So, although I started this topic with my interest in the TS Photon and Unc F4 or 5, all this talk about the Boren Simon scope has been interesting. I just skimmed the link you provided and it’s not clear what the native F ratio is for this scope. It appears that at 2.8 it requires and corrector / reducer and going to F 4 requires and coma corrector.....so it sounds like an F4 that ships with the corrector/ reducer so it functions at 2.8 out of the box. If you want to use it for higher resolution imaging, take out the corrector/ reducer and put in the coma corrector. A good marketing strategy to sell reducer/ correctors and coma corrector accessories....you guys know more than me, am I misunderstanding this?
Next question, they mention several times that this mates well with DLSR with aps-c sensors. Not sure what that is but I use ZWO 178 and 294 sensors so I’m guessing the scopes optics and my cameras might not be a heavenly match. If I decide to pursue this scope, I’d certainly ask Simon that question.
thanks for the great discussion on all this.
I think we know the native focal length is about f4 because its a 0.75 reducer and you end up at 2.8.
APS-C refers to the size of the sensor, which is 22 x 17 mm. This is a very common sensor size for DSLRs. Most telescopes create an imaging circle that is a little too small for such a large sensor and you get vingetting. So being able to fully illuminate a DSLR sensor is a good thing if you are an APer and use a DSLR.
A smaller sensor won't give you as large of a field of view as a larger one. It looks like the ZWO 294 sensor is 19 x 13 mm, which is pretty nearly the same as an APS-C. Seems like a reasonable match to me.
Two pictures I took with the PowerNewt my very first night out are here.
Neither is a great picture, as both are underexposed and my unmodified DSLR took a lot of the color out of the nebula. But you can see that even my first night out the stars in the middle are pretty round. Those on the edge are oval because the spacing between the sensor and the corrector was way off.
Not showing this to indicate what the telescope is capable of, but just what I was able to get on my first night out without having optimized the spacing.
Edited by John Tucker, 21 September 2019 - 05:38 AM.