#astronomy question

Basically, on a scale of “negligible” to “everything is beyond fucked” how disastrous for the solar system would it be if the gravitational pull of the sun completely disappeared for ~10 minutes

What would it take to convert a radio telescope into a radar telescope?

For context: I’m writing, and what I’m writing involves radio telescopes. I had assumed, perhaps incorrectly, that most radio telescopes could be used as both receivers and transmitters, believing due to the parabolic-dish nature of many of both such devices, there’d be a relative ease of conversion. But thinking about it, the circuits required to transmit and receive radio waves are quite different from one another. So that nixes my initial thoughts.

However, I just found out about the Goldstone Deep Space Communications Complex, aka the Goldstone Observatory, which not only uses parabolic radio antennae as radio telescopes, but also (and mainly) as a communications array for NASA to keep in touch and transfer data to/from its satellites and deep-space probes. Structurally, the Goldstone radio antennae look not so different from those at, say, the Green Bank Observatory, but I know there’s some sort of equipment that sets them apart.

What I’d like to know is, what equipment is it that sets these dual-function dishes apart, exactly, and what would it take to convert a radio telescope for that function?

Thanks!

*Pic taken at my house just now (18:50) in Tennessee

Sometimes, though, it’s my nemesis. I want to research things for realism’s sake, but either I know I’ll get so distracted in the research that I’ll get totally derailed, or I just-- don’t have the attention span to understand what I discover.

Current problem: Astronomy, or whatever you call the movement of celestial bodies, as it pertains to world-building. 

I once wrote a throwaway line in a BuckyNat fic, describing the moon. I was like, ok, it’s gotta be like, at least half a moon, for the shadow, and I’ll have it rising so the shadow falls across the balcony. OK. No big, right? That’s vague enough that I could be right, right? 

No! I got a very sweet comment from someone who was an astronomy enthusiast informing me that there’s literally never a time when the moon would do the very vague thing I described it doing, and I should consult this chart or ask someone if I wanted to describe the moon. Here’s the thing: I live on Earth, and have for my whole life, and I notice the moon with a frequency relative to how often it is relevant to me, namely how often it is either really pretty or its presence or absence makes nighttime shenanigans either possible or not, casting shadows and whatnot. That’s the level of detail I have absorbed. And I fucked up this super basic thing? I don’t know, man. (It was a sweet comment and they were very apologetic but for real? The moon never rises at night when it’s waxing, or whatever? I -- it would not have occurred to me to ask someone if that were possible. I did not know the moon had so many rules.)

To come up to my current point. 

I want to set a story on an inhabitable world that is the moon orbiting a gas giant. OK? That’s my sole condition. That’s what I got.

How long are the days? How often would the planet reflect a sun-like amount of light onto the moon? How often would the moon be on the opposite side of the planet from the sun, and therefore be extremely dark and cold? What would happen? There wouldn’t just be one 12-hour “day” and one 12-hour “night” ever at any point anywhere on that moon’s surface, would there. There’s just no way. So i could come up with all kinds of crazy explanations to give the planet any climate I wanted, but there’s no way to escape the fact that the light levels are going to be absolutely wild, and there are *going* to be insane temperature fluctuations. 

There’s no way to avoid that, unless I want to just-- ignore the main condition, and make it just aesthetically have a really big planet in its skyscape.

But I don’t even know how I’d begin to work out what it would actually be like on this planet. I don’t know where to start. It’s beyond my abilities. I don’t want to just do that last thing, but I don’t think I have a choice, because I’m not capable of working out the complexities of what such a planet would really be like.

That’s pretty humbling, I guess. I mean-- I’d think about asking someone but who do you ask? And I’m gonna have to take their answer on faith because I’m not gonna understand it. 

Ugh, I’m gonna be late to work, but I had to set that down before I forgot it, again, because I’ve been forgetting things a lot and it’s getting old.

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I’m not an astronomy expert so forgive me if I get any of the terminology wrong here

If a binary star system passed by particularly massive star, would it be possible for the gravitational pull of the massive star to capture the smaller half of the binary system?

Like, say, hypothetically, you have a binary system consisting of a yellow dwarf about the same size and mass as our sun and a considerably less massive red dwarf. Say they orbit a good distance apart from each other, or perhaps the red dwarf has a very irregular orbit.