PV Gap

Ruben Said:

What does the Solar system look like from other stars?

We Answered:

The Sun is pretty ordinary. There are hundreds of stars in the sky that are similar. How bright it looks depends on how far away you are. From Alpha Centauri (4.3 ly), the Sun is pretty bright, but from the vicinity of Betelgeuse (over 600 ly), it wouldn't even be visible to the naked eye (Betelgeuse is NOT a sun-like star, it's a red supergiant, which is why it's bright in our sky even though it's so far away).

Lots of stars apparently have Oort clouds. Some have belts of material like our Kuiper Belt or Asteroid Belt. Some have planets. When I was a kid, we just theorized that, but now we've actually observed these things.

However, just as it was difficult to see those things around other stars, they'd be hard to see around the Sun from another star.

Lee Said:

How can I focus an Orion Starshoot Solar System color imaging camera II on a Meade ETX telescope?

We Answered:

The main problem with focusing on a nearby landmark is that it is most likely TOO nearby --- it is probably too close for the telescope to focus on --- at least as far as the camera goes. Now as far as celestial objects go:

The most straightforward approach is to aim the scope/camera on a star. Since the camera has (digital) zoom, zoom to the maximum. Then carefully adjust the focus until the star's image is as small as possible. Zoom out to normal (do not use zoom in the actual imaging).

The scope/camera should now be in focus for imaging the Moon and planets. If you need to insert an eyepiece to check things don't adjust the focus but either use the parfocal ring or move the eyepiece up the focuser tube until it is in focus as indicated in the manual, which can be found here:
http://content.telescope.com/rsc/img/cat…

Stanley Said:

What would the sky look like on each of the other planets in the Solar System if someone were looking up at it

We Answered:

(1) A transit of the Earth as seen from Mars will occur on November 10, 2084.

Just as we can see occasional transits of Venus and Mercury from Earth i.e. we see these inferior planets cross the disk of the Sun (with a telescope and protecting our eyes), an observer on Mars can see transits of Earth, Venus and Mercury, an observer on Jupiter can see transits of Mars, Earth, Venus and Mercury and so on, with an observer on Neptune being able to see transits of Uranus, Saturn, Jupiter, Mars, Earth, Venus and Mercury,

(2) Mars has a thinner atmosphere than Earth and therefore its armosphere would be less of a problem for astronomers using ground-based telescopes on Mars than it is on earth. There would be less need on Mars to build observatories on the top of mountains (scaling Olympus Mons might be rather difficult in any case).

Mercury too has little or no atmosphere and is similarly suitable for astronomers to work from, Venus however is perpetually covered in a thick, impenetrable layer of clouds, that we cannot see into, and Venusian astronomers could not see out of.

(3) Light pollution from cities, preventing dark sky viewing would not be a problem on any of the other 7 planets, though. But those planets with large moons could limit the observer's visual acuity (the amount of sunlight they would reflect). The more moons, the bigger the problem, potentially.

(4) The furrther away from the Sun the planet is, the less sunlight it will get, the colder it will be, and the size of the disc of the Sun in the sky will be correspondingly smaller.

(5) This in turn will mean that the Sun is able to be eclipsed by smaller and smaller moons, the further away from it that you go and it will also mean that some of those eclipses will last longer (and partial eclipses be rarer) given that large moons will easily more than cover the Sun's disc.

Mercury and Venus have no moons and this does not apply to them, obviously.

(6) Comets can be expected to be seen from all the other 7 planets, and also meteor showers (as these are the result of debris left behind in the wake of a passing comet) can be expected on all but Mercury (as these involve the debris burning up in the planet's atmosphere and Mercury hasn't got one).

(7) As all four gas giants have rings (not just Saturn, it simply has the most spectacular rings) they would be a permanent feature of the night sky on Jupiter, Saturn, Uranus and Neptune.

(8) And of course there would be robotic probes from earth, flying by and occasionally landing on the other 7 planets!

Randall Said:

Is it possible to build a transmitter that could transmit a message out into the solar system?

We Answered:

It's already been done, with commands sent to the Voyager space probes.

But those used large dishes, several hundred of feet in diameter, and millions of watts of power, nothing you can do at home.

.