As an exercise I calculated the field of view for my 4 most used eyepieces for my three scopes (10.1" f4.5/C8/C5). Unfortunately 1.xxx degrees doesn't really translate into "what can I see in this eyepiece" in my head very well. A little googling got me a page which converted degrees to cm for the Pocket Sky Atlas (my main goto chart). It happens to be .4991 cm per degree.
Armed with this information, I used Adobe Illustrator to design 3 small guides --->
In addition to the eyepiece FOV circles I included a set of Telrad and Rigel QuickFinder rings as well. Before I sent them off for laser cutting I printed them out on paper and did a quick check to make sure my measurements were correct.
It took some fiddling about before Ponoko would accept my design for cutting but once I figured out the idiosyncrasies and decoded the somewhat cryptic error I was getting from Ponoko I was able to select my material, in this case 1mm PETG plastic, and submit my designs for lasercutting.
|I was pretty excited when they showed up.|
The shipping was quite fast
I received the results today in the mail.
|What was in the box.|
I quickly removed my pieces from the attached paper which is attached to the sheet in order to keep the parts from falling out and getting loose in the box.
|Here are two of them with the film removed for contrast|
|The plastic comes with a protective film on one side|
Hence the "frosted" appearance
A quick check of my guide against my Pocket Sky Atlas using the Telrad scale shows that my measurements were good and the final result matches well.
|Another check using the FOV for|
my 24mm panoptic matches
what I have seen in the scope
using M81 and M82
Overall I am very pleased with the results however the engraving was difficult to read. As and experiment I have used an oil pastel to fill in the engraved lines. I think the results speak for themselves. Before I do it to the others I plan on seeing how well the coloring holds up under normal use. I think paint might ultimately be the final permanent solution. It took me about an hour or two to design the guides and get it to be accepted.
Costs : $19.36 for making costs (time on the laser)
$1.86 Materials Costs
$9.75 for shipping
$9.75 for shipping
$30.98 total plus $1.98 international transaction fee from my bank since Ponoko is based out of NZ, something to be aware of should anyone else use their service.