The telescope manufacturer William Optics offers very high-quality apochromatic and achromatic refractors which are very well suited to visual observation, and especially to astrophotography.
William Optics
Focusing Mask Bahtinov 105-148mm
$ 92.43
ready for shipping in 24
h
William Optics
Focusing Mask Bahtinov 75-110mm
$ 80.51
ready for shipping in 24
h
William Optics
Focusing Mask Bahtinov 172-235mm
$ 207.73
ready for shipping in 3-5
weeks
William Optics
Focusing Mask Bahtinov 243-308mm
$ 184.87
ready for shipping in 3-5
weeks