heydo anons,
Recently got my hands on a good condition celestron C90 Mak (orange tube) with some good optics (fully coated K30mm, and K18mm) and all and I have been having quite a blast with it mostly bird spotting and at low mag (lunar and planetary observing), even printed some accessories for it, however I want to do more...
>inb4 buy a barlow
my scope uses the old Japanese 0.925" eyepieces, and no "major" manufacturer makes these any more
>inb4 k, just buy a 1.25" adapter
well I did that but |I wouldn't be able to use my eyepieces with it even if I could use my barlow
>inb4 k, just buy a 0.925" barlow then faggot OP
well u see I did find them but I am susy of their legit-ness?
let me show u:
https://www.ebay.com/itm/334567511306?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=0MMUqRegQH6&sssrc=2047675&ssuid=fuw5H0NJR2W&widget_ver=artemis&media=COPY

https://www.ebay.com/itm/185777414493?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=u4nf4o0mrnc&sssrc=2047675&ssuid=fuw5H0NJR2W&widget_ver=artemis&media=COPY

and others more...
they seem to be slightly smaller 23.2mm instead of the ~23.34mm that i need also they are used for microscopes... also:
>made in china
which doesn't instill much confidence, did some deep search for a review but nothing of value came up (-_-)
so here are my Q's:
>are these Chinese eyepieces any good?
>are there any cheaper configurations I should be looking at, currently (x2 or x3 barlow) with my current eyepieces gonna give me gr8 range on magnification without being too excessive (x66.66 and x111.11) for x2 barlow and (x100 and x166.66) for x3 barlow?
>is canned compressed air/Windex/soapy water bad for lens coatings?
>can i get by not entirely upgrading my eyepieces if i want to do low budget astrophotography?

thank for reading this and sorry for the txt wall
here is a pic of a rainbow in front of the collage to cleanse ur palate