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DIY Polar Scope Illuminator


Zaphod360

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After reading lots of different threads on here and on tinterweb I thought I'd have a go at making a polar scope illuminator for my EQ5 mount.

This is what I came up with:

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Now I'm going from memory as I didn't keep my receipts, but this is what I used:

LED - Maplin Code: CK46A

3 AA Battery Holder - Maplin Code: YR61R

Enclosure - Maplin Code: KC91Y

Switch - Maplin Code: FH94C

Pipe fitting - B&Q 34mm push fit pipe fitting

Total cost is around £8

I removed the pipe fitting nut and turned it around, when tight this would give me a larger area to fix the battery enclosure. The pipe was then cut to length (approx 37mm past the nut). I filed a flat on the bottom of the pipe, again to help with fixing the battery enclosure.

I drilled a hole through the enclosure and another through the bottom of the pipe fitting for the LED.

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This shows the arrangement of the batteries etc.

The LED is 5v but with three 1.2v rechargeable AA's it will illuminate dimly. With some trial and error I routed the LED up into the pipe and masked with insulation tape.

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The LED needs to point away from the polar scope or it will be too bright.

A couple of wraps of insulation tape on the end of the pipe fitting gives a secure fitment when slotted into the end of the polar scope (see pics above).

I've tested this out when the moon is nearly full and can still see Polaris through the illuminated scope clearly. It keeps both hands free for easier alignment.

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Here are some of the links I used for inspiration:

Polarscope LED Installation

Telescope Reviews: DIY Polar Scope Illuminator using PVC

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Thats a nice neat mod well done , i kind of made a temporary one which is just a small led and a few button cell batteries connected to a switch which all sits inside the polar scope housing but your mod is a lot more elegant so i'll sure have a go at your method thanks a lot for posting ;)

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  • 3 weeks later...

Hi, I have just bought the list of components to make the illuminator but then realised i have no knowledge of how to put it together. Looking at the parts i have i am not sure if i am missing something? Do i need to solder anything when assembling it please?:)

Andy

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Yes you'll need to solder your wires onto the LED, I kind of made this up as I went along, so sorry if this isn't very technical. I got some wire and connected them to the battery box. I ran one to the switch, another from the switch to the LED, then one back from the LED to the battery box. The feed to the LED only goes one way so make sure you check this before soldering. You'll need some 'heat shrink' sleeving to protect the soldered joints and stop them shorting out. I made sure I had plenty of spare wire to be able to align everything in the box.

I'm posting this from my iPhone, if I can think of any more details I'll add them tomorrow.

Hope this helps, this little illuminator has become one of my favourite tools, it makes setting up so much easier, good luck.

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an excellent idea, much along the lines of the instrument your GP uses to look in your ears. I have one hand holding the red LED torch shining into the polarscope and the other doing the adjustments - egad!

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The led you used LED must have an inbuilt resistor? - if not it will fail immediately. If you make one of these check on the web for an appropriate resistor value (Google "led resistor").

Have a look here: Optoelectronics and scroll down to the led selection/developement kit about half way down the page for a cheap selection of suitable bits (usual disclaimer - Bitsbox have given me and others very good service over the years).

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Yes you'll need to solder your wires onto the LED, I kind of made this up as I went along, so sorry if this isn't very technical. I got some wire and connected them to the battery box. I ran one to the switch, another from the switch to the LED, then one back from the LED to the battery box. The feed to the LED only goes one way so make sure you check this before soldering. You'll need some 'heat shrink' sleeving to protect the soldered joints and stop them shorting out. I made sure I had plenty of spare wire to be able to align everything in the box.

I'm posting this from my iPhone, if I can think of any more details I'll add them tomorrow.

Hope this helps, this little illuminator has become one of my favourite tools, it makes setting up so much easier, good luck.

I think i have figured it out in my head. Please see diagram and if this is not correct will you please indicate one way or the other?

Andy

Polar scope illuminator.xls

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Thats an extremely good idea and well thought out as it is self contained, just as a thought though, you could create the same device without the batteries and use a direct wire connection to your 12v supply using a Maplins LED code CJ66W red standard brightness or CJ70M high brightness, both are 3mm 12v with built in resistors, if you want to vary the illumination then just place a 470 Kohm pot in the circuit and use the same project box and switch, which is what I will do when I get round to making one, thanks for the input :)

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If you want a cheaper solution to this, then look for 'LED tealights' in poundland, poundstretcher etc. They come in packs of 3 or 4 and have everything built in, battery, switch, all you would need would be the pipe fitting and some hot glue.

If you want to dial down the amount of light thumping out of the led, you can use some sandpaper on the outside of the LED to diffuse the light somewhat.

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Love it! Great idea. :)

Holding a torch with one hand, adjusting bolts with the other hand, whilst down on one knee and craning your neck skywards sounds easy until you try it. Much easier with 2 spare hands.

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Following on from this DIY led theme, Old vitiamin pill bottles and a red led might be useful as an astro freindly lamp, they produce a very diffuse light, and of course using a higher value used in conjunction with the led will allow you to limit the amount of light it chucks out :)

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Just adding to the all polar scope thread, i have seen somewhere where the grub screws to adjust the scope have been replaced with thumb screws. Has anyone any idea what thread size they are and where to source them from?

Andy

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I've just tried to make an illuminator and think I've over done the LED! I hadn't see this thread before I started so I used a 9v LED with a 9v battery. Now having tried to use it I think it might be a bit ott! Does the LED need to be quite dim for it to work properly?

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Yes, otherwise you can't see Polaris through the red glow, I'm not any good at electronics but a suitable resister or potentiometer should help, you just need someone who can do the calcs to figure out what size.

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  • 1 month later...

I dont know what celestron were thinking when releasing a polar scope with no back lighting?? Basically you can see nothing without the led. I too have ordered some LED's to make similar to the above, so thanks for the suggestions for construction mate. Im gonna go down the road of 12v Led (pre soldered Resistor) wired through a 470k pot to the 12v supply for the scope. This will let me vary the brightness. I may also fit one to my spotting scope, as it could do with a minimal of back as well

Dave

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Thanks mate -- its really basic, my scope is powered from 12v so i can tap into this power source. 12V LED's can be had from ebay or maplin really cheap (i got 6 of them from ebay for £1.69) the variable resistor is wired in on the positive supply to the led allowing you to vary the voltage thus dimming the LED. The only problem i for see is that it means another cable trailing off the scope (dew heater cables and camera ones) if i use it on the spotting scope that could get tangled when it slews etc, the polar scope wont be a problem as it doesnt move much.

Im planning on making it simple as possible as once i have set the brightness to what i think is best for my setup, i will measure the resistance on the variable resistor and substitute it for a normal resistor that can be wired and hidden on the supply cable to the LED, thus making it look just like a single cable with no electronics going to the scope to power the LED

Hope the above makes sense LOL

Dave

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After reading this post, I went into maplin to pick up the bits and pieces listed above.

But I got sidetracked by this little beauty for £3.00 by the checkouts:

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(It looks big here, but in reality its quite small)

You can unscrew the four little screws and pull out the mirror/led platform then angle it so it should shine into the polar scope hole. A bit a red nail varnish on the leds and it seems perfectly acceptable.

It has a proper on/off switch too and as its a wind-up one it seems dim enough to be useful without binding the scope markings and polaris with too much red.

Its by no means as pretty and I'll have to find a neat way to attach it to the mount, but I'll see how it works out tonight. My worry is that it will get enough light into the aperture with the mirror and leds angled 45 degrees and secured by black gaffer tape.

Besides, the wife has banned me from soldering after 'the great table cloth incident of 2004'....

Badgers

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Tested this just now, and the £3.00 maplin solution with some nail polish on the leds worked fantastic.

Secured with a some elastic strapping from an old headlamp, it is very small, secure and doesn't interfere with the mount's movement and can still be removed to be used as a hand-held red led torch.

Polaris was perfectly visible and the 45degree angling of the leds puts just enough light out to highlight the markings.

Badgers

PS: I'd recommend Rimmel "Coral Romance", gave me a very pleasing colour : )

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PS: I'd recommend Rimmel "Coral Romance", gave me a very pleasing colour : )

LOL -- is that your own or your wifes recommendation?

Well done with the mod, looks nice and simple and working well

Dave

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Hi All.

Couldn't get mine to work correctly and then found out that the guy i bought the mount from hadn't adjust the distance focus on the polar scope. Now some wise owl has shown me the error of my ways i will try it out. In the mean time i was frustrated about it not working and went back to Maplins and bought some more bits. I got a slightly wider battery box and a variable resistor so that i can fit it all in and dim the LED as needed. I will take pic's and post the new version on here when its finished. These will be the only pic's i will have taken with my new camera after the first try ended with blurry images not being able to polar align.

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