Is my DIY refractor telescope out of focus with the eyepiece?

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SUMMARY

The discussion centers on a DIY refractor telescope with an 80mm objective lens and a 900mm focal length, experiencing focus issues when using a 25mm eyepiece. The user reports clear images without the eyepiece but encounters blurriness when it is attached. The advice provided suggests that the tube length of 998mm may be too long, requiring shortening to achieve proper focus. The recommendation includes manually adjusting the eyepiece to determine the necessary travel for the focuser.

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Klause
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So, I recently finished my refractor telescope. I have a objective lens of 80mm and focal length of 900mm, 70mm focuser, tube length is 99.8 cm. I have a 25mm and 9mm eyepiece.

I have been testing it out during the day time, on objects I can easily spot. First I use no eyepiece to focus on an object, then I use the 25 mm eyepiece to view the object.

So here's the problem: Without the eyepiece and just looking through the focuser I can see objects as I should inverted and clear just like it should be. But once I put the 25 mm eyepiece, it just turns completely blurry and empty (since it's daytime it just turns bright white). So i use the focuser to try to get a clear image, but no matter what I do I cannot get an image. I have tried several different object at different distances.

I'm just wondering if there's something I can do to fix this.
Thanks for any advice.
Cheers!
 
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Try holding the eyepiece by hand and see how far out you need to go to bring it into focus. That will tell you how much travel your focuser needs. Sounds like you have too much travel. Your tube length is 998 mm and your objective focal lenth is 900mm. So you probably need to shorten the tube to reach focus.
 
Chronos said:
Try holding the eyepiece by hand and see how far out you need to go to bring it into focus. That will tell you how much travel your focuser needs. Sounds like you have too much travel. Your tube length is 998 mm and your objective focal lenth is 900mm. So you probably need to shorten the tube to reach focus.
Thanks. I will try this!
 

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