Mick
  • Member for 5 years, 5 months
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Are there more stars in the universe than grains of sand in the Earth?
34 votes

A quick google gave me these (approximate) figures: 7.5 x 1018 grains of sand in all the beaches and deserts of the world 7 x 1022 stars in the observable universe If these are reasonable estimates, ...

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Which planet is this (if any)?
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30 votes

Stellarium shows the Moon and Mars very close together in the sky tonight (Saturday, 3rd October 2020), so yes, it was probably Mars that you saw. Moon and Mars on 2020/10/03 (Stellarium) Stellarium ...

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What's the white glow around this star?
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18 votes

Astrometry.net has identified your star field as being part of the Andromeda constellation. The diffuse object in the centre of your image is the Andromeda Galaxy (Messier 31). The bright star to the ...

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Does this smartphone photo show Mars just below the Sun?
15 votes

Stellarium shows Mars close to the Sun and just above the horizon at that date and time. Unfortunately, Mars is only 2° above the horizon (and also on the other side of the Sun to the Earth), so it is ...

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How can I identify a star?
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8 votes

If an astronomical object appears to be very bright, and does not appear to 'twinkle' very much, then it is probably a planet, rather than a star. Jupiter is almost on the opposite side of the Earth ...

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Powerful-enough telescopes to observe the Lunar Roving Vehicle from Earth?
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5 votes

I don't think so. In order to resolve an object one metre across (as a single pixel) at a distance of 384,400km (the diameter of the Moon's orbit), you would need a telescope mirror about 200 metres ...

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What kind of reddish wood is it exactly that was historically used to line the inside of observatory cupolas (domes), in order to absorb moisture?
5 votes

Probably western red cedar, thuja plicata, especially if the observatory is in North America. Western red cedar is easily obtainable in North America. It has a light, red, wood that is particularly ...

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Need advice on mirror-making for a home-made amateur reflector
4 votes

I second the comment about Texereau -- originally written in French; it's the best, bar none. You won't need anything else. Remember the old adage that is quicker to make a 4" mirror and then an 8" ...

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Long tube for eyepiece
3 votes

The reason that some telescopes have long eye-piece tubes is that the focal plane of the objective has been placed far enough outside the main tube assembly to allow erecting prisms or binocular ...

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About more than 15 stars moving in straight line through the sky
2 votes

These will be SpaceX's second batch of 60 Starlink communications satellites. They were launched on 11 November 2019, and are still in roughly the same orbit, although they are slowly dispersing. ...

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Did I see the dragon capsule on Friday night?
2 votes

I have certainly watched the ISS and an undocked Shuttle Orbiter chase each other across the sky. Since they appeared to be of equal brightness, I didn't know which was which. Their angular separation ...

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Eclipse comparison: May 20 2012 vs Aug 21 2017 as observed from San Francisco, CA
2 votes

This is going to be the eclipse of the century for the USA. To make the most of it, you need to be on the path of totality (see map) to see a total eclipse. If you stay in San Francisco, you will only ...

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Which eyepiece should I use to view planets with a Slokey Skyways 50080 telescope?
1 votes

General guidance seems to be to use a magnification of 30 to 50 times the diameter in inches of your telescope's aperture. An aperture of 80mm is just over 3", so we are looking at ...

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I am beginner here.Could any one please suggest telescope on AliExpress
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0 votes

AliExpress advertise Celestron astronomical telescopes. Celestron is a reputable manufacturer, and these scopes should be good quality, providing that they are genuine Celestron scopes and not Chinese ...

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