Quote:
Originally Posted by Quark
Brian, there is no modern mass produced scope that will go within a bulls roar of comparing with Sir John Herschels 18" creation. No doubt you will be able to purchase a scope of comparable apertures but it will have nothing like the focal ratio. Herschels scope you talk about was approx F13. the performance of it would be nothing like an F 4.5. The FOV would have been nothing like a modern F 4.5 and the images would not have been as bright as a modern scope of similar dia but faster focal ratio.
Cheers
Trevor.
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Hi Trevor, you summed up my dilemma quite nicely. Unless I go the replica route it is not going to be right in whichever way I choose to ignore. I can get the reflectivity close by downsizing the mirror but the fast versus slow is a serious problem. It has been suggested that if I went with an ep with a very narrow fov it would bring the balance in a bit.
Perhaps if I tried this from a different direction? J.H. describes the Triffid Nebula as having a line of 3 faint stars in its core. Stellarium software does show the 3 stars but my 8" reflector doesn't. (on a good night it does show 6 in the trapezium)
In your opinion what would be the minimum size reflector that would allow me to see the 3
Brian