Hi
I am looking for a 3x barlow to use for imaging with my telescope. I have been trying to pick up the long GSO ED x3 but it is out of stock...
There are only 3 budget barlows available after that and I'm wondering if any of them are worthwhile.
The first is this "Achromatic, multicoated, cemented doublet" from 365Astronomy
https://www.365astronomy.com/365Astronomy-1.25-2x-LONG-Achromatic-Barlow-VSB36501-LONG-2X1.html
Then there's this "Universal broadband multicoated, internally blackened" one from Harrison Telescopes
https://www.harrisontelescopes.co.uk/acatalog/universal-3x-barlow.html#SID=564
And finally this "High Quality Fully Multicoated One"...bit of a standard, suspicious-looking design??
https://www.rothervalleyoptics.co.uk/rvo-x3-barlow-lens-with-t-thread-125.html
Any of them worth anything, or does anyone have any experience with them?