I had an idea about how I could “dress” up my star party scope, (6 inch GSO on a Dobson mount) the one I use for public viewing on Astronomy Day. I wanted to change some parts that would add interest and visibility when explaining parts of the telescope and a bit of class to draw attention.
I started with the secondary holder, normally black in color and hard to see in darkness. Since I own a 65-watt laser engraver and cutter, could I design a simple replacement? I have been working with color acrylics and thought that this would be a good choice. Since the secondary is lite in weight and limited to 6.75" diameter, it should work. I started with clear color first (I had a lot of this material about), I cut the standard 4 vane (5mm thick, 3mm wide) with a center hole and tapped it for Nylon adjustment screws (another reason why I chose acrylic, it machines well with the laser).
I replaced the 3 vane metal one that came with the scope. The sample worked great, limited flexure, easy to cut, and tapped OK. (Yes, I did a star test, clear acrylic is NOT an optical element, and it introduced “extra” spikes and odd images of the spikes.) Since this did work, I decided the best color to use for visibility at the star party was white. I cut a piece, mounted it and tested it. It worked great at the last Astronomy Day outing, I was able to point out when the secondary was mounted (some times these questions do get asked, “How does the light come out of the side of the tube?”) So does the white color transmit its color in the tube? The answer is no (or at least not enough to interfere with viewing, even with a bright moon). I decided to try other colors for fun and wood as well. Each does work well.
The optical performance (star test) is what you would normally expect I was not looking for improvements.
The wood is 5mm birch wood 3-layer plywood, a standard in the industry for laser cutting and engraving. The wood needs brass screw inserts, since the screw size is small (8-32 and 6-32) and hard to maintain the threads without stripping them when holding the secondary.
The laser can make holders for my other scopes up to 12 inches diameter (for 10 inch scope). I would limit it to this size, as the secondary gets heavier. I am trying ideas how to make them larger.
To “dress” up the scope I added an engraved image of Orion in a human form on a wood sheet. It is mounted on the plastic cover that came with the scope. It does add an interesting detail to the scope (along with the many stickers on the side of the tube) The star party scope is an education tool. I explain how a telescope works and details of the objects they are looking at. I wanted draw attention (it did!) while standing out on the sidewalk asking people to look through the scope (which is the point of Astronomy Day). I am designing side panels with images to add to the scope mount. This adds nice details to the Dobson type scope (or any other type)
I am also testing various designs, curved holders to see what works best. Being an optical engineer, I can use my knowledge to test new ideas. The laser system gives me the freedom to design and make. I can try aperture limiters, masks, etc. It can also engrave (only, not cut) on anodized or powder coated metal, like setting circles. (working on that too)
I thought it would be of interest to hear about what one could do with a CO2 laser system (Boss Laser 1420) since they became very popular in the past few years. They are expensive, software works OK, vector graphics. It is fun to watch the laser do it’s work, it’s totally enclosed and safety interlocked (safety first always!)
I'll add to the thread as I finish the various projects.
Contact me privately if you have an interest (Being a vendor, I have to draw a clear line between business and fun projects)
Edited by Oregon-raybender, 03 August 2019 - 01:05 PM.