At first-glance, our staff, mistook the image below to be a photograph of the Double Cluster. It turned out NOT to be a photograph, but the deft work of talented hands and a good eye at the eyepiece.
Tom Corstjens, from Belgium, created this accurate, hand-drawn representation of the cluster. We’ve admired Tom’s sketches ever since, and started following his twitter feed to see his latest work. We’ve never been disappointed.
Copious notes in the corners of each sketch explain the object, orientation, location, date, seeing conditions and hardware used. All the sketches we’ve seen were made with an Alkaid 16″ f/4.2 Dobsonian with Paracorr to correct the coma from the fast mirror. The eyepiece is usually a Delos, Nagler, or Panoptic. The sky condition notes include the naked eye limiting magnitude (NELM), narrow field Sky Quality Meter (SQM-L) reading, and the seeing (S) and transparency (T) according to the Antoniadi scale: 1 is good, 5 is poor.
Tom’s home location is in a sub-rural area where he observers from the garden. In search of darker skies, he frequently drives to sites in Belgium, the Netherlands, and France to fully enjoy deepsky observing and sketching. We asked Tom about what technology he used to create these sketches at the eyepiece:
I’m sketching with regular graphite pencil (HB, 1B and 3B) on white paper. Stars are finished with black fineliner. Then sketch is digitally scanned (flatbed), dust speckles cleaned and text is added in GIMP software. That’s it – no complex digital processing and keep the raw nature of paper and pencil.
Tom explained to us his choice of eyepieces for his setup :
I’m using primarily Delos eyepieces because their 72° field is ideal for sketching: full large field can be seen to the edge, but still compact enough to orientate the marker stars on sketch paper. Stars are pinpoint sharp to the edge, objects are very crisp with subtle details detectable, where other eyepieces fail to perform on this level.
Over the past 20 years I have used various eyepieces, also Tele Vue Plössls, Nagler, and Ethos aside of other brands. The Delos series are near-perfection for me, with comfortable viewing, and adjustable eye relief blocking any indirect light. Also the dimension and weight are acceptable and do not cause balance issues on my 16″ Dob.