Epsilon Lyrae - what will I need to see it?

[Pig]

The DD sure is a very memorable first timer, almost as memorable as the first view of Saturn...... I was surprised by the fact there were double stars up there let alone double doubles  I also gave it a go last night, as it goes the seeing has been almost perfect in the early hours for two nights on the bounce here in Northampton.

[CraigT82]

22 hours ago, wookie1965 said:

I split it last night in my Tal 100rs (4") with 12.4mm 80x mag. 

When I had a Tal100RS I could regular split both doubles with a 12mm BST. Probably the best value star splitter ever made the 4" TAL!

[Ags]

It was an easy split with my 102mm mak, but I can only partially split the doubles with my 150mm Newt. Stars were much cleaner in the mak.

[Paul73]

It is only easy once you've done it!

The wide double is pretty straightforward. But splitting each part into two is far more fun.

As with all double splitting. Getting a cooled scoe and steady atmosphere is a must.

Paul

[Moonshane]

Here's a sketch with an 80mm refractor at 150x

While in the area don't forget to check out Vega which is also an often forgotten double

[Dave In Vermont]

11 hours ago, Moonshane said:

Here's a sketch with an 80mm refractor at 150x

While in the area don't forget to check out Vega which is also an often forgotten double

That top drawing of the double-double is very similar to my view at 180X with my 3" F/15 refractor!

Thanks for posting that - brings it all back!

Dave

[Stub Mandrel]

I split teh main pair with my bins a couple of nights ago, with a scope it's easy to split the double double and it looks great.

[JOC]

Well I sitting out here with them in EP, no trouble to find - in the same view ss Vega.  However, I'm up to 6mm snd They are only on the verge of splitting for the second time.  The focusser almost doen't seem fine enough.  Just off inside to see what other TMB clones I experimented with.  I might be able to creep closer.

[JOC]

OK so I pushed my luck with my cheap experimental 4mm TMB clone.  They are def. 2 pairs, but that is really pushing my telescope in what  I think could have been iffy viewing conditions.  The moon had big illuminated halo around it that was perhaps water vapour in the air maybe?  I could not get a clean split.  It's almost as though I can't adjust the focus fine enough.  I tried at all sorts of focal lengths with all th EPs I could rummage up, but it still wouldn't break cleanly into 4 though I did pull back sufficent to say thete were 4 there.  Will write more on my log thread tomorrow.

[wookie1965]

In case anyone uses the SAO catalogue the other double double is SAO 067870 very easy split, I did it with the Tal 4" with 15mm x66. 

[DHEB]

On 05/28/2017 at 19:13, Mr Spock said:

I've attached a few charts to make finding things easier. Charts include constellation labels and magnitudes.

I've also put a label on Albireo as it's always a favourite double.

Wide field showing where ε Lyr is in relation to Vega and surrounding constellations.

A closer view showing ε Lyr in relation to Vega and the top of Lyra.

And a close up of ε Lyr for those who like to challenge their scopes, complete with magnitudes down to 16.50. Thie field in and around ε Lyr is great for testing the limiting magnitude of your scope.

These charts look very neat and useful. Which software did you use to plot them?

[Stub Mandrel]

I split the double double with my C90 Mak a week ago. The bottom one (note right side up image with this scope) was easy, but the other required critical focusing and a bit of patience, so not as easy as when I did it with my 150PL but clearly doable with a 90mm scope.

<Edit> for the record the 150PL is 1200mm and the mak is 1250mm fl and I used the same Skywatcher 'Super 10mm' (i.e. basic) EP.

[Mr niall]

Funnily enough split these last night for the first time - took me about 5 mins to find and I am truly dreadful at finding targets so must be easy! If you can find Vega, look for two reasonably bright stars about the width of a pencil to the left of it (from staffs at 11pm anyway) they are very close to Vega - you'll know you've found them because those two and Vega form an almost perfect compact equilateral triangle - epsilon Lyrae is the upper most of the two "other stars" its that easy really. I split the "double double" at 208x in my Mak 127 but think they could have taken more - as a side note I noticed a lot of dew on the lens when I packed up so that probably made things much less clear than it could have been! Was a very cool sight.

 

[Mr Spock]

57 minutes ago, Cinco Sauces said:

These charts look very neat and useful. Which software did you use to plot them?

They are from Cartes du Ciel

[Les Ewan]

A 6" f8 Newt at around 100X both doubles are fairly easy to split but with a 90mm f10 refractor I find epsilon 2 challenging sometimes failing to see it at all.

[Ouroboros]

About a week ago I managed to split each member of the pair with my Skywatcher Evostar 80ED DS-Pro using a Celestron 7mm eyepiece (x86).  I wouldn't say they were well resolved, but sufficiently well to say both stars were doubles. 

[Stub Mandrel]

Last night I failed with my 130P-DS, with a 10mm EP the one had a hint of being extended and when I used a cheap 4mm EP they were just fuzzy blobs, I think that ep is binnable... for some reason it didn't occur to me to use a barlow with the 10mm which should have done it.

[Arcturus D]

Good transparency plays an important role, as well as excellent collimation.

130x did the trick for me @ F6  200mm.

[Roy Challen]

On nights of excellent transparency and seeing, which doesn't happen much in Watford, I have split the DD with my Skylight and 25mm Zeiss Huygens (x50) pretty easily. Conditions are more important than magnification.

[Stu]

Not so sure about transparency but certainly seeing is the major factor in this one, along with cooling and collimation as said

[chiltonstar]

Seeing certainly is critical, and therefore it needs to be some way above the horizon. A couple of nights ago with my ED80, it was easy as the seeing was 4/5 and it had risen sufficiently (40 degrees or so above the horizon), but impossible when it was lower down earlier in the year. My ED80 just produces a dark line between the more difficult pair of Epsilon Lyrae, whereas with my 180 Mak, there is a very wide dark space between each star of the two pairs (see below).

To split a double, it is said that the minimum mag required is about 160/(sep in arcsec), which certainly seems to work with my eyes, ie for the DD x100 shows it to be a double, but x200 is required to produce a clean split.

Chris

 

 

[Arcturus D]

I agree, there is a big difference in magnification needed in order to see the difference between a mere elongation and a clean split. 

Around 130x is usually where I start seeing the clean split. 

A lot of this also depends on one's eyes. Some people are better than others when it comes to seeing small items, e.g. the scope might split the item bit one's eyes cannot see the split.

Sirius B is a good example, which is very difficult.

[Stub Mandrel]

As this is the 'observing and imaging double stars' topic... this was with my 150PL on 14 May, ZWO ASI120MC, no barlow.

 

[Cosmic Geoff]

I have split the Epsilon Lyrae close pairs with more than one of my scopes, most memorably with my vintage brass 70mm Ross refractor, fitted with an astro eyepiece giving a high but unknown magnification.  According to Norton's Star Atlas, a 70mm should manage this comfortably, so if your (larger) instrument doesn't, you may have an issue.

One might imagine that a telescope sold for astronomical use would perform to the theoretical limit but sadly this isn't always the case.  A budget 70mm telescope I used to own turned out to have a very poor objective lens.  My 127mm Mak would not resolve e1 e2 Lyrae clearly till I invested in two better quality eyepieces, which disclosed that there was nothing wrong with the Mak, which now showed, at x187, tiny pairs complete with diffraction rings. The original 10mm eyepiece is now retired.

The larger the instrument, the more the actual results will depend on atmospheric conditions. In other words, the larger the aperture, the higher the magnification required to test the resolving power becomes, and the greater the likelihood of the atmosphere spoiling the party.

I have also tried imaging this star, (with 203mm SCT + ASI120MC camera) and found that it shows clearly as a double-double in the live view and processed image.

[iPeace]

Got a nice split last night using the Borg 71FL refractor (71mm aperture, 400mm f/l) and a 4mm TeleVue DeLite (100x) with a Takahashi prism diagonal. Took some patience (especially with my undriven alt-az mount - and my eyesight), but there finally was clear separation in both pairs. Could use more magnification, but where's the fun in that?

Bjorn on the Double Double. Nothing satisfies quite like a DIY dewshield that actually works.