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:
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.)
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.
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 😉