Proposal for 17.5" rebuild I. Introduction A group of active Lowbrows were interested in re-biulding the 17.5" Coulter Odyssey that is currently stotred at the Observatory on PEach Mountain. Several vocal and enthusastic volunteers have since joined the original group and expressed an interesting in helping with the rebuild. Nathan Murphy volunteered to (re-) form an ATM group specifically to handle this task. Active Members of Lowbrow-ATM to date: Nathan Murphy (VP, ATM chair) Mark Deprest (Newletter Editor, ATM Secretary) Mike Kurylo Jack Brisbin Doug Nelle Doug Scobel Jim Forrester (VP) Don Fohey Ken Cook Yasuharu Inugi Yumi Inugi Russ Vente Paul Walkowski As can be seen in the above list, the members involved are the most active observers and ATMs in the club, and some of the officers. The impetus for this project is a strong commitment from a few core members in the ARM group to design a new scope for the Coulter mirror, as it the existing scope is nearly useless for club functions, and is a hazard while operating the McMath. A scope of that size would provide excellent views for interested club members and the public. It complements the McMath and large member scopes such as Causland's 61cm Starmaster, Doug Nelle and Chris Sarneckis 18" dobs among others. There has been a recent influx of new members that have recently bought scopes without the knowledge that there are scopes that belong to the club, for member use, readily available. Access to an 18" dob would provide both new and established members access to a very large scope, without the time and expense of keeping one at their house, and transporting it to peach mountain once a month. Other benefits to building a new scope with the Coulter mirror: - a two-piece, truss-dob design (see below) allows the scope to be portable, if needed - it will encourage members new to astronomy (young and old) to graduate from observing simple bright objects in small scopes to observe dimmer, fainter, more challenging objects - It will enrich our membership - It will provide a flagship scope that can be brought to club sponsered events away from Peach Mountain such as Astronomy at the Beach, our various elementary and middle school functions, and even long-distance star parties such as GLSG and BFSP - It will provide an opprtunity for the interested members to learn telescope construction and design II. Concept The first meeting of the Lowbrw-ATM group was a the May 2006 meeting. There, it was established that the group, for the time being, will concentrate solely on the 17.5" rebuild, and not entertain other, parallel projects at this time. The group also decided to design and build a dobsonian telescope using the primary from the Coulter. The design will be along the lines of an Obsession or Starmaster design, with a square mirror box, 18-point floatation cell for the mirror and circular upper tube with truss-tube supports. Photos of similar scopes are below. II. Tasks - detailed design of the mirror box, ground board, truss system - detailed design of the secondary spider and primary mirror cell - design of the ground board and altitude bearings - disassembly of the Coulter Odyssey - Cleaning and storage of primary during construction - Acquisition of material - fabrication - assembly - testing and adjustment XXX has volunteered the use of his woodshop. There are enough tools and expertise wihtin the Lowbrow-ATM group to complete this project. Mike Kurylo will be handling CAD modeling and drafting Mike Kurylo has a source for machining if necessary The primary will be stored in a suitable place determined by the ATM group, not at the observatory Different parts of the scope may be worked on at different locations as suitable. the ATM group should take responsibility for fabrication and assembly. III. Budget Below is a breakdown of costs for the different compenents involved in the construction of the scope. They are reasonable estimates. The budget should be considered an upper limit that shall not be exceeded by the ATM group without prior approval from the Membership. All reasonable efforts will be made to stay well within the budget. The purpose of this excerise is to build a scope the ULA are proud of, not to build the minimum structure that will hold the primary and form a star image. Structure Teflon bearing blocks: Ebony star laminate: Aluminum truss tubes Truss connectors Kydex for baffling Truss Shroud Fasteners Wood Primary mirror cell Steel and aluminum Bearings, bolts, fasteners Sling material Cooling fans and batteries Primary mirror Secondary Mount Spider Mirror holder dew heater secondary mirror Upper tube assembly focsuer finder scope telrad dew heaters dew heater control