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If you have eye-relief problems with that 9mm eyepiece, you can do three things.
1. Buy longer eye-relief eyepieces. I use TMB ones which can be found for around $70 on Ebay from the UK,
or
2. Get an 18mm eyepiece and use it with a 2X barlow, or find a 2.7X barlow (they do exist) and use it with your 25mm eyepiece - this way you get the equivalent to a 9mm eyepiece but with longer eye-relief,
or
3. Take off your eyeglasses when using the 9mm. With high powered eyepieces you get small exit pupils, which generally aren't affected as much by vision defects. Sometimes with the very small eyerelief eyepieces, you have to take their rubber eye-guard off to be able to see the entire field. The problem then becomes how long one's eyelashes are - either everything is fine, or you find yourself often having to clean smudges on the eyepiece lens.
Certainly, if you read equipment books like "The Backyard Astronomer's Guide" by Dickenson &Dwyer, they tend to favour using Barlows and Powermates for high power views. But I personally have never been that fond of them, despite using Televue Barlows and a Powermate.
Regards,
Renato
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