WictImov

WictImov t1_j65rdv4 wrote

I don't think using a black hole as a gravitational lens would achieve your objective. A simple lens like a magnifying glass does not work like a set of lenses with well-placed relative distances like a telescope (or microscope). Try using a magnifying glass to see something in the distance. It doesn't work, it will only focus on something closer to it than it is to your eye.

This is all moot however because you would see those things with more clarity if you placed the space telescope close to them, to begin with.

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WictImov t1_j4lfjbt wrote

Do not go with high magnification, go with a larger aperture (the second of the two numbers). A 10x50 is a reasonable compromise for beginners with limited budgets, if you can find an 8x60 or 10x60 it would be even better. Do not get higher magnification than 10 if you do not have a stand to hold the binoculars or have learned and gained experience sky gazing with them.

When holding binoculars, keep your elbows close to the body. It might be better to sit in a lawn chair or something you can comfortably recline in so you can hold them steady for a longer period of time.

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WictImov t1_j4bjzab wrote

Apollo 8 was the real defining mission, taking man to the Moon and back. Way too much focus is on Apollo 11 & 13.

b.t.w., I was 8 when Apollo 8 took place, and remember it well. Going out in the snow and looking up at the crescent Moon, and wishing I was there or at least could see them. Squinting my eyes, and saying I think I can see them. Yes, even at that age I knew that was a fantasy, but a nice one to have. Then we go inside (probably the other way around, don't remember for sure) and watch the Christmas Eve message from the Moon.

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WictImov t1_ixsn596 wrote

  1. These are not the final images we will see, just what has been priortized on the downlink.
  2. There are a couple of dozen camera's on Orion, we are only seeing images from a limited few of them.
  3. Sunlight in space (and on the Lunar surface) is very harsh. Even on Earth, photographers like to take images at dawn and dusk for a reason but even noontime sunlight is filtered by a lot of atmosphere and reflections from the landscape. The sunlight hitting Orion has no filter at all, so expect them to be very high contrast.
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WictImov t1_ixjs3qi wrote

Halley's comet travels inside of Earth's orbit. It's perihelion is ~0.6au (aphelion is over 35 au). 1 au (astronomical unit) is the distance of the Earth from the Sun.

Halley's comet is roughly equal parts ice and dust. The ice is about 80% water, and most of the rest is carbon monoxide. Yes the Sun's irradiance will sublimate the ice, but there is also a time factor.

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WictImov t1_ixjiift wrote

I am not familiar with that telescope, but from the picture, I see it has a very flimsy-looking tripod. As someone else mentioned, you are probably better sticking with a Dobsonian mount which is used on reflecting telescopes. While there are excellent refractors out there as well, they are well over $1000 entry cost and need an equally expensive tripod or other mount. With a flimsy tripod, you will not get a stable image. The higher magnification you use the worse it will get. That is why many people are turned off of astronomy, they got the wrong equipment to begin with.

Low-end refractors are fairly good in many respects but suffer from chromatic aberration (can't bring different colours into focus). That can be corrected with better optics, and that is why people pay much more. A good refractor makes an excellent telescope, but will not be cheap compared to an equivalent reflector (light gathering).

Reflector telescopes don't have the above problem (a mirror reflects the entire spectrum equally). The other advantage of reflector telescopes is that for the same objective size they are far cheaper, or for the same money you can get a much larger objective size and collect a lot more light. A 6" reflector will collect almost 4.5 times the light as the 72mm refractor.

Dobsonian mounts are more stable for the dollar than a tripod. Dobsonian mounts require a reflector telescope. A Dobsonian telescope is a reflector telescope on a Dobsonian mount.

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WictImov t1_ixek2zw wrote

The closed loop model is a different animal, it would suggest you could end back at your starting point if you travel in one direction far enough (just like going around the world in an airplane). While possible, I am unaware of any evidence that leads us in that direction. I would say the cosmic microwave background suggests otherwise.

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WictImov t1_ixej9vc wrote

If you get to the edge, you would find Milliways.

Since the universe is [still] expanding, then no matter how far you travel (limited by the speed of light) you would never reach the edge. The rate of expansion is estimated* to be 73 million kilometres per second per megaparsec. Both parts of that number are important because the expansion is not at the edges but throughout the universe. Don't think of the expansion as a ripple in water that travels outward from a point, but rather an elastic band that stretches everywhere along its length.

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* Yes, I know about the discrepency with the 67.5 kilometres per second per megaparsec estimate but that is too much detail for here.

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WictImov t1_ix08km3 wrote

At approximately 350 million meters away currently, you would need a telescope of 200-meter diameter minimum to be able to resolve it (Dawes limit). No such telescope exists and at that size, the atmospheric disturbances would be almost impossible to filter out.

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