Quantitatively assessing the performance of computerized mounts. Case study: CGX-L

Derik DeVecchio

Presentation at Telescope Technology Workshops

There are many inflated, non-quantitative, claims about new mounts with “superb performance”. How do we evaluate these claims and test their veracity?  Astrophotography images with blobby stars do not make it easy to discriminate between poor technique, poor mount design, or defective/damaged equipment. It is difficult to tell whether better results from one mount resulted from better equipment, better technique or better conditions. Fortunately, there are more quantitative techniques that can be used to evaluate a mount’s true performance quantitatively, but they are not well known by telescope users. Such techniques can help you evaluate the right time to send your mount in in for a specific repair, and when it is time to upgrade your equipment to something quantitatively better.



Derik DeVecchio is a firmware engineer at Celestron for 9 years. He designed the motor control electronics and the firmware inside CGX mounts. He has been known to do a little diagnostic tech support for end users, and some community outreach at public star parties. In this presentation Derik will discuss how prototype mounts, like Celestron’s new CGX-L, are tested and evaluated quantitatively. He will present case studies from real mounts using data taken by Celestron staff as well as end users. Most of data collection and analysis does not require special equipment or software, so the techniques discussed here are applicable to most astrophotographers with computerized mounts from any manufacturer. Following the presentation, there will be a question and answer period.


Thursday, August 17, 2017 - 10:00 to 12:00
Saturday, August 19, 2017 - 13:45 to 15:00


Champagne Room