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ΟΣΣ36 and Σ485 by way of the Cascade and Camelopardalis

On an early winter evening there’s a big hole in the northern sky imaginatively called Camelopardalis, and if you scan this hole with binoculars or finder you may stumble upon  three bright  (magnitude 5) stars in an arc which point to a fourth which is,  in turn,  right in the middle of a wonderful tumble of seventh and eighth magnitude stars known as Kemble’s Cascade.  This celestial waterfall sort of starts with a double  – ΟΣΣ36 – and  the sparkling “waters” at the bottom of it are dominated by a second double –  Σ485.  And as a bonus you get a neat star cluster thrown in, NGC 1502, and an unnamed asterism I’ve dubbed  “Triskelion , because it’s very suggestive of the symbol used by some nasty folks in an early episode of the original Star Trek.  Not too shabby for a hole in the sky! And did I mention all this was in that constellation with the obscure name of Camelopardalis? Oh boy! So let’s get serious.

ΟΣΣ 36  (STTA 36)
RA:  03h 40.0m   Dec:  +63° 52′
Magnitudes         A: 6.92    B: 8.27
Separation          45.7″
Position Angle    71° (WDS 2010)
Distance:  138 LY
Spectral Classification: A is F5, B is G5

(ΟΣΣ – Omicron Sigma Sigma – stands for Otto Struve’s 1843 Pulkovo catalog supplement – where as Σ (Sigma) simply means Wilhelm Struve’s 1827 Dorpat catalog.)

Naked-eye view to help locate Kemble’s Cascade. Click image for larger version. (Prepared from Stellarium screenshot.)

How do you find all this? I always used to star hop to Kemble’s Cascade by starting  with Eta Persei. From there I would work my way east  about six degrees to a nearly matched pair of 4th magnitude stars – well, the dimmer one just slips into the fifth magnitude category – that are about a degree apart. From these two I slid northeast roughly 3.5 degrees and there were the three bright (5th and 6th magnitude) stars in an arc less than a degree apart – quite distinctive.  I always thought of these three as being at the “top” of the cascade – really the northwestern end. Actually, they’re not part of it, but they are so linked to the cascade visually that I consider them part of the experience. Especially since a fourth star of about the same brightness – and following the same arc, but split from the other three – lands smack in the center of the cascade. All that seemed a bit complicated, however, and last  night I noticed another, simpler relationship. The cascade marks one corner of a triangle made up of the cascade, Mirfak ( the brightest star in Perseus) and Capella, brightest star in Auriga.  So I just pointed my binoculars – and later the finder on the Orion 110Ed – in this general direction and prowled about a little bit until I saw that distinctive arc of stars.  You can see these relationships in the finder chart above – especially if you click on it and get the larger view.

Once you have located the three bright stars in an arc you need to turn to a magnified view. Here’s what binoculars, or a correct image finder reveal as you zoom in near the three stars in an arc. The cascade proper – that tumbling stream of fainter stars – is about three degrees long. A five-degree field will capture all that is shown here.

Click image for larger version. (Prepared from Stellarium screenshot.)

When you zoom in on ΟΣΣ36 with a low power eyepiece you should find it east to split, though rather delicate. Haas describes a “wide pair of stars, lemon white and beige, in the field with a bright red star and a bright yellow star.”  At first I wasn’t sure what she meant because I didn’t see these bright red and yellow stars – but I was using too much power and too small a field of view. I switched to a 30mm Tak LE – 26X – and slid ΟΣΣ36 over to one side – then I picked up the brilliant red and yellow stars – the top two stars in the arc I’ve been using to find Kenble’s Cascade. The double itself I see as pale yellow and  blushing blue – that is a very modest blue. I really had trouble assigning colors to this pair and finally did after viewing them with a 7.5 Tak LE  which gave me 103X in the 110ED.

The Cascade itself really demands a wide field, as mentioned – I find it very appealing in my 15X70 binoculars – but  it’s fun to follow it in a telescope, counting the stars as you go until you end up at the “bottom.” Doing this with the 30mm in the 110 I found myself looking at a pair of brilliant, perfectly matched stars sitting atop a sprinkling of powdered sugar – Σ485 in the middle of NGC 1502.

Σ485 (AE)
RA:  04h 07.8m   Dec:  +62° 20′
Magnitudes         A: 6.91    E: 6.94
Separation          17.9″
Position Angle    300° (WDS 2012)
Distance:  A has a negative parallax (distance unreliable)  E: 2202 LY
Spectral Classification: A and E are BO

This is a real keeper – something to come back to again and again and to show off to guests. Jeremy Perez has done a real nice drawing of this cluster which shows the dominance of Σ485 very well. He’s published it on this Belt of Venus site  – take a look.

I cranked up the power to 62X with a 12,5 eyepiece and counted over two dozen cluster members. Looked a bit like a sting ray to me – very compact. But I was more intrigued with the wide view and returned to it and that’s when the Triskelion came into my consciousness.  I love the metaphor of the “cascade” tumbling into the “pool,” but when I rteurn to this I know I’m going to always be looking for this triskelion.

Is this a triskellion? Or just suggestive of one? In any event, it works for me and cluster with double are near its center. Click image for larger view. (Prepared frm Stellarium screenshot.)

Oh an if you’re wondering what a camelopardalis is, I found the answer in  Urania’s Mirror, an 1832 publication which says:

The Camelopard is an Abysinnian animal, taller than the elephant, but not so thick. He is so named because he has a head and neck like a camel, and is spotted like a leopard; but his spots are white upon a reddish brown ground. The Italians call him giraffa. To Hevelius, who formed the constellation, he owes his celestial honors.

Ah, giraffe! Thank you, Italians!

There’s much more worth exploring in this “black hole,” with no danger of being crushed, including a double double. I plan to spend several fine evenings here!

(WDS data updated 6/5/2016 – JN)

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2 Responses

  1. I think your RA/DEC is off for Struve 485. Also I have mag 6.9/6.9 for this one, but I can’t remember what source I used.

    • Hi Jim,

      Thanks for catching that. That data has been wrong for quite a while — surprised someone else didn’t catch it. Greg wrote that post, so I wasn’t familiar with STF 485. It took a few minutes to figure out which pair he was referring to since there are well over twenty components in this multiple star. I’ve corrected the data to show the AE pair is the one he was referring to, corrected the coordinates and magnitudes, and updated the other data as well. The data for the first star, STTA 36, has also been updated.

      Many thanks!

      John

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