Tips for Those Wearing Glasses

Some of you that wear glasses may notice that it makes astronomical observing more difficult, sometimes even aggravating. These tips from Michael Gilmer, a fellow member of the Cloudy Nights forum, will make your observing sessions work out much better and more enjoyable. Michael Gilmer is an amateur astronomer, and also sells meteorite pieces at his company Galactic Stone and Ironworks. So if you wear glasses, try Mike's tips next time you go out to the telescope.

1. Consider purchasing a pair of dedicated observing glasses. Do NOT use polycarbonate lenses, plastic lightweight lenses, or any material other than optical-grade glass. Glass is heavier and is a special-order item at some eyeglass retailers. It's worth the extra expense and weight because it's more scratch resistant than the lightweight stuff and because it introduces fewer aberrations into the view. Keep these observing glasses in your eyepiece case and only wear them while stargazing.
   
   
2. Treat your eyeglasses like you would a part of your scope. Your eyeglasses lenses are glass in the light path, just like the primary/objective or your eyepieces. Clean them very carefully. In fact, clean them the same way you would your objective lens or primary mirror. Wash them with a brisk stream of water to remove particles that may scratch and then carefully pass a series of clean/virginal cotton cloth or tissue paper over them, disposing of the cloth/paper after each pass. A scratch on your eyeglass will introduce negative refractive effects and visual aberrations into your view, just the same as a scratched primary, objective or eyepiece element.
   
   
3. When purchasing observing-only glasses, make sure they have anti-reflective coatings on them. The Zeiss-branded anti-reflection coating is actually a very nice multi-coating. This will help cut back on reflections from your eyeglass lens to the eyelens of your eyepiece - which can be annoying.
   
   
4. Get frames that hug the face. The closer to your face, the better. That extra millimeter or two of eye relief can make the difference between seeing the full field with your glasses on, and only seeing part of the field - if the eye relief on a given eyepiece is marginal.
   
   
5. This one sounds obvious, but I suspect many of us have done it a few times - be careful when leaning down to look into the eyepiece if the eyepiece doesn't have a rubber eyecup. Some eyepieces, like the older RKE's, do not have a rubber eyecup, so the metal rim of the eyepiece housing can nick/ding/scratch your eyeglass lens if they come into contact.
   
   
6. Don't use those "lens cleaning cloths" that are saturated with a "special cleaning solution" that you see at the drugstore. Regardless of what promises the package makes, it's not worth it. Typically these leave an oily residue that is hard to remove and leaves sleeks on your lenses. Use water.

Regards and clear skies,

Mike G