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80mm long focal length refractor

brino

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#91
Argh!!!!!!!!!!!!!! when will it end.
I think we all get that feeling when working on a large project.

I hope it helps to know that your build quality is remarkable.
You will end up with a beautiful and functional treasure when you're done!

-brino
 

savarin

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#92
Thanks Brino, The phenomenal amount I have learnt and the skills gained since starting this whole exercise have been absolutely priceless so really I shouldnt complain.
 

ch2co

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#93
The only reason that I really wanted a lathe (and minimill), was to repair, modify, rebuild and make from new, parts for my real hobby, astronomy.
I knew very little about machining before buying my tools. I know that a lathe could turn round stuff and thats about it. I was fortunate enough
to run into a good deal on a well maintained and upgraded G0602 lathe that came with tons of added tooling and including the G8689 mini mill, that
I thought that I would probable just resell to someone. Then after turning a little bit of aluminum, I tried out the mill and not knowing at all
what I was really doing I came up with a decent adjustable laser mount for my 4" f15 Jaegers scope. The learning curve was steep and only
motivated by what I wanted to actually make. No regrets! Just as Savarin said, the whole exercise has been absolutely priceless.
The Hobby-Machinist forum pulled me out of many dead ends that ended up as highly successful pieces of astronomical equipment.

CHuck the grumpy old guy
 

savarin

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#94
Hi Chuck, any chance of some pictures of what you have made for your scopes?
 

savarin

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#95
Change of pace today.
Made the pair of holding rings for the finder scope.
70mm dia, marked of and drilled each hole,
drill-rings.jpg
Then replaced the drill with the tap, started the thread,
tap-rings.jpg
removed it from the jig and finished it by hand.

finish-rings.jpg
now comes ---- you guessed it---polish them.
 

savarin

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#96
I had occasion to try out the shortie finder scope the other night, yuk! coma all around the outer quarter of the field.
I had another 50mm doublet handy of a longer focal length and as luck would have it it fit straight into the original cell.
All I had to do was make a longer tube.
longer-finder-scope.jpg
Thats the shorter tube underneath so the new focal length is approx 15mm longer.
Now its a clean image across the field.
The gold tint is reflection from my shirt not brass tubes.
 

savarin

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#98
Thanks Tony thats really appreciated.
(I thought I had already sent this but cant find it so have done it again)
Made another brass screw today, only 11 more to go. I dislike repetitive jobs so am making them a few at a time.
small-brass-screw.jpg
Also made the clamps to hold the finder to the mounting rods.
They were somewhat roughly chopped out of some scrap and needed too much filing to get into shape so I attempted to remove as much as I could in the lathe.
Bolted together using the rear of the clamps as a register to the chuck body.
finder-clamps-1.jpg
That then allowed me to reverse them using the new flat on the chuck body and bring the two to the same thickness.
finder-clamps-2.jpg
Back to the other way to face as much as I could from the inside edge.
finder-clamps-3.jpg
Now its just a little bit of filing. So after cleaning the remaining ends and face up with a file it was time to round the fat ends.
finder-clamps-4.jpg
To get this,
finder-clamps-5.jpg
repeat again plus some extra filing for these.
finder-clamps-6.jpg
Now to split them from the inside corner to the hole, drill and tap for a 4mm clamping bolt and then its more sanding and polishing again.
 

savarin

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#99
After splitting the clamps I bolted them to a chunk of ally plate,
clamp-jig.jpg
I filed a groove for the 8mm shaft to sit in preventing the clamp from spinning round the bolt when I fly cut the profile in the end for the finder rings to sit.
Ask me how I knew that would happen.
flycut-clamps.jpg
both clamps profiled to fit the rings BUT........
argh.jpg
Yep, when originally splitting the clamps into two I went too far with the saw and nicked the end.
Never mind, a quick design change and round these ones over. (no I'm not going back to do the others so they look the same)
finder-rings-and-clamp.jpg
And now for another design change, sorry, advanced feature.
The finder scope wont pass through the rings now the bolt is in place so I had to shave a little from the screw head, flatten the inside of the ring so the bolt head sat flat and lower and took a shaving from the offending lens cell of the finder.
finder-rings-and-clamp2.jpg
Next stop powder coating the lens cell and hope I left enough clearance.
 

savarin

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Have to wait for the powder coating till I get the spray booth finished so I decided to assemble it all and have a quick squiz at the universe.
Saw jupiters bands, 4 moons and it focussed nice and sharp but Wide Angle 15mm was the smallest eye piece I had on hand.I still have to finish off the slow motion controls and add a brace under the support plate as I noticed it flexed a tiny amount.
Here it is with the sun finder, laser pointer and wide angle finder scope.
finished-scope-1.jpg finished-scope-2.jpg
finished-scope-3.jpg finished-scope-4.jpg
I rather pleased with its image results. And it looks cool.
 

turnitupper

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. And it looks cool.
You stole that from the TARDIS, I'm telling the Doctor!:no no no:
Seriously, very nice work, I have been following this build and it is good to see the (almost) end result.
P.S., I noticed the neighbours coming over for a squiz,
John.
 

savarin

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Thanks John. There are a couple of things have popped up that need something done.
The central support needs a join in the middle for easier transport.
The scope support cage needs a handle as the fully assembled scope is rather heavy. I will weigh it later.
I'm considering a counterweight for the front.
I think two right angle scrolls bolted to the centreline of the support plate and the top casting as a brace.
A "Y" shaped yoke for the scope to sit into when at rest.
Hopefully that will be it.
 

savarin

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And the gods of astronomy have reared their fickle heads again and produced thick clouds and rain (which we need) to bless the new telescope. :bang head:
 

hman

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... And it looks cool.
I disagree. I think it looks ABSOLUTELY MAGNIFICENT!!! ... and to think that you made the whole thing, including the milling, with just a 9x20 lathe and "some rusty files and a hammer." ABSOLUTE WOWSERS! Yours is an amazing accomplishment.
 

savarin

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Thank you for that John much appreciated.
I suppose I should update the equipment list to add a drill press and welder:shhh:
All I managed today was to make the patterns for those new bits
 

MozamPete

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That is an amazing piece of art to be proud of - and a functional scope as well! It will probably be in use for generations to come.

And the beauty of it is when you can combine two of your hobbies in one nothing seem like work - it's all pure joy. Well done mate.
 

savarin

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Thanks Peter,
I find it hard to believe the, dare I say, "astronomical" amount of knowledge I've gained in the two years its taken to get this far.
Its been well worth the journey.
 

hman

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I recall from 'way back in history (when I was more into electronics), that a friend told me, "There's nothing more expensive than a free microprocessor." I guess we can come up with a corollary - there's nothing more expensive than a free objective lens. :)

... and, of course, Jon Miller is going through the same gyrations in his thread: http://www.hobby-machinist.com/threads/free-is-never-free.47471/#post-401782
 
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FOMOGO

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You stole that from the TARDIS, I'm telling the Doctor!:no no no:
Seriously, very nice work, I have been following this build and it is good to see the (almost) end result.
P.S., I noticed the neighbours coming over for a squiz,
John.
I was thinking exactly the same thing when I saw it. The Darlic wouldn't stand a chance against that thing. Very nice work Savarin
 

savarin

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Thanks heaps guys.
I'm working on the two gussets at the moment but its all hand filing due to the silly shape I wanted.
Then I will be able to contour the short edge where it will butt onto the large aluminium boss at the top of the pier.
I'm waiting on a length of 20mm aluminium rod for the handle that will fit between the two split flanges that clamp the scope into the cradle.
Still so much to do.
 

12bolts

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Charles, I must say i'm impressed with how far you've come with this during my absence. Its a little bit steampunk'ish. I really like the polished look. Have you considered keeping it like that rather than powdercoating?
 

savarin

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Thanks Phil, I'm only powder coating odd bits that wont polish.
 

hoth2o

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That is awesome! Were can I find out more about making a telescope?
 

CraigB1960

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Savarin, absolutely outstanding work there! I have a passion for astronomy, used to have a C8, but sold it due to bad location. Now that I'm in Tucson, AZ, which is very light friendly for astronomy, you have motivated me to look back into it. Perhaps making my own.....

Thanks for a great thread!
 

savarin

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That is awesome! Were can I find out more about making a telescope?
Hi hoth2o,
do you want to build a refractor (what mine is) or a reflector?
Both have good and bad points
If a reflector do you want to buy the mirror or make one? Carl Zambuto makes what are considered to be the very best mirrors.
If a refractor then its easier to buy the objective lens and these two seem a good buy with a quick glance.
http://www.surplusshed.com/pages/item/l14233.html
http://www.surplusshed.com/pages/item/l3968.html

There are heaps of books available such as
Amateur Telescope Making 2nd ed - S. Tonkin (Springer, 1999)
Berry R. Build your own Telescope (1985)
MAKING YOUR OWN TELESCOPE by JJ PERSISTENT PUBLISHING INC
Texereau-HowToMakeATelescope (considered to be the classic)

atm_free@yahoogroups.com is worth while trolling through as well.
 

savarin

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Thanks Craig, still making small bits to add on and a large casting to make a joiner for the central pier so it can be collapsed.
 

Tony Wells

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Mighty fine work, Sav. Certainly shows that there is a lot of detail in a nice optical piece like that, and shows that it's not out of reach for some determined person.
 

savarin

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Now I've built the vertical slide I can at last get back to this project.
set up to mill out the curve to fit around the 90mm dia boss at the top of the pier.
milling-brackets1.jpg

I found this interesting as this face is the as purchased plate.
Its swollen in the middle according to this first cut.
At least it follows the centre line

milling-brackets2.jpg

The third pass and its almost done.
Still a bit of blue left.
milling-brackets3.jpg

Final pass, no blue and smoother than it looks. The curve can just be seen.
milling-brackets4.jpg

This is where they will bolt on and hopefully prevent the azimuth plate from flexing.
They still need the final polish.
milling-brackets5.jpg
I still have to make a decision on how I will fix it to the boss, just pegs, or, a bolt from the edge of the large hole.
I will sleep on it.

(edit - changed fourth pass to third pass)
 
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rwm

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I'm pleasantly surprised that worked so well with that much tool hanging out on that bar.
That looks like hours of polishing. What is your process? Do you sand first and then polish?
Robert
 
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