Galileoscope - First Impressions.
- Oct 6, 2009 at 4:16PM
What do you think of the Galileoscope? Did you get one for IYA2009? Used it yet? What did you observe? What are your impressions of the telescope?
I will start.
I put the telescope together with my 6 year old son. It was a nice weekend project. The instructions included with the scope were lacking but I used them to see how easy it would be for a novice if she/he opened the box and followed the write-up. For example there were four included rubber O-rings in the box but only two are mentioned in the packing list. The good thing is that the scope is designed in such a way that putting it together is like assembling a 3-d puzzle. The only thing you might get wrong by going down this path is the assembly of the Barlow lens. Better instructions with color images can be found here: https://www.galileoscope.org/gs/sites/galileoscope.org.gs/files/Galileoscope-Instructions-20090710rtf.pdf
Western Washington has lately been enjoying a few clear nights. My son and I began by pointing the scope at the nearly full moon (9/4/09). Under instructions he was able to use the built-in sights to point the scope at the moon successfully. Focusing is another matter. Being of the slide-in variety, you have to use a light touch and much patience to get good focus. Without a tripod, or mount it will be difficult to keep your target in the field of view. Even with a tripod objects move about as you push or pull on the focuser. However, once focused the image was very good with the included low power eyepiece. Chromatic aberration (CA) was not very obvious. I then used a good 6mm planetary eyepiece (EP) I have which yields a magnification of 83. We admired the large crater Copernicus with its rays among other things. At this magnification some CA was noticeable with purple fringing on the Moon's limb.
Then we trained the scope on Jupiter. My son had a little difficulty getting this target in sight, but he was close. With the best focus I could manage we spotted three satellites and Jupiter displayed a nice small disk with the included low power EP. With the 6mm EP, we were able to spot two of the prominent Jovian atmospheric bands as well. Focusing was a little tedious at this power.
Overall the Galileoscope has good optics. The large focal length to diameter ratio (500mm/50mm=f10) makes it easier to design a lens with little CA. Baffles in the tube improve contrast. During daytime observing the included low power EP showed very little curvature at the edges. The weak link in the design is the focuser - nothing a little patience cannot compensate for. I have not had a chance to try other targets because of the bright moon, but under moderately dark skies some of the brighter globular clusters in the Messier Catalog should make good targets. There are numerous hacks people have tried and have documented all over the web. The simplest one I would recommend is to attach some type of light rigid tube about 1 cm in diameter to the sighting posts. Looking through this "finder" will make it easier to acquire targets.
This is a wonderful tool to learn from or to teach the basic principles of telescopes especially at this price. IMO it is a little limited as an outreach tool for actual observations. Being light on the mechanical design side (especially the focuser) I think one will be limited to the brightest objects in the sky, but I could be pleasantly surprised as I try out more targets.
Ajay Narayanan SPS Chapter Advisor / Zone 17 Councilor