psf) there is PSF model for me to download. I could ...
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Typical astronomical and astrophysical problems in various programming languages
As a rule, work in the field of observational astronomy and astrophysics requires knowledge of such programming languages as: C/C++ and the principles of OOP, MPI, CUDA. Sometimes additional ...
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ds9 configuration issue
I'm trying to use DS9 for X-ray image analysis. Before that I have to configure it for use, I need to click on option using web proxy.
Beside use internal web browser checkbox there should be another ...
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How do you estimate standard deviation of sky from (Hubble) image
I'm working on a simulation project with Hubble data and I need the standard deviation of the sky in ADU per pixel. Sometimes I can obtain a fits file (e.g. hdfs image), open this with astropy, and ...
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How can I differentiate between Jupiter and Venus in the sky?
Venus and Jupiter both appear to be of similar brightness in the sky, although, Venus appears to be slightly brighter than Jupiter. Sometimes when only one of them is in the sky, it is difficult to ...
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Satellite angular velocity at an angle
Suppose I am observing a satellite that is not at my zenith. I know the altitude(α) and azimuth(γ) of my telescope and I was able to get a relative angular velocity of the satellite.
Based on this ...
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How do they see BOTH "anomalously cool with a significant mid-IR excess" rather than one or the other? (SN 2023ixf progenitor)
The abstract of the arXiv preprint SN 2023ixf in Messier 101: A Variable Red Supergiant as the Progenitor Candidate to a Type II Supernova (itself recently "discovered" in the observatory) ...
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Which star has the highest known metallicity?
Which star has the highest known metallicity?
The highest I know of is Sirius
Which a Metallicity of +0.5, which corresponds to have a Ratio of Fe to H 3 times that of the sun.
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What's the relation between the parallax distance and the luminosity distance?
I have read that Riess and his team are able to measure $H_0$ from supernovae calibrated using Cepheid in a model independent way.
from what I have gathered they find the absolute luminosity of ...
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Why is asteroid 2001VB still on the risk list?
Why is asteroid 2001VB still on the risk list and how likely is it to impact the Earth this year? Moreover, on July 23, 2023 it will be several kilometers from us according to NASA's orbit view, how ...
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How to obtain the SDSS’s five-part imaging ID number for a list of galaxies whose Ra Dec is known?
I am trying to obtain the FITS file of a few hundreds galaxy from SDSS DR12 Survey. SDSS tries to download the FITS File with the link that contains the information about SDSS’s five-part imaging ID ...
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What Parts of the Observable Universe have we Observed?
Everyone talks about how big the observable universe is, all of the complexity, etc... But what parts of the observable universe have we actually seen? What Parts are hidden in relative shadows? Is ...
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Finding Position angle and ellipticity to Deproject galaxy image using IRAF
I am trying to obtain position angle and ellipticity for a galaxy image by fitting elliptic isophotes using IRAF routine stsdas.isophote.ellipse package. After fitting the isophotes, I have a table ...
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Can the collapse of a gas cloud lead to an elliptical structure?
Is it likely, unlikely, or impossible for an elliptical structure to form when a gas cloud collapses?
Due to the conservation of angular momentum, one would expect that disk structures are much more ...
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Sky coverage plot using Python/Astropy
I want to recreate a plot where the area that is not visible from a certain point on earth (latitude and longitude) trough a full year. An example of this plots for example can be:
Where in white is ...
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Why did it take so long to invent telescopes given glass was used 4000 years ago in Mesopotamia?
Is a telescope difficult to make? Does glass have to be polished and shaped very precisely? Or is a device using two or more lenses to magnify things just not obvious?
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What is the unit of the correlation function between logarithmically rebinned galaxy spectrum and stellar template spectrum?
Assume I have a logarithmically rebinned galactic spectrum $G(x)$ and a stellar template spectrum $S(x)$, where $x = \ln{\lambda}$. When $[\lambda] = 1 Å$, then $[x] = 1 Np/Å$. The fourier transformed ...
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Does RA/Dec vary with the Earth's orbit around the Sun?
I think the RA and Dec of a celestial object should change (ever so slightly) with the Earth's position in its orbit. So do we ignore this in general?
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Creating a small data pipeline
I wanted to create a small data pipeline such that it consists of images of sky in the filters F125W, F160W, F606W and F850LP. The 4 images for a single object should be in a single FITS File which ...
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How to construct optimal Wiener Filter?
I am trying to construct a Wiener Filter, to filter the ratio of the peak from the cross-correlation function, between a galaxy spectra and a template spectra, with the peak of the auto-correlation ...
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Is there any observational evidence for dark matter vortices?
The paper here "Vortices and waves in light dark matter" https://arxiv.org/abs/2004.01188
says that in dark matter halos vortices arise. In a vortex some particles move faster than others - ...
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