Observe Einstein Cross?

[erick (Eric)]

I'm moved to ask the question, now I've learnt from another thread and some subsequent research about the Einstein Cross.

http://www.trisectingwaveegypt.com/E...7+0305A_03.jpg

http://observing.skyhound.com/archiv...237+0305A.html
http://astronomy-mall.com/Adventures...rossobsrpt.htm

OK, so who has observed it?

A Snake Valley challenge?

[mithrandir (Andrew)]

Originally Posted by erick

OK, so who has observed it?
A Snake Valley challenge?

Mag 16.78. What size scope and seeing will that take?

[DavidU (Dave)]

Originally Posted by mithrandir

Mag 16.78. What size scope and seeing will that take?

A 32" at 200 mag with 5.5 vis magnitude limit, with very very good optics will do it. (But not in Melbourne)

[pgc hunter]

The Lensing Galaxy is Mag 15.1(B), which is possible with a 12" scope under dark skies, but as for the actual cross, yeah I reckon you'll need something in the order of 20" at the least, very good seeing and extremely high magnification. The seperation between the A and B components is 2".

[xstream (John)]

Eric, We did observe it a few years ago but it took a 30" to see the lensing effect.

[Paddy (Patrick)]

Maybe if there is a big enough scope at VicSouth - should be good dark skies there!

[ngcles]

Hi Erick, John & All,

Originally Posted by xstream

Eric, We did observe it a few years ago but it took a 30" to see the lensing effect.

Never seen it. Haven't tried .. yet -- but I'd say John's comment above is right on the money. 18" would be the absolute minimum in perfect conditions (seeing and transparency) to see the A component alone. You have to remember that the individual components of the lens are inside the halo of the galaxy -- so its harder than seeing a mag 17.4 star alone in native sky. Your looking for a 17th mag star against the background of the halo of a galaxy (faint though it be).

Very, very, very difficult. Need more telescope I think ...

Having said all that, I've got little doubt that someone on "another forum elsewhere" will announce to the world that they have observed the four components in an 8" 'scope ...

Best,

Les D

[pgc hunter]

Originally Posted by ngcles

Hi Erick, John & All,



Never seen it. Haven't tried .. yet -- but I'd say John's comment above is right on the money. 18" would be the absolute minimum in perfect conditions (seeing and transparency) to see the A component alone. You have to remember that the individual components of the lens are inside the halo of the galaxy -- so its harder than seeing a mag 17.4 star alone in native sky. Your looking for a 17th mag star against the background of the halo of a galaxy (faint though it be).

Very, very, very difficult. Need more telescope I think ...

Having said all that, I've got little doubt that someone on "another forum elsewhere" will announce to the world that they have observed the four components in an 8" 'scope ...

Best,

Les D

And to add to that, the seperation between the 2 widest seperated components is 2".