What We Do
Time: 7:30 – 9:00 PM
Although the Messier objects were considered a time wasting problem for comet hunter Charles Messier, they remain a source of wonder and beauty for both amateur and professional astronomers. Messier’s final list included 103 objects. Astronomers and historians discovered evidence of another seven objects that were later observed either by Messier or by his friend and assistant, Pierre Méchain. These seven objects, M104 through M110, are now accepted by astronomers as “official” Messier objects.
The list includes star clusters, galaxies and beautiful nebulae. They are visible from the northern hemisphere since Messier observed mostly from Paris.
Rediscovery of the 110 objects presents a rewarding challenge. We will discuss the perspectives of an observer and of a photographer. Drawings made after star hopping and patiently viewing through an eyepiece reveal the complexity of the objects and show how much can be seen if one takes the time to look, Astrophotography over a twelve year period shows great detail in full color. Collaboration through the project has influenced both of us in many positive ways.
“Collimation” (“collinear” or ‘in-line) means that all optical elements of a telescope are centered and square to its optical axis and its imaging system. Lenses must be accurately spaced; primary and secondary mirrors must be accurately separated and aligned; focal reducers, field-flatteners, field correctors and focus draw tubes require accurate alignment (centered/moving parallel to the optical axis); additionally, filter holders need to be well-centered. NOTE: the mirror grinding error on the Hubble Space Telescope (HST) primary mirror (later fixed and subsequently serviced by four Space Shuttle crews) was off as little as 4 micrometers (microns) at the edge of a 2.4 meter (94.5 inch) mirror.
A number of collimation options exist including (but not limited to):
1. “By Eye” or “Star Collimation” in which one relies upon experience and judgment to achieve good collimation (making a star image as small, round, and sharp as possible. This technique is subjective with accuracy diminished by diffraction limits and atmospheric conditions.)
2. “Defocused Star” or “Concentric Ring” Collimation utilizing a defocused star image is used for telescopes having a secondary mirror obstruction (e.g. [Newtonian] reflectors or catadioptrics [Schmidt-Cassegrains]) whereby in the presence of poor collimation a severely defocused star image shows an elongation or off-center distortion. One adjusts the secondary mirror so as to make the defocused star image as round and symmetric as possible. This technique is also subjective (it can be a difficult to visually determine when the defocused star image is perfectly round and symmetric).
3. Cheshire (external light source) and/or Laser Collimation (built-in laser) employs instruments whose accuracy is limited to one or two millimeters and by the accuracy of alignment in the eyepiece holder. “Rev’s” presentation will highlight the “GoldFocus Plus Collimation System” he uses for focusing and collimating his Celestron 11″ SCT. The system involves a GoldFocus Plus Collimation Mask and Analysis Software which measure collimation in the same way a CCDcamera forms its image with the requisite accuracy for high quality digital imaging. GoldFocus Analysis Software displays the objective measure of an image’s quality of focus and collimation on one’s computer screen in real-time. NO GUESSWORK – focus and collimation qualities are objective and accurate – neither limited by diffraction limits nor conditions. This system (mask and software) ensures proper focus and collimation (in the exact way that one’s astrophotography imager sees.
When most people think of Vermont, they have visions of rolling hills, dairy barns, cows in picturesque pastures. But tucked away here and there you will also find state-of-the-art science and engineering.
One such place is GreenScale Technologies. Here, Ryan and a team of researchers, engineers and entrepreneurs work on cutting edge technologies for the CubeSat market. Ryan will present some of the work they are doing on microscale propulsion, heat transfer and mass transport. He will also present information on the broader CubeSat field.
Ryan McDevitt co-founded GreenScale Technologies with Matt Shea in 2014 to continue work begun at the University of Vermont. Ryan is a mechanical engineer specializing in computational and experimental studies of micropropulsion and thermal management systems.
GreenScale Technologies was selected as a 2016 University of Vermont SPARK VT Awardee. Ryan McDevitt, in partnership with University of Vermont Professor of Mechanical Engineering Darren Hitt, was awarded the SPARK VT award to develop and commercialize the GST-M125 micropropulsion system.
Visit their web site at www.greenscaletechnologies.com
For more info contact: firstname.lastname@example.org
In case of inclement weather contact:
Paul Walker 802-388-4220 (H), 802-861-8640 (W)
Jack St. Louis 802-658-0184