20" f/4 Dob build

[estwing]

camo dob! now thats cool...

[swamp thing]

1366045995[/url'>' post='1904300']

camo dob! now thats cool...

Not sure I'd wanna be using that on Salisbury plain.......could end very badly

Don't think I wanna do my observing with a challenger II tank shooting holes in me. Besides, all that ordnance going off plays hell with ya dark adaption.

[Daniel-K]

very nice steve how did you fix them>?

[Moonshane]

rock solid mate - just like a proper mirror box should be are you doing your truss clamps inside the box?

[swamp thing]

1366054012[/url'>' post='1904430']

very nice steve how did you fix them>?

They're stuck at the mo, I will put some screws in for belt and braces job.

1366055108[/url'>' post='1904450']

rock solid mate - just like a proper mirror box should be are you doing your truss clamps inside the box?

No mate. External clamps. Helps keep the mirror box down in size. It's pretty big on a 20" as you can well imagine.

The UTA won't stow inside like one of your scopes. It will be stored separately in its own box I'll make this later.

[nightfisher]

Steve, your doing a grand job, coming on well

[Rustysplit]

What varnish did you go for Steve?

[swamp thing]

Cheers Jules, getting there......at last.

Alan. Varnish is an exterior solvent based yacht one. I don't trust water based finishes on exterior wood. I was going to go with a two part epoxy but, it's a scope....not a yacht

It'll get five layers in total, same as the UTA.

[Damo636]

Lookin' great Steve, really lookin' forward to seeing the finished job :-)

[swamp thing]

Okay so I've managed to almost finish the mirror box now haven't had a great deal of spare time of late.

The inside I've painted Matt black, the outside has five cats of varnish. There is still a bit of finishing to do on the inside.

However I have managed to attach the alt bearings and truss clamps to the finished outside.

Now I just couldn't resist cutting the truss tube o rough length and having a mock up of the OTA

Getting there at last. I can start to smell first light now.

[Moonshane]

that's starting to look fabulous Steve! you are on the home strait now for sure. those clamps look the business.

[estwing]

looking top notch steve..nearly there...

[Beulah]

Fantastic! You're getting there...

F/4 makes for quite a 'short' telescope, looks like even a short person could reach the eyepiece without perhaps the help of a step?

Ahhh yes, I can remember the smell of first light...

[Rustysplit]

That is looking the business Steve. As Shane has said, the clamps are really nice. What have you still to do? Just the rocker box? I bet you are itching to get on now it is so close to completion. That Summer Triangle won't know what hit it!!

Looks like we might make First Light about the same time.

[estwing]

thats two first lights i gotta read..good luck gentlemen!

[swamp thing]

That is looking the business Steve. As Shane has said, the clamps are really nice. What have you still to do? Just the rocker box? I bet you are itching to get on now it is so close to completion. That Summer Triangle won't know what hit it!!

Looks like we might make First Light about the same time.

Theres a bit more finishin on the inside of the mirror box. Gotta install the cell. Rocker box. Then just install optics and cut trusses to exact length.

After completion both mirrors will get a recoat. As this needs doing too.

[swamp thing]

F/4 makes for quite a 'short' telescope, looks like even a short person could reach the eyepiece without perhaps the help of a step?

It looks like a milk crate sized step at the zenith. Everywhere else should be feet on floor

[Beulah]

Wow, this does not help the aperture fever! I've always thought a 20" dob was beyond me...

[swamp thing]

I really don't know what I'm gonna do if I come down with it again

[Rustysplit]

I really don't know what I'm gonna do if I come down with it again

If???? There is no known cure Steve.

[Naemeth]

The best fix for aperture fever is probably owning the E-ELT. Mind you, I'm sure, in a few years, decades, people will want something 10 or 20 times the size, possibly orbiting the Earth like the ISS. Something with enough aperture to actually make out the flag pole on the Moon . Of course, it would be very expensive to send that thing up...

[Moonshane]

The best fix for aperture fever is probably owning the E-ELT. Mind you, I'm sure, in a few years, decades, people will want something 10 or 20 times the size, possibly orbiting the Earth like the ISS. Something with enough aperture to actually make out the flag pole on the Moon . Of course, it would be very expensive to send that thing up...

probably cheaper to land on the moon than make a telescope capable of seeing the flag from Earth.

[Moonshane]

the best cure for aperture fever is force yourself to keep it indoors. then you'll stick to scopes that have to fit through them

[swamp thing]

For sure Shane. I have just been locating some hinges that allow my front door to move right out of the way to allow the full aperture of the doorway (2'8") to be utilised. This means the 20" will fit through the door. Otherwise it's too big.

The 20" comes out at just too big for a regular doorway. 18" would be IMHO the best size if indoor storage is needed.

Eventually my 20" will live in my army truck, so fitting through doors isn't such a problem in the long run, but in the meantime it has to fit. The hinges I've sourced will see to this.

[billhinge]

Nice

I've got a partially finished 10" mirror and a 16" blank laying around for years. The 20" doesn't look too unmanageable so I may get around finishing the 10 and 16 off some time in the distant future