From the December 2014 issue

Two perspectives

Celestial sketcher Erika Rix uses emission nebula IC 1805 and open star cluster Melotte 15 to show how observers create different sketches of the same objects.
By | Published: December 29, 2014 | Last updated on May 18, 2023
Ask two observers to point their telescopes toward the same large celestial object and then to sketch the views. You might be surprised at how different the results turn out. The focus of the observation, and indeed the technique used to record it, is personal to each individual. I’ll use IC 1805, also known as the Heart Nebula, to explain.

This beautiful heart-shaped emission nebula covers more than three and a half times the area of the Full Moon in the constellation Cassiopeia. Observers and imagers often pair it with the Baby Nebula (IC 1848), which lies nearby. Another pair of emission nebulae, IC 1795 and NGC 896, lies at the western point of the heart, making the complex a prominent active stellar nursery within the Perseus Arm of our galaxy.

At the core of IC 1805 lies the newborn open cluster Melotte 15, a scant 1.5 million years old. It’s composed of more than 40 loose stars across a diameter of 22′. Stellar winds and ultraviolet radiation from the cluster’s massive stars contour the nebula’s glowing hydrogen clouds to form its heart shape.

Sketch of northern lobe of IC 1805
To sketch the northern lobe of IC 1805, Rony De Laet used a 4-inch refractor, a 26mm eyepiece for a magnification of 20x, and a UHC filter. He then created the image with Corel Photo-Paint based on the pencil sketch he did at the eyepiece. He mirrored and rotated the image so that north is up and west is to the right.
Rony De Laet
You’ll be able to spot Melotte 15 as a handful of 8th- to 9th-magnitude stars through a 4-inch telescope. You also can see faint nebulous patches of IC 1805 with averted vision by incorporating an Oxygen-III (OIII) or Ultra High Contrast (UHC) filter. Through a 12-inch instrument, upwards of 30 cluster stars reveal themselves embedded in a faint, hazy glow.

During my observation, the focus of the sketch was Melotte 15. I created the star field with pen and graphite before I began observing through an OIII filter. I then used a blending stump to draw the hazy glow. This simple technique provides a finished sketch directly at the eyepiece. You then can scan the sketch, remove stray markings with photo-editing software, and invert the image to represent the eyepiece view.

Rony De Laet of Bekkevoort, Belgium, provided a different perspective. Using an UHC filter, he chose the northern half of IC 1805 for a low-magnification view that included both Melotte 15 and open cluster NGC 1027.

Melotte 15
The author created this eyepiece sketch of Melotte 15 by observing through a 16-inch f/4.5 reflector with a 13mm eyepiece (138x) and an OIII filter. She used white printer paper, a super-fine black felt-tipped artist pen, a No. 2 pencil, a 0.5mm mechanical pencil, and a blending stump. She scanned her sketch and inverted the colors, also adjusting the contrast to match eyepiece view. She rotated the image so that north is up and west is to the right.
Erika Rix
Rather than producing a finished sketch at the eyepiece, De Laet created only a rough pencil drawing during his observation. Afterward, he used digital drawing software to recreate the view based on his observing notes and eyepiece sketch.

His technique has advantages. Once you become accustomed to using the program’s tools, you can create glows around stars, emphasize stars with different magnitudes, and add colors with ease. If you make a mistake, simply press “Undo” or revert to a previously saved version. Perhaps the handiest element is the ability to draw in layers — one for the background, another for the star field, and yet another for the nebulosity. You can make adjustments to any layer without affecting the others.

Now and again, try venturing out of your comfort zone by dabbling with a new technique or type of object. You’ll expand your skill set and might just find the new method more rewarding.