Some actual observing...

Mostly the weather has been bad and I've been really busy, so I haven't had much time to observe.

However yesterday afternoon the moon was out in the afternoon sky, and could be seen in my home office window. I was able to get a nice view without ever leaving my chair care of my 15x70 binoculars. This morning as I got up before dawn to go to Natz* Jupiter was shining high in the south. Maybe one day this week I will get up to get a good look, as I didn't have a chance to get the binoculars out.

*Natz, is the jewish morning prayers done literally at dawn (IE The first possible moment you can) . I go because there won't be a long sermon to listen to.

Tools needed

So I figure to build these scopes I will need these power tools:

• Plunge Router (with some bits and jigs)
• Miter saw. Specifically I will need to make an angle of 32° (as I live 32° north)
• Hand drill
• Jig saw

(Tools I have)

Non power tools that I may need:

• Goggles (for eye protection)
• Sandpaper
• Clamps (a bunch)
• hammer, screwdrivers etc
• Tape Measure
  

All of this will also put me in a good position to build a bunch of bookshelves.

As for router bits, I think a Dado bit and something to let me cut circles, the dado may work there, a small quarter round might be helpful too.

I'm going to see if my jigsaw can cut on an angle with a jig. Cutting at 30° should be good enough. Or I can see if a neighbor has a miter saw that can do 32°

Two scopes

So for right now I'm working on the 4.5" starter scope, after that I plan to make a larger (10-12") scope. The question is really how big a scope can I make that will still fit in the trunk of my car. It will be some time until I can afford the optics etc for this scope, so at this point its more a theoretical thing. For now I am planning on taking a tape measure to the trunk of the car.

Building an equitorial mount (Some Math)

I want to build a simple equatorial mount, which is to say a mount that can be aimed at the North Celestial Pole, and then turn at the rate of 1 turn per sidereal day. Or 1 turn in 1436.06 minutes. This will match the rate at which the stars move across the sky.

To do this I will need a main gear which will be a wood disk cut on a router of radius R.
This will be driven by a threaded rod with 20 turns per inch turning at 1 rpm. This will move the disk at the rate of 1/2oth of an inch per minute. As such the circumference of the drive wheel must be (1436.06 minutes * 1/20 inches /minute) which is 71.8 inches.

Thus the radius (R) of the drive wheel should be 11.4278 Inches. I expect 11.45 or so will be about as close as I can machine the thing, this should be close enough for visual use and for astrophotoraphy as long as the exposures are short (say 10-15 minutes max).

In need of tools

I found a few episodes of "The New Yankee Workshop", and have been watching them to learn something about woodworking. Last night I saw the router 101 episodes (as well as the lathe episode). It looks like plunge router and a few jigs will get me a long way to where I want to go.

To build various scope parts I will need a circle jig, which he showed how to make, and it looks quite doable.

Starting Small

So I think I am going to start by building a 4.5" F8 small dob. The primary & Secondary will cost me about $53 (USD) with shipping plus any customs. I sent an email to the customs service to see how much that will be.

The next thing to decide is do I want to make it a solid sonotube or some sort of truss travel scope. I am looking around talpiot for sonotube, and will try to see how much it goes for. From there I can decide if I want to lug the scope around in 1 piece or not. I'm thinking with this one a solid tube makes sense.

Finding optics

I have found these 3 companies that sell telescope mirrors on the low end.

• Anttlers Optics
• Hands On Optics
  
• Meridian Telescopes

Meridian has a 4.25" F8 mirror for about $32, which would be about $40 with shipping. This also includes a secondary mirror. It would make a decent long tube for a narrow field of view.

A 6" F5 mirror seems to be about $80. This would make a nice wide field scope. including a spider and mirror cell it would run me about $150.

If I want to go larger then I found a 12" F4.5 with secondary for about $399. It would need a mirror cell and a bunch of other stuff. This is a plan for the future.

I think for now the 6" rich field scope makes the most sense.