13 replies to this topic

[pete543]

Would you see color? Would it be too bright to look at? Would it be way too far outside of your maximum field of view?
Also, would it affect AP because of the brightness of it? I heard that when it does "go boom" it will be visible in the daytime, so would the brightness ruin shots of Orion and the surrounding areas?

[StargazerLuigi]

This article predicts that Betelgeuse would be about as bright as a first-quarter Moon, would easily be visible in the daytime, and would cast shadows at night.

https://www.astronom...ike-from-earth/

 

I've seen other articles suggesting it would be as bright as the Full Moon. Probably the guesses on its potential brightness differ because I don't think we know how far away Betelgeuse is. I would expect it to be intensely white. 

 

I don't know what you mean by 'too far outside of your maximum field of view'. It will be an intensely bright point source.

 

Since 2019 or so there have been a lot of click bait about Betelgeuse going supernova; current stellar modeling suggests it will probably be on the order of 100,000 years or more before anything goes boom.

[skysurfer]

This article predicts that Betelgeuse would be about as bright as a first-quarter Moon, would easily be visible in the daytime, and would cast shadows at night.

https://www.astronom...ike-from-earth/

 

I've seen other articles suggesting it would be as bright as the Full Moon. Probably the guesses on its potential brightness differ because I don't think we know how far away Betelgeuse is. I would expect it to be intensely white. 

 

I don't know what you mean by 'too far outside of your maximum field of view'. It will be an intensely bright point source.

 

Since 2019 or so there have been a lot of click bait about Betelgeuse going supernova; current stellar modeling suggests it will probably be on the order of 100,000 years or more before anything goes boom.

The color will be bright blue because of the immense thermonuclear explosion taking place expelling lots and LOTS of heat. When it happens, say goodbye to pristine skies for months, worldwide.

When it occurs in daylight, the star won't be missed to the naked eye, even when it is close to the Sun.

 

As seen from Uluru NT Australia.

Edited by skysurfer, 16 February 2025 - 10:08 AM.

[Tony Flanders]

My guess is that you would damage your eyes looking at Betelgeuse through a 10-inch Dob when it's still near maximum visible magnitude. The total quantity of light wouldn't be overwhelming; after all I routinely view the full Moon through my 12.5-inch Dob. But having all that energy concentrated into a sub-arcsecond circle doesn't sound very safe.

[pete543]

This article predicts that Betelgeuse would be about as bright as a first-quarter Moon, would easily be visible in the daytime, and would cast shadows at night.
https://www.astronom...ike-from-earth/

I've seen other articles suggesting it would be as bright as the Full Moon. Probably the guesses on its potential brightness differ because I don't think we know how far away Betelgeuse is. I would expect it to be intensely white.

I don't know what you mean by 'too far outside of your maximum field of view'. It will be an intensely bright point source.

Since 2019 or so there have been a lot of click bait about Betelgeuse going supernova; current stellar modeling suggests it will probably be on the order of 100,000 years or more before anything goes boom.

I'm dumb lol, I thought it would be like a very wide nebula but I'm guessing it would take centuries for it to get that big

[JayinUT]

Visual reports of Supernova: 

 

SN 1056 (supernova that created Messier 1, the Crab Nebula) from the Yongle Encyclopedia: 

 

 

Zhihe era, first year, seventh lunar month, 22nd day. [...] Yang Weide declared: "I humbly observe that a guest star has appeared; above the star there is a feeble yellow glimmer. If one examines the divination regarding the Emperor, the interpretation [of the presence of this guest star] is the following: The fact that the star has not overrun Bi and that its brightness must represent a person of great value. I demand that the Office of Historiography is informed of this." All officials congratulated the Emperor, who ordered his congratulations be [back] forwarded to the Office of Historiography. First year of the era of Jiayou, third lunar month, the director of the Astronomical Office said "The guest star has disappeared, which means the departure of the host [that it represents]." Previously, during the first year of the Zhihe era, during the fifth lunar month, it had appeared at dawn, in the direction of the east, under the watch of Tiānguān (天關, Zeta Tauri). It had been seen in daylight, like Venus. It had rays stemming in all directions, and its colour was reddish white. Altogether visible for 23 days.

Note it appeared here as reddish white and it was seen in daylight like Venus. 

 

SN 1006: 

 

 

"Egyptian astrologer and astronomer Ali ibn Ridwan, writing in a commentary on Ptolemy's Tetrabiblos, stated that the "spectacle was a large circular body, 2 1/2  to 3 times as large as Venus. The sky was shining because of its light."

Interesting here that this SN was reported as a large circular body, 2 1/2 to 3 times as large as Venus in the sky and the sky was shinning. 

 

 

SN 185: 

 

 

 

The Book of Later Han gives the following description:

In the 2nd year of the epoch Zhongping [中平], the 10th month, on the day Guihai [癸亥] [December 7, Year 185], a 'guest star' appeared in the middle of the Southern Gate [南門] [an asterism consisting of ε Centauri and α Centauri], The size was half a bamboo mat. It displayed various colors, both pleasing and otherwise. It gradually lessened. In the 6th month of the succeeding year it disappeared.

Size here was half a bamboo mat and the SN displayed "various colors, both pleasing and otherwise." 

 

I would imagine based on these accounts that you would see color in a SN from Betelgeuse naked eye. 

 

A YouTube Video that tries to stimulate what it would look like naked eye: LINK

 

It just might limit deep sky observing if it is visible at night as Orion is up. 

Edited by JayinUT, 16 February 2025 - 05:21 PM.

[KBHornblower]

The Crab Nebula at Betelgeuse's distance would subtend about a degree, and it has taken close to 1,000 years to get that big.  That suggests that the ejecta from Betelgeuse would expand to a few arcseconds in the first year after it blows.  In the first few days of the event, when it is brightest, it should be indistinguishable from a point source.  After a year it will be down several magnitudes, and my best estimate is that in a telescope it will resemble Venus at superior conjunction.

 

My estimates are from examining light curves such as this:

 

https://external-con...4916&ipo=images

[louisr65]

Visual reports of Supernova: 

 

SN 1056 (supernova that created Messier 1, the Crab Nebula) from the Yongle Encyclopedia: 

 

Note it appeared here as reddish white and it was seen in daylight like Venus. 

 

SN 1006: 

 

Interesting here that this SN was reported as a large circular body, 2 1/2 to 3 times as large as Venus in the sky and the sky was shinning. 

 

 

SN 185: 

 

Size here was half a bamboo mat and the SN displayed "various colors, both pleasing and otherwise." 

 

I would imagine based on these accounts that you would see color in a SN from Betelgeuse naked eye. 

 

A YouTube Video that tries to stimulate what it would look like naked eye: LINK

 

It just might limit deep sky observing if it is visible at night as Orion is up. 

Betelgeuse is expected to explode as SN IIp. It will be in the photospheric phase for the entire time it's a naked-eye object, so H-alpha emission should be strong but not a dominant part of the light, and mostly towards the end of that phase. It's colour will be set primarily by photospheric temperature just like a normal star - and will change relatively quickly. Typically, SNIIp start out as blue as Sirius, or even Rigel, and redden as they age, but most only get about as red as Aldebaran, and it's not unusual for them to get bluer again starting around 100-120 days after peak. SN as red as Antares or Betelgeuse are unusual but probably not super rare. [1 in 15? I'd have to do some digging to come up with a number] I would say that an object as red as Aldebaran and as bright as Venus would register as coloured to the naked eye, although perhaps only for a few weeks.

 

Emission in the nebular phase probably will be dominated by H-alpha, but by that point it will have faded enough that the colour won't register to the naked eye. Probably clear in even fairly small telescopes, though.

 

Most of the analyses of ancient observation records I've seen tend to attribute the reported size and colour, and other characteristics, to optical illusion and poetic license. How justified that is, I can't say, since it's based on comparisons with what we could expect to see naked-eye in the same circumstances, and recovering what could have been seen from the records is something of a guessing game.

[KBHornblower]

I just made another estimate.  In a 10" telescope, Betelgeuse at is supernova maximum would resemble the reflection of the Sun in a baseball-sized silver Christmas tree ornament held at arm's length.  That would be too bright to stare at, and possibly dangerous.

[areyoukiddingme]

According to Grok, the supernova would lack sufficient UV to damage eyesight when viewed through a telescope.

[JimMo]

According to Grok, the supernova would lack sufficient UV to damage eyesight when viewed through a telescope.

That may be but I'm not going to test it if it ever happens. Naked eye will be just fine for me until it settles down after a few years.

[michaeledward64]

I'm dumb lol, I thought it would be like a very wide nebula but I'm guessing it would take centuries for it to get that big

The Crab Nebula is expanding at something like 1,000 miles per second. ...

I guess you could expect Betelgeuse to expand at a similar speed.

But it is very far away.

The crab has been expanding for close to a millennia ... and it is 7 arcminutes now. 

Betelgeuse is ... I think ... 10 times closer

 

All that being said ... soon ... is somewhere in the next million years, right?

[areyoukiddingme]

That may be but I'm not going to test it if it ever happens. Naked eye will be just fine for me until it settles down after a few years.

 

I did a cursory check of a few sources, and opinions appear quite mixed about what the consequences would be. I agree that better safe than sorry is the best policy.

[KBHornblower]

I just now took a look at the reflection of the Sun in a 3" silver ornament.  At arm's length, roughly simulating the view in a 10" telescope, I would not risk eye damage by staring at it.  At 60 or 70 feet, simulating the naked eye view, no problem.

 

The Crab Nebula supernova reportedly disappeared after about a year and a half.  At 600 lightyears that would be somewhere around 1st magnitude, and the constellation would still look much as it does today.  The remnant would continue to fade and become more diffuse, but I do not know how much it would fade or how bright the remnant would be after 1,000 years.  The Crab would be about as bright as the Andromeda galaxy, but I imagine much would depend on the spin rate and magnetic properties of the neutron star.  The Crab is now powered by synchrotron action from the rapidly spinning pulsar.