RE: [APML] 35 mm Camera & Focuser

["Serge Theberge" <serge.theberge@wti.on.ca>]

> > 1. Stiletto and Hutech
> Both can be calibrated by anyone possessing the proper 
> implement to do so. The STI requires a digital depth gauge 
> with a narrower profile. There are other subtle differences 
> between the two. The STI enables you to get "close" to focus 
> very quickly. From that point the ronchi screen is used like 
> a knife edge to refine your focus. The Hutech is simply a 
> knife edge. Personally I would opt for the Hutech because its 
> cheaper IIRC. But thats opinion so YMMV.

> > 4. Nikon, Olympus
> > You are saying here that it doesn't really matter since knife-edge 
> > focusing is available for both cameras. Olympus though is lighter, 
> > Nikon has more flexibility...
> 
> Or the camera that you currently have too .... Personally (since you
> asked) I like Nikons. The are built like a tank and I have 
> dropped mine and it survived without a scratch. But the Oly's 
> are fine too. I just prefer the Nikon's for prime focus work.

Hutech doesn't provide knife-edge focuser for the Canon.  I called STI and
the owner (Richard) says that their Stiletto has adapters for the Canon
AT-1.  If there is no significant difference with the Hutech, I might as
well get the STI Stiletto so that I won't have to buy another camera body.

> 
> > 5. Off-axis vs guidescope
> Lumicon 2 inch Newtonian Off Axis Guider. *But* you might 
> need something different because at f/4 you will need the 
> coma corrector and I am not sure what the Vixen specifics are 
> on theirs and how it mounts. Lumicon has a coma corrector 
> that threads into the bottom of the OAG. You can still put 
> filters into the imaging patrh without interfering with the 
> guiding path which is a nice feature. Especially if using a 
> Ha filter because you will not be able to guide through it. I 
> have a very strong opinion on this subject so take that into 
> consideration Serge. I wasted a year and half trying to use a 
> seperate guidescope before I wised up. Others have gotten 
> good results. The Vixen 203 f/4 has a robust secondary and I 
> believe that Herm images using a seperate guidescope so it 
> can be done. Perhaps someone can fill in the blanks on the 
> Vixen coma corrector and the appropriate spacing to optimise 
> results and that would help. I am certain it can be done though ....

I have purchased the Vixen coma corrector with the R200SS so if there is any
way to setup the off-axis guider within the existing arrangement, that would
make life easier.
> 
> 
> Are you planning on manually guiding? or will you be using an 
> Autoguider ?
> 
I am planning to manually guide.  John Mirtle has convinced me that I should
learn to do everything manually before considering autoguiders, CCD cameras
etc.  Remember that I am a total novice when it comes to astrophotography,
so I will be focusing (!) on fairly bright DSO for the foreseeable future,
hence reasonably short exposures on this f/4 scope.

Serge


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