The Horse and Rider (Mizar and Alcor)

[tooth_dr]

Trying out imaging with the 12", it was misty and then cloudy so just grabbed a couple of subs as the weather deterioriated.

I always knew that the middle star in the handle of the plough was a double, but I didn't realise that one of those was actually a visual double too (I've since learnt there are actually 6 stars altogether).  I did a very short exposure too, which showed up the three star separately, but the diffraction spikes in this one help highlight it.

 

30s subs, no guiding, 7 subs stacked.

 

 

[Pete Presland]

Very nice, a simple but very effective image. As you have said the diffraction spikes help you notice the double.

[Rodd]

So the widely separate pair is what we see with the unaided eye, correct?  The second brightest star in the image, and the brightest one.  The really close double is not visible with unaided eye--or do I have this wrong?  Multiple star imaging is really cool--I have yet to attempt it.

Rodd

[Guest]

Cool

[Stu]

3 hours ago, Rodd said:

So the widely separate pair is what we see with the unaided eye, correct?  The second brightest star in the image, and the brightest one.  The really close double is not visible with unaided eye--or do I have this wrong?  Multiple star imaging is really cool--I have yet to attempt it.

Rodd

That’s correct. The close double is Mizar, which can be split even at low power in a scope or high power binoculars into Mizar A and B. The wide pair which you can see with the naked eye is Mizar (A/B) and Alcor.

@tooth_dr a lovely image of a very nice object. It was the first object I viewed through a scope having read a description of it by SPM in one of his books. It’s still one I look at on most occasions when out with the scope; simple but beautiful.

[tooth_dr]

Thanks all! It never fails to amaze me the depth of knowledge that visual observers hold.

[Stu]

There is an interesting little story about the star which appears offset between Alcor and Mizar, Sidus Ludoviciana. Plenty of info on the web about it, one link below.

http://www.astropix.com/html/observing/doubles/doubles06.html

For me, the system has always been fascinating because it is a naked eye double, telescopic double and also each element is a spectroscopic double (as I understand it)