Finally Joined the Dob Mob

[SnakeyJ]

It may not be pretty, but it certainly wasn't expensive and I'm now almost a member of the mob.

Obviously it's going to take some work and the optics will definitely need an inspection to check they are worth re-coating.   But I couldn't resist at the price and have a good feeling that the optics (Inscription "Pyrex Fours 61 1/2 ins.  F/6.15 Parabolic aug 1982 H. Wildey) will be good.

It's not going to be quite so cheap after collecting, coating the mirrors, making a new mount and fitting a 2" crayford - but I'm a sucker for anything with a bit of history.    At 6' 2" I should just be able to manage this at zenith and I reckon the focal length and small obstruction should make this quite a nice performer even with a handful of reasonably priced EPs.

[swamp thing]

It may not be pretty, 

I disagree. Personally I love this original Dob look (my 10" is the same) its form follows function at its very best.

Its just scope......no frills. simple and beautiful IMO.

Welcome to the squad BTW

[SnakeyJ]

I disagree. Personally I love this original Dob look (my 10" is the same) its form follows function at its very best.

Its just scope......no frills. simple and beautiful IMO.

Welcome to the squad BTW

I agree the form is good simple and elegant, but I've been spoiled by pictures of Shane's wonderful woodwork

[swamp thing]

He makes a cracking scope does Shane. I have seen Johns 12" on a mount that Shane made, and Shane's own 16" both very nice indeed. 

[Gina]

Doesn't matter what it looks like on the outside as long as the inside works well

[Floater]

I have nothing but admiration for you DIY wizards. Great stuff.

Keep us up to date with the project, please.

Dib, Dib, Dob, Dob.

[Laurie61]

Nice to see an older scope being put back on the r̶o̶a̶d̶ back garden again. 

[scarp15]

'It may not be pretty' but it looks pretty cool.

[Astro Imp]

Let's face it this isn't a beauty contest, it just needs to work.

[Moonshane]

congrats - will be a great scope I reckon. cheers for the compliments but in fairness Steve's woodwork is better than mine. I am in the if it works it works camp

[SnakeyJ]

Cheers Shane, I'll do my best to follow your excellent examples, but first I'll give it a try and enjoy the view. It will be great fun to have the freedom of a nudge to, to explore while the dslr is clicking away :-)

[Beulah]

Excellent find! Restoring a scope like this will be a labour of love and you will really enjoy it when that hand ground ten inch mirror has been re-coated. Nice bit of aperture and the FL is slightly in favour of being a planet killer, too!

Nothing better than to use a scope you have repaired and pretty much built yourself.  

Please keep us updated with your progress.

[Casus belli]

Please let us know how you get on with it. I love the idea of home made scopes

[SnakeyJ]

The optics should be okay - H Wildey was well known and made a lot of mirrors and lenses. His mirrors were often cited as better than 1/10 wave. However, 1982 was getting close to his retirement and several reports suggest quality deteriorated with his eyesight.

Have to see how this one performs, at least relative to my OO and Vixen mirrors, which should be around 1/8 wave - though for deep sky in the UK, the difference is probably negligible.

[SnakeyJ]

It's taken a little while, but I've just been to Bodiam to collect this.

First impressions, beyond my goodness that's huge, are very good. The build quality looks good, particularly the spider and mirror cell.

The scope has some pedigree, being made by Ken Budd who was a Founder member of Orpington AS and talented mosaic artist. His son Olly, who now runs the business, gave me a lot of the history and a book and photos. One nice part was that his father was still carrying this scope downstairs and into the garden in his 70's. Hopefully, I will be able to repeat this feat. It seems likely that SPM may also have admired the views.

The mirrors are overdue a recoating and I'm not sure what to make of the helical focuser, but certain this deserves the attention and will repay with good views :-)

[SnakeyJ]

Here's a picture of Ken Budd with his dobsonian in his garden, though not sure what year this was taken.   The picture was kindly donated by his son Olly.

[swamp thing]

How cool is that.

[SnakeyJ]

The mirrors went up to Galvoptics for recoating yesterday (delivered by a friend who was taking his 16" LB mirror up).   Currently a three week turnaround, so I'm expecting to go up and collect around mid Feb.    This should allow the silica a chance to harden off before our local star party over the solar eclipse in March.

Meanwhile the scope is stripped down for some over due renovation and modification.  

[SnakeyJ]

Long time getting around to this, but a whole lot of other stuff taking priority at the moment.   I got the mirrors back from Galvoptics in February, but with a house move in March, I left everything packed up until the dust had settled.   I figure 7 months should be enough to allow the SiO2 overcoat to harden off nicely

I was hoping the weather might be kind this evening, so I decided to get the dob out of the shed and fix it enough for a test of the optics.    If the optics show promise I will rebuild this, though probably as a truss tube dob.

Edit - some may notice more than a passing resemblance to the original owner in post 16

The inside of the tube was thick with stone dust, which I flushed out with soapy water and a mop to give me the reach to do the whole tube.   Big tube this and sure it would comfortably fit a 12" F5!   The helical focuser had taken a bit of a knock and come unstuck, so I glued this back with gorilla glue.

Rather than reuse the original mirror cell, I decided to use the orphaned OO Europa 250 cell - which presented a few challenges later...

I mounted the secondary mirror on three blobs of silicon:

Challenges - when Mr H Widley made a 10" mirror, he made a proper 10" mirror - not one of your modern 250mm blanks, this measured nearly 260mm wide and is a good 35-40mm thick.   The long and short being that it was marginally too big to fit in the mirror cell.      Having committed to this method, I got my file out and took an 1/8" of each of the mirror surrounds.    

This very nearly worked, but a couple were bent in slightly and I broke one off applying moderate force with the hammer.      This has been temporarily araldited back in place and the whole cell will be replaced once the optics have been tested.

Anyway I finally got the mirror mounted:

Just in time to look out and realise that we were clouded out    So everything is now packed away for the next week or so looking at the forecast!

[Dave In Vermont]

That things looks like it would easily provide a lifetime of awe-inspiring views! Nice. I'm glad you finally got it back together, and I'm sure you are, too.

Gorilla Glue can be an astronomer's best friend. That stuff would glue a grand-piano to the ceiling! It's Super-Glue on steroids.

Please let us know about your First Light,

Dave

[SnakeyJ]

The repaired mirror cell.

Making the most of the foul weather, I stayed up last night reassembling and collimating the scope.    The recycled OO Europa mirror cell works rather well and holds the mirror well.    The secondary is stable, but adjustment is difficult with a 10mm spanner and I'm very paranoid about dropping the spanner on to my newly coated primary.    The helical focuser is agricultural, sloppy, coarse adjustment, 1.25" only and is top of my list to replace!

These aside I managed to get a reasonable collimation with cheshire and laser and I'm ready to take it out tonight if the promised gaps in the cloud appear.   Failing this there are more promising gaps for tomorrow and the outlook seems to improve somewhat next week 

[Moonshane]

what a great thread this is. hope it's a cracking first light. not far away now.

[SnakeyJ]

what a great thread this is. hope it's a cracking first light. not far away now.

Thanks Shane, looks like we should see a couple of clear hours down here tonight.   The main test will be can I achieve focus, as the OTA is drilled out for two positions of the mirror cell and I'm starting at the bottom!    The base plate for the mirror cell is a very tight fit inside the OTA and requires careful rotation to align the three retaining bolts - manageable but time consuming!

Just spent the afternoon browsing the usual sites for some truss tube design inspiration, including a closer look at some of your own

[SnakeyJ]

Just setup and re-collimated under clear skies and the cloud has come over and started raining - not giving up just yet though!

[SnakeyJ]

I managed to catch some out of focus photons, with insufficient in focus even after moving the mirror forward by an inch. Best view was by holding my 24mm ep just at the end of the ota, but lots of coma from being so far of axis.

Still it goes to show I'm not too far off. Perhaps I shall sacrifice the helical focuser and mount my old Europa OC1 - should give another inch of in focus..