Greetings all...newbie to this site and fairly new to telescopes in general, and have been enjoying the hobby thus far. All has been pretty straightforward from an equipment perspective, but I recently ran into an interesting issue that has me a little confused. For Christmas, I was gifted an ES Firstlight 102mm refractor, and attempted to replace the included diagonal with my Orion model 8880 1.25 inch dielectric star diagonal. There is no issue fitting the Orion diagonal into the 1.25mm drawtube, but no matter what EPs I use with it, I cannot resolve any images. Even with the drawtube all the way in or all the way out, everything is a blur. When I use the diagonal that came with the telescope, I can resolve everything just fine, no matter which EPs I use. Strangely, the Orion diagonal works fine in other 102mm telescopes, and I haven't had any issues with it until I plugged it into the Firstlight 102mm. Given this info, can anyone explain why this telescope/diagonal combo is wonky? No need to explain that the Firstlight is a low end refractor...I am very much aware of this, but it still doesn't seem to be the cause because other diagonals work just fine with it.
While we are on this subject, I am also seeking an affordable 2x barlow for this telescope, and would appreciate any recommendations.
Thanks in advance for your assistance, and glad to be part of this great community!