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Did anyone find Izar an easy split last night? With my 120 achro I couldn’t manage it except fo a second or two when they seemed to wobble apart. Tried an 8mm then 12mm Barlowed but no luck. It was a clear night: do you think it was the seeing or do I need a better scope!

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Separation is now about 2.8" with a magnitude difference of 2.2. I'm pretty sure it can be done with your scope, but you need steady air and a decent magnification, Izar can be tough to split. Good luck!

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my 10" dob easily splits the tightest ones.

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I find Izar is a good test of the conditions. With my 4 inch refractor I can split it at 90x on a good night. Most nights stars are fuzzy and unsatisfying at 150x but when they are tight I try to make the most of it. Your scope is bigger than mine so you should be fine. I've had many clear nights recently but only a few when I can split tight doubles cleanly.

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Hi Rob,

Every ones eye are differant,but I've always had difficulty with Izar even with a 200mm Newt.Of course usually I've managed to  split them with a 300mm reflector when conditions are favourable,but my new 400mm Dob splits them with ease under most conditions on all but the lowest powers.

Its worth remembering that the very clear skies over the last few days that have been so awesome for fuzzies does not necessarily mean that its all that great for doubles more often than not it wont be due to turbalance,more likely have more luck with still slightly misty skies.

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I've been looking at Izar myself for a few nights in various scopes over the last week:

75mm Pentax SDHF refractor: marginal split at *125 because the fainter component is close to the 1st diffraction ring

80mm GT81 refractor; marginal split at *120 slightly clearer than the Pentax. 

200mm f/4.5 Newtonian; easy at *150. Very clean split 20 April

I could regularly split this star with my old 5" achro, and I've done it in a ST120.

Your long focus achro should split it comfortably.

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102 gave a delightful colour easy split. Seeing was variable across the sky. Try closing a bit of aperture , it might help,

Nick.

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Last night although the seeing was poor here it was easily split in my 180 Mak at x 190 which showed very nicely the fantastic colour contrast of the pair, even though they were dancing around a bit. It has surely got to be one of the most beautiful doubles! An image using my 180 Mak with an ASI224 Colour camera from last year:-

Chris

 

 

Izar23_57_18_g3_ap1Izaradjusted.png.6e8441a48780c85c7b1406b5d23b1b2d.png

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I tried a few nights ago with my Tal did not get it seeing was awful at high mag.

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Izar has a lot of attractions as a binary pair, the colour contrast, the tightness of the separation and it's relatively easy to find. A "must see" in the springtime and a good test of seeing conditons :smiley:

 

 

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I've just been observing Izar with my 100mm Takahashi refractor. The pair are split at 97x and become progressively more split as I boost the magnification (I have a 9mm - 3.2mm zoom / barlow combo in use currently). Beautifully well defined primary and secondary star at 281x with quite wide gap between them. The differing colours get more clearly defined as the magnification increases as well. Very nice indeed :smiley:

 

 

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Thanks, all. Well I finally managed it tonight. Despite or because of a high cloud cover when relatively few stars came out I had a clean split with a 12mm and 2.5x Barlow then a cleaner split with the 8mm barlowed. That’s probably 200 to 250 or so mag so it wasn’t split as easily as for some people!

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I tried this evening with my 8" Dobs, without any success.  To be honest, I think it was a bit hazy this evening, so conditions weren't as good as earlier in the week.

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Izar was a beautiful sight last night at x265 in the Tak TSA 120 +  Vixen HR 3.4 eyepiece.

Good to hear you were successful @robhatherton!

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Splitting Izar is weather dependent.

 

On good nights I can do it at 133x with an 8" Dobsonian.

I tried it the other night and I had to use about 192x to get a clean split. 

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Inspired by your post @robhatherton, I thought I would have a little play around with a couple of my tiniest scopes to see what they could do. Quite impressive results given the small apertures, but I do think smallish refractors often have an easier time of it on these doubles due to their tighter stars and lack of diffraction spikes. Post here.

 

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On 22/04/2020 at 09:33, robhatherton said:

Did anyone find Izar an easy split last night? With my 120 achro I couldn’t manage it except fo a second or two when they seemed to wobble apart. Tried an 8mm then 12mm Barlowed but no luck. It was a clear night: do you think it was the seeing or do I need a better scope!

With my 100mm achro, it is an easy split, so keep trying! Seeing is everything for doubles - wait for a good warm hazy evening with the stars barely twinkling visually.

Chris

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I've always had trouble splitting it. Every time I tried the conditions haven't been right. I'll have to have another go at it as I do like colour contrasting doubles

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I could not do it last night with my old 60mm refractor. I could see it was a double star - a sort of peanut shape. Each end of the "peanut" had a different tint to it. Just no dark line separating the two. The conditions were not great (tin cloud cover) and the scope 50+ years old with the old .965 inch eyepieces used being of the same vintage.

It did give me nice splits of Gamma Leonis and Gamma Virginis though.

 

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33 minutes ago, John said:

I could not do it last night with my old 60mm refractor. I could see it was a double star - a sort of peanut shape. Each end of the "peanut" had a different tint to it. Just no dark line separating the two. The conditions were not great (tin cloud cover) and the scope 50+ years old with the old .965 inch eyepieces used being of the same vintage.

It did give me nice splits of Gamma Leonis and Gamma Virginis though.

 

What magnification can you get to with the original eyepieces John? I’m sure you will have more luck with modern ones though.

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18 minutes ago, Stu said:

What magnification can you get to with the original eyepieces John? I’m sure you will have more luck with modern ones though.

I had a choice of 64x, 133x or 200x Stu. Simple Huygenian type - 2 elements in 2 groups !

Mind you, F/13.3 fracs are not too fussy.

A cloud free night, a stable mount and a modern eyepiece / diagonal and the results may well be different :smiley:

Edit: my earlier post should have read thin cloud cover rather than tin cloud cover. Doh ! :rolleyes2:

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Yep, should be good to try. What’s the CA like? I guess it’s similar to the Telementor which is heavy on Venus but actually pretty well controlled everywhere else.

I thought maybe I had some Huygens eyepieces with the Vixen FL102 but I just checked them out and they are 0.96” Vixen Orthos, might be quite nice but I would have to refit the original focuser to use them. Might do it just to give them a go, or might be easier to buy an adaptor.

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2 hours ago, Stu said:

Yep, should be good to try. What’s the CA like? I guess it’s similar to the Telementor which is heavy on Venus but actually pretty well controlled everywhere else.

I thought maybe I had some Huygens eyepieces with the Vixen FL102 but I just checked them out and they are 0.96” Vixen Orthos, might be quite nice but I would have to refit the original focuser to use them. Might do it just to give them a go, or might be easier to buy an adaptor.

The CA levels are pretty low. Venus looked very nicely defined at 133x and was surprisingly good even at 200x. Some CA fringing the edges of the crescent but really not distracting.

Those old Vixen Or's are quite nice eyepieces - I used to use them with a Vixen 102M achromat. A lot better than the Huygens ones I got with the Tasco.

 

 

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6 hours ago, John said:

The CA levels are pretty low. Venus looked very nicely defined at 133x and was surprisingly good even at 200x. Some CA fringing the edges of the crescent but really not distracting.

Those old Vixen Or's are quite nice eyepieces - I used to use them with a Vixen 102M achromat. A lot better than the Huygens ones I got with the Tasco.

 

 

Sounds good John, seems CA is lower than the Telementor. Nice!

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