Finderscopes:Best of Both Worlds? for free!!

[mike-h]

This is an idea that I hope is good and I want to share it with any one who finds pointing a scope tricky.

Opinion is divided over which type of finderscope works best.

Some people prefer Red Dot or telrads.

Others prefer the magnifying type (straight or diagonal)

Certainly looking into the magnifying type AND seeing the whole sky at the same time is tricky.

The ones that magnify (like my 9x50) have a small FOV (field of view) that makes it tricky to initailly get objects in the FOV.

Red dot finders often don't magnify. This makes it easier to locate the object initially but doesnt allow for the finetuning of location that the magnifyers do.

Here is a cheap way for beginners to have the BEST OF BOTH WORLDS.

It works like a telrad crossed with a red dot finder

This is the best gadget for my 250px dob and i made it myself.

Time 20-30 mins

Cost £nothing

It makes it a heck of a lot easier to locate objects in the finder and eyepiece.

You need:

a card tube e.g. loo roll (i used some of the tube from wrapping paper cos it was longer and narrower)

sellotape

white cotton

blutak

a red light (eg red led torch).

See below for photos

Cut the middle out of the tune using a knife (See the fotos).

Make 2 sets of crosshairs out of the cotton and sellotape.

Use 2 big blobs of blutak to fix it to your 9x50.

Once attached to the 9x50, you can align it in daylight by looking at a distant object and by squeezing or flattening the 2 blobs of blutak. (you may want to cover the card completey with sellotape to make it water resistant)

HOW TO USE IT

To use it you need to crouch down at the back end of your dob (by the primary mirror).

From the back of your scope, use one hand to shine your red torch at the finder/card tube (at an angle so that both sets of crosshairs light up) . Use the other hand to move the scope towards the object you want to see (eg m42).

Over lap the two sets of crosshairs with the object. Finetune with a very quick look thru the 9x50 finderscope.

It can be surprisingly accurate if you get the blutak blobs correct (it wil get an object in the FOV of a low powered eyepice without even needing the 9x50 at all).

It saves a lot of neckache and potential trapped nerves!!

Give it a try. 20-30 minutes and its free.

Hope it helps.

Mike H

Attached Thumbnails

[mike-h]

Hopefully I'll be able to put it to good use tonight along with the wixey.

Mike H

[DemonicOmelette]

That's awsome! Well done!

-eli

[dark knight]

Excellent and very resourceful.

[The Warthog]

That is a good idea. If you made it with a piece of ABS tubing, it would be even more durable. It won't fog up, either.

[barkis]

Anything that saves money is worthwhile. That's a great piece of resourcefullness. Nice one.

Ron.

[Chris Stacey]

This might sound like a stupud question Mike, but what's the need for cutting the center section of the tube out?

[mike-h]

Originally I cut the middle of the tube so i could see as much sky as possible when my eye was close to the tube (if the tube is closed then all you see if a small circle of sky at the other end- if its open you can see nearly all the sky even when your eye is close to the tube). I then realised it worked better if you are further away from the tube eg close to the back of the scope. The missing section then became handy as i could see two concentirc circles (c-shapes actually) when at the back of the scope (also the cotton was hard to see against a dark sky). Then i decided to use the red torch and was chuffed with how the cotton lights up. Also it turned out that cutting out the middle section makes it easier to light up both sets of crosshairs i.e you can shine the torch at an angle. It all worked out by accident!

Mike H

[Chris Stacey]

Originally I cut the middle of the tube so i could see as much sky as possible when my eye was close to the tube (if the tube is closed then all you see if a small circle of sky at the other end- if its open you can see nearly all the sky even when your eye is close to the tube). I then realised it worked better if you are further away from the tube eg close to the back of the scope. The missing section then became handy as i could see two concentirc circles (c-shapes actually) when at the back of the scope (also the cotton was hard to see against a dark sky). Then i decided to use the red torch and was chuffed with how the cotton lights up. Also it turned out that cutting out the middle section makes it easier to light up both sets of crosshairs i.e you can shine the torch at an angle. It all worked out by accident!

Mike H

I see, it makes sense now.