Theta Auriga

[John]

New one for me, this

Easy to find and well placed at the moment. Theta Auriga is an unequal brightness binary with 3 componants, A (mag 2.7), B (mag 7.2) and C (mag 11). C is around 50 arc seconds away from A and is an optical companion. The challenging bit is the split between the uneven brightness A and B componants which is just 3.7 arc seconds.

With careful focusing I found the split clear and achievable with my ED120mm refractor at 180x. I was testing 5mm eyepieces at the time and found the split looked pretty much the same with a UO HD ortho, a TMB Monocentric and an 8mm Tele Vue Ethos barlowed to 5mm with an Antares 1.6x barlow.

Another one to add to my list of "test" binaries

[ploughc]

Hi John,

Theta Auriga is a lovely double i need 120x or more

to split it with my 80mm Zeiss, I use it as a test of

the seeing if I can split it I try the difficult doubles.

Pat.

[ploughc]

Hi John,

Just to correct my last post I should have said 200x

instead of 120x , althought I think once on a night of

very good seeing I did split it at 120x.

Pat.

[John]

Thats a great performance for an 80mm scope Pat - but then it is a Zeiss

I'll give this pair a go with my Vixen 102mm ED when I get a chance and see how that fares. I like using challenging doubles to test seeing / collimation as well.

[Moonshane]

Oooh. I'll try this next time out too. Cheers for posting.

[John]

Oooh. I'll try this next time out too. Cheers for posting.

Go for it Shane - it's nicely positioned ATM and it should be lovely in your 6" F/11

[Moonshane]

defo John. looking forward to it.

[ploughc]

Hi John,

Yes the Zeiss is pretty good, on nights of good seeing I have

split Delta Cygnus with it which is a bit closer althought not

as big a difference in magnitude.

Pat.

[John]

I've split Delta Cygnus with a 5" scope but, so far, not with less aperture.

Tonight I've split Eta Orionis with my ED120. First time I've noticed this one but it's such an obvious star to find. Pretty close pair - split is about 1.7 arc seconds and the components are 3.8 and 4.8 mag respectively.

[ploughc]

One night last week I tried Eta Orionis with the Zeiss

but no luck I have split it with a 150mm reflector last

year. The weather here has been awful all year very few

clear nights.

Pat.

[Nexus 6]

am enjoying the views of double's this year..... has made up for a pretty poor year observing wise, will have to check out those mentioned here

thanks for posting

[Moonshane]

just tried this and split it readily with my 6" f11 after it had eventually cooled down enough. this scope seems to take more time than usual to cool (about an hour) even with a small fan. initially I split at 200x and then tried 160x and it split then too. Feeling cocky I put in my 15mm TV plossl and split at 107x which was pleasing.

not sure which star is C though. is it the one below the double or above right (assuming the newt view with A top and B bottom)?