69 votes

Why does it take so long to transmit an image from New Horizons to Earth?

New Horizons has just passed the Kuiper Belt Object (KBO) 2014 MU69 also known as Ultima Thule. KBOs form a belt of asteroids (the Kuiper Belt) from Neptune's orbit outwards and of which Pluto is the ...
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  • 7,250
47 votes

Why does it take so long to transmit an image from New Horizons to Earth?

The other answer mentions it, but this gives a bit more theory as to the why. It's effectively for the same reason that your phone or Wi-Fi don't work as well and slow down when that they are far ...
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19 votes
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What is sin i in this graph and why is it there?

If you discover an exoplanet via the Doppler (radial velocity) method, then the amplitude of the radial velocity variations depends on the inclination, $i,$ of the exoplanet's orbital axis with ...
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16 votes

Why does it take so long to transmit an image from New Horizons to Earth?

On top of the slow data transmission rate (explained in astrosnapper's answer), I think it is worth pointing out that New Horizons will enter solar conjunction next week, meaning that we won't be able ...
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  • 265
16 votes

Why does it take so long to transmit an image from New Horizons to Earth?

Just to put some perspective on things: 1. New Horizons is really far away from the Earth. At the moment of closest approach, New Horizons was over 6,600,000,000 kilometers away from Earth. This is ...
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  • 431
14 votes
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Does the cosmic microwave background change over time?

The CMB patterns do indeed change over time, although statistically they remain the same, and although it will not be noticeable on human timescales. The CMB we observe now comes from a thin shell ...
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14 votes
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On what basis is the information about the distance and velocity of the Voyager probes determined?

On what basis is the information about the distance and velocity of the Voyager probes determined? For distance: round-trip travel time of radio signals For velocity: Doppler-shift of round-trip ...
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13 votes
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Role of power laws in astronomy?

Scale invariance and self-similarity Power laws basically mean that there is no preferred scale, i.e. that a physical property is scale invariant. Any deviation from a power law means that the ...
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12 votes
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How do you propagate asymmetric errors? (on the practical way to...)

I'm not sure this question really belongs here, but you mention the word "astronomy", and I'm an astronomer and I have an opinion on how to add numbers with asymmetric uncertainties: ...
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11 votes
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Why do we use FITS format for scientific images especially in astronomy? How is it different from formats such as JPEG, PNG etc?

File formats tend to be industry/field-specific, with the format, tools, and expectations of the field coevolving to become more dependent on each other over time. JPEG co-evolved with amateur digital ...
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11 votes
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Will there be public access to the New Horizons data from Ultima Thule?

The raw images1 from LORRI (high resolution greyscale) are available from JHU APL but the rest of the data such MVIC (wide angle in greyscale plus four color bands: near IR, methane, red, and blue), ...
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  • 1,169
11 votes
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Locate stars in sky from list of (x, y) co-ordinates

Upload your photo to nova.astrometry.net and in a few minutes you will get a result page that tells you the plate scale in arcseconds/pixel, the celestial coordinates of the center of the frame, the ...
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  • 1,450
10 votes
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Acquirable Raw Data in Amateur Astrophotography

First off, pairing a classic dob with a DSLR is a bit like a shotgun marriage. A dobsonian is fundamentally a visual telescope. Most manufacturers don't even consider the possibility that these ...
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10 votes
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Is there any site with telescopes data?

Most general purpose observatories release the data taken on their facilities after the expiration of the proprietary period (this is the time, typically 12-18 months, where the data is only available ...
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  • 7,250
9 votes
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Questions about convolving/deconvolving with a PSF

Convolution is not a uniquely invertible process in the presence of random noise in your image. Deconvolving a noisy image can give misleading results, even if you have perfect knowledge of the PSF. ...
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9 votes
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What is the "lost light" in this unusual Hubble Deep Sky image?

Let me see if I can explain the main aim and accomplishment of this work. First off: the picture you're puzzling over is a "luminance RGB" image, in which the bright regions are represented by color (...
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8 votes

What is the "lost light" in this unusual Hubble Deep Sky image?

When you plug the lead researcher's name into Arxiv, the first search result is The missing light of the Hubble Ultra Deep Field. 3 main steps: Creation of sky flat fields for the four filters....
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  • 2,956
8 votes
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Is there a database of all known star names/identifiers?

The closest service to what you are describing is the SIMBAD Astronomical Database from the Université de Strasbourg/CNRS. At the time I write this post, it contains 10.8M objects and 35.5M ...
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  • 236
8 votes
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Is looking through a telescope to do astronomy a thing of the past?

Scientifically there's little to gain when you look through a telescope with your own eyes. Attach a camera to the telescope and you immediately document what you observe and take out the subjective ...
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  • 12.3k
8 votes

Role of power laws in astronomy?

I have to admit that power-laws (in general) used to be my shtick so I am happy to shed some light on their general importance in physics which obviously also hold for astronomy. The main idea of a ...
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  • 5,304
8 votes
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What is z in this program?

Welcome to the world of software developed by scientists for their own use. There are not many clues. The top-level README cites Nemravová et al. 2016. That paper mentions PYTERPOL briefly in section ...
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7 votes

Acquirable Raw Data in Amateur Astrophotography

You are absolutely right: amateurs can do a lot of science with the apparatus you own. The book "Astronomical Discoveries You Can Make, Too!", by Robert Buchheim, lists famous historical observations ...
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  • 71
7 votes

Where can I find a catalog of all stars in the Milky Way?

Hipparcos, the predecessor to Gaia, has a dataset (http://cdsarc.u-strasbg.fr/viz-bin/Cat?I/239) with 3D positions for 100,000 stars. While we have much larger datasets of galactic stars, such as SDSS,...
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  • 1,453
7 votes

Sample bias' contribution to "Planet 9" hypothesis, why was this not thoroughly addressed before?

I think the underlying premise of the question -- e.g., "Why was this sample bias not thoroughly addressed before?" -- is somewhat incorrect. Previous papers, including papers by those ...
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7 votes
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Conventional units for astronomical object coordinates

Right ascension is usually given in hours, minutes and seconds, but declination is usually given in degrees, arcminutes (') and arcseconds ("), with one arcminute being 1/60th of a degree and one ...
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6 votes

Are there any astronomical phenomena that could emit strong radio waves with multiples of a discrete frequency?

I think you've misunderstood the article - the quantity that seemed to be occurring at integer multiples of some number isn't the frequency of the radio emission but rather the dispersion measure (DM) ...
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6 votes
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Planets and moons positions in cartesian coordinates?

Horizons Ephemeris Generator Here is a screen capture where vector option is chosen:
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  • 1,352
6 votes

Does the cosmic microwave background change over time?

When we observe the CMBR we are observing the surface of last scattering, however the comoving points that make up the surface of last scattering (which infact will actually have a comparitvely very ...
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  • 1,795
6 votes

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

There are two separate points of interest you're looking at so I'll separate this into sections. Sudden Drop at Day 1559 As near as I can tell, this is the result of a quarterly roll of the ...
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