Elvira's owner/builder Ed here. Although my schedule is jammed I will try and answer as many questions as time will allow. Please be civil and constructive in your posts. I am working on an article for posting on Mr. Lockwood's website that will provide more detail of the build with "glam" pictures and will post notice here when it is up. I want to thank the following, in no particular order, for their direct or virtual assistance that without would have been an impossible project: Mike Lockwood, Mel Bartels, Dan Gray (SiTech), Randy (Astrosystems), Nate (Aurora Precision), Howard Banich & Tom Osypowski for added inspiration, Kris (my local CNC shop), Mike (my powdercoater) and Jim (aluminum welder extraordinaire). There are others so if I missed you let me know. Thanks again guys.
For those of us old enough to remember, Elivra was a Friday night TV personality sensation in the 80's with the subtitle: "Mistress of the Dark". Her hourglass figure, "valley girl" meets Morticia stick, double-entendre and self-deprecating humor were some of her character's most memorable hallmarks. For many, myself included, she was quite the temptress and with this nightly passion of ours using her name just somehow seemed appropriate.
Why design & build something with these optics and which obviously bucks the trend of lighter construction?
It starts with my particular home locale: a reasonably dark site with decent transparency but unfortunately saddled with terrible seeing conditions most of the time due to nearby mountains, windy (a lot) and loads of agricultural & dirt road dust. Fortunately, seeing conditions are on occasion, and usually without much notice, steady for short periods of time. Since Elvira was to be kept in the garage, I simply wanted a deep sky/richfield instrument with moderate light-gathering ability that could be deployed quickly and easily, and be put away the same. So when the transport & support unit concept was entertained it allowed reshuffling of the design/build priority list, moving instrument weight from near the top to near the bottom, which in-turn enabled many of the design features to be incorporated. I'll just borrow and twist a line from the great Stan Lee: "with great weight comes great stability". So with mass, a low/short profile due to a fast-ratio primary and a locking electronic clutch system operation in a breeze is well, now a breeze. Two other major design constraints at the top of the list were: eyepiece height...I'm uncomfortable with ladders after dark especially after I assisted in a public outreach event a few years back where a visitor [not at my scope], viewing through a StarSplitter fell 3-1/2' off a ladder+platform [with handrail !!] onto pavement breaking an ankle and two fingers. Must've been some view huh? . Anyway, the second constraint is lifting...I'm not getting any younger and didn't want to lift anything over 40 lbs, especially overhead, even when transporting off-site to a star party. The fast ratio was again an answer to these restrictions.
I'd like to stop a moment and ask: what's up with all this perceived difficulty with collimating fast newts? Sure tolerances are tighter, flexure must be controlled, etc. but this is the easiest dob to collimate I've ever worked with regardless of speed. It's a 10-15 second job and that's after transporting 600 miles in a trailer! I simply use the late great Howie's laser & aperture reducer plus TuBlug and collimate with the Paracor SIPS left in-place and observe...
There are so many aspects to this project I really don't know where to start. Maybe in the next set of posts I'll expand on viewing experiences and thermal strategies. Since the transport/support unit [partially seen in Tom's photo] garnered the most inquires at the Eden Valley SP I'll start there. It obviously carries Elvira around, cradles, protects and recharges her (automatically if docked or with a cord undocked). It sports a swing-arm/platform that holds the secondary cage about 9" off the ground when inserting/removing the truss tubes (in lieu of setting the cage on the ground or a table). It also safely holds the mirror cover during observing. Some interesting tidbits to share regarding the transport unit: range 6-8 miles on level terrain, can recharge Elvira 3 to 4 times (each good for about 3 nights observing) plus some drive-around power before itself needs a charge. Weight is 201 lbs. Balance is 90% on drive wheels & 10% on casters which translates to a 2/3 drive-wheel to 1/3 caster-wheel weight distribution with Elvira on board. Loaded, it can climb a 20 degree grade, is ZTR (zero-turn-radius) and fits the bed of a full-size pickup. It has auxiliary ports for running other 12-volt devices including a 12-volt "hair dryer", extra USB charge jacks and carries the truss-tubes stowed horizontally in padded pockets. Confession: at night I double-duty the tube pockets as handy beer...I...mean cupholders. It has a 25' pull-out AC power cord for automatic & indefinite charging [means no fear of overcharging] of the internal 24-volt 70 Amp-hour SLA system, has red down-facing LED ground-markers, red driving lights,and yes even has a mini-tow hitch for pulling a cart . To complete the power picture Elvira has USB ports located on the pedestal for tablet charging and uses an internal automatic & indefinite charge Lithium Iron Phosphate 12-volt 180 Watt-Hour system.
To explain everything will probably take many posts so please be patient.