Out of Alignment

[Stargazer 2013]

Hi guys

I think I may have a problem.For a week now my red dot finder seems to be way off.I have tried to get it in the center but as you can see from the pic the dot is about 7 on a clock,surely if it was out it would be either same level ?

I hope  I don't need to collimate my new Newtonian scope?

Thanks for looking

[Stargazer 2013]

By the way this is where I need the red dot to get anything centered in my scope..

[ronin]

You need to point the main scope at something stationary, but a long way off (2 miles or more), and adjust the RDF.

Problem that occurs is that there is insufficent adjustment in an RDF to align it to a scope. In this case you need to shim the base of the RDF to get the RDF to sit better for your scope.

The "mistake" made is assuming that an RDF will magically fit ideally on any scope and that the adjustment required is within the range of the RDF.

You diagram indicates insufficent upwards and right hand adjustment is present, if the adjustment is at the maximum possible then you need to add shims to the base plate of the RDF. You probably will have to make any shims yourself. Suggest locating a model making shop for possible suitable material.

[Stargazer 2013]

Thanks for reply,yes I understand what you say. I will have to find something to shim it,maybe soft cardboard will do the trick

[swag72]

Thanks for reply,yes I understand what you say. I will have to find something to shim it,maybe soft cardboard will do the trick

I would imagine that you will be better off with something less moveable than soft cardboard. In my shimming days I used a cut up Coke can - It worked a treat and was thin enough to bend into quite small deep squares if needed.

[Alien 13]

+1 for the coke or beer can shim its a thing of beauty.

[Stargazer 2013]

I have used firm slim card and it's now tight but I can't really set a focus on anything ,when looking through the scope with no lens I see this.

Best diagram I can do lol..I am sure this is ok?

[Stargazer 2013]

The orange thing is my eye and my pupil is right in center of the small circle

[Stargazer 2013]

I have used firm slim card and it's now tight but I can't really set a focus on anything ,when looking through the scope with no lens I see this.

Best diagram I can do lol..I am sure this is ok?

Can anyone please tell me if this looks ok? I am sure it looks fine but not 100%

[brantuk]

Looks like it's out of collimation to me if that's a true representation.

You need to center the secondary so everything looks circular with your eye in the middle, and such that you can see all three mirror clips on the primary when looking down the focuser tube.

Then you can tweak up the secondary using the collimation screws, followed by tweaking up the mirror tilt using the primary collimation screws. Do you have a collimation tool? I use the Hotech laser - but you can choose from about three different methods depending what you prefer. Hth

[happy-kat]

When ligning up/adjusting your red dot finder you use an eyepeice in the focuser, I used a tree furthest away from my garden was not two miles but so far the alignment has been OK.

[Moonshane]

if you can travel to me (I am in Stockport) then next clear night, I would happily help / show you how to collimate / aign things. it's easy when you see how.

[Stargazer 2013]

if you can travel to me (I am in Stockport) then next clear night, I would happily help / show you how to collimate / aign things. it's easy when you see how.

Hi,I am unable to travel at the moment due to illness,thanks for the offer though,think I need to do this myself so I can learn,bit nervous though lol

When ligning up/adjusting your red dot finder you use an eyepeice in the focuser, I used a tree furthest away from my garden was not two miles but so far the alignment has been OK.

nearest trees are only 100 yards from me.

Looks like it's out of collimation to me if that's a true representation.

You need to center the secondary so everything looks circular with your eye in the middle, and such that you can see all three mirror clips on the primary when looking down the focuser tube.

Then you can tweak up the secondary using the collimation screws, followed by tweaking up the mirror tilt using the primary collimation screws. Do you have a collimation tool? I use the Hotech laser - but you can choose from about three different methods depending what you prefer. Hth

Pardon

I do get a bit of white colour while looking through all of the eyepiecesI have so yes it could need collimation

[Moonshane]

no worries. collimation is easy enough when you have done it a few times.

 take a slightly different approach to many online guides

http://stargazerslounge.com/topic/197640-collimation-and-star-hopping/