46 votes
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How is it possible that we haven't discovered anything in the Oort cloud yet?

It's not very surprising that no Oort Cloud objects have been detected via occultations. They're extremely rare, even for our most advanced space-based observatories. According to Ofek & Nakar ...
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24 votes
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What caused this mysterious stellar occultation on July 10, 2017 from something ~100 km away from 486958 Arrokoth?

There were three attempts to measure Arrokoth by occultation, and the June 3rd attempt didn't detect anything. The July 10th attempt had a tiny blip, that appeared to be in the "wrong place"...
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12 votes

What caused this mysterious stellar occultation on July 10, 2017 from something ~100 km away from 486958 Arrokoth?

According to Wikipedia: A preliminary analysis of all collected data suggested that Arrokoth was accompanied by an orbiting moonlet about 200–300 km (120–190 mi) away from the primary. It was later ...
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9 votes
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Can lunar occultation of Venus occur during solar eclipse?

Yes, but such an event would be very rare. Venusian transits last only about 7 hours, and there are only two in 113 years, So Venus is in transit for about 0.0015% of the time. So as a back-of-the-...
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6 votes
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How long would an occultation by a TNO last?

From the observer's point of view 1 million km away, the TNO's apparent angular motion is $$\mathrm{\frac{8~m/s}{10^9~m} = 8 \times 10^{-9}~rad/s = 0.00165~^\circ/h}.$$ Assuming that the observer at ...
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5 votes
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When are the planets occulted by the sun?

The search for sungrazing comets requires looking very close to the Sun for faint objects. This requires a chronograph and for faint objects is better done above the atmosphere. The SOHO spacecraft ...
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5 votes
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How does an eclipse differ from an occultation?

There are a number of terms for these things: conjunction: When two objects have either the same right ascension or the same ecliptic longitude (usually as observed from Earth). That is, they lie in (...
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4 votes
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Occultations of Triton

Pluto is actually smaller in diameter than Triton, and is also farther away, meaning that Triton covers roughly 1.4x (according to WA) the angle that Pluto does, making occultation that much more ...
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  • 312
4 votes
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Is 486958 Arrokoth (2014 MU69 aka Ultima Thule) the only solar-system object determined to be binary by occultation?

Actually, the very first binary asteroid was discovered by stellar occultation in 1980. The evidence was rejected by the IAU, and wikipedia credits the first binary asteroid discovery to the Galileo ...
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4 votes

How to understand the meaning of this International Occultation Timing Association (IOTA) lunar occultation of Mars map?

Unfortunately, there was a server problem in the days leading up to the exciting Mars occultation. (It didn't matter to me because it was, unfortunately, cloudy where I live.) This description of the ...
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  • 7,085
4 votes
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Possible occultation of HIP 99314 and Ganymede

For what it's worth, I just got a shot of what looked like a 5th Galilean moon near Ganymede tonight (from South Florida). Here's a quick, unprocessed image. I thought I was going crazy seeing an ...
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  • 56
3 votes

Possible occultation of HIP 99314 and Ganymede

The answer is a strong maybe. The International Occultation Timing Association (IOTA) produces predictions for such events. Their webpage Major Planet Occultation Predictions lists the occultation of ...
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  • 7,085
3 votes

What celestial mechanics parameters define a lunar occultation of Venus visible from Earth?

A lunar occultation of Venus happens when light from Venus can not reach the observer because the Moon blocks it. The simplest model for this would be to draw a line in 3D from Venus to the observer ...
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3 votes
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Determining the shape of ʻOumuamua via stellar occultation

Observing star occultations is dependent on the object passing in front of a star. During its short time in the inner solar system, ʻOumuamua didn't pass in front of a star (from the point of view of ...
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  • 88.7k
3 votes

How does an eclipse differ from an occultation?

Is there a more rigorous definition of these three terms that distinguishes an eclipse from an occultation or a transit? Not quite rigorous, but Occultations refer to events where the intervening ...
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3 votes
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What is the farthest reported distance from observer from which a solar system body has occulted a star?

Wikipedia lists some of the most farthest objects from the sun in the solar system. The third farthest object "Eris" was the subject of one of the most distant stellar occultations observed ...
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  • 3,226
2 votes

Does a lunar occultation of Mars happen twice a year?

Moon-Mars Occultations occur every 174 to 188 Days Average worldwide interval (based on 500 years) between occultations is 180 days. In a calendar year, zero to five occultations can occur. Annual ...
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  • 3,226
2 votes
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Does a lunar occultation of Mars happen twice a year?

Does a lunar occultation of Mars happen twice a year? No, in the sense that the number of lunar occultations of Mars per year is quite variable and not always two. I do not have a reference handy, ...
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  • 7,085
2 votes
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What star was the asteroid 2014 MU69 predicted to occult on 2018-08-04?

A VizieR query within 15 arcseconds of Buie's coordinates returns a 13th magnitude star, variously identified as: 2MASS 19042146-2035362 UCAC4 348-170642 Gaia DR2 4082342058110504064
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  • 16.5k
1 vote

Can lunar occultation of Venus occur during solar eclipse?

Some of your description, and the answers to date, assume that Venus has to transit the Sun. That is not a requirement for the literal question "can lunar occultation of Venus occur during a ...
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