OK - doubtless you were getting light on the chip. However, 2 seconds is
far too long. Even 4 ms (the shortest 216 exposure, if I remember
correctly) may be overexposed on a full moon.

You might want to try putting a neutral density filter in the light path,
or stopping down your aperture using a Hartmann mask or some such ilk
(actually, a piece of cardboard with a hole in it taped to the front of
your OTA will work fine).

The Stilleto focuser will solve the focus problem you are having with the
scotch tape. You probably won't need the parfocal eyepiece, at least at
first. If you decide later to use a flip mirror, OAG, or other such
assembly, then you'll still want the eyepiece.

Best of luck! Let me know if I can be of any more help...

Mike F
http://fullerastropix.web.com


At 08:09 AM 10/3/2001 +0800, you wrote:

>I was imaging the full moon, using the Lunar1 standard exposure setting (2
>seconds).
>
>
>The moon filled about 1/2 of the FOV and centered, so I'm certain light was
>falling on the chip. Perhaps too much light :-)
>
>Also, I actually have the Stiletto knife-edge focuser from
>www.stellar-international.com
>for use with my 216XT, but didn't have time to try it last night. This will
>be my obvious next step.
>
>Jeff
>
> >Subject: Re: [M]: Problems with 216XT
> >Date: Wed, 03 Oct 2001 07:54:12 -0500
> >
> >Hi Jeff!
> >
> >First off, I find the "scotch tape" method Meade recommends to be useless.
>
> >Others may have had success with it, but I did not. A better approach is to
>
> >find an eyepiece with a similar edge-of-barrel-to-glass distance as the
> >nosepiece-to-chip distance for your 216 (assuming you are using the
> >nosepiece in a 1.25" visual back). It's gotta be pretty close.
> >
> >The noise you describe sounds about right; this would suggest that the
> >scope wasn't precisely aimed at anything - or at least, not precisely
> >enough for the image to fall on the chip. The 216's chip is very small, and
>
> >hard to get something right on without a flip mirror (or some such device)
>
> >to help.
> >
> >The "half-white half-black" phenomenon you describe is something I have
> >personally seen. You didn't mention what it was you were trying to image; I
>
> >got this "symptom" when I had a very out of focus, off-center Saturn in my
>
> >FOV. Tweaking the focus helped, and as it came into focus the wide white
> >swath became more narrow and eventually disappeared revealing just a blurry
>
> >Saturn (until I finished the focusing). Incidentally, you should always
> >focus on a star, and preferably a bright one for a beginner. Just make sure
>
> >to keep your exposure times short enough to not overexpose it.
> >
> >Chances are, *subtle* focusing is not what you need - you need a lot of
> >focal movement. Like I said, my experience with the "scotch tape" a few
> >years back was really a fiasco. The scope was nowhere near focus - some
> >10-15 turns of the knob off. Don't be afraid to spin in a while in one
> >direction or the other. Since this will induce image shift, you'll have to
>
> >be careful to recenter your object (which for a while may mean recentering
>
> >a donut or a white swath...)
> >
> >Good luck - you'll get there, and believe me, it does get easier...
> >
> >Mike F
> >http://fullerastropix.web.com
> >
> >
> >At 11:49 PM 10/2/2001 -0700, you wrote:
> >>I took advantage of a clear night and the full harvest moon to try out my
>
> >>216XT for the first time.
> >>
> >>I followed the CCD tutorial as described in the manual, using the "scotch
>
> >>tape" method to achieve focus before attaching the CCD.
> >>
> >>All the images were nothing but noise. Mostly like 50 vertical white lines
>
> >>about a pixel or two across. Sometimes nothing but black, but pressing the
>
> >>left/right arrow keys a couple of times would display solid white on the
> >>right 1/2, and solid black on the left 1/2 of the image. Nothing even close
>
> >>to an image.
> >>
> >>I tried subtle focusing in and out many times, but the images were always
>
> >>pretty much the same noise.
> >>
> >>I had essentially the same results using MaximDL and PictorView.
> >>
> >>Any ideas? Just symptoms of poor focusing perhaps?
> >>
> >>Jeff
> >
> >
> >
> >
> >
> >_________________________________________________________________
> >Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp
>
> >
> >
> >
>
>http://www.fidalgo.net/mail

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