Collimating SCT.

[JohnP]

Wow! - I never knew supbright LEDS drew that much current.... no wonder it's bright...

Don't forget your average Alkaline PP3 (9V battery) has a capacity of something like 500mAh so depending on how many hours it takes you to do your collimation battery may not last too long.....

John

[Ian]

I've got a 3W LED that draws 350mA and here's one (the white one) that can draw 1A http://www.jaycar.com.au/productView.asp?ID=ZD0442&keywords=bright+led&form=KEYWORD

They need mounting on substantial heat sinks to prevent them from self-destructing.

[MarkS]

Chris,

I thought you said "EACH OF THE 64 STRANDS IS 0.25mm DIAMETER".  That means a diameter of 250 microns not 25microns. 

Mac reckons he got 0.2 mm (200 microns) with his borate silicate glass (or whatever).

Last night I sawed the collimating lens off a cheap & nasty key-chain red diode laser.  Ran it off 3V with a 4700ohm resistor in series to keep the power right down.  This produced a pinprick light source which I measured photographically to be approx 0.08-0.1mm wide i.e. 70-100 microns.  This is still slightly too large to act as an artificial star for collimating my C11 at 25metres (the length of my garden) - it subtends 0.7arcsec.

Mark

[Mac]

If i get a chance today, i'll have another go at making a nice very fine, glass fibre with the glass i've got,
I'll bring it tomorrow to high elms, and i'll bring in some glass for you to have a go with.
All you need is a blow torch to heat it up and you just pull it apart, the glass solidifies
in to a ver thin strand.

the .2mm strand i ended up with was a lot thinner, but the end piece broke off.

Mac.

[JohnP]

I'll bring it tomorrow to high elms

Mac - remind me what's up tomorrow...... thks

[Ian]

do you want me to bring my blowtorch to dsc? my propane bottle will be there anyway...

[Mac]

I'll bring it tomorrow to high elms

Mac - remind me what's up tomorrow...... thks

sorry just me having a blond moment,
I thought the meeting was this thursday,

I'll bring some down on saturday then instead, as well as a pair of plyers and some gloves.

anyone got a micrometer?

[Ian]

anyone got a micrometer?

yup, shall I bring that too?

[MarkS]

So if it's cloudy, at least we'll get some collimation practice.  Sounds like we'll have a whole constellation of artificial stars!

Mark

[Mac]

anyone got a micrometer?
yup, shall I bring that too?

might as well, just to see how thin the fibres realy are,

[Rocket Pooch]

Chris,

If you have any left - I'll buy a few fibres.

Mark

I have 2 meters of the stuff, I will accept payment in beer please, not point in cashing in or it, it was very cheap...

[Rocket Pooch]

Wow! - I never knew supbright LEDS drew that much current.... no wonder it's bright...

Seriously you don't want to look into the end of one when its on.

[Mac]