Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

ES 20mm 100 or Masuyama 26mm 85 decision

  • Please log in to reply
4 replies to this topic

#1 Sweep

Sweep

    Sputnik

  • -----
  • topic starter
  • Posts: 37
  • Joined: 20 Dec 2018

Posted 05 April 2020 - 02:17 PM

Hi

#2 SeattleScott

SeattleScott

    Cosmos

  • *****
  • Posts: 7,763
  • Joined: 14 Oct 2011

Posted 05 April 2020 - 02:23 PM

Do you plan to use it below F10?

#3 Sweep

Sweep

    Sputnik

  • -----
  • topic starter
  • Posts: 37
  • Joined: 20 Dec 2018

Posted 05 April 2020 - 02:37 PM

Hi
Going to purchase either one of these, opinions appreciated?
For F7 refractor have ES 17 92 and ES 30 82 looking for something in between.
The 20mm will give mag of 46x while the Masuyama 26 will give mag of 36x with wider field of view.
The ES 17 mag is 54x while the ES 30 is 31x
Fov in Es 20 splits evenly Fov between 17 and 30mm
Also with 20mm will suit remainder of my 2” eyepieces which are similar weight.
Masuyama should give better viiews on axis, offf axis ES likely better.
Not considering anything else, Ethos 21 goog alternative but too expensive.

#4 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 83,994
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 05 April 2020 - 02:43 PM

My two cents:

 

If you have the 30mm ES 82 degree and the 17mm ES 92degree, you don't really have much use for a 20mm.  At these exit pupils, your eye determines on-axis sharpness... 

 

Jon


  • Illinois likes this

#5 SeattleScott

SeattleScott

    Cosmos

  • *****
  • Posts: 7,763
  • Joined: 14 Oct 2011

Posted 05 April 2020 - 03:08 PM

At F7 you are probably better off with the ES but I kind of agree with Jon that you are filling a gap that doesn’t exist. Your 30mm is max FOV. What is the ES 20/100 going to show you that won’t fit in the view of the 17/92? Pleiades would be better in the ES, maybe Beehive. A lot to spend to improve the view of one or two targets.

Scott
  • j.gardavsky likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics