What is Reddit's opinion of 2 Inch 32mm -Plossl Eyepiece Fully Multi-Coated for Astronomy Telescope?

From 3.5 billion Reddit comments

Great!

The Erfle-type works okay with F/6 aperture ratio telescopes. Toward the outer field, sharpness decreases slightly.

You will also notice that toward the outer field the stars will be elongated. Coma. Coma is not eyepiece related but happens in "fast" aperture ratios. .

In F/6 it's not as drastic. It is more severe in F/5 or even F/4. https://imgur.com/a/lzlNKnd

 

For the 8" F/6 dobsonians erfle are a decent choice and do not break the bank.

The SWAN Erfle are more expensive but are pretty good.

Generic Erfle cost significantly less and aren't quite as good.

Avoid the Orion Deepview as they've a relaitvely small field. E.g. the 28mm Deepview doesn't show more than a cheap 32mm Plössl 1.25" eyepiece can :-)

 

• Overview eyepiece field of view simulation

  • http://blog.pixelgiraffe.com/wp-content/uploads/2020/04/1200-overview-eyepieces.png

• A 40mm eyepiece will give you 6.67mm exit pupil

  • (http://blog.pixelgiraffe.com/wp-content/uploads/2020/07/exit-pupil-small.png) on the F/6 telescope. This only works if you're at a truly dark site (Namib desert for example ;-))

 

Check what the limiting magnitude at your observing location is in order to decide what the eyepiece's maximum focal length you can use is.

• You can do that by checking what the dimmest star is you can see after letting your eyes adjust for half an hour (no phone, lights...).

  • https://darkskydiary.wordpress.com/2012/01/20/naked-eye-limiting-magnitude-assessing-sky-brightness/
  • http://spiff.rit.edu/classes/phys301/extra/lim_mag/lim_mag.html

 

So usually you'll do better with a 30-36mm 65-72° Erfle-type.

• SWAN

  • https://agenaastro.com/william-optics-33mm-swan-eyepiece.html

• "Generic"

  • https://agenaastro.com/gso-30mm-superview-eyepiece.html (Out of Stock, you'll find 32mm and 30mm Erfle all over from GSO, Svbony, and other brands)

• Cheaping out

  • These are sold via eBay, Aliexpress and Amazon Marketplace (ships from China) for $30-$40: https://www.amazon.com/gazechimp-Super-Plossl-Multi-Coated-Astronomy-Telescope/dp/B07SGG6R93 YMMV!

• MOAR FIIIELD

  • There are cheap 30mm 80° Erfle. While they would show a large field at a smaller exit pupil than a 40mm, even at F/6, the performance of the last 10° is not good. (https://www.amazon.com/Astromania-Multi-Coated-Untra-Wide-Eyepiece-Telescope/dp/B06W5XNJHP/ --- There's also the 20mm, which has a barlow you can unscrew, and isn't very good. These eyepieces are a bit cheaper at Aliexpress or such without the barlow.)

• ...

  • :-) https://agenaastro.com/explore-scientific-100-deg-series-3-inch-argon-purged-eyepiece-30mm.html :-)