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The Lion’s double double – Tau and 83 Leonis

Tau (τ) and 83 Leonis are a charming pair of pairs in Leo just a bit west of  where it borders Virgo and not very far away from the fabled Porrima. Though it has neither the magic nor the challenge of the Double Double in Lyra, it’s fun  to track down and very rewarding in its own right.  I was able to split these pairs easily, first using an 8-inch SCT, then the next night using a 50mm Stellarvue “Little Rascal” at 20-40X.

Tau (τ)  Leonis aka Σ119
RA: 11h 28m   Dec:  02° 51′
Magnitudes: 5.1, 7.5   Sep: 88.9″   PA: 181°
Distance:  621 LY   Spectral Type: G8II-III

83  Leonis aka Σ119
RA: 11h 27m   Dec:  03° 01′
Magnitudes: 6.6, 7.5   Sep: 28.6″   PA: 150°
Distance:  58 LY   Spectral Type: G7V

This was an enjoyable star hop that started with Denebola,  the second magnitude star that mark’s the Lion’s tail. You can be sure you have it in your finder because there’s a sixth magnitude star just 20 minutes south of it.  In fact, use this companion as a guide – it’s pointing you in the right direction.  Tau is going to be about 12-degrees along the line between Denebola and it’s companion – a bit more than two finders fields for me.  When about half way to Tau you should encounter a distinctive trio of triangles. This was a marker for me that told me I was on the right track – like hopping from stone to stone across a brook, this was the big, flat, stone in the middle where you could pause to catch your breath and take your bearings.  It looks like this:

Three triangles in Virgo as seen in a correct image finder. Click image for larger view. (Prepared from Starry Nights Pro screenshot.)

Nu Virginis is magnitude 4, Omega magnitude 5.  Treat Omega as the tip of an arrowhead and it’s pointing you right towards Tau Leonis. When you get in the vicinity, here’s what the typical correct image  finder should reveal. (Notice we started in Leo with Denebola, crossed the border into Virgo where the three triangles are located, then hopped back over into Leo to find the two doubles, Tau and 83 Leonis.)

Binocular or correct image finder view of the Tau and 83 Leonis region. (Developed from Starry Nights Pro screenshot.)

Here’s the view in a Celestron EdgeHD SCT with  a 30mm Take LE eyepiece that gives a field of  view of about 47 minutes, this view from Starry Nights Pro does a good job of approximating what I saw.

Tak 30

The widefield view has a certain charm. It’s not at all like the uniformity of the Double Double in Lyra where the stars are about equal in brightness and the split of each pair is baout the same. Here the two secondary stars in each pair are the same brightness, but the primarys differ and the split differs significantly, though both are wide and easy, especially in the 8-inch. They jump out at you, but I checked the PA just to be positive I had the correct stars.

I examined both pairs more closely in an 18mm Tak at about 111X.  In both cases the colors seemed obvious to me. Tau was a lemon yellow and pale blue.  The closer pair – 83 Leonis – showed pale yellow and pale violet. Sissy Haas describes the colors this way:”a yellow-white star and a lemon-yellow star – each with a small grey companion.”  Well – at least we agree ont he shades of yellow – and”gray” isn’t that far off from the pale blue and violet that I saw.

Will I come back? Yes. Matter of fact, I’ve been here before. I made a notation in the Haas book – “5/2/07.” That means I saw it then – but I wish I had written a complete report. Sometimes I really spin my wheels. But then, so what?  I don’t remember the earlier observation,  so I  get the thrill of discovery twice this way ! Got to be some advantage to growing old  😉


One Response

  1. I’ve had this pair of doubles on my list ever since Greg posted his observation, but hadn’t been able to get to them until last night, April 7th.

    And on a very frustrating night of intermittent waves of clouds and extremely poor seeing, these two pair of stars were a welcome sight. Two clearly split doubles in a single field of view requiring very little magnification, on an evening when even the view in a 60mm scope at 40x was vibrating, saved the night from being a total disappointment.

    And on top of that, they’re relatively bright, so when they came into view, there was no chance of skipping past them. I star-hopped to them from Iota Leonis using my Sky & Telescope pocket Atlas — red flashlight gripped firmly against page 34 in my left hand while peering into a RACI 8×50 finder and guiding the scope with my right hand.

    My first view of them was through my 60mm f16.7 refractor and a 20mm TV Plossl (50x). That scope was riding on the top of a 105mm f14.3 refractor equipped with a 16mm Meade SWA (94x). The image was shimmering in both scopes, and in fact the focus kept changing so frequently I gave up trying to catch it and just got close and let the stars come into focus when the atmosphere felt like cooperating. And that wasn’t often, but often enough to provide a rewarding view.

    The Tau primary I saw as white with a bit of yellow and the secondary was impossible to describe — gray maybe, but I’ll have to make a better determination on a calmer night. The primary of 83 Leonis was also white — maybe there was a slight bit of yellow in it, but if so, it was less that what I saw in Tau. Again, the secondary was impossible to assign a color to — if I was pressed, I might call it gray, also.

    So thanks to Greg’s initial observation, my night was saved! If you want a pleasing sight to relieve eyes strained after a night of poor seeing, or after trying to split close doubles, try these two. They’re a nice place to land for a short break after a difficult night of photon ferreting. 😉

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