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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Fitting PSF to an image to get total flux (Python)

I have an image of a single unsaturated source (asteroid) that I'd like to fit guesses for various model PSFs to, so that I can then compare the total flux in each case. I've only recently begun ...
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1 answer
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Which star with a Bayer designation is the farthest from the Sun?

The key to finding the answer seems to involve processing data from astronomical databases, which I'm not sure how to do in this case. I'd prefer to limit the answer to the original list of ...
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Dataset containing list of known globular clusters

Does anybody know if there is an existing dataset that consists of all known star clusters, their name, and their apparent dimensions or similar? Is it possible to make a query to, or download all ...
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2 votes
0 answers
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Efficiently calculating power spectra from galaxy catalogs

I am dealing with a problem which requires calculating either the correlation function or the power spectrum. At times, the 2-point-correlator seems the better route, at others, the PS. Right now I am ...
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Correctly scaling Power Spectrum and Correlation Function of Galaxies from Mock Catalogues

I'm currently writing a code to compute the two-point correlation function of a set of galaxies. As I work with a loooot of galaxies, it was suggested to me not to do it in real space, but to compute ...
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Generating random galaxy catalogs for correlation functions

The galaxy correlation function, when computed directly from a galaxy catalog, relies on computing a randomly generated counterpart catalog. When dealing with a simulated galaxy mock-catalog, where ...
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1 answer
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Where can I find source data for the graph of metric expansion over time, as shown in this ESA web page?

This web page from ESA/Hubble, shows the size of the universe over time. (I know that "size of the universe" is a gross simplification and open to multiple definitions and ambiguity, but this kind of ...
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4 votes
1 answer
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Tests for code that computes two-point correlation function of galaxies

I'm currently writing a code to compute the two-point correlation function of a set of galaxies. As I work with a loooot of galaxies, it was suggested to me not to do it in real space, but to compute ...
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  • 193
2 votes
1 answer
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Obtain IR diffuse data from WISE

I need some help obtaining IR background diffuse data from the WISE observation. There is already some work done in this regard; see: http://wise.skymaps.info/ . These are .fits files. How do I find ...
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2 votes
0 answers
138 views

How to calculate the various properties of a star?

I am wanting to plot a velocity profile (a plot of velocity against the star's distance from the galactic core) from the Gaia DR2, but so far my efforts have been disappointing. The information I ...
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3 votes
1 answer
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Locating a star cluster on a Hertzsprung-Russell diagram with other color index

Recently I took pictures of the NGC 884 cluster in the B and I bands and selected some 30-what stars from them. I've reduced the data to a colour-magnitude diagram (absolute magnitude in the I band $...
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4 votes
2 answers
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Understanding expected TESS data structure

I'm interested in trying to use the data that will be returned by TESS to apply some machine learning/computer sciences concepts. I'm not sure yet what I want to try to do with it (though I have some ...
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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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4 votes
1 answer
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What is equation of straight line for a ideal blackbody on the color color diagram?

The color-color diagram is a plot between $U-B$ vs $B-V$ values. For a ideal blackbody, what is the equation of this line? In other words, what does the linear relation between $U-B$ and $B-V$ look ...
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1 vote
1 answer
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Why are the spherical and cartesian galactic coordinates in the ATNF Pulsar Catalogue different?

I am trying to relate Galactic Latitude (b) and Longitude (l) (spherical coordinates) to galactic cartesian x,y,z coordinates in the ATNF pulsar catalog. This query shows some sample data with ...
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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 ...
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4 votes
3 answers
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Observed lunar distance data?

Where can I find free/open data for the observed (not calculated/theoretical) distance between the Earth & Moon? I want to see the observed distance of the Moon, hour by hour.
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2 votes
0 answers
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How does the ESPRESSO Echelle spectrograph fold the spectrum so nicely?

The CBC News Technology and Science Q&A This ESPRESSO machine doesn't make coffee but scans the skies for habitable planets includes a nice description of ESPRESSO (Echelle SPectrograph for Rocky ...
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4 votes
1 answer
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Strong Gravitational Lensing Dataset

I'm a Machine Learning Student and I'm working on Strong Lensing Image Classification. this is a hot topic nowadays but strangely after days of searching and communicating with different people I ...
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7 votes
1 answer
339 views

What does the active area on a typical CCD based detector look like?

Pixel based detectors, particularly optical CCDs like what was used in the SDSS camera, are ubiquitous in astronomy. Is there any dead area on the detectors? Not the obvious gaps between each ...
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1 vote
2 answers
386 views

Problems with FITS headers

I'm working with some NEOWISE images that seem to have incomplete header tags. I've been advised by the SAO (because I'm using DS9 to view them) that I have "a partial PC matrix defined, yet it does ...
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3 votes
2 answers
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Where can I find a visible star dataset?

I'm trying to do a project for a databases class where I have a user enter their current location and I tell them what constellations/planets/etc are visible in their area. I've seen this data ...
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2 votes
1 answer
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where to obtain ephemeris data for geodesy satellites?

Is anyone aware of where one can obtain ephemeris data in Geocentric Celestial Reference Systems (GCRS) coordinates for a geodesy satellite such as LAGEOS (It doesn't really matter which mission)? Or, ...
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2 votes
2 answers
130 views

Stuck with SDSS data [closed]

I want to do project on astronomical dataset. Regarding that project, I try SDSS who give public dataset but it is quite complicated for me. I gone through public dataset and downloaded some .FITS ...
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2 votes
2 answers
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Practicing image processing and analysis

I'm just getting into image processing and analysis using Python, and I'm looking for astronomical images (preferably raw, unprocessed images) to practice on. Can anyone suggest some places I can ...
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3 votes
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How to find period of a pulsar from a given time sampled voltage data?

I've a data file with 2 columns, each containing time sampled voltage output (a sequence of real numbers) from a radio telescope, so there is a pair of telescope which are measuring the signal here. ...
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1 vote
0 answers
232 views

Are there any ready-made machine-learning datasets of photometric data that are easy to use?

Disclaimer: I have a Machine Learning/Computer Vision background, not Astrophysics, so please be a bit patient with me. If you feel like this question is too far out there it would be great if you ...
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0 votes
1 answer
257 views

Image processing techniques to distinguish between stars and galaxies in an image? [closed]

Say I have an arbitary image of stars and galaxies without any extra information (no other spectra info other than image itself). Can you help me distinguish them? Are there any specific features / ...
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1 vote
1 answer
122 views

I want a galaxy count database, also how do I use SDSS skyserver to fetch galaxies?

I'm new to all this and trying to implement galaxy counting. For the initial stage I need raw image data, that is images with galaxies and stars along with a count of how many galaxies there are in ...
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3 votes
2 answers
209 views

Observation of Gravitional waves by LIGO from binary black hole merger

I read the paper "Observation of Gravitational Waves from a Binary Black Hole Merger" https://physics.aps.org/featured-article-pdf/10.1103/PhysRevLett.116.061102 I tried to understand all the graphs ...
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1 vote
1 answer
93 views

Are there more images with different filters available for the April 6 Hubble image of Jupiter?

This recent HST image of Jupiter near opposition is described here and here and was made under HST proposal 14756. It was taken with WFC3/UVIS. It is made from three images using narrow-band filters ...
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5 votes
1 answer
157 views

What caused instant jumps and exactly flat periods in Kepler's light curves?

Last 65 days of Kepler's light curve for the infamous KIC 8462852 star is shown below from the published paper's graph. Skip the dips here, I wonder about two other features: Day 1559, during a ...
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3 votes
3 answers
1k views

Python with image in fits format

I'm trying to write a Python program that will do the following: take an image in fits format and a reg file with a list of regions in the sky, and determine which regions in the list are inside the ...
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1 vote
0 answers
37 views

Error associated with Sersic Profile calculations?

I am working on a Bayesian analysis project for class using data I gathered some data from NASA's Sloan Atlas (http://www.nsatlas.org/). One of the variables I am dealing with is the Sérsic Index (...
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4 votes
1 answer
253 views

Why is the moon's motion more complicated than that of those planets?

I am of course not an expert on astronomy. But from the literature, I have the impression that the lunar motion is very complicated. It seems that Kepler can make sense of the motion of the planets ...
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1 vote
0 answers
47 views

Tracing back OMNI data to the sun

I have been reading the OMNIWeb data documentation in order to clarify one particular question without success. I need to associate each measurement in the OMNI dataset to a moment in time at the sun (...
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2 votes
0 answers
35 views

Any benefit for analyzing the depth of craters across the surface of a planet?

I would like to know what conclusions one could draw from mathematically analyzing the depth of various craters across the surface of a given planet, and then relating that to their position on said ...
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2 votes
1 answer
58 views

Detector Pixel Geometry?

When analyzing an image I'm used to thinking of the pixels as a grid of boxes the photons have fallen into. I assume that there's zero space between the boxes. That seems obviously wrong, since there ...
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0 votes
1 answer
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If a star orbited another star, how would that affect parallax measurements of the other star from the vantage point of the first?

Example: If hypothetically, the vantage point would move 2AU along an orbit around the star being measured, would that make it seem as if the other star moved twice the distance over the back-drop?
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2 votes
1 answer
280 views

Getting light curves from Kepler/K2

Hello I'd like to ask what are steps to get a light curve wfrom Kepler/K2 database. Let's say I'd need to get light curves of 10 random K type stars. How should I access the databases and what should ...
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2 votes
0 answers
62 views

Visible Light Ground-Based Solar Observatory Data Archives?

I'm mainly searching for the best(or good/significant/important) solar data archives via ground-based telescopes. If I'm not being very straightforward... Say if I wanted high quality/resolution ...
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2 votes
0 answers
86 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 ...
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1 vote
1 answer
97 views

Astronomy online degrees

I have a masters degree in computer science and statistics but would like to advance my knowledge in astronomy, ideally in getting some kind of online degree. Does anybody have experience, ...
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1 vote
1 answer
208 views

Rebinning with a non-integer factor

I'm in doubt whether I should put this in the astronomy or rather the coding exchange, but since my interest goes out to the former I will try my luck here. Suppose I have an image with a certain ...
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2 votes
1 answer
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Which data should I use to take the fast Fourier transform (FFT) to find time period for eclipsing binaries?

I am trying to use Kepler Data for Eclipsing Binaries to estimate time period, and then other parameters such as mass, eccentricity, semi-major axis, distance, etc. of the system. I want to write code ...
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2 votes
1 answer
151 views

Why does the neutral hydrogen velocity have this characteristic behavior in the galactic plane?

The recently released map of galactic neutral hydrogen density and velocity is really beautiful. The work has been relased by the HI4PI collaboration (HI = neutral hydrogen, $4\pi$ = complete ...
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4 votes
2 answers
525 views

Questions about convolving/deconvolving with a PSF

A point spread function (PSF) has many different uses. Consider for instance the following quote: To extract the maximum information out of an observation, even the smallest details of the ...
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0 votes
1 answer
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Can we manipulate cosmic rays?

Is it possible to send data using cosmic rays? Like sending high and low energy cosmic rays, since they can travel farther. And this data can be converted to binary form that can be processed by ...
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1 vote
1 answer
537 views

Astronomy & machine learning. Where to start? [closed]

I am a Computer Engineering major and would like to learn more about machine learning methods in Astronomy. What books or other resources could I use?
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1 vote
0 answers
384 views

Sloan Digital Sky Survey (SDSS) HDU `or_mask` - what does it mean exactly?

I'm looking at the Sloan Digital Sky Survey data. I'm primarily using the flux data, from the documentation I see the first extend (HDU 1) has flux, ...
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