Herschel's Quandry

In Taurus just over the border from Perseus is NGC 1514, a planetary nebula with an important role in history. William Herschel, based on his experience resolving globular clusters, believed that all nebulae were clusters of stars that were too faint or too remote to resolve. But when he discovered NGC 1514 in 1790, Herschel encountered a solitary star “surrounded with a faintly luminous atmosphere”. This object forced him to revise his thinking and conclude that “Our judgement I may venture to say, will be, that the nebulosity about the star is not of a starry nature”.

Although officially listed at magnitude 9.4, NGC 1514’s relatively low surface brightness and its bright central star make it a rather challenging object to see from an urban environment. Even though it isn’t the most beautiful planetary, it is worth tracking down simply because of historical interest. Here is some information to help you find NGC 1514...

(Photo courtesy of Chris Cole)

The “atmosphere” that Herschel described is actually quite tenuous and hard to see if there is any light pollution. So under washed-out skies, the key to finding NGC 1514 is first finding the central star, and then looking for the nebulosity around it. To help you, I’ve produced two finder charts using the AAVSO Variable Star Plotter (remember, you can use this tool to create finder charts for any coordinates, not just variable stars). The first chart has a 15 deg FOV; cross-hairs at the center of the chart mark where NGC 1514 is located. The chart also shows ζ Persei on the upper right, and the Pleiades on lower right so you can locate this chart relative to the rest of the sky. I’ve also labeled two 7th magnitude stars to the north of NGC 1514 as “A” and “B”. The second chart (3 deg FOV) zooms in on NGC 1514’s central star (marked with cross-hairs). I've also marked the same two 7th magnitude stars (“A” and “B”) from the first chart so you can easily navigate from the first chart to the second.

At magnitude 9.5, the central star is easy to see in even small telescope. Once you find it, the challenge is to see the faint nebula that surrounds it. It is particularly hard to see because unlike many planetaries, the nebula is brightest near the center and fades away without any distinct edges. I've seen NGC 1514 with my 4.25" (100 mm) Newtonian from dark sites, but under washed-out skies I’ve never seen it with less than a 10" (250 mm) aperature (although friends have sighted it with a 6" scope in suburban areas). With my 10" at 80x the only hint of NGC 1514 is that the central star looks slightly out of focus. Using 175x it is clearly something more than an out-of-focus star, but very indistinct. Only when I use an UltraBlock filter can I clearly see the nebula. The two photos below simulate what you might see.  The photo on the left is an extract of the photo above converted to black-and-white; the photo on the right is the same image altered to resemble what I saw through my telescope with the UltraBlock.

The quotation from Herschel comes from: Herschel, William (February 10, 1791), "On Nebulous Stars, Properly So Called.", Philosophical Transactions of the Royal Society of London, Volume 81, pp. 81: 71–88.