First space images captured by balloon-borne telescope | Hacker News Reader

First space images captured by balloon-borne telescope

utoronto.ca

170 pointscolinprince47 comments

Title is very misleading. Other balloon-borne telescopes have captured images. These are just the first images of "this specific telescope".

Funny how this is the same misleading language that tripped up Bard during the Google demo [0]. What's with telescope image headlines and the use of ambiguous language?

[0] https://twitter.com/astrogrant/status/1623091683603918849?s=...

Oh, I misread it, I thought these were the first space images captured, and they just happened to have been captured by a balloon-borne telescope.

Would suggest renaming to “First space images captured by SuperBIT balloon-borne telescope”

Or "Balloon-borne telescope captures its first space images".

Yes, the preceding suggestion still had an (admittedly somewhat implausible) alternative reading, that "its" helps avoid.

> The Super Pressure Balloon-Borne Imaging Telescope (SuperBIT) was flown to the edge of space

> SuperBIT flies at an altitude of 33.5 kilometres

Just no. I could understand say, shaving a few km off to get the project into "space". Maybe ten. I get that space is a bit of a blurry boundary and somewhat arbitrary up there.

But not seventy.

“Edge” is doing a lot of work here, haha. In fact, a paper airplane has flown higher than this balloon!

Only after it was dropped from an even higher altitude. You could also do it with a rock.

I too did a quick return to "Space Elevator"!

https://news.ycombinator.com/item?id=35629972

For others, the definition is generally https://en.m.wikipedia.org/wiki/Kármán_line

"Edge of space" is a pretty loosey-goosey expression. For instance:

"What it takes to fly spy plane U-2 to the edge of space" https://www.bbc.com/future/article/20140224-flying-at-the-ed...

(The U-2 flies at something around 21 to 25 kilometers, depending on what source you go by.)

Interesting. Apparently some people consider the Armstrong Line [1] (where pressure is low enough that water boils at body temperature, at about 18km) to be the start of "near space". As opposed to "outer space" which starts at the Kármán line at 100km (unless you are in the US, where outer space starts at 50miles/80km instead)

1: https://en.wikipedia.org/wiki/Armstrong_limit

It is a normal human thing to make categories when nature is like "nah we got a continuous spectrum here y'all" and then humans argue about the categories forever.

Mammals, animals that give birth to live young, have fur. Monotremes say wat!!?

TIL:

https://en.m.wikipedia.org/wiki/Monotreme

Something like 99.6% of the atmosphere is below you at 100,000 feet. This is what matters, not the fact you're in space, but the fact you're not looking through a hot(ish) dense gas filled with moisture.

That's still equivalent to an martian atmosphere above.

That is an interesting note, but I’m not sure how much intuition it adds. Mars somewhat famously have not a ton of atmosphere, right?

Still good enough to take some great infrared pictures. Sure, it’s not even close to the same league as JWST, but most astronomers on the planet are jumping over each other to submit proposals for observation on that.

Yes, both are very thin indeed, Mars has 6-10 millibars vs 1013 millibars at Earth sea level.

Except thay the mars atmosphere contains considerable amoints of dust and weather. Earth's atmosphere at these altitudes is bone dry and homogeneous. Presssures may be similar but the optical properties are totally different.

Who cares, given that for a telescope what matters is the fraction of the atmosphere below it and that it is viewing things that are for all practical purposes at infinity it might as well be in space, the images wouldn't be any different unless the angle was very oblique, and even then the difference between being on the ground and being truly in space would be rather smaller for the second.

> scientific balloon the size of a football stadium.

In the photo, it doesn't look that big - or does the balloon expand significantly more within the high-altitude low-pressure atmosphere?

...

Also: here is the SuperBIT Wikipedia article: https://en.m.wikipedia.org/wiki/Super-pressure_Balloon-borne...

According to the description of this NASA image [1], they flew a 7-million-cubic-feet super-pressure balloon in 2009. Approximating as a perfect sphere, that's around 120 feet in radius / 80 yards in diameter. And "When development ends, NASA will have a 22 million-cubic-foot balloon", which is around 170 feet in radius / 110 yards in diameter. These things also look squashed when inflated [2], so they're probably even wider horizontally. Basically, you can fit an entire football field inside along with some stands.

1. https://commons.wikimedia.org/wiki/File:NASA-NSF_super_press...

2. https://commons.wikimedia.org/wiki/File:Super_v_zero_pressur...

40 yds*

radius vs diameter

I think it would be more accurate to say it’s the size of a football field than a stadium.

The stabilization mechanics must be very interesting. The earth rotates so it will need to move to track objects. There’s probably also still some vibration from the atmosphere. Then it’s on a tether so any movement will cause it to swing. Pretty cool!

Can't it all be done computationally?

Probably yes, I meant the entire system for stabilization including electronics.

So if we can do these, why do we want to launch super expensive orbital telescopes?

Because these are still inside Earth's atmosphere — there's much less of it up there, sure, but even that little air can have a great impact.

Because orbital telescopes can stay up there for years.

That said, there's a need for both. It takes a whole lot less capital and time to get a telescope up under a balloon, and it can come down, be refurbished, and sent back up again.

The James Webb's unique selling point is that it's cooled to -233 degrees science, eliminating a lot of infrared "noise" that an earth-bound telescope would not have.

For some scientific purposes, eliminating 99.6% of the Earth’s atmosphere is approximately the same as eliminating 100% of it. E.g. precise imaging and characterization of nearby interstellar bodies, those projects get Hubble-tier data thousands of times cheaper.

For other scientific purposes, eliminating 99.6% of the Earth’s atmosphere is approximately the same as eliminating 0% of it. E.g. trying to divine the values of physical constants in the earliest moments of the universe by looking as far into the past as possible, those projects are far too sensitive and their observations would be completely swamped by the noise of the remaining 0.4% of Earth’s atmosphere.

For one, they can't fly for too long, and they tend to move around a lot...

So, the balloon flies above 99.5% of the atmosphere, but the telescope hangs under the balloon, so it have to take photos more sideways than straight up? Got to be a lot more than 0.5% of the atmosphere in the frame then.

They have a video of it launching on their instagram (superbit.telescope), it looks like it has a very long tether beneath the balloon

I found a photo also of the long tether:

https://ras.ac.uk/news-and-press/news/superbit-low-cost-ball...

So even if it can't look directly up 90°, it can probably get up to 85° vertical, so it's totally fine.

Good picture, but at least part of that length is yet-to-be-inflated balloon. I'm guessing that the thicker section is the canopy of the descent parachute, so everything above that is likely part of the balloon. Assuming it is, and the balloon inflates to a sphere with the top at the same height, it looks like the telescope can point about 60° above the horizon.

Hah, I was at CSBF for this launch (working on a different balloon payload...)

This telescope will look at the same angle that a ground-based telescope would -- it's dictated by the object you want to look at.

Nice. Surprisingly, although balloon-borne optical telescopes were a thing in the 1950s and 1960s, there have been very few since. Wikipedia has a list of balloon-borne telescopes for microwave and X-ray bands.

The key metric is buried towards the end of the article: Its mirror has a diameter of 50cm.

Unfortunately there is no further information about the exposure time of these images

I couldn't even find a repository of the images, which I would assume would have information on exposure time. Makes me wonder if these are testing images. The closest I could find was 17 minutes for an image from their 2016 run.

https://www.mn.uio.no/astro/forskning/aktuelt/arrangementer/...

Glad this one wasn't shot down.

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