# Questions tagged [planetary-transits]

For questions about transits of planets in front of the Sun, as seen from another, more distant planet; for example, the transits of Mercury and Venus which are visible from the Earth.

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### How to calculate the angle formed between 2 planets?

I am interested in calculating the angles formed between planets like Saturn opposite to Neptune - 180 degrees, PlanetX opposite/trine/square to PlanetY. How to find such degrees? I use Stellarium ...
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### When will the next transit of Earth be visible from Mars? Was the last one really on May 11, 1984?

@PM2Ring's comment mentions the story Transit of Earth written by the famous British science fiction writer, science writer and futurist,3 inventor, undersea explorer, television series host, Fellow ...
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### How does a Solar Transit give more accurate determination of Earth-to-Sun distance?

I understand how Solar Parallax calculation determines the Earth-Sun distance using measurements of (a) the baseline distance between two widely-separated terrestrial telescopes and the (b) two angles ...
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### Guess inclination angle from radial velocity measurements

I came upon this question where the situation is I have radial velocity measurements of a star with two circular orbiting exoplanets and the question is how to find out if the inclination angles of ...
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### How long does it take the center of the Earth to complete a full orbit?

If we take midnight of 1/1/2017 in any country and mark in space where the center of the Earth is located, at what date, in the same country, has the center completed a full orbit. I am almost ...
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### How (the heck) was this photo of Venus at inferior conjunction (between us and the Sun) taken?

This great answer by @gerrit discussing planetary phases seen in visible light contains the image I've included below. According to the Wikimedia Commons link these are ESO images from the Venus ...
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### Detection of exo-planets

One method used for detecting exo-planets is to look for a slight dip in the parent star's luminosity as the planet transits the stellar disc. Intuitively, it seems to me that if planetary systems in ...
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### What's the influence of a tilted orbital plane, when observing an exoplanet transit?

I made an illustration to explain what i mean : If we assume we have two similar planet/star systems (similars in size/mass/period..) but tilted differently relative to us. How can we predict that ...
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### How do we know the order of the new Trappist-1 planets?

Using transit photometry astronomers were able to discover Trappist b through h. Based on this question we learn that the naming of planets is based on their distance from their star (b being the ...
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### Exoplanet rotation period

Is there any way through which we could determine the ROTATION period of an exoplanet based on the data we observed?(from transit)
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### Is it possible to tell if a certain extrasolar planet produces its own magnetic field?

I know by observing the dimness of a star it is possible to calculate an exoplanet's distance from the star and its mass by how much the star wobbles. However, is there any way to accurately determine ...
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### Can a telescope be built to focus on a point source star?

If a Kepler telescope were built to focus on one point source star at a time, would it provide more information, or did Kepler capture virtually every photon from any given star anyway? In order to ...
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### What telescopes have observed anomalies in the light curve of Tabby's star, KIC 8462852?

KIC 8462852, the F-star that inexplicably dims by up to 20% for short periods, is still getting alot of attention. A slow continuous dimming by about 0.3% a year has been identified recently. But all ...
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### (How) Can one determine if an exoplanet is synchronously tidally locked or not? [duplicate]

Mercury is asynchronously tidally locked so that all of its surface regularly sees the Sun. But an exoplanet which is synchronously locked to its star, could we tell that it is? It would have a hot ...
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### Does Earth transit look like a black dot surrounded by red light?

As we know, lunar eclipse appear red, if we can see Earth transit from Mars, does it look like a black dot surrounded by red light on the sun?
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### Capability of observing transits with terrestrial telescopes of various sizes?

I have access to my university's telescope, Dearborn Observatory, an 18.5 inch refractor on the shore of Lake Michigan, just north of Chicago (yes, it's an atrocious location, but the telescope still ...
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### Which elements are an indication of habitable exoplanets?

Using spectroscopy the chemical composition of exoplanets atmosphere is determined. As a scientist, what spectral lines would you look for? Which elements are relevant in pursue of a second earth?
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### Why did Mercury not appear to transit through the middle of the sun?

Why did Mercury not appear to transit through the middle of the sun (the equator)? I initially thought that this was because of the ecliptic, but, then I thought that actually we'd see it above the ...
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### Why was the size of the solar system not defined by Mercury Transits?

The first measurements of the (absolute) size of the solar system was made using the Transit of Venus, an event that arguably will only happen twice in a lifetime. Transits of Mercury occur far more ...
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### Why aren't all planets in the same plane?

Obviously all planets are not in same perfect plane. Because if at all they were in the exact same plane, it would mean that Mercury transits and Venus transits would not be that rare. Any ...
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### Pinhole Projector: Can I use a specific solar optical eye piece to focus the Transit of Mercury?

The title pretty much explains this one. Can I use a specific solar optical eye piece, or other optical device, in conjunction with the pinhole projector method to focus the Transit of Mercury? ...
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### Pinhole projector for the Transit of Mercury

Very quick and simple one today. What would be the best/optimal pinhole size for a pinhole projector to observe the transit of Mercury on May 9th? I want to get the optimum between resolution and ...
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### Watching the Mercury transit with improvised devices

I have learned that it is not possible to watch the upcoming Mercury transit with the plain eye (using special filter glasses). Is it possible to watch the transit with improvised devices (like a ...
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### Were there any images of a transitary event of Jupiter or Saturn as imaged by a deep probe mission

I'm quite certain that there isn't any actual images of a transitory event of Jupiter or Saturn across the solar disk from say e.g.,s the Voyager probe, Pioneer 10/11 or even recent New Horizons ...
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### Blackhole Finding Techniques

I know of two methods for finding exoplanets: the transit method and the radial velocity method. These two methods work as follows: Transit: we observe stars and watch for when a planet obstructs the ...
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### Are there ever any simultaneous transits of both Mercury and Venus as seen from the Earth?

Transits of Mercury happen fairly frequently due to its short period, but transits of Venus are less frequent. I've looked over the data available to me and found that there have been transits of ...
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### Venus transiting behind the Earth’s moon December 7, 2015

Observing from Earth what are the odds that Venus does not line up in conjunction with Earth’s moon and does not transit behind the moon but slightly below or above with a complete visual of Venus ...
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### Occurrence of Venusian transits

As transits of Venus come in pairs, each separated by 8 years, wouldn't that imply an accurate ratio between Earth's and Venus' revolution period? I've found the ratio to be about 0.681. I presume one ...
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