<p>The <a href="https://www.celestron.com/products/nexstar-102-gt-computerized-telescope" rel="nofollow noreferrer">manual</a> says the original eyepieces had 1¼ inch barrels and focal lengths of 25 mm, 20 mm, 12.5 mm, 8 mm (all reasonable) and 4 mm (not so much).
If I had to pick two replacements for a beginner, I'd get a 25 mm and a 10 mm.
You can probably get an entry-level Plössl by Meade, Celestron, or Orion for US \$20-25 from the Cloudy Nights <a href="https://www.cloudynights.com/classifieds/category/13-eyepieces/" rel="nofollow noreferrer">classifieds</a> or \$30-40 new.</p>

CC BY-SA 4.0
2020-09-01T21:49:15.377Z
2020-09-01T21:49:15.377Z
Mike G
<p>For the moon, you would normally not need a very high power eyepiece. 20mm would seem sufficient, on a telescope with a focal ratio of f/9.8. As this is a refracting telescope, if you get too much magnification you end up just magnifying the chromatic aberration. Smaller numbers mean more magnification.</p>
<p>Planets would require more magnification, on the other hand, fuzzy deep sky objects are easier to see with lower levels of magnification.</p>
<p>Amazon or any other major online retailer would be fine.</p>
<p>All the reviews say that this is a nice, easy to use telescope, but not that the tripod is rather lightweight and shaky. If that is an issue, you might try adding weight to it to the tripod to stabilise it.</p>

CC BY-SA 4.0
2020-09-01T21:11:40.910Z
2020-09-01T21:11:40.910Z
James K
<p>Good day folks.
My Grandson would like to start using this Telescope Celestron Nexstar GT102, has been in the basement for years, and unfortunately, we appear to have misplaced the eyepieces.</p>
<p>Just wondering if anyone had any insight what would be a reasonable eyepiece for me to buy so he can see the moon at the very least decently enough.</p>
<p>Also, would Amazon be a good start for eyepieces that way I can get them fairly cheap and quick.</p>
<p>Thanks in advance</p>

CC BY-SA 4.0
2020-09-02T04:08:29.723Z
Was the eyepiece end of the telescope closed with a cover all of this time, or was it left open? If open, you might want to also ask a separate question about how to deal with dust, bugs, and anything else that may have gotten into it!
uhoh
<the-moon><star-systems>
Celestron Nexstar 102GT
SteveT
# Celestron Nexstar 102GT

(Asked by: username_0 on 2020-09-01)

Good day folks.
My Grandson would like to start using this Telescope Celestron Nexstar GT102, has been in the basement for years, and unfortunately, we appear to have misplaced the eyepieces.

Just wondering if anyone had any insight what would be a reasonable eyepiece for me to buy so he can see the moon at the very least decently enough.

Also, would Amazon be a good start for eyepieces that way I can get them fairly cheap and quick.

Thanks in advance

**Tags:** the-moon, star-systems
> **Comments:**
> **username_1**: Was the eyepiece end of the telescope closed with a cover all of this time, or was it left open? If open, you might want to also ask a separate question about how to deal with dust, bugs, and anything else that may have gotten into it!  

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## 2 answers

### Answer by username_2 on 2020-09-01. Score: 4

The [manual](https://www.celestron.com/products/nexstar-102-gt-computerized-telescope) says the original eyepieces had 1¼ inch barrels and focal lengths of 25 mm, 20 mm, 12.5 mm, 8 mm (all reasonable) and 4 mm (not so much).
If I had to pick two replacements for a beginner, I'd get a 25 mm and a 10 mm.
You can probably get an entry-level Plössl by Meade, Celestron, or Orion for US \$20-25 from the Cloudy Nights [classifieds](https://www.cloudynights.com/classifieds/category/13-eyepieces/) or \$30-40 new.


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### Answer by username_3 on 2020-09-01. Score: 2

For the moon, you would normally not need a very high power eyepiece. 20mm would seem sufficient, on a telescope with a focal ratio of f/9.8. As this is a refracting telescope, if you get too much magnification you end up just magnifying the chromatic aberration. Smaller numbers mean more magnification.

Planets would require more magnification, on the other hand, fuzzy deep sky objects are easier to see with lower levels of magnification.

Amazon or any other major online retailer would be fine.

All the reviews say that this is a nice, easy to use telescope, but not that the tripod is rather lightweight and shaky. If that is an issue, you might try adding weight to it to the tripod to stabilise it.


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