Talk:Optical telescope

Lenses and Filters

Dark glass is not safe enough, see Arc welding lenses, see Telescope solar lenses.

was added as correction

Please either say nothing, refer to manufacturer instructions, or correctly say it is a special solar lense. Dark glass alone will cause blindness over time.

This is also true for cheap* sunglasses but don't tell anyone!

(Cheap sunglasses use dark material and the eye feels safe but is actually being damaged at wavelengths that do not cause pain. A doctor would suggest squinting eye lids instead of relying on cheap sunglasses for eye pain situations)

Never look at arc welding using dark sunglasses. — Preceding unsigned comment added by 72.219.202.186 (talk) 14:51, 9 April 2014 (UTC)

Schematic of a Keplerian refracting telescope

Isn't this diagram utterly useless? It completely lacks clear labelling,and for the life of me,I can't figure out what difference between the red and black lines are.

Perhaps it should be clearly labelled,so the people who lack knowledge about telescopes(i.e,your target audience) should be able to gain knowledge about telescopes. As it is now,I think it is quite useless.182.181.152.111 (talk) 06:33, 28 April 2014 (UTC)

Inverted, everted

I found no evidence in the OED, in Wiktionary, or elsewhere that either "everted" or "reverted" means "reversed left to right". Maybe I read the entries too hurriedly. Is there another source?

It confusing to say that "telescope designs produce an inverted image" and at the same time "the image is both inverted and reverted". This gives "inverted" two incompatible meanings, one of which is defined as the other plus something else. While it could be argued from dictionary entries that "inverted" could mean either of these, the reader should leave with only one meaning for this technical term in the telescope context. 129.132.209.199 (talk) 23:42, 7 June 2014 (UTC)

Afocal system

Should it be mentioned somewhere that optical telescopes are afocal systems? Shmayo (talk) 13:29, 12 March 2015 (UTC)

"Directly proportional"

Hi folks. As an astronomy professor, I thank you all for your contributions to making this article better. I made a change in the introduction, to clearly state the proportionality between a telescopes aperture and its light gathering power and its resolving power. Resolving power, as previously stated in the article is "directly proportional" to aperture, in the mathematical sense:

https://en.wikipedia.org/wiki/Proportionality_(mathematics)#Direct_proportionality

Light gather power of course is proportional to a telescope's area, and thus to at the size of its aperture *squared*, as state later in the article.

Substar (talk) 17:25, 20 September 2019 (UTC)Substar