Posts Made By: Allan Meyer

November 15, 2020 02:46 PM Forum: Telescope Making

Setting Circles???

Posted By Allan Meyer

Hi Lane,
I see you posted your query almost two years ago, so don't know if you'll see this.  Sending this new bit of info along in case anyone searches the forum regarding setting circles.  

Just recently corresponded with the author of the web site " blocklayer.com ", which provides a very large suite of very nicely done versatile tools for construction layout & calculations, belt/pulley drives, bolt circles, etc. etc.  The author has kindly upgraded the protractor page to offer the typical numeric sequence of a declination setting circle (0 to 90 degrees in 4 quadrants).  You specify O.D., I.D., major tick labeling style, etc.  Includes option for a properly scaled vernier.  The "circle divider" tool (different page) can be configured to generate an R.A. or H.A. setting circle.  Needs 144 ticks, 2.5 degree spacing.  Choose counterclockwise increment for R.A.,  clockwise for H.A.  
There are also tools for formatting and printing tapes, such as one might put on the outer edge face of a setting circle, so that the tick marks and their labels face radially outward.  
In all cases one saves the graphic as a pdf, so you can print yourself and/or print and laminate at places like Staples, FedEx/Kinkos, etc.  
There are other nice layout tools at that site that may be useful for planning e.g. observatory construction.