Print Page - 8" F4 Astrograph

Title: 8" F4 Astrograph
Post by: Rocket Pooch on May 20, 2011, 07:57:42

Right,

After the stepper focuser was completed I now have the carbon tube (10mm thick walls), it's been in the bedroom for a few weeks, on its way from the good old USA is a 3 vane custom curved spider for the seconday.

Flock, Baffles and Ultra Black flat paint here, as well as the holo primary spot....

I just need to decide what to do with the focuser and primary support, the rings already on the way.....

Then I have to start drilling and assembling!

Then it's the QSI upgrade and finder scopes?

Nearly there.

Title: Re: 8" F4 Astrograph
Post by: MarkS on May 20, 2011, 08:17:50

Will there be anything original remaining? Primary mirror I guess ...

Mark

Title: Re: 8" F4 Astrograph
Post by: Rocket Pooch on May 20, 2011, 08:31:40

That's about it!

Title: Re: 8" F4 Astrograph
Post by: Rocket Pooch on Jun 22, 2011, 11:15:25

Hi,

Couple of updates whilst I'm waiting for my custom primary holder!

I found these guys for my electronic focuser pullys http://www.technobotsonline.com/, they have loads of robotics parts.

My secondary holder arrived some time ago, its cool, look below, ignore the fabric in the tube this will come out later.

Chris

(http://farm4.static.flickr.com/3064/5859777698_7c02594ca8_b.jpg) (http://www.flickr.com/photos/13007140@N05/5859777698/)
IMG_1897 (http://www.flickr.com/photos/13007140@N05/5859777698/) by chrissuddell (http://www.flickr.com/people/13007140@N05/), on Flickr

Title: Re: 8" F4 Astrograph
Post by: mickw on Jun 22, 2011, 13:45:38

Has the secondary holder got a wire attached ?

and why ?

Title: Re: 8" F4 Astrograph
Post by: Mike on Jun 22, 2011, 15:42:19

If anyone eve orders from Technobots, let me know as I can get you 10% off.

Title: Re: 8" F4 Astrograph
Post by: RobertM on Jun 22, 2011, 18:56:24

FWIW I've used these people http://www.ondrives.com/index.php (http://www.ondrives.com/index.php)

They supplied the coupling I used to connect my focuser to the stepper motor and have an incredible range of bits.

Title: Re: 8" F4 Astrograph
Post by: Rocket Pooch on Jun 22, 2011, 22:21:19

Mick,

The wires are for a secondary heater, you put a + and - on seperate spider legs, cool eh!

Chris

Title: Re: 8" F4 Astrograph
Post by: MarkS on Jun 23, 2011, 06:41:05

It's looking very good Chris!

Mark

Title: Re: 8" F4 Astrograph
Post by: mickw on Jun 23, 2011, 08:22:17

QuoteThe wires are for a secondary heater, you put a + and - on seperate spider legs, cool eh!

Clever idea, but I think carbon fibre is conductive :(

You would need to insulate the legs from the tube

Title: Re: 8" F4 Astrograph
Post by: Mike on Jun 23, 2011, 09:47:01

Carbon fibre is conductive but I am sure that tube has some kind of coating.

Title: Re: 8" F4 Astrograph
Post by: mickw on Jun 23, 2011, 12:16:48

The gelcoat would be an insulator but fixing bolts would be in contact with the carbon unless they were sleeved.

Title: Re: 8" F4 Astrograph
Post by: Rocket Pooch on Jun 23, 2011, 14:45:57

Hi All,

I think you have managed to answer the conductive question yourself :-)

Chris

Title: Re: 8" F4 Astrograph
Post by: Whitters on Jul 17, 2011, 22:02:26

Like the look of that Chris. The secondary heater is a nice touch. :D

Orpington Astronomical Society

Astronomy => Technical => Topic started by: Rocket Pooch on May 20, 2011, 07:57:42