Splitting the Double Double...

[F15Rules]

On 22/08/2018 at 00:36, RobertI said:

Just been out to try this with the Heritage 130P.  To cut a long story short, I could split the easier pair (EL 2) at a minimum of 65x and the harder pair (EL 1) at a minimum of 85x. In order to split I had to see a consistent clear gap to pass the test; I could make out elongation and fleeting gaps at lower mags than these. The test was done using my 10mm Hyperion with fine tuning rings, and my Seben zoom. I even tried  Bahtinov mask on Vega to get accurate focussing but bizzarely this made things slightly worse and I had to do a slight refocus on the double double. And oh for 10:1 Crayford focusser for such a job, the helical focusser was a pain! I hear a 130PDS calling me ......

I see you also have a Tal 100RS Rob..would be interesting to see how that does for you...I owned several in the past and found them very good on tightish doubles 

Dave

[F15Rules]

20 hours ago, Ibbo! said:

We split it with the Tak FS 60 a few years ago with quite a low magification.

 

The 60 is out on loan at the moment but I think it was about x50.

We started at a higher mag and worked down.

It might even be in a report on SGL somewhere - I will have a look back.

Steve,

That is a cracking split, well done! And I envy your eyes!

Dave

[John]

I think visual acuity must play a role in this challenge. Some will have an observing eye that is better for this task than others. It's not all down to the scope I think ?

 

[Macavity]

ISTR splitting all 4 components with a MAK90 (can't recall mag!).
From then on, I believed in all that stuff about Astro "seeing" etc. ?
Sometimes, despite previous attempts, surprising stuff happens?

[Saganite]

1 hour ago, F15Rules said:

That does surprise me Steve. Were the seeing conditions and eyepiece types used similar? (Obviously you'd get different magnifications with a 24mm Ultima in the D&G, but did you use a similar type of ep, such as a 30mm Ultima, which would give you 63.5 in the D&G)?

It's just that I'd expect the latter to beat the Tak 100 in equal conditions

Dave

Spot on Dave.

I also was surprised, but thinking about it conditions probably changed. It was at about 10.30 that I first looked at the double double and used the 30mm Ultima, almost seeing a split, but then changed to the 24mm Pan to see a clear split at 79x. After spending some time there I had a look at favourite objects for a while and then hunted down Neptune which took longer than perhaps it should have ( though definitely worth it ) because thanks to my decision to upgrade the mount, I had no power and was moving the scope manually instead of controlled slewing. The transparency had definitely deteriorated by then, and at about 1.15 am, I decided to try the Tak on the double double but this time I used a UOVT 12.5mm and a 24mm Ultima with the Ultima barlow.

I actually think that a split was shown at 63.5X through Andromeda but It was so close ( " did I see the F star then or not ?) and my eyes, on their 66th journey around the Sun, are not as good as they once were, so I cannot claim it .

 

[Highburymark]

68x is the lowest mag split for me - Nagler T6 in Tak FC-100DC - though I should have a go with the Leica zoom

[JeremyS]

Using the Tak FC76DCU I couldn’t split at x50, but could just at x80. Easy at x100

[RobertI]

2 hours ago, F15Rules said:

I still think that a good 4" F15 frac is one of the best double stars splitters you can get 

Dave

Not quite F15, but i’m going to try the Tal100RS to see how it compares. ?

 

Edit: Just your seen your earlier post Dave, suggesting that very thing!  

[Ibbo!]

2 hours ago, F15Rules said:

Steve,

That is a cracking split, well done! And I envy your eyes!

Dave

Hi Dave there was a group of about 6 of us and most managed to to do it , we worked down. We used my tak eyepieces it was a cracking night to be fair and I also had the fs 102  on the mount as well IIRC.

if it was  down to eyes i doubt i could do it now.

[John]

When I was in my late teens I could split the double double with 8x30 binoculars and cheap ones at that.

40 years of this:

  

and now it's "where is Lyra ?????"

[Macavity]

33 minutes ago, John said:

40 years of this:

This is what we like to hear... And of course the "Men with Beards" etc. ?

[Geoff Barnes]

Just been out for a quick look through the trusty old Celestron C4R (while the 12" Dob is away being "Inspected").

I could just see glimpses of Vega through the gum trees to our north, and should have a clear view in an hour or two when Lyra clears the mountain ridge top, so will give the double double my best shot.

While I was waiting I had a look at Jupiter with all the main moons well to the right of the planet with Europa and Io doing their own double act with E just a fraction above I.

Could clearly make out the equatorial belts but that was all.

Despite the nearly full moon I managed to hide it behind a big tree and had a good view of Mars just above and was rewarded with the clearest view yet this year with distinct darker areas clearly visible although slightly blurry and a hint of the northern ice cap.

A very satisfying little session indeed considering it wasn't even planned. Dinner time calls now, so back out in an hour to do a bit of double double spotting in Lyra. ?

[Saganite]

Good that you are getting reasonable views of Mars Geoff, pretty dire from my location.

[Geoff Barnes]

Thanks Steve.

I really wasn't expecting to get such a good view tonight, especially with the bright moon so close by, but there it was for the first time this dusty opposition, clear darker shades on the disc.

I've just returned indoors from successfully splitting the double doubles! It was a real struggle I must admit, the poor old C4R was at its limit, but she just about managed it at around 100x with the Baader zoom.

Really hoping to get the big Dob back in action before Lyra exits our skies in a couple of months.

[John]

I had some decent Martian views with my Tak FC-100 last night as well. The dark features were in the S hemisphere (Mare Sirenum I think) as was the small white spot of the polar cap. The N polar are was pale but I was not sure if that was a pole cap or simply a paler part of the disk.

Getting better but I still got better views with my Tasco 60mm refractor in 1984 !

Without that dust storm this would have been a stunning opposition to observe

Sorry, bit off topic for a thread on Epsilon Lyrae !

[F15Rules]

I've tried Mars a half dozen times this past 6 weeks and all I get is orange mush!

I know it's not the scope as I've had some great views (like Epsilon Lyrae), so it has to be the very low elevation and the storm and the unsteady air and and.... but I have had some nice views of Saturn at a similar elevation?

Dave

[Saganite]

2 hours ago, F15Rules said:

I've tried Mars a half dozen times this past 6 weeks and all I get is orange mush!

I know it's not the scope as I've had some great views (like Epsilon Lyrae), so it has to be the very low elevation and the storm and the unsteady air and and.... but I have had some nice views of Saturn at a similar elevation?

Dave

Same here Dave, really lovely views of Saturn, but Mars so far is a great disappointment.

[John]

Mostly my views of Mars have shown a nicely crisp disk but lacking almost entirely in features. The ones showing now are really quite vague compared with how they can look. Spending time observing helps define them a little more but it does seem hard work ATM.

[jock1958]

Just spent the last hour on Mars and only managed occasional detail towards the bottom half of the planet, this opposition is a bit of an anti climax really ?

 

[John]

15 minutes ago, jock1958 said:

Just spent the last hour on Mars and only managed occasional detail towards the bottom half of the planet, this opposition is a bit of an anti climax really ?

 

Agreed. The S polar cap is reasonably distinct and there is a vague dark elongated smudge to the N of it which I think is the Mare Sirenum but nothing distinct.

 

[Geoff Barnes]

Doh! I keep forgetting I'm in the southern hemisphere, so the polar cap I could just make out would have been the southern one as everything appears upside down compared to in the UK. ?

[jock1958]

8 hours ago, Geoff Barnes said:

Doh! I keep forgetting I'm in the southern hemisphere, so the polar cap I could just make out would have been the southern one as everything appears upside down compared to in the UK. ?

Ha ha yeh, I was in Cape Town a few months back and first time I’ve seen Orion upside down, took a bit of getting used to.

[Owmuchonomy]

I posted my results to this topic in this thread.

 

[Macavity]

I suppose the NICE thing about the Double-double is that the 
"geometry" of the components is very characteristic... There is
relatively little less doubt whether you are seeing it or not? ?

http://earthsky.org/brightest-stars/epsilon-lyrae-the-famous-double-double-star

People talk about "First Saturns" etc., but I remember THIS! ?
Even if your scope / skills are not the best, worth a look...

[RobertI]

On 23/08/2018 at 11:11, F15Rules said:

I see you also have a Tal 100RS Rob..would be interesting to see how that does for you...I owned several in the past and found them very good on tightish doubles 

Dave

Well, I managed to get out with the Tal tonight, conditions were less than perfect, there was thin cloud, a nearly full moon and I had just had a curry and two pints. But seeing and transparency were good. Slightly strange result though, I managed to split the easier pair at around 55x (slightly better result than the 130P) but could only split the harder pair at around 85x (same as the 130P). Trouble is magnifications are approximate as I was using the zoom, possibly +/- 5%? Anyway, seems the frac could better the larger newt on the brighter pair, but not the dimmer pair. Not a scientific enough a test to draw any real conclusions I think, will have to do a side by side test one night.