Zeta Hercules and a few others

[John]

After a fine period of time spent observing the close conjunction of the Moon and Jupiter this evening, with the ED120 up and running I moved on to having a short session looking at some familliar double stars.

While the seeing had been a little shakey at times on Jupiter and the Moon, ED120 was showing almost text book star images so the doubles I viewed were really looking their best. My targets included Iota Leonis, Izar (Epsilon Bootes), Zeta Herculis (best split I've had of this tight one), Epsilon Lyrae, Delta Cygni and finally just clearing the conifers to the East, Albiero.

The steady seeing was outstanding for double star viewing and I found that I was getting really well defined stars throughout the range of the Nagler 2-4mm zoom eyepiece, ie: 225x to a dizzying 450x !

I was particularly pleased with the clean and well defined split of Zeta Herculis. This is a double that I've been pitting my scopes and eye against for around 5 years now and it's a pretty difficult one to split IMHO. The separation between the primary and secondary stars is only about 1.2 arc seconds and there is quite a difference in brightness between the two stars (mags 3.0 and 5.5) to make things even more awkward. Tonight was pretty much the best split that I've managed of this one and the tiny gap between the stars was clear even at 400x plus.

When using such high powers under these excellent conditions these (mostly) fairly tight pairs take on a new look. The gaps between the star pairs of Epsilon Lyrae, for example, seemed ridiculously wide and even Delta Cygni, which can be tricky in small apertures, showed quite a tract of black space between the two unequal brightness stars.

I have to hand it to the Skywatcher ED120, it has an excellent objective lens which shows a vey clean star test, little or no false colour in visual use and, when conditions allow, can absorb the sort of magnifications that are usually the preserve of much more exotic (and expensive !) refractors. Synta got this one right !

 

[cotterless45]

Excellent , Zeta has been my nemesis . You can't beat a proper scope under even poor skies,

Nick.

[Stu]

Great report John. Like Nick, Zeta Herc is indeed my nemesis and is one I've never managed!

[kerrylewis]

Nice report John. I've not managed Zeta either.

There's  been a lot of discussion on the forum recently regarding the merits (or otherwise) of various refractors and I'm interested to see that for a session such a last night's you choose to use the 120ED rather than your Tak 100DL. Is this because of  a particular preference or just what happens to be at hand?

 

 

[chiltonstar]

Well done re Zeta Herculis John - one that needs near-perfect seeing! Confirms what everyone (well almost) says about the ED120. I bet Izar looked pretty impressive as well.

Chris

[John]

1 hour ago, kerrylewis said:

..There's  been a lot of discussion on the forum recently regarding the merits (or otherwise) of various refractors and I'm interested to see that for a session such a last night's you choose to use the 120ED rather than your Tak 100DL. Is this because of  a particular preference or just what happens to be at hand?

 

 

It was the ED120's "turn" to have an evening out Kerry !

The Tak 100DL would have been excellent as would the TMB / LZOS 130 of course and the Vixen ED102SS is no slouch either. I'm very lucky to have these choices

I generally try to avoid skipping from scope to scope during an evening, unless the conditons or intended targets change. If I have 2 or more scopes out I find myself in "comparing mode" rather than "observing mode" which is generally not what I like to do these days.

 

[Moonshane]

I do much the same John. I choose a scope dependent on expected targets and conditions / time available and stick to it. It's a great way to get a different perspective I feel.

Generally, seeing and transparency (plus the number of neighbours leaving lights on)  play a much larger role in what I see than the scope used.

[kerrylewis]

Thanks John and Shane. I do about the same - pick one (based on ease of set up and likely weather) and stick with it. I don't like comparing as it interferes with the observing.

Double stars are always a favourite  - as you have demonstrated they are less affected by moonlight etc and present a challenge or delight on any night. I've been reading Starlight Nights by Leslie Peltier (following a mention on SGL) and this has inspired me to give variable stars a go as I've never really studied them. Always something in this wonderful pastime....