Questions tagged [data-analysis]
Analysis of data is a process of inspecting, cleaning, transforming, and modeling data with the goal of discovering useful information, suggesting conclusions, and supporting decision making.
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Calculating intensity of moonlight per unit area
I have a photodiode that can measure intensity in pw to milli watt range.
I have a telescope of 5 inch diameter. I want to calculate the intensity of moonlight received by this area? This will help me ...
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Radio Astronomy Data Handling (Filtering What One Needs)
Suppose we have some radio astronomy data for some specific moment (not a time series). Can we, using some computer program, filter out and get, say, only the data (EM radiation), whose sources are at ...
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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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Sloan Digital Sky Survey - Obtaining Spectral and Photometric Datasets
I am working on a soft computing (fuzzy logic), genetic algorithm, explainable AI (XAI) classification system for astronomical objects from the Sloan Digital Sky Survey. The dataset I am currently ...
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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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Bad syntax for region SIMPLE -- dmextract CIAO 4.15
I am trying to perform a radial profile analysis using Chandra's CIAO 4.15 dmextract function but keep getting the following error: "bad syntax for region SIMPLE". I cannot find any relevant ...
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How to get star position from the Gaia data set?
I’m trying to recreate the Milky Way as a particle system inside Houdini, and I wanted to explore using the Gaia data as a starting point.
I’ve downloaded an example source file from the data set but ...
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Unusual amount of white dwarfs in star clusters in my analysis
I'm trying to plot H-R Diagrams of open clusters using data from Gaia DR3. My workflow is something like this:
Plot apparent magnitude vs log(distance) in pc. An overdensity would indicate the ...
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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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What are examples of spatio-temporal data sets such that subjects are observed only once and are, thus, indexed in time only once?
What are examples of spatio-temporal data sets such that subjects are observed only once and are, thus, indexed in time only once?
Here's a hypothetical example in the ecology realm: consider a tree's ...
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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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What courses should one take for working towards Astronomy from an AI / Data Analysis perspective?
Note:- This is a suggestions seeking question
As a prospective student about to embark on pursuing the MEngg. in Applied AI program, I am eager to align my education with my passion for Astronomy. I ...
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What am I doing wrong in this ppxf application?
I am trying to derive the kinematics of a galaxy spectra. To test my results I want to implement the Penalized Pixel Fitting method. For the galaxy spectrum I use a central line with sufficient S/N. I ...
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How can someone take narrowband data from an OSC narrowband filter
To those who aren’t aware, an OSC narrowband filter is a filter with multiple band passes, for different emission lines. These can include a combination of Hα, Hβ, OIII, SII, and other emission lines. ...
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Where can I get raw photos of planets clicked by HST, Voyager 1 and 2, Cassini for Saturn and Galileo for Jupiter?
I intend to process RAW images of planets clicked by HST,Voyager 1 and 2, Cassini and Gallileo spacecrafts using a few softwares.
I am in search of where I can get these raw images from.
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Convert image from Jy/sr to Jy/pix
I want to convert the units of an image from Jy/sr (Janskys per steradian) to Jy/pix and I know the pixel scale in arcsec. The way I do this, in python, is the following:
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Solar-winds: public NOAA data
I was searching for interesting data from space recently, and stumbled onto https://www.swpc.noaa.gov/.
The long and short is that they offer some interesting solar wind data
Of particular interest to ...
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Finding the uncertainty in period for String-Length Minimization calculation
I wrote a Python script that calculates the period of an unevenly sampled data set using the String-Length Minimization method.
You can read about that method here: A period-finding method for sparse ...
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What's a good example of published astronomy pipeline coding libraries
I am a software engineer and I am preparing a presentation to aspiring astronomy PhDs on how to use best-practice software engineering when publishing code (such as include documentation, modular ...
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Do astronomical datasets exist that receive duplicates or are there multiple datasets that contain the same entities (stars)?
I am currently doing my PhD in computer science, and I have almost no astronomical knowledge. I am currently researching on duplicate detection in databases (so detection of multiple entries referring ...
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2D Galaxy Spectrum taken by long-slit-spectrograph
I have the 2D data (shape(1125,2058) taken by a long slit spectrograph, which looks as follows:
The y-axis corresponds to the distance from the center, where the center is at the most bright green ...
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How did asteroid (7482) 1994 PC1 get its "face"? Is it reconstructed from optical or radar imaging, or something else?
(Image sources linked below)
NPR's March 10, 2023 Newly found asteroid has a 'very small chance' of hitting Earth, NASA says includes an image of what looks like a computer reconstructed 3D surface of ...
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How has the resolution of astronomical spectrographs improved over time?
Is there something like a Moore's law for spectral resolution? Maybe a chart from which one could extrapolate?
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Best resource for exoplanet statistics?
While the number of detected exoplanets is still low, is there a model that, considering the number and duration of made observations, and the fact that (non)detections depend on orbital plane ...
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How does one actually fold a light curve?
I'm studying the variable stars (periodic variables with brightness changes repeating over time), and to examine the shape of the light curve it is useful to fold the data points at this period and ...
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Reduced chi square value
I am currently plotting a continuum of observed data. I need to check the effectiveness of the fitted continuum with the reduced chi-square method. Ideally, should the reduced chi-square value ...
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What is the most common activity of astronomers in the JWST? [closed]
I am no astronomer. I am a computer scientist.
I recently read this article: JWST has changed the speed of discovery, for better or for worse - Astronomers are working at a furious pace to analyze and ...
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How can we make sure that it is physically the same source when we do cross matching?
When we go through multiple astronomy catalogs, we often do Cross-matching. We compare the position parameters $(\alpha, \delta)$ of different sources (galaxies, quasars, etc.) in the equatorial ...
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What determines how accurate a particular method is at finding the period between Lomb-Scargle and String Length Minimization?
I've been using the Lomb-Scargle and String Length Minimization methods to find the periods of various astronomical objects with unevenly spaced data. I wanted to see if I could find any patterns ...
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Database for distant stars
I'm looking for a database of stars that lists as many of the known stars as possible. Ideally, I'd like it to have information on the radius of the stars, the distance from the earth and the ...
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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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Where to get MOST data?
Where to get MOST data (light curves), please? Does a database or a list of objects that were exist? I mean MOST spacecraft.
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What Simple and Multiple Linear and Logistic Regressions Would Be Valuable for a Celestial Mechanical Data Set for Exoplanets with Density?
I have created a celestial mechanical data set for exoplanets with density values (https://github.com/tslever/Tom_Levers_Git_Repository/blob/main/UVA/2--Linear_Models_For_Data_Science/Project_2/...
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Tables or software for some astronomical data
Recently I saw a beautiful (but not rare) phenomenon - Jupiter was "directly above" the Moon, that is, they had the same azimuth and a small difference in altitude.
I would like to see on ...
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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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What 1° x 1° region is the optically darkest patch in the sky?
What 1° x 1° region of the night sky has the lowest flux of light?
(considering the typical visual/luminance filter range, approximations using other filters/bands are acceptable, but should be in the ...
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How do I get temperature and diameter from a light curve?
I recently learned that short-period pulsating stars vary in diameter and temperature when they pulsate. If I have a light curve for such an object, is it possible to calculate its diameter and ...
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What does a fitted curve for the period of a variable star, tell me about the star?
If I have enough data of a variable star to make a light curve for it's whole period, and If I fit a function to that light curve, can that fitted function tell me anything about the properties of ...
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How do cross-matching algorithms deal with unequal-sized catalogues?
Let's say I'm using a service like TOPCAT or Vizier's cross-matching service and I'm trying to match the RA and dec of the sources in Catalogue 1, with 100,000 sources, to those in Catalogue 2, with a ...
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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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How do I create well a weighted black hole mass function?
I'm running a set of simulations to study the evolution of Super Massive black holes.
In principle, I have the black hole masses and other property called merger tree weight in Mpc-3 unit which is ...
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Are astronomical studies with no "proprietary period" for data organized differently than studies with "proprietary period"?"
Let's assume you are a group of astronomers that proposed an observation by a telescope.
The observation has been conducted, so you have got the data you wanted. But the data has no proprietary period....
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Is there a centralized database of all stars?
Is there a centralized database for all stars, sourced from Gaia and other missions?
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I was finding the period of crab pulsar using efsearch(xronos)
I was finding the period of crab pulsar(one orbit data from ASTROSAT/laxpc) using efsearch (heasarc/xronos). Despite considering period = 33ms, I am not getting sharp peaks at higher Resolution for ...
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If I can't unscramble an egg, how do Astronomers unscramble views gravitationally lensed by complex mass distributions?
Quanta Magazine's Two Weeks In, the Webb Space Telescope Is Reshaping Astronomy highlights two submissions to arXiv soon after the first images were released: "Three days later, just minutes ...
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Astrometry and Geometric Distortions
CCD's are widely used for astrometry. Since a spherical surface (the celestial sphere) is projected onto a rectangular surface, the plate scale or pixel scale (approximated with 1/focal length etc) is ...
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Database of distant stars
I'm writing a report on using machine learning techniques in astrophysics. I'd like to perform 3 tasks:
Generating a Hertzsprung-Russel diagram and clustering the results into the main types of stars ...
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Locate stars in sky from list of (x, y) co-ordinates
Imagine we have a photographic plate that clearly shows a few stars, but we do not know where in the sky these stars are located.
We can digitize the location of stars on this plate and now have a set ...
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SNR computation + noise correlation [closed]
My question splits in two parts:
If I have an image with N x N pixels, and an object in the center (star, galaxy what have you), spanning M x M, how do I compute its signal to noise ratio exactly?
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What sort of exploratory procedures should be carried out on astronomical data? [closed]
Upon downloading an astronomical dataset such as SDSS DR12 from VizieR, what kind of exploratory techniques should be performed? I start with the basics, like this tutorial, and how much missing data ...
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