It's been ages since I could have a full day in the shed . And I've been stockpiling lots of stuff that I have bought from folks here, or taken off their hands for the cost of postage, or bought new. Thank you all 'cause I had a great day.
Made up for the fact that I had a disappointing Friday night at Snake Valley non-observing. I went on the promise of clear skies and it looked very promising before sunset, but the cloud settled in to stay. I packed up before midnight. Of course, Sat and Sun nights have been clear - but I couldn't go out either of them.
OK, here is a summary of today's work.
Made up two little boxes to distribute heater power to four RCA sockets. Basically small quadruple adapters! Lovely clear blue perspex boxes - cute. Also tried out a little 12V red indicator light I found in Jaycar, fitting one to each box. On PWM-controlled 12V, it faintly glows at minimum, increasing brightness to maximum about 50%, then stays there. Might be too bright, but nothing that a dab of my red paint won't fix. I've been looking for something like this to illuminate the inside of my eyepiece box instead of making up a LED and series resistor. This little light might be it. Didn't measure the current draw, but it hardly worried the ammeter I have inline with the battery.
Then looked at the EQ5 mount. Friday night, looking for things to play with while the clouds persisted, I had a close look at the club's EQ5. It had knobs on the axes where mine had none. I worked out how they worked (loosen the lock nut and can move the axes regardless of the motors). Brilliant - I need that. So I searched my electronics box and found two old amplifier knobs that fitted. Done!
Next, I turned my attention to a bigger job. Fitting a replacement wedge, base and fork arms to my C8 OTA. Genuine Celestron parts and much more recent than mine. My base has developed worse and worse RA backlash - I just don't know how to built it up properly after dismantle, clean and re-grease. So time to replace. Cleaned and re-greased the fork arms. Checked the electrics in the power cable and base - all fine, so plugged in and set it going. After 10 minutes - yes, its moving - and in the right direction! First issue - Celestron must have redesigned the tripod for this base. To use it in simple alt-azi mode, my old one had one central hole in the tripod and a big threaded hole in the centre of the base. This one, instead, had a large bolt holding the base together. It had a little threaded hole into the bolt. After some thinking, I decided to open out the hole in the bolt and tap it for a larger thread. I finally went to M6 (not that large, But I'll try to get the longest high tensile M6 thread I can get and use that. It just has to stop the scope tipping over - there is not much load on it). Only had a cheap set of taps, so it was a slow job to ensure I didn't break off the tap or ruin the thread. Happy with the result. Turned my attention to the genuine Celestron wedge. Much more elegant that the home made battleship-solid wedge that I have been using. A bit of cleaning up and painting. It had a rubber spacer between scope and wedge, but that had fallen off and seemed to have shrunken. So cleaned off the residual glue before the paint job and went for metal to metal - which is what I have with the previous one. Super happy with the result. In fact, I set it up this evening and tested the tracking and handling of the mount and wedge. Really good. No backlash, good tracking, easy adjustment - a happy camper am I.
In the January toss out at work, I saw an old hand trolley in the skip. One rubber tyre was broken - and very dirty and greasy overall. Scrooge Eric thinks - I'll have that! Some de-greasing, scrubbing, scraping and a nice paint job (royal blue!) I have a hand trolly that I will use for something? Bought a couple of small garden trowels for $1 each, pulled off the plastic handles, filed fown the inner ridges and hammered them on as handles - very spiffy! One small problem. I bought new wheels from Bunnings but, the axles are just too large for them - probably an imperial versus metric problem. I will get them on (the old wheels have really had it). I gave axle a good thrashing with the angle grinder and am getting close to the right diameter. As long as I get it on. The old wheels turned on the axle. The new wheel has its own bearings so I just have to get it into place and it'll work fine. Gave up there. I'll wait for a cooler day. Though I'm working on concrete with no grass at risk of fire, I want to be cautious. It was hot today and a little breeze blowing.
My son was cleaning up on Saturday and tossed a Yamaha saxophone case. I thought - I think my Synta refractor will fit into that? Well it will, so I spent an annoying time trying to get the moulded interior out - wood, polystyrene, padding and fluffy lining and lots of glue. Well it is out, so off to Clark Rubber to but some good foam. Only poked the screwdriver through the side once and I managed to repair that back to barely noticeable! Do Yamaha make telescopes? This will confuse people - seeing the Yamaha brand on the telescope case!
I picked up a basic tripod (one cannot have too many tripods!) - cheap because no quick release plate. So I fashioned one up out of hardwood. Didn't quite go as planned, but I do have a functional tripod. I wouldn't cal it a quick release plate, but I have a solid 1/4" bolt to mount whatever I want (light weight).
Then turned my attention to my 8" reflector. I still haven't worked out what it is - just grabbed it from an IISer last year. Probably a GSO. Designed as an astrograph - I needed 35-50mm of extension to bring eyepieces into focus. Not sure if it is an f6 or f5. I'll work that out one day. I took this and the EQ5 to Snake Valley last Friday and noticed that one of the primary mirror collimation screws wasn't moving through a full range of movement and the spring seemed much more compressed than the other two. So started by pulling the primary out and it looked like it might have been a little crooked. The holes in the OTA are quite large, so it is possible to pull up all six screws tight and have the mirror cell not quite 90 deg to the OTA axis. Just means one has to use the collimation screws to get the mirror to 90 deg - explaining why one spring was under more compression. Also looked at the mirror clips - one was very tight and the other two quite firm. Loosened them off until could slide the sheet of paper between them and the mirror. Discover the mirror is not glued to the cell - it flopped a bit against one clip, so had to nip that one up a bit more. The mirror would just rotate under the clips when I tried.
OK, got the primary back in and tightened the six screws after more carefully setting the mirror cell so the screw holes were much the same position in each OTA hole. That reduced the difference previously seen between the three collimation screws.
Now to the real job of the day - replacing the GSO focusser with a JMI focusser I picked up. Had been worrying about squaring the focusser. The JMI comes with four grub screws, one at each corner, to allow the focusser to be tilted. I started by removing the secondary mirror (and loosened off that retaining clip until there was a small gap - that was also pulled down tightly against the secondary, when I first looked). Then I fitted the laser collimator in the focusser (in the 35 mm extension - not sure why, but thought I'd emulate the observing situation). Turned it on and observed the spot on the opposite inside wall. Cranked the focusser in and out - the spot didn't move. Marked its location with a texta. Pulled the GSO focuser off and fitted the JMI. Previous owner had an 8" tube curved spacer made up, so I bought that as well. Almost fitted. I just had to file two of the holes in the OTA a half a mm, then it fitted. I used new stainless steel bolts and nuts and, with the grub screws retracted, pulled the focusser and spacer up firm. Inserted the laser (and 35mm extension) into the JMI and switched on. Would you believe it, the spot was right on the texta mark - if different, well hardly half a mm, if that! Well, that will do for me. Firmed up the grub screws, checked the spot location again (hadn't moved), slapped some matt black paint on the shiny nuts and the part of the aluminium spacer visible from inside the tube, refitted the secondary, recollimated the scope (easy-peasy) then packed it away. The JMI focusser feels good, looks professional! I plan a few DSLR photos through this scope this year. I'll give it a test out some evening in the back yard.
Well that was it - a full day. Lost a little blood to a chisel at one stage. Left a solder burn spot on my thigh at one point as well. A few suspicious burnt spots on my socks from the angle grinder. All "par for the course"!
What didn't get done and is held over:-
Fitting the new wheels to the trolley.
Building a multi-resister heater to fit to the rear of my "bounce mirror" for neck strain-free binocular viewing. A large flat mirror open to the sky and moisture will be a dew magnet!
Setting up the bounce mirror stand and the binoculars with eyepiece and objective heaters and wiring all the heating together cleanly.
Installing my Orion Accufocusser electric focusser on the JMI focusser on the 8" reflector.
Installing a Meade Autostar setup onto the EQ5, replacing existing motors and tidying up the wiring - then a full test (and learning how to track and use goto on the EQ5).
Finishing the Yamaha case for the refractor.
Congratulations if you read this far and have enjoyed my day with me.
