Questions tagged [sky-survey]
A sky-survey is a general map or image of a region of the sky which lacks a specific observational target, but this tag also applies to surveys of a given class of objects, (e.g. TESS)
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Comparing the mapping regions of sky surveys - southern hemisphere in particular
I'm looking for information on the field of view of sky surveys, particularly in the southern hemisphere. The only ones I know of are DESI, WiggleZ and 6dF. I'd like to look specifically at their ...
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Efficient sky searches with HEALPix-alchemy
I am trying to implement a cone search for a catalog with the HEALPix-alchemy package. I have the following models set up, based on the examples here: https://arxiv.org/pdf/2112.06947
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Would we know if the universe was rotating?
I was wondering what we would observe if the universe had a small rotation. My conclusion was that galaxies on the equatorial plane of the universe would be slightly more redshifted than galaxies than ...
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Errors in SDSS photometry
In plotting out the magnitude errors in SDSS photometry, I get the following pattern:
Why do the errors go up to about 0.5, then down? In other words, why does it look like a high-heeled shoe (or ...
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Published magnitude limits of surveys
I'm working with several astronomical catagloues (mostly SDSS, GALEX and WISE), and I'm trying to find information on their magnitude limits (i.e. the highest magnitude objects they can detect). They ...
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Is there any way to detect the three-dimensional distribution of baryonic gas in our Universe?
As the title suggests, can the current observational techniques detect the 3D large-scale distribution of the baryonic gas, rather than just the gas within groups or clusters?
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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 are radio frequencies sensitive to in galaxies?
Apart from 21cm line studies, radio emissions as well as signatures of different radio sources, do radio frequencies help in the identification of a particular physical structure or presence of some ...
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Are more stars or more galaxies cataloged, currently, and how has the ratio evolved over time?
I recall that there are of order 100 billion stars in a galaxy and 100 billion galaxies in the (observable) universe, or something roughly like that.
Since we are IN a galaxy we have an opportunity to ...
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Sky surface brightness vs magnitude limit visibility
I am wondering how we can calculate the magnitude limit of the celestial object, which could be visible at the given sky surface brightness conditions.
We already know that Venus and Jupiter are ...
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Are there any new/latest/recent radio sky surveys' data release which is publicly accessible?
There are many sky surveys that have been conducted by telescopes in different wavelengths of the electromagnetic spectrum like DSS (Digitized Sky Survey), SDSS (Sloan Digital Sky Survey), WISE (wide-...
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Where can I find MITEoR 150 Mhz radio data?
I was working on the Aladin Sky Atlas v12 software and while working on the radio data, I came across this Radio sky survey that said MITEoR 150 MHz. Initially, I mistook it to be GMRT because GMRT ...
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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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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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General questions about SDSS
I'm considering doing research on SDSS spectral classification (STAR, GALAXY, QSO) with machine learning for my school dissertation. Not sure if this is an appropriate place for these kinds of ...
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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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Why was the NVSS(NRAO VLS Sky Survey) conducted at 1.4 GHz continuum?
I am observing the nature of some galaxies looking at their radio images and contours from NVSS. So, the data collected have radio flux at other wavelengths but I am studying it at 1.4GHz. I have been ...
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Querying VizieR using SQL interface on their website
I'm trying to query http://tapvizier.u-strasbg.fr/adql/?%20V/147/sdss12 using the following query, built by clicking Construct your query and ...
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Why are the sky distributions of SDSS DR16 and DR16Q different?
I've downloaded the csv files for SDSS DR16 and DR16Q and made a map of their sky distributions:
The coordinates come from:
DR16: RA_ICRS and ...
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How does SDSS estimate photometric redshift of sources?
I'm looking through the data in SDSS DR 12:
...
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LSR and peculiar motion corrections to RAVE survey velocities
I am working towards getting a bunch of halo stars in our galaxy for my thesis. I am doing this with the help of a Toomre diagram and I am stuck. I am using the RAVE survey in conjunction with Gaia as ...
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Reasons for extremely high number density of galaxies at low redshift
I am currently analyzing the SDSS data especially in the extremely low redshift area, in order to measure the cosmological statistics. What I mean by extremely low is z<0.1. One peculiarity that I ...
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What does the celestial sphere look like in thermal IR?
The Space SE question JWST detector heat load asks
...what is the heat load from the collected radiation of the main mirrors on the detector, and how does that vary depending on what objects or ...
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How close are we to observing all of the sky all of the time?
I was musing on how amateur astronomy is still a heavy contributor to the overall field, and how on any given night there will be plenty of small telescopes pointing into the void and capturing the ...
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14,000 square degrees
The DESI Legacy Imaging Surveys says it produces a model of “the 14,000 square degrees of extragalactic sky visible from the northern hemisphere”. But I thought the whole celestial sphere (like any ...
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Calculating comoving volume of 2dF survey
Say I want to calculate the comoving volume in the 2dFGRS survey:
I'm using $H_{0} = 70 km s^{-1} Mpc^{-1}$ and the default values for the matter and vacuum density parameters in this calculator (...
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Could more objects from the Oort cloud with highly elliptical orbits be discovered in the future?
It took the modern astronomy to live to the year of 2014 to discover 2014 UN2711 (sized roughly 100-200 km and now being re-qualified from a comet to mini object), which has "extremely" ...
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What is the most grazing exoplanet transit that has been reported with high confidence?
The abstract of Past, present and future stars that can see Earth as a transiting exoplanet reads:
In the search for life in the cosmos, transiting exoplanets are currently our best targets. With ...
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Star visibility above horizon map likewise day & light map or moonlight world map
I am looking for an option to present the given star visibility world map likewise day & night map or moonlight world map like below:
Question: Is it possible to generate a map like this for some ...
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spider image in Samuel Oschin Schmidt Telescope DSS imagery
I was puzzled by image artifacts that appear in DSS-2 (blue) survey.
These images were taken by the Samuel Oschin Schmidt Telescope on photographic plates and later digitized. They are also available ...
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Calculating and mapping the best visibility of celestial occurrence
Recently I found a fantastic website in-the-sky.org, from here we can simply pick up any astronomical event and check its visibility in any part of the Globe.
For occultations, for example, we have ...
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Is the discovery of a "mass gap" black hole by this tiny telescope just plain luck/serendipity or could it be the first of many similar discoveries?
The Kilodegree Extremely Little Telescope is a pair of modest lenses with high quality medium format CCDs attached sitting on oversized mounts in Arizona and Sutherland.
These very modest instruments ...
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Are features in the CMB correlated with features in the SDSS map of the most distant galaxies?
This is a follow up to an earlier question to which @pela gave an excellent answer. Apparently the statistics of the length-scales of the CMB fluctuations are similar to those obtained from other ...
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Is there any correlation between the Cosmic Microwave Background (CMB) and the distribution of distant galaxies?
The Cosmic Microwave Background (CMB) is remarkably isotropic but does exhibit a distinct dipolar Doppler shift and also much smaller but measurable fluctuations in intensity and polarization. ...
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Accessing SDSS server SQL server via python
Is there a way to directly access any of the Sloan Digital Sky Survey servers via SQL via Python?
Currently I have been able to run SQL queries from the website they provide (for example https://...
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Using SDSS data / finding a catalog
I am looking for a catalog of low redshift galaxies (preferably SDSS) with information on line fluxes and stellar mass. My Google searches keep pointing me to work by the Portsmouth group, so I ...
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Heat map of portion of the sky visible for a given observatory on Earth?
Reading Calculating area of visible sky I started wondering which portion of the sky one could observe how long given the 3D coordinates of an observatory, and two points in time.
In other words, I ...
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What is the completeness of an observation and how do I calculate it?
Many publications write about "completeness". I have a vague idea that it has to do with the ratio of how many sources from an observation are detected and how many sources are actually in ...
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Searching dataset for Constellation detection
I need to develop an Machine Learning (ML) model for predicting constellation seen in a picture taken from a mobile. This I need to develop from scratch. Firstly, I need help finding a database which ...
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Basic explanation of baryon acoustic oscillations; what if anything is actually oscillating?
Sci-News' Sloan Digital Sky Survey Collaboration Releases New 3D Map of Universe links to the two videos
The eBOSS 3D map of the Universe
SDSS releases largest 3D map of the universe ever created
...
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How to plot curvilinear coordinates in the frame of a Cartesian telescope field of view
I am wondering what projection is used to produce plots like this:
(Image taken from here, author: NASA/Ames/JPL-Caltech, Image credit: Software Bisque)
More generally, I am trying to figure out the ...
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Google Sky Rectangle with No Stars
I've been viewing Google Sky, which is quite amazing, and came across a rather expansive rectangle where no stars are visible at 22h13m04.44s 4°59'29.49" (see image below). My only thought is that ...
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Dozens of Oblong Green Objects in Google Sky
In reviewing Google Sky today for the first time, zoomed in at the southern end of the Aquarius constellation, there's dozens of oblong objects, many of which are green. Considering their general ...
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Why do all the stars near this comet show up as four separate dots in a row?
After seeing this tweet about our not-so-new but at least newly-discovered "mini-moon" I scrolled down and saw the tweeted image below.
Since the object is the known short-period comet 114P/Wiseman–...
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How are small objects automatically identified and their locations determined in digital images?
I have a large quantity of old digital images of low energy electron diffraction (LEED) patterns that I must process to identify and locate small, sometimes elongated gaussian-like blobs of a few ...
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What is the LSST now? Where does LSST end and Vera C. Rubin Observatory begin?
Space.com's It's Official: Vera Rubin Observatory Named to Honor Dark Matter Scientist says:
"We're here today to focus on the major renaming of the facility after a pioneering astronomer, that ...
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Are the stars distributed in uniform distribution, on the celestial dome, with respect to brightness?
Has there ever been a statistical analysis of the distribution of stars in the sky (on the surface of the celestial dome), by brightness? I want to know if they are uniformly distributed.
For example, ...
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Estimating the abundance of type-Ia supernovae using magnitude limited survey
I would like to estimate the fraction of type-Ia supernovae in a magnitude limited survey (only including those supernovae that are brighter than a certain than a given fixed apparent magnitude).
I ...
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Any plans for TESS after it finishes northern sky survey?
TESS has provided the astronomy community with a treasure trove of information.
Once TESS completes its one year survey of the northern sky, are there any plans for an extended mission?
Just seems ...
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How to check what telescopes were looking at a certain portion of sky at a particular time?
I have some data that I collected from observations at a specific RA, DEC and I am trying to figure out what telescope surveys were looking at that portion of the sky at that particular time? I am ...
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