Saturday, January 11, 2014

Blessed Event

Baby arrived yesterday in four boxes from Dobstuff.  For most babies, that would not be a good thing.


Nice touch on the label.

Inside the biggest and heaviest box, a new use for Fedex delivery boxes:


Some had stuff in them; many were simply cheap and effective padding to protect stuff from moving.

The top ring of the telescope, with the spider installed:


Lots of parts wrapped in bubble wrap, many of which had quite obscure purposes at first:


Here is the lower cage assembly, being investigated by Tater Tot:


This is a light shield that installs opposite the eyepiece focuser to reduce stray light.  I do have a vast quantity of black velvet that I might use if I do a star party in an insufficiently dark place:


A number of boxes usefully labeled:


Beautiful wood work, by the way.

It took a couple of minutes to figure out where and how to install the eyepiece focuser on the upper ring:


The focuser is a Moonlite dual speed focuser that I salvaged from Big Bertha 2.0.  I would have blackened some of these surfaces.  They probably do not need it, but it looks better, and I like to believe that it reduces scattered light.  But that's easy to fix with some flat black paint and a brush.

Now I have lots of parts, and it was not immediately obvious how to put some of them together.


For an instrument of this cost, I prefer not experimenting.  Dennis Steele, who runs Dobstuff, was immediately available on the phone and talked me through it.  At some point, he reminded me that there was a picture of my telescope, all assembled, on the Dobstuff blog.   A picture is definitely worth a thousand words.  From that point, it went together pretty quickly.  It also helped that my wife is very mechanically inclined, and could see how to put some parts together where I was temporarily confused.

The mirror box was incredibly thick for such a thin mirror, because there were several layers of styrofoam on either side of it.  Nice packaging.


We completed most of the assembly in the bedroom, the moved the lower cage and base out to the garage to put the truss tubes in place -- and voila!  Together!


The next step was to collimate the mirror.  This went really quite well.  This picture does not do justice to how perfectly the laser collimator has everything centered:






A couple of nice touches were the counterweights, mounted on one of he truss tubes, for making adjustments for heavy cameras, eyepieces, that sort of thing


and the dust cover for the mirror -- which fits very tightly, but not so tightly that you have to worry about hitting the mirror:


I am not quite done.  I still need to install the secondary heater to prevent dew formation, and I need to turn the top ring -- the eyepiece should be on the same side as the digital setting circle controller.  I also need to fabricate a base for the finder scope rings.  And, I need to make it mobile.  Of course, we will be clouded over for weeks because of this acquisition, so I had to be content with this prime focus picture of the hillside.


I have no idea which section this is.  Even prime focus on this beast is a lot of magnification.

UPDATE: A reader asks if this telescope has the rigidity that I had hoped for, when doing the Big Bertha 3.0 build.  Oh yes!  As I explained at the time, the truss tubes were plenty stiff enough... enough that the pseudo-fiberglass cages were now flexing.  In the present case, the lower cage is quite stiff, because it is a pretty massive piece of wood, and the upper cage is quite light because it is only a ring, not a two-ring cage.  I suppose that I could have built something of similar stiffness using aluminum, and perhaps even had something a bit lighter, but I was running out of energy.

I find myself suffering a severe fantasy of replacing almost every component in the current telescope with carbon fiber composite, one at a time.  Start with the blocks in which the truss tubes mount -- those are just rectangles with two ball end mill holes and a couple of through holes.  Replace the block holding the eyepiece focuser with carbon fiber composite -- it is a rectangular solid of aluminum with several holes in it.  Keep replacing parts until everything on the telescope made of wood or metal is carbon fiber composite.  I suspect that the weight would then be about 45 pounds.  Then it might be mountable on an equatorial mount.  And doing it one part at a time would mean the absurd cost would be spread over a period of a year or so, and it would not be so expensive.  But more likely, I will just not have time for that -- too many things to do at my day job doing software, my night job teaching, my historical research job, my ScopeRoller job, my Shotgun News column writing job... and yeah, sleep!

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