Revamp of club 12" Dob scope commences.

Dave Lillis · Post by **Dave Lillis** » Tue Sep 30, 2008 11:23 am

IF you want to buy a cell for the scope, have a look at this (scroll down)
http://astrosky.homestead.com/price.html

Frank Ryan · Post by **Frank Ryan** » Tue Sep 30, 2008 6:48 pm

Actually, after looking at the club coffers it looks like we will have
to call on your talents Dave!!
How much you reckon a timber one would cost?

Dave Lillis · Post by **Dave Lillis** » Tue Sep 30, 2008 7:15 pm

we could be using tooth picks yet

I cant see the wood costing alot, I'd say we need about 7-8 feet of 2x2 and a small bit of plywood (I have that already).

Frank Ryan · Post by **Frank Ryan** » Tue Sep 30, 2008 8:35 pm

I know!

Yea, that sounds fine.
What kind of timber did Phil recommend?

Dave Lillis · Post by **Dave Lillis** » Tue Sep 30, 2008 9:50 pm

He didnt, but I'd imagine its not too important, just that its varnished, it we can get treated stuff then all the better,

Frank Ryan · Post by **Frank Ryan** » Tue Sep 30, 2008 11:44 pm

Not to sound argumentative but I reckon it's very important!
We don't want any warping or swelling down the road...
that would be a nightmare...
Varnishing is only the final treatment...

Dave Lillis · Post by **Dave Lillis** » Wed Oct 01, 2008 1:24 am

well, once its treated like patio wood (thats what I had in mind), then what more can you do besides giving it many coats of varnish in hope of keeping the water out of it.
To a point, so what if it swells?, its not going to be alot and would only require re-collimating be done which would be needed after transport anyway.

Eventually it might rot, well if so then we'll build another one when it happen in 10+ or so years.

Frank Ryan · Post by **Frank Ryan** » Fri Oct 03, 2008 11:06 pm

Youd be surprised how much untreated
(and by that I mean, regular timber) can swell.

We can hash that one out but..
I got a quote sort of for some of the bits and pieces...
I did say 're silver' but I think the mirror needs more than that,
Dave, you would definatly know more about this than I would...

Anyway here is the reply...

Hi Frank,
I would be happy to supply you with all you need, for costing please see below comments. the only thing I am not sure about would be shipping costs as it is wholly dependant upon weight (would need weight of mirror/flat to give a guide price). if the below prices are acceptable then all I would need from you is the mirror/flat and details of the remainder. if you have any questions or need any more information then please call me direct on 01507 363 381 and I would be happy to help.
Barrie Watts

To: BK.Watts@iname.com
Sent: Monday, September 29, 2008 11:54 AM
Subject: Dobsonian Parts

Hello Barry.
I found a link to your store here:
http://www.gm4jjj.co.uk/astronomy/dobson.html

I am the club sec. of Shannonside Astronomy Club.
We are in the process of renovating our club dob which hads been left fall into disrepair.

Here it is (pictured with a face you may be familiar with!)
http://farm3.static.flickr.com/2034/151 ... 01e3_o.jpg

We have treated the timber to prevent any further decay
but we still need to carry out this list:
All including VAT

Re Silver the 12'' Mirror and secondary mirror.
Cost: Â£68.00 for mirror. Â£9.50 for flat

Make a new cell for the mirror.
Would need to know exact requirments for cell but approx Â£68.00 dependant upon specification

Replace the base with a formica surface.
Dependant upon size but relatively cheap
Replace all teflon pads.
Again dependant but few pounds

Install a modern telrad and laser pointer finder system.
Dont actually deal with these, would probably be able to source one for you, its cost would be comparable to anywhere else you may find it

I would be interested to know would you be able to supply
the materials we need to carry this out and if so,
could you recommend which parts and how much they would be.

We are hoping to have the refurbishment finished by the end of October.

Kind regards,

Frank Ryan Jr.
Club Secretary
www.shannonsideastronomyclub.com

Dave Lillis · Post by **Dave Lillis** » Fri Oct 03, 2008 11:46 pm

Hey Frank,
Cant we just get the Formica from B&Q,
ok, its time to get serious,

A telrad from astromart is between 30-45$ +P&P

Teflon, spider, secondary mirror can be got from
http://www.astrosystems.biz/products.htm

I was thinking Orion optics for recoating the primary. They come highly recommended
http://www.orionoptics.co.uk/OPTICS/mir ... ating.html

lasers and laser holders can be got on ebay.

The cell is the only real unknown, if he can build it for that money, I'd be inclined to go for that option.

Frank Ryan · Post by **Frank Ryan** » Sat Oct 04, 2008 12:37 am

Dave Lillis wrote: Cant we just get the Formica from B&Q,

Yup. Actually, I can get it from my mate in Irish Wire for free.
(I threw it in there so he might being the overall quote down if there was
more to quote - thats just the salesman in me again

Dave Lillis wrote: A telrad from astromart is between 30-45$ +P&P

Very good. Cheaper than I thought.
If you can remember where the old finder scope in positinoned,
would this be just a straight replacement?

Dave Lillis wrote:Teflon, spider, secondary mirror can be got from
http://www.astrosystems.biz/products.htm

Ok.
Do we need a new spider and 2ndary?
Why?

Dave Lillis wrote:I was thinking Orion optics for recoating the primary. They come highly recommended
http://www.orionoptics.co.uk/OPTICS/mir ... ating.html

Ok cool.
Can you get a quote off them?

lasers etc we will sort out at the end.

Phill Lardner gave a few suggestions also I'll go into later...

The Mirror cell looks like good value doesn't it!

donkearns · Post by **donkearns** » Sat Oct 04, 2008 9:53 am

Guys you are doing great work.
Is there anything anyone else, including myself, can do to help?

Don

Dave Lillis · Post by **Dave Lillis** » Sat Oct 04, 2008 12:13 pm

Frank,
The standard coating from orion is 111.23 pounds sterling
and the hilux coating is 173.60 sterling
so suddenly this is looking pricey, can you ask they guy you found what reflectivity % and durability are his coatings. Can you also ask the guy how many support points does the cell have and is it suspended on a sling, this is very important.

The telrad can be a straight swap but we can leave the finder on the scope somewhere else since we have it anyway.

The secondary mirror glass might not need replacement but does need recoating. Can you measure the minor axis of the secondary so we can get a price on recoating it.

The spider and secondary collimation setup on that scope is atrocious and is difficult to setup. I can look at it again and see what we can do with it. If it was mine I'd dump it.

hi Don, not sure really......

donkearns · Post by **donkearns** » Sat Oct 04, 2008 8:01 pm

Hi Dave (and Frank)

Pricey?
I wouldn't mind contributing to this noble project.
Perhaps a bit of fund raising needs to be done at the club meetings?
I wouldn't like to think that abandoning this is an option.

Don

Frank Ryan · Post by **Frank Ryan** » Sat Oct 04, 2008 8:03 pm

donkearns wrote:Guys you are doing great work.
Is there anything anyone else, including myself, can do to help?

Don

Hey don, thanks for offering.

I've kind of pressganged Dave into this lately as
he is 'de man' as far as I'm concerned when it comes
to mirrors and spiders and all things telescopic!

BUT. If you happen to have a spare shiny piece of kitchen
counter top board handy (formica) that would be cool.

donkearns · Post by **donkearns** » Sat Oct 04, 2008 8:08 pm

Frank,

I know a kitchen installer.
How much do we need.
What thickness etc.

My own is granite so that wouldn't suit

Don