It could just be you’re trying too much magnification. “mass market” telescopes often come with one and in some cases two barlow lenses. Generally speaking, these will rarely be useful for observing because the mounts those scopes come with usually aren’t sturdy. Also, you need a night with very stable air (good “seeing conditions”) to use high power.

If that’s not it, odds are the problem is too much distance between the eyepiece and the primary mirror. The question is Why?

Perhaps you’re using an extension you don’t need.

It’s also possible someone may have replaced the original focuser with one that’s too tall, or the collimation screws for the primary mirror could be backed out too far. It’s also possible somebody took it apart and put it together wrong.

In any case, someone who is experienced with the type of scope you have will probably be able to identify the problem quickly. If it’s simple they may be able to help you fix it on the spot. If it’s more involved, they can at least tell you what needs to be done so you can do it at home later. Mark H

It sounds to me like the focuser is not assembled properly, or the eyepieces that you have are not matched to the focuser - or perhaps you are using a Barlow improperly where it shouldn’t be used. Where did you buy this scope (hopefully, you bought it new). I think you should contact the dealer / seller and see if he can help you. If not, please provide more details at this site, like:

1. What brand of scope is it?
2. What diameter eyepiece / focuser are you using?
3. Do you have a Barlow (if so, leave it out)?
4. Can you provide any pictures of what you are dealing with?

We can probably help you here, but only if we have enough info. If you have a reputable dealer, he should be able to get it working in a few minutes, or replace it. Larry454