69

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 largest member of the Belt. During the encounter with Ultima Thule, all of the 7 instruments on New Horizons were gathering data (although not all at the same ...


46

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 from the hotspot or cannot get a clear line of access to the cell tower, more commonly known as having "few bars": the signal gets weaker and as a result the ...


19

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 respect to your line of sight. Conventionally, $i=90^{\circ}$ corresponds to viewing an orbit "edge-on", which maximises the velocity variations, while a ...


16

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 to receive any transmissions from it due to the Sun blocking them. I don't know how many times this will happen over those 24 months, but it is an additional ...


16

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 about 6 light-hours. And the spacecraft is continuing to get farther by about 14 kilometres per second. 2. Transmissions from farther away are weaker. The ...


14

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 with us in the center, and with a radius equal to the distance that the light has traveled from the Universe was 379,000 years old and until now. As time passes, ...


14

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 radio signals, and by the rate of increase in distance as discussed above. The Voyagers as well as many other deep-space spacecraft before and after carry what's ...


13

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 Universe somehow thinks that the scale where it breaks down has some special significance. In other words, a power law describes self-similarity$^\dagger$. You can see ...


11

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 photography, PNG co-evolved with the web. Likewise, FITS co-evolved with astronomical data processing, and so is naturally more suited for that purpose than ...


11

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), LEISA (infrared spectroscopic imagery), Alice (ultraviolet spectroscopic imagery), as well as other instruments seems not to be available yet. Some processed ...


10

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 instruments could be used for data collection via a sensor. There are 2 issues here: 1. The dobsonian is not tracking The sky is moving, the dob stays still. You ...


10

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 to the proposers for the telescope time so they can work on it without being "scooped"). "Focused telescopes" in the sense of those that are performing surveys ...


10

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: Inherent ambiguity in a solution If you have the full probability distribution functions (PDFs) of two asymmetric distributions, they should be added by a convolution. ...


9

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. In general, when you are fitting models to data, it is far better to compare the models and data in the observational space of the data, where the uncertainties ...


9

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 (a sort of pseudo-true color using near-infrared images), with the second faintest parts represented with black and the very faintest parts with white. The ...


8

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. This process is fully described in Sect. 2.4. – Creation of a catalogue of all WFC3/IR datasets that may affect our mosaics (including calibration ...


8

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 identifiers. It does not have a single CSV you can download with this information (to the best of my knowledge, and I've asked), but there is an API and TAP service ...


8

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 factor from it at the same time and allow careful analysis and more detailed. Additionally you gain improved sensitivity enhanced observation duration and ...


8

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 power law is nicely written in Wikipedia, but the essential part is the I highlighted in the following quote: [A Powerlaw is] a functional relationship between ...


8

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 3.4 and says "solar metallicity was assumed" for the components of ξ Tauri. pyterpol/fitting/parameter.py has this code: parameter_definitions=dict( ...


7

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, finding the distances to stars is much harder. Parallax is the most precise technique for finding distances. Even for Gaia, we will only be able to measure ...


7

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 that can be replicated by amateurs.


7

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 making the "Planet 9" claim, have attempted to address sample biases; a secondary issue is that the new paper uses data unavailable to previous studies (...


7

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 arcsecond being 1/60th of an arcminute. This means that the declination of the source you list should be 40$^{\circ}$08"55.6', in accordance with the SDSS ...


6

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 small, but non-zero thickness rather than being a 2D surface) change with time, which in theory should correspond to a change in the observed pattern (of ...


6

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) of the source. As photons travel through the interstellar medium, interactions with free electrons mean that lower frequency photons take longer to reach the ...


6

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 satellite, specifically the end of quarter 17. Every 90 days, which NASA calls a quarter, the space craft does a 90 degree roll to optimize the solar panel efficiency. ...


6

You can do it via the astroquery SDSS module; there is a function called query_sql.


5

Horizons Ephemeris Generator Here is a screen capture where vector option is chosen:


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