Jump to content

SkySurveyBanner.jpg.21855908fce40597655603b6c9af720d.jpg

Eyepiece decision


Recommended Posts

Hi Lance,

My advice would be "dont do it !!!"

8SE has focal length of 2050mm

4.7mm eyepiece will give x436 !! and 3.5 would give an eye watering x585 !!!

These magnifications are way too much for both your scope and the atmosphere!

100 degree FOV is pointless with that much magnification (even if you could get a sharp focus)!

Useable magnification is x50 per inch of aperture with the earth's atmosphere forcing a limit of around x230 in the UK.

 

When I had a CPC800, I found eyepieces down to 10mm great (x200 magnification). If you want an Ethos, get the 21mm, 17mm or the 13mm,  all would be excellent in your scope with the lower magnifcations making full use of the 100 degree FOV of the ethos.

These ethos would get loads of use as they hit the sweet spot of magnifications (in your 8SE).

Anything less than 10mm, then get Delos - wide FOV has little benefit in an SCT at high magnifications, save some money and go Delos or Delite below 10mm.

HTH,

Alan

Link to comment
Share on other sites

a 3.5mm will give you nearly x600 magnification - I'm not sure you would get much use out of that, your image will degrade too much - not sure if SCTs are the same, but the normal advice is 2x apperture in mm or 50x in inches, so x400 in your case.

and @alanjgreen beat me to it :)

 

Link to comment
Share on other sites

Lance
I am in agreement with Alan, the magnification will be far too high in the 8" SCT.
A very good alternative eyepiece would be the Pentax XW 10mm, they deliver stunning views of just about everything and spectacular lunar views.

Link to comment
Share on other sites

I have both the 3.7mm and 4.7mm Ethos SX eyepieces. Superb tools but my longest focal length scope is 1590mm. I can imagine the 4.7mm getting occasional use on the Moon, Mars and tight double stars but the 3.7mm would gather dust I fear.

Now the 8mm Ethos would be a great high power eyepiece in the 8SE :icon_biggrin:

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.