Confusion with focuser Skyliner 250px

[Brunty12345]

Hello,

I have a question regarding the focusing. For some reason, I cannot seem to gain focus on any of my eyepieces without combining the 1.25" and 2" adapters. If I use just the 1.25" alone, I cannot gain focus, but if I attach that to the 2" focuser adapter and then insert it into the focuser, I am able to gain focus? Is this a collimation issue? Or is it something specific to this scope? It is a Skywatcher Skyliner 250PX. It seems as if I cannot draw the focuser out far enough with just the 1.25 attached, if I have both adapter attached I seem to be able to bring out the focuser far enough to focus. Thanks.

Edited May 11, 2020 by Brunty12345

[johninderby]

You might want to watch this Youtube vid which shows a Skywatcher 200p dob but works the same as the 250px.

 

[Brunty12345]

Update: as I look through the eyepiece at a star, all i can see it inside my tube, with the 4 lines and circle in the middle, never reaching focus. Any help is appreciated. 

[Ricochet]

1 hour ago, Brunty12345 said:

I cannot seem to gain focus on any of my eyepieces without combining the 1.25" and 2" adapters. If I use just the 1.25" alone, I cannot gain focus, but if I attach that to the 2" focuser adapter and then insert it into the focuser, I am able to gain focus?

Is this in the day time on terrestrial objects? The closer an object is, the further out the eyepiece will need to be in order to focus. If you are trying to focus on terrestrial targets (which the scope is not designed to do), then you will need some sort of extension tube (i.e. an additional adaptor) in order to focus.

11 minutes ago, Brunty12345 said:

Update: as I look through the eyepiece at a star, all i can see it inside my tube, with the 4 lines and circle in the middle, never reaching focus. Any help is appreciated. 

This means you are way out of focus. Assuming my earlier assumption was correct, remove the additional eyepiece adaptor so that you only have either the 1.25" or 2" adaptor in the focuser. This should allow the telescope to focus properly. When you turn the focuser wheel, which way does the focuser move to make the circle of light smaller? This is the direction you need to continue to go to achieve focus.

1 hour ago, Brunty12345 said:

Is this a collimation issue?

Absolutely not.

[johninderby]

One thought. The eyepiece adapters come stacked together but that’s just for shipping and not to be used that way.

Have a look at the focuser in the how to vid.

Edited May 11, 2020 by johninderby

[Brunty12345]

1 minute ago, Ricochet said:

Is this in the day time on terrestrial objects? The closer an object is, the further out the eyepiece will need to be in order to focus. If you are trying to focus on terrestrial targets (which the scope is not designed to do), then you will need some sort of extension tube (i.e. an additional adaptor) in order to focus.

This means you are way out of focus. Assuming my earlier assumption was correct, remove the additional eyepiece adaptor so that you only have either the 1.25" or 2" adaptor in the focuser. This should allow the telescope to focus properly. When you turn the focuser wheel, which way does the focuser move to make the circle of light smaller? This is the direction you need to continue to go to achieve focus.

Absolutely not.

I had just the 1.25" adapter in earlier when I had it out during the night sky, and either way I extended it all the way in or all the way out of focus, the weird inside tube view was still present. I tried finetuning the focuser to no avail. I cannot remember entirely in regards to which way makes the circle of light smaller, sorry.

[Victor Boesen]

I have the exact scope you're talking about and I've always been combining the two parts, extension tube and 2" to 1.25" to reach focus. It's not a problem. That's just how it is with some scopes. Keep in mind that a longer draw tube on the focuser would cover up more of the mirror and therefore block some of the light entering the scope. That's why you use an extension tube instead.