<p>I own a tabletop Sky-Watcher Heritage 130mm tabletop Dobsonian with a f/5 130mm aperture and 630mm focal length. 25mm wide-field eyepiece and a 10mm narrow-angle eyepiece. Last night I took it out to see the crescent moon. Initially, I used the 25mm wide-field on focused on the Moon and the image came out properly with minimal blur. However, when I replaced the 25mm with the 10mm narrow-angle eyepiece, the image was really blurred, making the moon a blob. Am I doing something wrong?</p>

CC BY-SA 4.0
2022-05-06T14:37:24.117Z
Is this the first time you experience this issue ?
Kavin Ishwaran
CC BY-SA 4.0
2022-05-06T14:38:26.350Z
@KavinIshwaran I got this telescope last week, first time using the narrow-angle eyepiece.
WarpPrime
CC BY-SA 4.0
2022-05-06T14:41:02.060Z
What is focal length and what is the clear apperture of the telescope? That is: is the 10mm producing useless magnification, magnifying only the diffraction rings (which sadly is frequently found for cheaper telescopes for one of the shipped eye pieces)?
planetmaker
CC BY-SA 4.0
2022-05-06T14:45:42.613Z
https://astronomy.stackexchange.com/questions/45230/not-getting-quality-images-in-telescope or https://astronomy.stackexchange.com/questions/20981/whats-the-useful-magnification-for-a-scope-with-70mm-objective-lens/21998#21998 might give some answer
planetmaker
CC BY-SA 4.0
2022-05-06T14:46:11.147Z
This scope comes with a 650mm Focal length, I own a similar telescope, the astromaster 130eq which has the same 650mm focal length and the 10mm should be perfectly fine with observing moon. I see that this scope has no focusing knob, instead it comes with a "wheel" have you checked with the focusing wheel ? Is that adjusted in focus ?
Kavin Ishwaran
CC BY-SA 4.0
2022-05-06T14:49:39.450Z
@KavinIshwaran Instructions manual said that the focus wheel is behind the eyepiece mount. It turns but doesn't seem to have any improvement. I might be reading the manual wrong though...
WarpPrime
CC BY-SA 4.0
2022-05-06T14:58:55.200Z
There are some a few possible things that can go wrong with this type of telescope. firstly, lift up the secondary mirror assembly to the maximum, even a slight difference in height of the secondary mirror assembly will affect your image, secondly the focusing knob, focus the moon and experiment with all possible focusing point with the focusing wheel. Does this scope does well with terrestrial targets ?
Kavin Ishwaran
CC BY-SA 4.0
2022-05-06T15:01:04.597Z
@KavinIshwaran The secondary mirror assembly is raised to the maximum height and the focusing knob does nothing, unless I am turning the wrong thing. The scope claims to be good for terrestrial targets but I can't verify yet as I've only viewed the Moon. The place that I live hasn't gotten clear nights yet.
WarpPrime
CC BY-SA 4.0
2022-05-06T15:09:59.430Z
The focusing knob is the hexagonal thing in the eyepiece fitting. If you can view the moon with an unaided eye, then definitely you should get good image in the scope. Atleast an image that is hazy but gives enough details about the moon
Kavin Ishwaran
CC BY-SA 4.0
2022-05-06T15:12:14.400Z
@KavinIshwaran Looks like I got the focusing knob correct. Like I said in the original question, the 25mm eyepiece gives clear images but the 10mm piece is extremely blurry.
WarpPrime
CC BY-SA 4.0
2022-05-06T15:17:56.323Z
Let us [continue this discussion in chat](https://chat.stackexchange.com/rooms/136103/discussion-between-kavin-ishwaran-and-fasterthanlight).
Kavin Ishwaran
<telescope><amateur-observing><eyepiece>
Why does my 10mm eyepiece produce blurry images?
WarpPrime
# Why does my 10mm eyepiece produce blurry images?

(Asked by: username_0 on 2022-05-06)

I own a tabletop Sky-Watcher Heritage 130mm tabletop Dobsonian with a f/5 130mm aperture and 630mm focal length. 25mm wide-field eyepiece and a 10mm narrow-angle eyepiece. Last night I took it out to see the crescent moon. Initially, I used the 25mm wide-field on focused on the Moon and the image came out properly with minimal blur. However, when I replaced the 25mm with the 10mm narrow-angle eyepiece, the image was really blurred, making the moon a blob. Am I doing something wrong?

**Tags:** telescope, amateur-observing, eyepiece
> **Comments:**
> **username_1**: Is this the first time you experience this issue ?  
> **username_0**: @KavinIshwaran I got this telescope last week, first time using the narrow-angle eyepiece.  
> **username_2**: What is focal length and what is the clear apperture of the telescope? That is: is the 10mm producing useless magnification, magnifying only the diffraction rings (which sadly is frequently found for cheaper telescopes for one of the shipped eye pieces)?  
> **username_2**: https://astronomy.stackexchange.com/questions/45230/not-getting-quality-images-in-telescope or https://astronomy.stackexchange.com/questions/20981/whats-the-useful-magnification-for-a-scope-with-70mm-objective-lens/21998#21998 might give some answer  
> **username_1**: This scope comes with a 650mm Focal length, I own a similar telescope, the astromaster 130eq which has the same 650mm focal length and the 10mm should be perfectly fine with observing moon. I see that this scope has no focusing knob, instead it comes with a "wheel" have you checked with the focusing wheel ? Is that adjusted in focus ?  
> **username_0**: @KavinIshwaran Instructions manual said that the focus wheel is behind the eyepiece mount. It turns but doesn't seem to have any improvement. I might be reading the manual wrong though...  
> **username_1**: There are some a few possible things that can go wrong with this type of telescope. firstly, lift up the secondary mirror assembly to the maximum, even a slight difference in height of the secondary mirror assembly will affect your image, secondly the focusing knob, focus the moon and experiment with all possible focusing point with the focusing wheel. Does this scope does well with terrestrial targets ?  
> **username_0**: @KavinIshwaran The secondary mirror assembly is raised to the maximum height and the focusing knob does nothing, unless I am turning the wrong thing. The scope claims to be good for terrestrial targets but I can't verify yet as I've only viewed the Moon. The place that I live hasn't gotten clear nights yet.  
> **username_1**: The focusing knob is the hexagonal thing in the eyepiece fitting. If you can view the moon with an unaided eye, then definitely you should get good image in the scope. Atleast an image that is hazy but gives enough details about the moon  
> **username_0**: @KavinIshwaran Looks like I got the focusing knob correct. Like I said in the original question, the 25mm eyepiece gives clear images but the 10mm piece is extremely blurry.  
> **username_1**: Let us [continue this discussion in chat](https://chat.stackexchange.com/rooms/136103/discussion-between-kavin-ishwaran-and-fasterthanlight).  

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## 0 answers

