Help with telescope. 10” Skywatcher Dobsonian. Using a 2x Barlow lens with either a 10mm or 25mm. I've even tried using the extender. My results are why you see in the pic,
SkyWatcher 1.25 Inch 2x Deluxe Barlow Double Lens
Zhumell 2" 2x ED Barlow Lens with 1.25" Adapter
Which of these two Celestron Barlows is best - Getting Started Equipment Help and Advice - Stargazers Lounge