This is a DSC-60 Project observation – for project details go here.
Stats from the Double Star Club List:
|Delta Herculis||17h 15m.0||+24° 50′||3.1, 8.2||8.9″||236°|
For a finder charts and a look at how Delta Hercules fares with other scopes read John’s post on it here, as well as the comments on that post.
The Double Star Club listing treats this as a double only and the listing appears out of date. Again, John’s post deal with all four stars and gives more recent stats for the B component which show a separation of 12.4 seconds and a PA of 286°. Given those numbers – in fact, given the earlier numbers even, you might expect this to be easy. It isn’t. The C and D components are easy, even though they’re a couple magnitudes fainter, because they are each roughly three minutes from the primary.
Locating that B component – the object you need for the Double Star Club, is much more difficult. With the 60mm and my 5.5 skies it was a will-o’-the-wisp. I saw it – but I suspect I saw it only because I had seen it a few nights before using an 85mm and 102mm, so I knew exactly where to find it. And with the little TV60 it definitely required averted vision and good dark adaption. I used a 4-2mm zoom and I could see it at the 4mm setting (90X), but only with averted vision. It pops in and out – more often out of view than in view.
So I would count this one as seen – barely – and also as a lesson in how difficult it is to see even a magnitude 8 star when it has a companion just 12 seconds away that is five magnitudes brighter. Much the same challenge you have with Polaris where the difference is greater, but so is the separation.