A rare occultation of Betelgeuse(spaceweatherarchive.com)
spaceweatherarchive.com
A rare occultation of Betelgeuse
https://spaceweatherarchive.com/2023/12/10/an-extremely-rare-occultation-of-betelgeuse/
37 comments
Did anyone capture it in video format, with a high-ISO camera mounted to a telescope? It would be fun to see it, if it's possible with today's image sensors.
Not a telescope, but this is the best video I've seen: https://www.youtube.com/watch?v=0dePmzxejd8
It happened over several seconds, and would have been so faint that you won't notice it without heavy video processing.
The photographer says it had been expected to decrease by 3 orders of magnitude, which would definitely be noticeable with the naked eye.
The video in a sibling comment by bscphil also seems to show it decreasing by ~2 orders of magnitude (compare it to the stars in the "sword") - do you think this is highly processed?
The video in a sibling comment by bscphil also seems to show it decreasing by ~2 orders of magnitude (compare it to the stars in the "sword") - do you think this is highly processed?
What's expected and what actually happens are totally different things. How many times have we heard "comet of the year/decade" only for it to barely even survive the approach?
A 1 minute exposure is different than highly processed video. It is definitely artificial compared to naked eye viewing due to amount of photons captured. To see it dimming over the course of 3 seconds that matches the differences seen in the long minute exposure, I doubt the average person would see it in a video, but I could be wrong. Reading about this event in the run up to it occurring, I came to the same conclusion that I would try a long exposure the same way using the equipment that I have. At least, until I realized I wasn't in the path.
The amount of information that can be captured with a 1 minute exposure is totally different from a video camera running at 24-50fps. It's just one of those things that becomes better understood with experience. People want to see things moving in realtime as video, but space doesn't bother itself with your wants. Best to just do what needs to be done to get the most information possible when you're available to get it.
A 1 minute exposure is different than highly processed video. It is definitely artificial compared to naked eye viewing due to amount of photons captured. To see it dimming over the course of 3 seconds that matches the differences seen in the long minute exposure, I doubt the average person would see it in a video, but I could be wrong. Reading about this event in the run up to it occurring, I came to the same conclusion that I would try a long exposure the same way using the equipment that I have. At least, until I realized I wasn't in the path.
The amount of information that can be captured with a 1 minute exposure is totally different from a video camera running at 24-50fps. It's just one of those things that becomes better understood with experience. People want to see things moving in realtime as video, but space doesn't bother itself with your wants. Best to just do what needs to be done to get the most information possible when you're available to get it.
That's likely what the picture is and according to the caption you could barely notice.
Just be careful about saying the name too much during such occult conditions.
I was excited to check it out last night, as it was clear in my area and I had a nice view of Orion. But then I realized you had to be waaaay down south, like southern FL, to see it :(
Welcome to astronomy! If it's not an issue with local cloud coverage, it'll be an issue of not being visible from your area. But when it does happen! To me, it's better than the proverbial golf shot. Even though I've experienced the golf shot, I've never spent thousands of dollars on anything golf related. I've never stood out in the freezing cold in the middle of the night working on a golf swing. Also unlike golf, you can get assistance and people are typically happy to provide it.
I was in Miami, but it was cloudy. :(
This seems an extremely strange coincidence to me, since I haven't often noted the extremely bright, redish star in Orion's shoulder, but I did last night, at about 10:00 PM EST. I don't suppose any brightening effect would have been expected because of this? I thought it was possibly Mars, but didn't look into it.
Betelgeuse does fluctuate in brightness from 0 to +1.6 apparent magnitude which makes it pretty bright. In fact, it is listed at the 10th brightest star[0]. It should be recognizable anytime you look up during season if it is not cloudy. I can see it in light polluted urban areas. As the saying goes, keep looking up!
There are 3 bright red dots that I use as sign posts, and it is fairly easy to narrow down which one it is. Is it part of Orion (easily ID'd by the belt and sword), then it is Betelgeuse. Is it part of Scorpio (ID'd by seeing the pinchers up and to the right), then it is Antares. Else, it is Mars. The fun thing about Scorpio is that it is a guide to finding the central portion of the Milky Way. You could also add winter/summer as filters in that as well.
[0] https://en.wikipedia.org/wiki/List_of_brightest_stars
There are 3 bright red dots that I use as sign posts, and it is fairly easy to narrow down which one it is. Is it part of Orion (easily ID'd by the belt and sword), then it is Betelgeuse. Is it part of Scorpio (ID'd by seeing the pinchers up and to the right), then it is Antares. Else, it is Mars. The fun thing about Scorpio is that it is a guide to finding the central portion of the Milky Way. You could also add winter/summer as filters in that as well.
[0] https://en.wikipedia.org/wiki/List_of_brightest_stars
Nope, Mars is currently on the opposite side of the sky from Orion (and only a few degrees away from the sun, so it's difficult to see at all).
Post date is 1970-01-01. Interesting.
That’s the user name of the submitter.
I did a double take as well - what an excellent username.
I figured it might be a pg bug that reset the story's timestamp to 0.
It’s a username
Let's say Betelgeuse exploded 550 years ago, and I happen to be looking at the star at the exact moment the light/EM reaches the earth. Would it be bright enough to cause an injury? If at night, would it make shadows on the ground next to me?
It will be comparable in brightness to a full Moon I believe.
Found this source quickly that says more like a half-moon, but it's all just estimates really. https://www.astronomy.com/science/when-betelgeuse-goes-super...
I think it's safe to say it would be unlikely to cause any damage to your eyes if you happened to be watching.
Found this source quickly that says more like a half-moon, but it's all just estimates really. https://www.astronomy.com/science/when-betelgeuse-goes-super...
I think it's safe to say it would be unlikely to cause any damage to your eyes if you happened to be watching.
Full moon energy concentrated on a small dot that has 100,000x smaller angular area might be able to damage your eye? I don't know, I didn't do the math
The sun is about 400,000x the brightness of the moon, with about the same apparent size. So I think the full moon's brightness concentrated 100,000x would be almost that bad. However, having the sun in your field of view momentarily doesn't blind you (disclaimer: don't stare at the sun until it blinds you; that will blind you ("solar retinopathy")).
There are a couple of other factors. Supernova "light curves" only reach their maximum gradually over several days. Also, your eye doesn't focus an arbitrarily small light source to an arbitrarily small spot on the retina. Instead it's something like an "airy disk". At some point, the relationship between apparent size and the size of the (blurred, "diffraction limited") image on the retina is appreciably non-linear. I think it matters in this case, because Betelgeuse is a lot smaller than the eye's "resolution" of about 1/60th degree. So its light is concentrated that much less (squared). In a supernova, the "size" of the star increases over time, though maybe not enough to matter, even for Betelgeuse.
There are a couple of other factors. Supernova "light curves" only reach their maximum gradually over several days. Also, your eye doesn't focus an arbitrarily small light source to an arbitrarily small spot on the retina. Instead it's something like an "airy disk". At some point, the relationship between apparent size and the size of the (blurred, "diffraction limited") image on the retina is appreciably non-linear. I think it matters in this case, because Betelgeuse is a lot smaller than the eye's "resolution" of about 1/60th degree. So its light is concentrated that much less (squared). In a supernova, the "size" of the star increases over time, though maybe not enough to matter, even for Betelgeuse.
The small dot would be equivalent in brightness to the full moon, meaning if you looked at both with a luxometer, they would look equally bright. It's not saying that the star will be as bright as the Moon, but concentrated down - that's not how brightness works...
For how long would it be that bright?
Besides the other reply, also it doesn't "turn on" to maximum brightness instantly. It takes on the order of several minutes for all the nuclei to absorb the neutrons and then start the radioactive decay that powers the light. Also you wouldn't see light from the whole star simultaneously - it would start from the center (because that's closer to you by the radius of the star), and light from the limb would take several more minutes to arrive (1 AU radius of the star = 8.3 minutes light travel time.)
So your eyes would have time to adjust.
So your eyes would have time to adjust.
Am I right, with ISS on the orbit it should happen several times every day. Not for 7 seconds, but..
No. There ISS needs to be exactly in the shadow of the asteroid Leona. Both the Earth and Leona are going around the Sun, so the shadow sweeps across the surface of the Earth, taking about 18 minutes to go from Mexico to China, and effectively never coming back.
Even if the ISS is in the shadow once - which would require amazing timing and last for fraction of a second - it is not fast enough to have a second interception.
Even if the ISS is in the shadow once - which would require amazing timing and last for fraction of a second - it is not fast enough to have a second interception.
I meant different thing. ISS is big enough to cast a small shadow on Earth. It moves fast and covers a star for some fraction of second (roughly size/orbital velocity). Still every day several times.
If I read https://www.aanda.org/articles/aa/full_html/2022/11/aa44496-... correctly, the occultation time for the ISS is under 20 ms (see figure 1, use a size of 100 m, and elevation of 400km).
The paper says the current generation of CCD detectors aren't fast enough to detect that change in light flux with >1% accuracy, as they integrate the light collected over tens of seconds.
The next generation of CMOS-based detectors might be fast enough.
There are some issues to handle, like the complex light curve of the satellite itself affecting the detection, and the relatively low density of bright-enough stars along the path between telescope and ISS.
The paper suggests using the tens-of-thousands of satellites in upcoming launches to improve the odds.
The paper says the current generation of CCD detectors aren't fast enough to detect that change in light flux with >1% accuracy, as they integrate the light collected over tens of seconds.
The next generation of CMOS-based detectors might be fast enough.
There are some issues to handle, like the complex light curve of the satellite itself affecting the detection, and the relatively low density of bright-enough stars along the path between telescope and ISS.
The paper suggests using the tens-of-thousands of satellites in upcoming launches to improve the odds.
Wouldn’t total occultation of a star be a great way to send signals to far away civilizations?
The star is occulted by a small asteroid in our solar system. For something in the Betelgeuse system to occult the star, it would have to be about the same size as the star.
We detect the presence of planets in other systems when they pass between us and the star, marginally decreasing the brightness.
Not a great way to send messages long distances
We detect the presence of planets in other systems when they pass between us and the star, marginally decreasing the brightness.
Not a great way to send messages long distances
If a star vanishes because you build a Dyson sphere that’s one way of sending a message
No need to build a whole Dyson Sphere, a simple starshade will do.
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