Hi Benoit- have been a fan for years :-) I certainly don't doubt your
ability to build stuff! But supporting a fairly heavy secondary 200mm back
will be a challenge to avoid vibration and maintain alignment. What would
the diffraction limited field be at that distance? I too considered putting
my corrector at the optimal distance - 1400mm- with a carbon fiber tube but
decided against it. Is field curvature the only aberration with the
corrector at about prime focus? The field curvature of a C14 is about the
same as that of a 6"f/8 refractor (1/7th focal length vs 1/3rd). A field
flattener for a 6" f/8 refractor should be pretty close it would seem.
I just haven't tried that yet. Charles

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Dear All,

I played around with OSLO to found out what is the optimal positioning of the Schmidt plate with the classic C14 design (ie. not relevant to the Edge-HD).

It turned out that if the Schmidt plate is set 400 mm ahead of its original position, the radius of the field limited by diffraction is enlarged by 4 (9 arcmin instead of 2.2 arcmin). This is not as large as the C14 Edge-HD (12.4 arcmin) but not far away.

Of course, the optical tube becomes much longer (there is no free meal ...).

The other optical characteristics do not look to be affected (Strelh ratio on the optical axis, variation of focus with wavelength).

More information here :

Best regards

Christian Viladrich

This may have been recently posted but now I'm having problems installing my feather touch focuser on my CLASSIC C14 Non Edge. I waited nearly 2 months to receive the parts for this along with the stepper motor and wired Starizona Micro Touch.

I never even got to the step of motor installation ; since the feather touch seems to be jammed and is not turning at all. Looks like I'll need to take a trip to Starizona in Tuscon and have Dean do his magic and try to get this installed.

I followed to the letter for installing this and thought it would be a piece of cake.

I was a bit confused from the cd installation instructions that were given to me. This came with no brass stop ; but just the round brass ring that gets screwed onto the bearing and locked in with a tiny 1/16th set screw. I called Starizona to verify if this was the correct way to install and they stated yes.

? Now I'm wondering if the wrong Feather Touch Focuser was sent to me. The package box label does state FTM C14 so it appears correct. I tried to back the focuser back out but then the focus rod was exposed. Now best advice for me is to leave it alone and let Dean look at it. I just don't want to mess with it as is and possibly risk the primary mirror from damage.

Don Curry

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Okay I have bought a LF Coma Corrector Focal Reducer from Starizona making

the scope F7.2 at 2650mm now and have it attached to a Paramount ME Mount with a

QSI 683 WSG-8. I was able to achieve focus on the system with perfect round stars;

although I now have the task of running an extensive? T-Point model with the scope

and manually picking 6 stars on the same meridian side to begin with.

? My question for everyone is there anyway to lock the mirror with the supplied shipping screws

you use when transporting the OTA around or do I just let it run a 300 point model and

just see what the results will be in SKY X.?

My experience with?SCT's and guide scopes is as follows.....

I have a C14-f5.5? and a 50mm guide scope/finder scope mounted directly to the telescope all on a AP1200 mount.?

I'm imaging with a SBIG ST8xme using a Remote guide head in the aforementioned guide scope and my control software is CCDSoft v5 and The Sky 6 pro.?

When calibrating the guider, I place a bright star in the center of the guider's field and calibrate for 45 seconds.?

The guiders fov is huge! Then I go to my target image and after choosing a guide star I begin my imaging. All my guiding is lower sub pixel even with 15-20 minute subs. and as long as I'm 25 degrees or so above the horizon, I rarely need to calibrate.?

Now about that pesky mirror flop! Yes, I have it. But unless I cross the Meridian, it doesn't happen! But if it did I'll lose one sub exposure while the guider catches up.

Another big plus is finding a guide star is so easy my pet Yorkie can do it. Not to mention problems from filters in the imager. Plus I can frame my image perfectly while the orientation of my guider stay the same.

By mounting such a short guide scope firmly to the telescope, the flexure problem is undetectable in my images.?

Many newer imagers have built in guide chips in front of their main chips but they still can have trouble finding a guide star while try to frame the main image.

I've had the OAG's and long focal length guide scopes and never got them to perform as well as my setup.?

My two cents,?

Bob?

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