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What Became of That Big Astrograph?


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What Became of That Big Astrograph?

By

Patrick Stevenson

Tucson, Arizona

 

Finished Product

In short, it fell victim to my age and physical condition!  But first it got to go outside and play some.  This story will tell the tale of the ultimate fate of the astrograph.

Ready to Run

There were two characteristics of the monster.  First, it was really big and cumbersome.  Second, it weighed forty-four pounds stripped.  Not difficult to imagine where it was going.

I decided that there was no way I was going to put that much work into a project of that magnitude and never give it a chance to fly, so I set about finding a way to use the creature without the task of moving it around.  An observatory was a likely solution.  Unfortunately I live on a VA pension and Social Security.  Even if I were capable of tackling another task of that magnitude, I couldn’t afford it.  You can check the back articles until you fine one about Fairhavens 1 that was a 10x12 roll-off a few years ago to see that I at least KNOW what to do. Current circumstances simply did not allow that solution.

 

I had a CGX mount that was marginal for the weight but I figured if I balanced it well enough that would suffice.  Of course I had to include the weight of the coma corrector, camera, guide scope and I think some other stuff that easily surpassed the specified maximum weight for the mount.  Frankly, that never even crossed my mind until after I was done with the scope.

 

Concrete Block Floor

I sat in the back yard for a few hours looking at a pile of scrap from another small roll-off that I built when it became apparent that the big scope would not fit.

Original Observatory too small

 

Clearly the traditional observatory was not in the works so I conjured up the idea that I could make a roll-off observatory by using the hardware from the former roll-off roof.  With a budget that wasn’t worth documenting I constructed a frame at ground level supported on cinder block top caps.  I then attached the aluminum rails that came from the top of the previous building.

Using all the scrap lumber that would work I built a nearly square 5x5x5 shed with the steel “V” wheels off of the old roof.  I did have to buy new T111 3/8ths thick siding to add strength to the structure.  The previous structure had a subfloor with holes in the floor for the tripod legs so once the subfloor was gone I just had pea gravel.

 

I used 12”x12” concrete blocks to set the tripod legs on that worked well for that particular purpose.  Did you ever try to work on pea gravel in the dark?  All I could think of was the broken hip I was going to earn by trying to walk on four inches of pea gravel in the dark.

 

Very unstable footing

I live in a leased home so I was restricted from doing anything permanent like a concrete slab.  Again, I sat and pondered.  Given some time I remembered a patio deck that I built some thirty or so years ago.  It is a simple technique.  I leveled the area that I thought would be adequate, laid cinder block fence caps in an attractive pattern (right on top of the pea gravel).  Once the blocks were in place, I dumped a couple of sacks of concrete on them, spread it around with a broom until all the spaces between the blocks were filled with the powder.  I then spent some time with the garden hose with the nozzle set on spray an wet the whole surface down until the concrete powder was thoroughly soaked.  By the next day I had a monolithic deck that functioned as well as a concrete slab.

 

More secure footing

The final result was that I had a shed large enough to contain the mount and telescope when rolled over them.  Of course, the scope had to be parked in a contorted position to fit.  I had the solution to getting the mount and telescope into a condition that they would be protected from the weather, and hot Arizona sun, simply by parking the scope and rolling the “box” over it.

 

Parked and enclosed in shed

Now that I document this project it doesn’t seem that hard or complicated.  I think, to a large extent, that is because of my failing memory; and my wife, who watched from a safe distance, and had an entirely different opinion.  I think it may have been based in part by the number of Tylenol bottles I went through.

To my feigned strutting, and utter amazement, it actually worked quite well.  I was now able to really test the new design on a tracking mount that surprisingly handled the weight just fine.  One would think with every problem solved the rest would be simple.  Not so.

That monster remained a monster.  Had I been thirty years younger, and much stronger, it would have been fine.  It’s amazing how much muscle was still required to manage something that big and heavy.  With not much regret I decided that retreat was the only way out.  I decided it was time to downsize to something that I could handle more easily.   My plan was to move to a relatively small refractor on a Celestron AVX mount .

So, here I am now with a new Explore Scientific ED 102 Triplet on an AVX mount.  The rig is fully populated with ASI cameras, ASIair Plus, etc.

Downsized and much lighter

 

So, what finally became of the monster?  In one of my brighter moments I had saved all the parts from my donor scope.  I de-populated the astrograph and re constructed a 10” f/4 newt that sold on Cloudy Nights in one day.  All is gone now except for one thing.  Anybody out there interested in a 48” aluminum tube?

 

Back to donor scope configuration

 

In summary.  I’m glad I did it, although I wouldn’t again.  I am pleased with the results and have many fond memories…… Yeah, I’d do it again.

EPILOG

The primary intent of this build was to determine if mechanical changes alone could resolve the problem of ambient light pollution without the utilization of various filters designed to block man-made artificial light which, by themselves alone, tend to block natural signal that then require excessive post-processing to at least appear to add such signal back into the final image.  In short, produce entirely natural image quality without the use of artificial signal modification.  And, if so, was it worth the extra engineering modifications?  In a word, yes.  And to a large extent, no.  It was effective, but at the same time, not worth the cost of implementation.  The final test would be to compare an image image both with and without these mechanical implementations.

  NGC2403 With no modifcations:

 

   NGC2403 With modifications:

 

The difference is clear.  The ambient light pollution can be removed without the use of filters. 

I have decided that after I heal up from this one it will most likely be my last project.  At least until the next one.  Although I do have some thoughts about collimating an RC.......                                                                                                 


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