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39 votes

Can a planet in our system eclipse the sun as seen from another one?

In our solar system, it is possible for one planet to partially eclipse the sun, but it is not possible for any planet to cause a full solar eclipse as seen from another planet. The sun is too big and ...
Connor Garcia's user avatar
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30 votes

Is it possible to see mercury transit "clearly" by the naked eye?

I did see the Venus transit before the Sun in 2004. I used no telescope, but of course I used proper solar eclipse glasses to protect my eyes. The black circle was small but clearly visible. But ...
Uwe's user avatar
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30 votes
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Exoplanet dip in transit light curve when the planet passes behind the star

Just before the planet goes behind the star, we see the light directly from the star as well as the light reflected from the planet's surface. When the planet is behind the star, we no longer see the ...
Connor Garcia's user avatar
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27 votes
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Is it possible to see mercury transit "clearly" by the naked eye?

I'll use the atmosphere as my big natural lens. So I'll watch the upcoming mercury transit at the sunset time where the sun looks bigger than usual. While the Sun and Moon might seem larger at the ...
uhoh's user avatar
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22 votes

Can a planet in our system eclipse the sun as seen from another one?

The short answer is no. The alignment occurs, but the eclipse does not, due to the distances and size differences involved. There are a few things to consider here. You already mentioned a lot of them,...
Flater's user avatar
  • 381
11 votes

Why was the size of the solar system not defined by Mercury Transits?

It is indeed possible to measure the AU using transits of Mercury, and Edmund Halley tried to do just that in 1677. However, there are two advantages to a transit of Venus. The first is that during ...
J. O'Brien Antognini's user avatar
10 votes
Accepted

Why do transits of Earth across the Sun seen from Mars follow a pattern of occurring after 26, 79 then 100 years?

Such transit events occur when Earth and Mars are simultaneously at a node where their orbital planes intersect. Between transits at the same node, both Earth and Mars must complete whole numbers of ...
Mike G's user avatar
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9 votes
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How (the heck) was this photo of Venus at inferior conjunction (between us and the Sun) taken?

I think you'll have to live with an incomplete answer. It appears this was taken by an amateur astronomer using a simple 4.5 inch telescope. You can find, on the ESO website, a collection of many ...
zephyr's user avatar
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9 votes

How do astronomers know if a planet is orbiting a star, or it's simply another star in the background?

I think there are two parts to this question: How do we know that the transiting object is a planet, and how do we know that it's gravitationally bound to the parent star, rather than an interloper? ...
HDE 226868's user avatar
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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-...
James K's user avatar
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8 votes
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Is it possible to tell if a certain extrasolar planet produces its own magnetic field?

There are three approaches with which people have looked for this, and not yet been too successful: A transiting planet planet with a strong magnetic dipole and/or very strong host star winds might ...
AtmosphericPrisonEscape's user avatar
8 votes
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How does a Solar Transit give more accurate determination of Earth-to-Sun distance?

The problem of determining the solar parallax (and inversely the Sun's distance from Earth) by classical optical astronomy has been in most periods since the 17th century dominated less by principle ...
terry-s's user avatar
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8 votes
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How do scientists differentiate between a total and a partial transit of a planet passing in front of its star?

The shape of the transit is different if there is a partial transit, not just the depth. As a planet passes fully in front of the star, the brightness is almost constant while it is transiting (bar ...
ProfRob's user avatar
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8 votes
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Is one transit enough to be confident that we detected an exoplanet

Is one transit enough to be confident that we detected an exoplanet? I will argue: No. and back it up with material contained in my earlier question After only one eclipse of its X-ray bright primary,...
uhoh's user avatar
  • 30.5k
6 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 (...
Mick's user avatar
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6 votes

Is it possible to see mercury transit "clearly" by the naked eye?

There is even more to @uhoh's "no" answer. Even if the planet were larger in the sky, as it would be with Venus, we still could not see it through clear air without a filter. The light from the ...
Oscar Lanzi's user avatar
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5 votes
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How do we know the order of the new Trappist-1 planets?

Using Kepler's laws. We can determine the orbital period, $P$, each planet has by just looking at the time between transits for a given planet. Each planet has a distinct transit so its easy to ...
zephyr's user avatar
  • 15k
5 votes

Pinhole Projector: Can I use a specific solar optical eye piece to focus the Transit of Mercury?

The whole point of a pin hole projector is that it doesn't need any optics just a pin hole. If you are after magnification then that is related to the distance you project the solar image behind the ...
James Screech's user avatar
5 votes
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Pinhole projector for the Transit of Mercury

I've just rewritten this answer - @MikeG caught a glaring error by pointing out a really basic handy relationship called the Rayleigh criterion. \begin{align} {\theta}_R \approx1.22 \frac{\lambda}{D}...
uhoh's user avatar
  • 30.5k
5 votes
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Watching the Mercury transit with improvised devices

Mercury's angular diameter on transit day will be 12 arcseconds. A camera obscura using a 12 mm aperture could resolve it; one lens from +0.75 diopter reading glasses, if you can get them, will ...
Mike G's user avatar
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5 votes
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When will the next transit of Earth be visible from Mars? Was the last one really on May 11, 1984?

Yes. The Clarke story is quite correct. Earth (and Moon) would transit the sun from the viewpoint of Mars on 8 May 1905, 11 May 1984 and again on 10 Nov 2084. full list over a period of about 1000 ...
James K's user avatar
  • 123k
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 ...
uhoh's user avatar
  • 30.5k
5 votes
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How could one use the transit of Mercury to try and find the Astronomical Unit?

Thanks to the Mercury transit, you can measure the parallax from the Earth. That happens due to TRACE , which tracks the transit of Mercury along the polar diameter of the Earth. During that tracking,...
Carlos Vázquez Monzón's user avatar
5 votes

How can a Grade-11 Student avail TESS data and learn to process?

I'll use the TESS satellite as an example, which you might use to look at transiting exoplanets for example. Go to https://heasarc.gsfc.nasa.gov/docs/tess/data-access.html this gives you a list of ...
ProfRob's user avatar
  • 153k
5 votes

Get orbital period of exoplanet from light curve using astropy.timeseries

The second light curve you show has no obvious periodic behaviour and I cannot see any sign of a planetary transit. The period-finding algorithm appears to be working correctly. The planet (if it ...
ProfRob's user avatar
  • 153k
5 votes
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Star brightness data to study exoplanets with the transit method?

I don't know of a source for the CSV data directly but if you are OK with a little bit of Python, this can be done with the NASA Exoplanet Archive. Looking at one famous example (HD 189733b), if you ...
astrosnapper's user avatar
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5 votes

How often does the configuration of the Trappist-1 system repeat

If the resonances are 2:3:4:6:9:15:24, we need to find the smallest number that is a multiple of all those numbers, so each planet has made an integer number of revolutions, and is back where it ...
David McKee's user avatar
4 votes
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Why aren't all planets in the same plane?

Your reasoning is correct: if Mercury orbited in the same plane as Earth, we'd see it transit the Sun every 4 months or so. In fact these orbital planes are inclined 7 degrees to each other, and the ...
Mike G's user avatar
  • 18.7k
4 votes

Pinhole Projector: Can I use a specific solar optical eye piece to focus the Transit of Mercury?

I built an optical projector to observe the Venus transit with a 10x50 monocular. I mounted the monocular inside a box, leaving a small window to observe the projection. The focusing capability of the ...
Jon R's user avatar
  • 41
4 votes

Capability of observing transits with terrestrial telescopes of various sizes?

An 18.5 inch telescope is easily large enough to collect the photons you require. So long as you have a good CCD camera, with a pixel size on the sky that is considerably smaller than the "seeing" and ...
ProfRob's user avatar
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