Splitting Izar

[Jim Smith]

I turned my 120mm refractor at 180x on Izar tonight, but it didn't even look slightly elongated.  Is it too close to split with my scope?

[Moonshane]

It should be pretty straight forward at that sort of magnification and with your scope. was it low in the sky? maybe seeing was the problem?

[steppenwolf]

You need exceptionally good seeing to split this pair but your 120mm will do it at that magnification if the conditions are right.

[Stu]

It should be relatively straight forward in your scope assuming the seeing is reasonable.

It is quite easy in my 76mm and beautiful in the 150 so the 120 should do it with no problem.

Stu

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[Jim Smith]

It was pretty high.  I suppose it must have been the seeing then... or the wrong star!

[steppenwolf]

or the wrong star!

I've done that!

[proflight2000]

Had a look at IZAR last night and did the split, I do like the double stars, Polaris is one I like as she is always out of the way of things.

[avtaram]

Should be easy to split with your scope at that magnification.

This is one I did last year in August.

[Moonshane]

I think everyone has looked at the wrong star at some point! never do it these days (honest).

[mdstuart]

I find Izar tough. I think its because the primary is so bright...

Its lovely though when you split it so keep trying..

Mark

[Moonshane]

an aperture mask works wonders on a big dob for this sort of object.

[Jim Smith]

avtaram,

Thanks for the great drawing.

In your sketch, which of the five stars you have drawn is Izar? (I'm going to use your sketch to check what is in the fov when I use Stellarium or Sky Safari.)

[Moonshane]

this is a typical view in my 6" f11 at about 150-200x

[Moonshane]

ps not my pic.

[Stu]

Good likeness there Shane. The secondary can sometimes get buried in the first diffraction ring from the primary, particularly on the smaller scopes. Nice colour contrast.

Stu

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[avtaram]

Jim, Izar is the yellow/orange star and its companion is the pale blue star just above and to the right.

This was in my 120 ed with a Baader Zoom set at 8mm.

Avtar

[Moonshane]

if the spec of the field of view is correct in that sketch I am sorry to say I don't think you managed a split of Izar. if the 0.6 degrees tfov and magnification is accurate then this equates to 36 arc minutes across the field. Izar's companion is only about three arc seconds from the primary and the one in your sketch is much further away than this (more like several arc minutes - maybe 8 arc minutes). I don't know if there is a coincidental blue star at this distance from Izar but could you have seen this?

[Stu]

Jim, Izar is the yellow/orange star and its companion is the pale blue star just above and to the right.

This was in my 120 ed with a Baader Zoom set at 8mm.

Avtar

Hi Avtar,

Maybe I'm mis interpreting the sketch or the secondary doesn't show up on your image? The separation to the blue star above right looks very big sketch though vs what I see??

Stu

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[avtaram]

Shane, Stu, looks like I may have to revisit this.

I can't remember all the details since the sketch was done a year ago but I think the placing of the stars in the field of view should be about right.

Avtar

[Jim Smith]

I'll try again next chance I get. 

Can anyone suggest some marginally easier splits for me to try?

[avtaram]

Mizar, Polaris, Dubhe all in the Plough

Delta Boo, Rasalgethi (alpha Her).

Avtar

[avtaram]

Sorry Polaris is not in the Plough.

Got a little carried away there.

Avtar

[Stu]

Give Albireo a go, nice and easy and a lovely colour contrast.

Almach is another lovely one though not conveniently positioned at the moment.

If you fancy a challenge, try the Double Double in Lyra. It's an easy double, but each component is a tight double in itself. Needs good seeing and collimation.

Cheers,

Stu

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[Astro Imp]

Izar is one of the doubles that seems to give me a lot of trouble. Most nights I am out and it is available I give it a go and sometimes see nothing, sometimes slightly elongated and occasionally a good split. When it pops out it's worth all the hassle to see this beauty.

[Jim Smith]

Last night was clear and the seeing was good. I tried Izar again and this time I saw the secondary just very slightly above the primary (180x).  It seemed to be lurking in the first diffraction ring just like Stu said.  I checked in Sky Safari and it confirmed the relative positions on the component stars.

I also split the "double double" in Lyra as suggested.  That was somewhat easier to do than Izar even though the separation is less.  I suppose the similar magnitudes helps.