Posts Made By: Bill Byrd

[COLOR="Purple"]I wanted to make my secondary adjustments tool-free. Hard to find pre-made thumbscrews in correct size & length.

Soooo....I made my own. $4.00 worth of threaded rod + some nuts and cap nuts.

Here are the parts before assembly.
Bill[/COLOR]

[COLOR="Purple"]Single upper ring flexed.
Double ring better.
Double ring with focuser board attached top and bottom best!!

This is still in the raw state...it will look a lot better once I've "prettied" it up by rounding corners, sanding and staining.

There is the slightest of flex if I grab the bottom of the focuser board and push hard. I'm not worried because I'm sure that push is a lot more force than even my heaviest EP will exert while in the focuser.

As a bonus, I may be able to use the nice open space of board above the focuser to mount a lightweight finder. As is, the upper "cage" weighs 6.5 pounds.

Here's a pic of the back side trying to show the hardware to mount to both rings.
Bill[/COLOR]

[COLOR="Purple"]In keeping with the constant theme for the 18.75" ATM project of doing everything multiple times, I'm now trying to salvage the USA (Upper Support Assembly) after applying the poly spray on finish yesterday. Dummy me had used a Sharpie marker to blacken the rings. Unfortunately, something in the Sharpie chemistry does not play well with poly. I sparayed several coats on the entire assembly before I noticed that the areas where I used the Sharpie were not curing. On the dowels, which had been stained with regular Minwax red oak, the finish set up just like it's supposed to. On everything else, the finish stayed tacky and never set up.

"Note to self: Do NOT use markers as a stain if finish is to be applied!!"

Rather than strip everything, which would be very messy and mess up the nice stain on the dowels, I am "rubbing out" the tacky areas using tung oil. This seems to get the tacky residue from the poly off and I'm hoping that it will cure where the poly would not.

If this fails, I'll have to strip all of it and just paint the whole flipp'n thing flat black. Boring!!

Bill[/COLOR]

[COLOR="Purple"]....from somewhere on the internet.

Here's the ground board in raw form. Teflon pads and feet obviously go in the solid areas between the cut outs. The cut outs aren't perfectly round but the ground board is not a part usually seen.

The board weighed 6 pounds without the cut outs. The three cut outs decreased the weight by a smidgen over two pounds.
Bill[/COLOR]

[COLOR="Purple"]Hi All!
It's taken a while but I think the USA for the 18.75" ATM project is done. When last I posted, I had added a second ring to the single, too floppy, original ring. That gave me a stiff enough structure to hang the focuser board off of. I was then trying to figure out how to improve the support for the focuser board. Here's the result in several pics. 1st is an overall view.
Bill[/COLOR]

[COLOR="Purple"]...I'd be rich!!

Tonight i spent 2.5 hours in the garage working on the latest scope. In that time I trimmed the laminate, sanded and stained on face of the alt bearings. That task alone took over 1.5 hours. I made a focuser baffle. I bolted together the rocker box and the ground board. Minor things that took a little time to do.

If I were paid $20/hour, I would have grossed $50.00. I probably have over 100 hours easily so far in this project. Maybe another 20 to go before I'm mostly done. I don't belittle the professional scope makers out there what they charge if they do a good job. Making a nice scope takes time!
Just rambling,
Bill[/COLOR]

[COLOR="Purple"]The hardware box house had some new 5', not 6', fibeglass ladders for $30.00 USD. I picked one up yesterday because it seems like it will be just right for the latest scope. Kinda heavy since it's fiberglass but it will take a beating and survive.

I can figure out how to make the existing steps wider but has anyone ever added new steps in between the existing steps on a fiberglass ladder? Can I safely drill the fiberglass without affecting the structural stability?
Bill[/COLOR]

[COLOR="Purple"]For those who've followed the trials and tribulations of building my upper ring, which morphed into the USA, here's a pic looking up from ground level. It is very stiff now...and looks cool too!

The string and wires are for the secondary heater which has yet to be hooked up.
Bill[/COLOR]

[COLOR="Purple"]It is a telescope...finally!! It's taken a couple of years but the 18.75" f/5.2 cellular mirrored scope lives! It's not completely done yet but it's close. I took a few days off from work hoping for a night of observing. I took the scope out to the sorta close by observing spot last night and tried it out for 3 hours.

Since it's not completely done the following were detriments to the use/views:
No heat shrink on the truss poles
Mirror & rocker boxes not blackened
No upper baffling to block stray light
No felt pads to keep mirror box centered
New finder location never really tried before
Cooling fan not hooked up - not really a problem with
the cellular mirror

I figured I'd just go out for an hour or so since it was nice and clear...see how it went together, how it moved and how I would do with having to use a ladder for observing. If I was able to have even so so views, I would be happy.

As it turned out, the night was pretty good sky wise and scope wise. First hurdle was fitting the largish rocker box and mirror boxes in "Scope Hauler" my PT Cruiser. As you can see from the pic, it fit but just barely. Poles and ladder rode on top of the stuff in back. I left the rear seats in the PT and just folded them forward...didn't have to remove them. Sooo...this can be a (sorta) grab and go set up since I can throw everything in the PT and be on the way in about 5 minutes. Not bad!

Set up in the dark went just fine. Collimation was easy. First views were a little soft and I was afraid maybe the simple mirror cell was not providing enough support to give good views. After about 20 minutes, the views were very good, so I'm pretty sure the first views were suffering form mirror/structure cool down issues.

All eyepieces reached focus (5-6 careful trims of the truss poles) except for the 12mm Nagler, which needs a lot of in focus when used with the Paracorr. Speaking of the PC, It may not be needed all of the time. I did some viewing with and without...a little better with...more FOV without and still pretty good. More viewing time will tell if the PC will be used much...maybe used for the longer focal length EPs and not with the shorter ones?

The views were definitely brighter than the 14.5" I'm used to using. Not a jaw dropping difference but definitely brighter. It may have been my imagination but I had the impression that more stars had color than in the 14.5". For example, M13 had 4 stars in the cluster that appeared much redder than I ever remember seeing.

I'm not crazy about having to use a ladder when observing but I guess I can get used to it. My old knees were complaining after two hours of up and down. Taking a short break every 10-15 minutes helped.

The place I was at is not the darkest. I mostly vivisted old favs while evaluating the performance. M31 was of course a showpiece...very bright and filled the FOV of even the 26mm Nagler. M13 was great! I looked quickly for the IC galaxy that lies close to the cluster but didn't see it. The NGC galaxy a little further away was very easy so the IC galaxy might just need a darker sky and more concentration on my part. Strangely, the Veil wasn't a lot better than in the 14.5" but it might have been the seeing.
NGC7789 was very nice. The Ring was brighter and it seemed like the center was more filled with nebulosity than with the 14.5". All in all, not bad at all!

The two piece truss poles performed just fine! I was afraid that there would be some "slop" from the joint where they screw together but everything was pretty solid once the poles were locked down top and bottom.

Having given the scope its first "real" use, I now have a few things to finish up. Since I was off today, I've already made the last cut on the truss poles to finalize their length. As much as I like the KineOptics focuser, I really missed having a non-rotating two speed focuser so after much consideration, I installed my old focuser. It's much heavier but I'm slightly back heavy at this point so I should be okay. I just tested the heat shrink I bought a while back and it works okay for being 11 years old. The areas where it was flattened in the roll don't flatten out like the newer heat shrink but it's not bad enough to make me go out and spend a lot of money on new stuff.

I have real pebbled Ebony Star on the alt bearings and glass board on the rocker box. Movements in both alt and az were a little stiff so I need to do some fine tuning. My alt teflon pads are the size K&B suggest...maybe the imbalance hurt the movement...maybe I need to clean the bearings and ES. The az teflon pads are a little small according to K&B so I'll put some larger pads on tomorrow and maybe shim the center pad a little more.

I'm off tomorrow too so I plan to paint, shrink, trim as necessary to get as much done as possible so this scope will be ready for a trip to really dark skies next month in west Texas.

Anyway, I'm sorry to ramble so much but it sure was nice to get out and try this scope after all of the time it's taken to put it together! All of you ATMs out there can appreciate the sweat equity that went into a scope like this so I thought I'd share.
Bill[/COLOR]

[COLOR="Purple"]Okay, my ultimate goal of alt bearings held in place by dowels & magnets will have to wait. I still think it will work but I need to do a proof of performance mock up and I've run out of time if I'm going to take this scope to west Texas next month during new moon.

Soooo...second choice is shown here. Can you tell that I couldn't find 6 matching knobs?? Seems to work but I haven't tried it with the mirror box on the rocker yet. It feels just as solid as the beefy wood screws I had them attached with for testing.

There are threaded inserts in the bearings and the knobs simply go through the mirror box side and screw into the inserts. Removal and installation will ONLY be done with the mirror cover in place for obvious reasons.
Bill[/COLOR]