If Sedna were at aphelion right now, would we be able to see it?

Question

If Sedna were at aphelion right now, would we be able to see it?

Answer 1

Well, it depends on what you mean by "see".  If you mean:

"Could we see it with the naked eye" the answer would be "no."  Even at perihelion, the closest point in its orbit, it would be far too faint to see with the naked eye.

If you mean:

"Could we see it through an amateur telescope" - the answer would almost certainly, again, be "no".  Sedna's is far too dim to see with even the largest optics.  (Currently it is magnitude 21, roughly 1000 times too faint to see with a large amateur scope.)

If you mean:

"Could we photograph Sedna at aphelion" - the answer would be "yes".    Sedna will likely be around magnitude 26 or 27 at aphelion.  While extremely faint, it should still be within reach of large telescopes with sensitive detectors.  (The Hubble Space Telescope has imaged objects as faint as Magnitude 30) It won't appear as much more than an extremely faint blip, but it will be detectable, especially in infrared.  Of course, this won't happen within our lifetimes.

Answer 2

Not with any earth based telescopes. Maybe the Hubble.

Sedna has a highly elliptical orbit, with its aphelion estimated at 975 AU and its perihelion at about 76.16 AU.

The astronomical unit (AU or au or a.u. or sometimes ua) is a unit of length of approximately 150 million kilometres, and is based on the distance from the Earth to the Sun. The precise value of the AU is currently accepted as 149,597,870,691 ± 30 metres (nearly 150 million kilometres or 93 million miles).

That is 90,675,000,000 miles away at aphelion.

This puppy is a long ways out. At it's closest point it is about 3 times as far from the sun as Neptune and just bearly visable, at it's furthest point away from us it is the furthest know and recorded object.

Good stuff and a great question!

Answer 3

Not with the naked eye.

Sedna is further out than Neptune, and much smaller. Even Neptune is invisible to the naked eye, so Sedna would definitely not be visible.

Answer 4

No.  Aphelion is farthest distance.  Even at perehelion (closest) Sedna is still about twice as far away as Pluto at its' farthest.  At aphelion, even the Hubble might have trouble making Sedna out of the background.  It's also smaller and probably darker than pluto, adding to the difficulty in seeing it.

Answer 5

Not without a large telescope, as it would be around magnitude 18-20 or fainter.

The human eye can see to magnitude 7.5 at a very dark site , on a moonless night, with your eyes fully dark adapted.

We cannot even see Neptune without optical aid, or Pluto at magnitude 15 without a large telescope, or Sedna which is even fainter, as it is many many times fainter than Neptune.

You would need something like a 350mm aperture telescope to see a most uninspiring tiny dot with no detail at all.

Answer 6

I would use a very powerful telescope to hope to get even close to seeing it, it is further away then that wack job theory "nemesis" star, it is basically in a gap between the Oort cloud and the Kipper belt

Answer 7

Not with the naked eye, and by a far margin. Sedna's magnitude is 20.4 at perihelion (the closest to the sun, hence the brightest it could get), the limit for unaided eyes under perfect conditions is 6.5. The limit with binoculars is around 9.5; so you'd need a rather large telescope to just catch a glimpse.