the double double split

[faulksy]

I believe the lower the magnification the better, as a test for optics, had a very clean split last night with my 18mm bgo, which gives me 130x, the separation was about half the size of the star but you could see the black sky between them both. so whats the lowest power any one has used

[chiltonstar]

x70 here (5" Mak).

Chris

[Qualia]

Don't want to appear pendantic but I feel the nomenclature for 'splitting doubles' is often a tad wide - if you pardon the pun - and so it's always handy to have in mind folk's own criteria.

This is Dawes' idea of a split double and this is Rayleigh's and this one is another idea and then we get the clean split and from there wider and wider.

I say all this for I feel one person's idea of a 'split double' might be another's idea of 'well you almost got there mate but not quite' and so on. Personally, I feel there's a nice aesthetic quality to the given solar system if the double can be split cleanly and sharply, regardless of the magnification used.

[Marki]

Clean split at x65 using 100mm f13 refractor in good seing (early June this year); previous best was x75 with 125mm f8.9 refractor in a crisp steady winter sky. Tried a couple of nights ago and struggled to get any version of a split below about x125 - too much heat haze and moisture in the atmosphere - amzing how much seeing can vary night by night.

Qualia's info on the different "criteria" for a split is really interesting (where did you get that info on Dawes and Rayleigh?). I guess there is a difference between being able to differentiate the components of a double, and actually fully splitting that system. Fascinating stuff. Whilst I enjoy the challenge in the split at lowest magnifications, I'll often up the mag again to enjoy the sharp view of a well split double; something about the knowledge of that relationship and the clear sense of space between primary and secondary gives me a real sense of wonder.

[faulksy]

Don't want to appear pendantic but I feel the nomenclature for 'splitting doubles' is often a tad wide - if you pardon the pun - and so it's always handy to have in mind folk's own criteria.

This is Dawes' idea of a split double and this is Rayleigh's and this one is another idea and then we get the clean split and from there wider and wider.

I say all this for I feel one person's idea of a 'split double' might be another's idea of 'well you almost got there mate but not quite' and so on. Personally, I feel there's a nice aesthetic quality to the given solar system if the double can be split cleanly and sharply, regardless of the magnification used.

thats brilliant qualia, the last pic is about were i was, maybe the skys wernt steady enough some of the main stars were twinkaling away but some were ok, thanks for that

[Qualia]

where did you get that info on Dawes and Rayleigh?

Cut and paste from here, Mark: Rules-of-thumb for splitting double stars

I'm not in anyway a stickler for rules and didn't want to write the above feeling that folk should be so. It was more supplied with the sense that folk should all be able to understand each other's criteria. To get a feel of what is going on.

[dick_dangerous]

Don't want to appear pendantic but I feel the nomenclature for 'splitting doubles' is often a tad wide - if you pardon the pun - and so it's always handy to have in mind folk's own criteria.

This is Dawes' idea of a split double and this is Rayleigh's and this one is another idea and then we get the clean split and from there wider and wider.

I say all this for I feel one person's idea of a 'split double' might be another's idea of 'well you almost got there mate but not quite' and so on. Personally, I feel there's a nice aesthetic quality to the given solar system if the double can be split cleanly and sharply, regardless of the magnification used.

I got to the Rayleigh level from my front step (With the street light right next to me). That was at 80x. For my telescope this is something of a huge achievement.

DD

[Stu]

x69 with a clean split on my 106mm triplet. Needs good seeing so it comes and goes depending on the conditions but definitely there as a black line between the two pairs. I reckon I almost had 1 pair at x55 too the other night but that was probably wishful thinking. Perhaps with good conditions it would be possible.

Stu

[chiltonstar]

x69 with a clean split on my 106mm triplet. Needs good seeing so it comes and goes depending on the conditions but definitely there as a black line between the two pairs. I reckon I almost had 1 pair at x55 too the other night but that was probably wishful thinking. Perhaps with good conditions it would be possible.

Stu

Yes - for a test like "the lowest power you can split the d-d with", I'd be happy with a black line between the components of each pair; something like the diagram before "clean split". The visual image is so small at low power anyway that it's more a test of visual acuity perhaps.chris

[Marki]

The visual image is so small at low power anyway that it's more a test of visual acuity perhaps.chris

I think that's right. The two times I got low magnification splits were at weekends, so my eyes weren't so tired after work (staring at a screen all day) - that and good conditions seem to be the key.

[Merlin66]

I achieved a "thin black thread" between the components with x49 on a Genesis 4" f5.

Majic!!!!