Guidescope Crosshairs made from my Daughters Hair!
Today I decided to put some crosshairs into the guidescope I am using for visual aligning whilst imaging.
After several experiments I discovered that crosshairs need to be located in the EP or they are just blurrs! I worked out which EP was better for my aligning and then the construction started.
I made a small ring out of a lid from a bottle of incense oil. I acheived this by hacksawing the top of the lid off, which then gave me a band. Then I cut down the side of the band and kept cutting until the band was small enough to fit up inside the EP I chose. (1.25" 25mm Wide angle)
Then using a craft knife I pushed the blade into the edge of the band to create 2 parallel nicks. then I rotated the band 90 degrees and made 2 more parallel nicks.
I then asked my 14yo daughter for 4 hairs ("You're wierd Dad!") and I placed them into the parallel nicks in the band and pushed the band into the EP.
It works a treat!
The hairs aren't exactly parallel or at 90 degrees to each other but when you work in such a small scale it's pretty hard to get it dead accurate. My next trick is to work out how to illuminate them!
The reason I used parallel hairs is so I created a box in the centre to place the Astro object.
Pics below are:
1. the EP I used,
2. the crosshairs in the EP
3. The view through the scope.
Last edited by ballaratdragons; 01-01-2006 at 08:43 PM.
Blast It!! Dag Nab it! and all those other cuss words!!!!
There was a hole in the clouds and I just went out and tried my new Crosshairs to see if an object was easy to see in the box in the middle of the crosshairs.
Ive attached an image of my illuminated finder. The bit on the left is a red led and battery holder.
This screws into the hole in the side of the eyepiece to place the led just behind the plane of the Xhairs.
My Orion 8x50 finder has non-illumated cross hairs in the eyepiece.
As you have found - useless (except with a bright background).
Yep Chris.
I have hardly ever seen the crosshairs in my GS Finderscope. Makes centreing in the FOV almost impossible. Same problem with this one I have just made.
Quote:
Originally Posted by Rajah
For a very simple solution for the 8 x 50 finder......
Laurie, sounds OK for planets & other brighter stuff but I don't think I will be able to see those faint fuzzies with a slight red glow on the objective lense.
I can hardly see them without the glow.
Quote:
Originally Posted by Vingo
so how are you going to illuminate the hair? drill a hole in the side for a led?
Dunno mate! I'm stumped with electronics.
Seems like I will have to get an illuminated Reticle EP. I had a look through Robins at Camp and it was excellent!
Ken lad, why not give it a go? Mine works a treat. Just get the feeblest red glow inside the finder... just enough to make out the X hairs against the objective lens. If it's too bright, simply increase the value of the resistor to make the LED dimmer.
When I modify a Telrad, I use an LED & 100k resistor to show when power is applied. The LED only gives a very soft glow. That is all you require.
HTH. L.
ps. What sort of finder are you using?
*My Finder is the standard GS 8x50 toy Pirates scope that they fit to all GS Dobs.
The finder has the standard crosshairs in it.
*My Guidescope I have no idea. Bert made it from an 84mm objective lense and PVC pipe with a 1.25" Prism diagonal and I use a 25mm wide Angle EP in it. This is the EP I placed the 'Hair' crosshairs in. The Focal length is approx 350mm. Bert (Avandonk) may be able to tell you more.
hope you get this to work Ken, I really admire your ingenuity and do-it-yourselfer and work-with-what-you-got attitude
Thanks Rob.
It isn't just a matter of have to coz I don't work and can't afford to buy things either. Even when I was working I liked to do things myself. I have a way of making items out of the strangest bits of junk in the shed! Even though I prefer to make things myself, unfortunately I am forced to these days.
Laurie's idea will work mate! But if you have it variable brightness it will work heaps better. You've seen my idea...yes? A polar alignment scope illuminator out of my EQ5 mount screwed into a plastic dew shroud on my finder. (which IS variable brightness) runs off a few watch batteries. Seeing its variable brightness, I can use it on faint fuzzies as well as planets.
I would imagine they would be pretty cheap if you could get one.
I will have to give Lauries idea a go but like you said, make it variable. If possible I will illuminate both finder & guidescope!
I'm no good at electronics (resistors & such) but I can wire in a Potentiometer to anything. I don't have any Red Leds but I will come up with something from the shed.
Here it is. Home-made dew shield (thin plastic) & the illuminator screws in. I just made a hole in the shield slightly smaller than the thread on the illuminator, then just screw it in & it will cut it's own thread in the dew shield.
The illuminator itself: the knurled knob on the end of it is the variable brightness control. Turn clock-wise to dim.
Luckily for me I had this item sitting in the EQ5 mount doing nothing I guess! (I don't bother polar aligning this way) Your not so lucky.
You never know, one of the guys on this forum may have a spare one kicking about?
But yeah, by all means have a go at making one yourself...(cheaper)
That looks easy John. Thanks. I wouldn't have thought of putting the red light in front of the objective lense!!!!
I've only ever seen Lauries 'Internal' version where the light it fitted inside the OTA of the finder. This outside method will make it a lot easier to make and won't damage the finder or Guidescope tube. I shall go attempt something now! Ta!
Guidescope Crosshairs made from my Daughters Hair!
