Whis and Beerus speed fix

[Faisal_Shourov]

Helix nebula is visible to human eye from 714 light year[1] , it beeing invisible from 541 ly makes no sense. Do you see the point? We can see it from further distance than the calc u posted

I converted ma/arc per second using the calc tool. As for why I took 1m as the surface density, I have posted the link above. I dont see how your calc makes more sense than mine

 

[IcarusXI]

So how much would that be in simple numbers for dummies?

 

[MasterHelix]

But that page in the link says: "The Helix Nebula is located only 695 light-years from Earth"

Where is 714 light-year coming from?...

 

[DontTalk]

"At magnitude +7.3 the Helix Nebula is the brightest planetary nebula in the sky. Based just on this information it would seem an easy target and indeed it is visible with just binoculars at a dark site on a moonless evening. "

From the source you posted right now. With binoculars is the key point. You can see every known object in the universe if you have the right tool, but for it being invisible to the POV we assume just the bare human eye. And at any magnitude over 7 it just is not visible to the typical human eye. Every scale will list the limit of the naked eye at the apparent magnitude of 6 or 7, like here or here or here.

"NGC 7293 lies roughly halfway along an imaginary line connecting Fomalhaut (╬▒ PsA - mag. +1.2) the brightest star in the southerly constellation of Piscis Austrinus and ╬╣ Aqr (mag. +4.3). Just over one degree to the east of the Helix Nebula is ¤à Aqr. At magnitude +5.2 this star is visible to the naked eye under dark skies, simplifying the search for the Helix Nebula."

If you mean that passage to say it is visible than I should point out the the sentence refers to the star Upsilon Aquarii (¤à Aqr), a star close to helix that is visible because it is brighter.

 

[DontTalk]

@MasterHelix: predictions of the distance of stars can vary a bit. Wikipedia states it as 714 ly with an error rate of +88 ly to -68 ly.

 

[MasterHelix]

@DontTalk: Oh, ok...thanks!