NGC1502, at the base of the cascade

Nov 30

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11/30/2013 8:38 PM  RssIcon

NGC 1502 is a small, open cluster in the dim, northern constellation of Camelopardalis. Containing approximately 45 stars down to 14th magnitude. About a dozen or more are 12-th magnitude and above, and at just 8 arc minutes across, the cluster displays a nice shape, despite it's irregular appearance. It is situated about 2,700 light years from Earth, and is rather young, at just 11 million years old.

Camelopardalis is a constellation with which most people are not familiar. Around 1614, German astronomer Jakob Bartsch identified the outline form - obviously in a time when it was easier to see those dimmer 4 and 4.5 magnitude stars. John Hevelius named it Camelopardalis which means "Camel Leopard" or "Spotted Camel." However, since then, it is now formally known as "The Giraffe."

NGC 1502 open clusterFinding where the constellation is located isn't too difficult - it's basically the blank spot of sky in-between Polaris, Capella, Mirfak in Perseus and Epsilon Cas in Cassiopeia. But triangulating to NGC 1502 isn't terribly hard - a straight light from the tips of the "W" (or "M") shape of Cassiopeia towards Auriga finds the observer in the right location with just a 15 degrees hop. This can be assisted by drawing a second imaginary line from Algol through Mirfak in Perseus; where these lines intersect is where NGC 1502 is located. 

Based on its small size, it may be easier to locate the three 5th and one 6th magnitude stars in the area, one of which is midway through the lovely Kemble's Cascade asterism. This is a string of 7th and 8th magnitude stars, that meander slightly along a 2 degree line across the sky, emptying into the NGC cluster.

At right is the approximate view of all of the stars of NGC 1502 as they might be seen at the eyepiece of a large telescope at about 150x in a 0.35 degree field of view. Not all observers will see all of these stars, but the more prominent, bright ones towards the middle should be apparent to all but the most light polluted areas. 

A couple of these stars are doubles; Struve 484 and Struve 485 are easily seen and split here, with most any small telescope. In this graphic, Struve 485 are the bright looking stars near the middle, though the graphic from Stellarium inaccurately shows three stars, where there are just two.

Struve 484 is the next double stars down (in this view) from Struve 485. This and the next pair of stars from there were easy to see in a 4.5" f/4 telescope from my moderately light polluted yard. I counted about 12 stars when I viewed the open cluster - far less than what the graphic shows, but they are a tight grouping, and have a pleasing look to them at the eyepiece.

Kemble's Cascade / NGC1502 triangulation graphicThat, along with Kemble's Cascade and the orange-red variable star UV Cam nearby, makes this a worthwhile area to locate and visit when this "empty" part of the sky is above Polaris, and well placed for viewing

TIPS FOR FINDING KEMBLE'S CASCADE AND NGC 1502:

  • If possible, locate the general area with binoculars first. Hopping two binocular fields of view from the Epsilon Cas (using the Beta ---> Epsilon line) will get you to the general location.
  • With good polar alignment, center Epsilon Cas, then dial 2 hours east in Right Ascension. This places the the 5th magnitude star HIP 18505 in the field of view, which is in the middle of Kemble's Cascade.
  • Also with good polar alignment, center the star Epsilon Persei, the dial 23 degrees north towards Polaris/celetial pole. This will center the star HIP 18505.
  • A red dot finder may be the easiest way to locate this area; simply triangulate from the Beta Cas ---> Epsilon Cas line and the Algol ---> Mirfak line to the Kemble's Cascade location (see graphic). 

And if you happened to have missed the Eyes on the Sky episode where these objects were discussed, you can check it out in the video below. You'll learn where to look in the sky for Camelopardalis among Cassiopeia, Perseus, Auriga and Ursa Minor, plus more about finding and observing these deep sky objects.

Want to know how to find and see these sights and more in the night sky with binoculars or a small telescope? Check out the homepage. For recent videos of other celestial sights to see, click the "Videos" link at the top of this page.


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The Nightlight

This blog includes what to see in the night and daytime skies, thoughts on telescopes, binoculars, and other astronomy observing accessories and equipment, plus my own occasional notes on objects I've seen and observed. Oh, and the random theater or other "my take on life" post. In other words, there is always something interesting. Check it out.