SingAstro

Looking to buy a Televue Barlow 3X and or Televue 15mm Plossl.

if you use a magnification that is too high for your scope, the image will be too soft. Have you try 2x barlow?

i don't think 133x is too high for a ETX-80?

I'd be interested in a 2.5X Powermate if someone is selling.

Hi,

i don't think 133x is too high for a ETX-80?

I think yes for a non-APO fast refractor. Although, usually the maximum practical magnification under that a scope can use is 50x per inch or 2 x diameter (in mm) of your scope (usually cap at 300x), but usually it is much lower for a fast non-APO refractor. IMHO, the maximum you should go is 100x. You can go slightly higher magnification for Moon, but you'll need to use a minus-violet filter.

Have a nice day.

133x will be at the real upper limit of the ETX80; If the scope has excellent optics 50x per inch is about the best so that will be 157x. It would be more useable at 100x to 110x. Going above 50x per inch or very near to it will usually not show more details because at that kind of magnification you see a bigger image scale but the resolution is already at its maxed.

Yup agreed, but i want to get as good a quality barlow as possible, i go to the northen hill resorts of india more or less every year and up there in the himalayas , the views are amazing so i want to be prepared . If the seeing is good ,maybe i will be able to get 130X or so.

what is the type of object you intend to observe?

Found the barlow 3X , still looking for the Plossl, or a decent wide angle lens.