A few notes about my achromatic objectives domain:
- all will be Clark type (echiconvex crown);
- all will use dense flints, from the N-SF range on the Schott diagrame. This means that the residual coma will be minimal to basicly fully corected.
PS: - the lenses (these and the future ones) are not coated. /PS
1. The first objective I have to prezent here is from the 100mm useful aperture:
- Db=107mm (the total lens diameter);
- F=1200mm (focal length).
- 522nm-C colour correction, that means photographicly, it has been design to be a great one using a deep yellow filter. And visually, just one colour (blue) hallo, around bright objects, the so called „planetary correction”, but a very pale, not harmfull blue. In my oppinion, this is a better colour correction for achromats.
With any doubt, it is a difraction limited objective. You can see the double pass (autocolimation) test below.
Because the flint lens stil have a crack on the edge from the original lens regrounded now by me, I cutted off some money from the price I would ask for a similar objective made from raw glass. But this crack have no effect on its functionality, it is not even in the useful aparture. The crown glass is perfectly intact.
Price (for the lenses and the ring): 150 euro + shipping.
This is just a small price for the optical excellence!
More info in pm. Thanks.
Edited by Tavi F., 20 September 2021 - 05:06 PM.