Should look nice perched on top of the colour co-ordinated 12"er.
The whole mount is coming up nice, I finished all the painting today and tomorrow is assembly day and if I get it finished in time (without rushing, I want to do it right) the mount may see some sky tracking tomorrow night with my boys 8" on it!!! The 12" isn't ready yet (tube rings for the 12" being sorted out as we speak).
Now you'll be able to use your 'third' eye, Ken. : L.
ps. Got 'Skype' working yet? I am now on broadband, so if you want to try again....
When you gunna get Firefox, huh? Gees I'm a pain ain't I?
Now you'll be able to use your 'third' eye, Ken. : L.
ps. Got 'Skype' working yet? I am now on broadband, so if you want to try again....
When you gunna get Firefox, huh? Gees I'm a pain ain't I?
My Skype didn't stop working Laurie, just the headset broke. I can still type on skype.
I've still got Firefox in the pooter, but I don't like it.
Was looking at this topic - how did you figure out the correct voltage for the LED? Am trying to do the same thing but not sure how many batteries I need to power mine - it's also off an old PC...
Thanks!
Quote:
Originally Posted by ballaratdragons
So Far So Good!
The problem: can't see the crosshairs against the dark sky.
The Solution: After hints, suggestions and help from Laurie and AsiJohn I have wacked together an illuminated set-up for the crosshairs made of my daughters hair I put in my Guidescope!
I got a RedLed light out of a busted computer in the shed but it blew coz I chucked 12v across it. It glowed nice for about 4 seconds then faded out!!!! Back to the shed for another RedLed (luckily the computer had 3). OK, got the voltage worked out. 2 x AA batteries.
Mounted the Red Led inside the dew shield like Asi suggested.
Now for something to hold the batteries? A 2 x AA battery holder was found in a toy outboard motor from a busted toy boat in the shed and instantly confiscated for the sake of astronomy.
Now I needed a switch and a Potentiometer
Ah Hah! Back to the shed to the old Busted pooter monitor!!! BINGO! One power switch and the Pot from the brightness control.
Soldered it all together and it works a treat.
All I have to do know it wait until it is very dark outside and test it on Orion Neb and a few stars.
I shall let you know how it works as soon as it is pitch black outside.
Below is a pic of the wired effort before I make a small box to put it all into (I want to see if it works first) The RedLed is turned on!!!!
Red LEDs - in the range 1.8-2.8 volts would do. Two rechargeable AAs or AAAs would be good being about 2.4 volts in series. Ordinary batteries are more like 3.0 volts in series - suggest you try a series resister with your LED - try 100 ohm.
If you are playing with white or blue LEDs, they need a higher voltage to operate - more like 3-4 volts as I recall. Look up the Jaycar site (www.jaycar.com.au), find LEDS - they have specs for most LEDS - look for the Vmax or Vtyp values to give you an idea. In my experience LEDS are pretty robust (unless you push 12 Volts onto a red LED!)
I have all the parts and waiting for the time to build it. I'm wondering whether it works well if you just generally light up the area beyond the finderscope objective, or would it work better if I aligned four LEDs with the ends of the cross hairs? I can do both.
Ken, the cloud may have driven people into their sheds to tidy up and stocktake their junk, I mean good stuff. Greg.
P.S. my pile is a great thought stimulator.
FWIW. (shaneaust)... Most normal LEDs run on 20 mA with a resistor to limit the current to that value, (with respect to the Voltage). They run fairly bright on this so, I recommend increasing the value of the series dropping resistor to run a little dimmer.
(I've made a few Telrad mods & with the 'power on' LED indicators, I ended up using a 100K resistor to get the brightness down).
If you really need to, you can run 'em off 240 Volt supply but you need the correct circuit to do so.
If you want to run an LED off 3 Volts, use a 100/150 Ohm resistor.
If you want to ditto.............. " 6 " , ..... " " 270/560 " " .
If you want to ditto............. " 12 " , ..... " " 680/1500 " " .
These will be reasonably bright as well, so you can 'UP' the resistor values if needed.
See link for more info.. http://www.kpsec.freeuk.com/components/led.htm
HTH. L.
OK, job done and tested. I went for overkill - four red LEDs fitted into the dewshield of my Finderscope, each in line with the end of the crosshairs (which are in the eyepiece end)
Batteries, on/off switch and pot (and resistors) are fitted into a small black box screwed to the mount for the finderscope and wires run to the dew shield which can be removed to put the end cap on, then the dew shield reversed and placed over the Finderscope objective lens for storage or transport. (I have to remove the Finderscope from the dovetail to transport my 8" in the car boot.)
Initial testing at home worried me - I couldn't see any illumination! So I made up an annulus of aluminium (a pain with a jig saw as the only tool!) and jammed that into the dewshield, up close to the LEDs, in an attempt to reflect more light towards the objective.
Finally got two dark sky nights of testing. It's working well. A nice red glow set against the sky - I had to turn the brightness back from maximum. Crosshairs nicely set off against the brighter sky objects. I could find the balance where I could see the crosshairs against the illumination, but the sky wasn't too washed out.
OK, job done and tested. I went for overkill - four red LEDs fitted into the dewshield of my Finderscope, each in line with the end of the crosshairs (which are in the eyepiece end)
Batteries, on/off switch and pot (and resistors) are fitted into a small black box screwed to the mount for the finderscope and wires run to the dew shield which can be removed to put the end cap on, then the dew shield reversed and placed over the Finderscope objective lens for storage or transport. (I have to remove the Finderscope from the dovetail to transport my 8" in the car boot.)
Initial testing at home worried me - I couldn't see any illumination! So I made up an annulus of aluminium (a pain with a jig saw as the only tool!) and jammed that into the dewshield, up close to the LEDs, in an attempt to reflect more light towards the objective.
Finally got two dark sky nights of testing. It's working well. A nice red glow set against the sky - I had to turn the brightness back from maximum. Crosshairs nicely set off against the brighter sky objects. I could find the balance where I could see the crosshairs against the illumination, but the sky wasn't too washed out.
: 
L.
