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

In summary, the speaker has recently finished their refractor telescope with an 80mm objective lens and 900mm focal length. They have been testing it during the day with a 25mm and 9mm eyepiece. However, when using the 25mm eyepiece, the image becomes blurry and they cannot get a clear image no matter what they do. They are wondering if there is a way to fix this, and have been advised to hold the eyepiece by hand to determine the necessary focuser travel and potentially shorten the tube length.
  • #1
Klause
4
0
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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  • #2
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.
 
  • #3
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!
 

1. What materials do I need to build a DIY refractor telescope?

To build a basic DIY refractor telescope, you will need a lens, a tube or frame to hold the lens, a tripod or mount, and some basic tools such as a ruler, drill, and screws. You may also need additional materials for more advanced features, such as a finder scope or motorized mount.

2. How much does it cost to build a DIY refractor telescope?

The cost of building a DIY refractor telescope can vary greatly depending on the materials and features you choose. A basic telescope can be built for under $50, while more advanced telescopes with additional features can cost several hundred dollars. It is important to research and plan your telescope build carefully to stay within your budget.

3. How difficult is it to build a DIY refractor telescope?

The difficulty level of building a DIY refractor telescope can range from easy to challenging, depending on your level of skill and experience with DIY projects. Basic telescopes can be built by beginners, while more advanced telescopes may require more technical knowledge and precision. It is important to carefully follow instructions and take your time during the building process.

4. How powerful is a DIY refractor telescope compared to a store-bought telescope?

The power and quality of a DIY refractor telescope can vary greatly depending on the materials and construction. In general, a high-quality store-bought telescope will have better optics and a higher magnification power than a DIY telescope. However, with careful planning and construction, a DIY telescope can still provide decent magnification and quality for amateur stargazing.

5. Can I see the same things with a DIY refractor telescope as I can with a store-bought telescope?

The objects and phenomena that can be seen with a telescope depend on its magnification power and the quality of its optics. A DIY refractor telescope may not have the same level of magnification or clarity as a store-bought telescope, but it can still provide views of the moon, planets, and some deep-sky objects such as star clusters and nebulae. The quality of the view may also be affected by light pollution and atmospheric conditions.

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