Question about Fastar

[traveller]

I got a surprise when my Nexstar 8SE purchase from the US turned out to be Fastar compatible. From what I can find out form CN and other forums, a few 8SE OTAs had Fastar compatible secondaries installed, but Celestron has since stopped this. I understand the basics of Fastar, turning a f/10 into a f/1.9. I also understand that Hyperstar is the aftermarket equivalent (or better) than the original Fastar. I have a couple of questions that people might be able to help me with:
1. How do you get Fastar/Hyperstar in Aust? Or do I need to turn to the US? Price? I did a search on the archives and didn't get many results.
2. Has anyone got one/used one? What are your impressions? I read (with a good pinch of salt) that the Nexstar Alt-Az mount can be good enough for AP work with a Fastar. Has anyone tried this?
I don't have a dedicated CCD AP camera, just a QuickCam Pro and a SPC 900. My aim of the 8SE is to use it for visuals and a grab and go for camping etc, and then get a GEM mount for AP work later.
But if I can start with basic AP with a Fastar, I might give it a go.
:help:
Cheers, Bo

[Merlin66]

Ex -USA
A great idea - f2 on a SCT!
Expensive - yes....
Does it work ....yes
IMHO I'd start with a x0.63 reducer first.....
(The focus tolerance on the Fastar optics is less than 10 micron! and you need a suitable camera etc etc)
Just my 0.02 Euro (after tax)

[frolinmod]

About ten years ago I bought a Fastar lens and played around with it on a C-14. I know they still make and sell Fastar compatible scopes, but does Celestron even make and sell Fastar lenses any more?

The only place I know of that sells Hyperstar lenses is Starizona. I even bought one for my EdgeHD 14. Haven't used it yet. I'm a bad boy.

If your Nexstar 8SE can handle the additional weight of a camera, then it'll probably track just fine for the minute or less it takes to capture images of at least the larger brighter showcase objects in mono or single shot color. A filter wheel may add too much weight. You probably shouldn't even think of going narrow band because of the long exposures needed.

[Merlin66]

No, Celestron don't do the Fastar lenses anymore.....

[Poita]

The only option these days is the Starizona Hyperstar. You can get them on their website, and for the C8, it is relatively cheap. USD$695

http://starizona.com/acb/hyperstar/ordering.aspx

Instructions etc. are here:
http://starizona.com/acb/HyperStar-Lens---8-Celestron-P991C648.aspx

[traveller]

Thanks for your responses everyone, much appreciated.
Yikes 10 micron!!!???? guess the 0.63 reducer has better torlance? (and therefore the 0.33 reducer somewhere in between??)


I need to get used to visuals on the new scope first and perhaps the 0.63 reducer later one. Fastar/Hyperstar is just a bit too steep on the old learning curve so far.



Definitely keep that in mind (and the cost :lol:)
Bo

[Merlin66]

The "Critical focus zone" is related to the f ratio
Don Goldman gives delta f = 1.6 fr^2 x Lamda
Where Lamda is wavelength in nm.
Other references (based on 1/4wave tolerance) give slightly different values

Summary
f10 - 220 micron
f8 - 141micron
f5 - 55 micron
f4 - 35 micron

HTH