|Nebulosity||Reflection Nebula||03h 47m 01s||+24° 07′ 00″||Taurus||+1.5||120 arcminutes|
Even if you don’t realise it, I can pretty much guarantee that you have seen the Pleiades cluster in the winter night sky.
Known informally as the Seven Sisters, this beautiful cluster is easily visible to the naked eye. In fact, once you know where to look it’s hard to not see the blurry patch of bright light nestled by Taurus and pointed at by Orion’s belt.
The beautiful image below shows exquisite detail of this cluster and its whispy nebulae.
To find the cluster of stars, which is also known as M45 in the Messier catalogue, use the image below as a finder. Follow the red arrow from the belt of Orion, up past the bright star Aldebaran in Taurus and arrive at the Pleiades.
This challenge is about seeing nebulosity around the brighter stars of the cluster but, before we do that, how many stars can you see with the naked eye? Most people will see around six under dark skies but there are good reports of people who have seen more than 10!
The whole Pleiades cluster shimmers behind the bluish glow of reflection nebula. You can see it strikingly bright in the picture at the top of this page.
For many years the nebulosity and cluster were assumed to be two sides of the same coin, however, we now know that the dust cloud which creates the nebula is moving in a different direction to the stars in the cluster, meaning they must have come from two different places. We now expect that one day, many, many years from now, the nebula and stars will part company.
Don’t let the image above fool you though, spotting the nebulae in your telescope is really tough. You need ideal conditions, which means no moon, a dark sky, and a well collimated telescope. More likely than not, you’ll also need bags of patience.
The dim light of the nebula which is known as NGC 1435 wraps itself around the star Merope and fans backwards from it, giving it the appearance of a comet. Merope is visible in the 3 o’clock position in the image below. The blue circle is 1° across, which is a good eyepiece field of view to use for this observation.
There are other areas of nebulosity within the Pleiades, such as that which surrounds Maia (in the 1 o’clock position, above). This is much fainter than the Merope’s and consequently is a much tougher spot.
Do not be too hard on yourself if you don’t see the gas cloud on your first attempt. As is so often the case with astronomy it is repeat visits and familiarity with the target that yield the best results.