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6 votes

Is the scaling in this composite photo reasonably correct?

Unfortunately, galaxies don't have a neat edge (and the Moon is not at a fixed distance) so your question is difficult to answer in absolute terms. However, a commonly quoted diameter for the disk of ...
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3 votes
Accepted

Calculate how many days left for synodic period from particular planet

If you know the date of the last opposition, then the next one will be about 399 days later (ie a year, a month and a bit). That is just counting days. So if you know that there was an opposition on ...
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7 votes

Will the first Event Horizon Telescope image of the Milky Way's black hole Sgr A* just be another lumpy orange donut?

Yes. See today's press release from the Event Horizon Telescope. The image is remarkably similar to M87, but note that this a time-averaged composite over about 10 hours, because the emission from the ...
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5 votes

Why doesn't the black hole in the center of the Milky Way glow similarly to the famous M87 image?

News were released today and a new image has been published which has similarities to the M87 image in the question. https://eventhorizontelescope.org/blog/astronomers-reveal-first-image-black-hole-...
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3 votes

How to fit LOSVD of a galaxy with gauss hermite parametrization

If you read the documentation for the curve_fit function, you’ll see that it has an optional parameter (p0) for the initial ...
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1 vote

Precision in the measurement of the distance to the Sun

According to E. V. Pitjeva & E. M. Standish, it is (on average) +/- 3 meters. The measurement was made with over half a million observations of different types in 2008. Generally using the ...
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4 votes

What else can we learn from a Foucault pendulum? Have they ever been used to determine anything more than that the Earth rotates on its axis?

Well, you can calculate your Latitude by observing how long the pendulum takes to complete a full circle. With many thanks to "d_e" for correcting my original statement. the time to ...
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0 votes

Pulling spectral data from Hubble Telescope automatically

First it should be noted that the Hubble Legacy Archive is indeed legacy in the sense that parts of it no longer work and it contains no observations taken since 2017 October 1. Fortunately there is ...
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3 votes
Accepted

What is being said here about the strange precession of DI Herculis?

The quoted passage says explicitly only that the stars observed velocity amplitude changes over time (due to precession); that does not imply that precession itself changes, but merely that we can ...
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2 votes

What are the main ways that pulsar "glitches" are noticed and documented? Do they have to be caught in the act of glitching to be catalogued?

The majority of pulsar glitches are detected via radio observations, but then again the majority of pulsar observations are conducted in the radio so this is not so surprising. X-ray and gamma-ray ...
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