Re: [APML] OT: Pleiades

[Chuck Vaughn <aa6g@aa6g.org>]

Hi  Alan,

I believe the two main things you need a computer for with a CCD  
camera is focusing and storing the downloaded data. The 20Da can do  
both of those. Like any current Digital camera it uses a compact  
flash card. I have a 1GB card in mine and that will hold 104 raw  
images. I know for sure you can buy a 4GB card.

The 20Da has a special live focus mode that displays either the  
center 4% or center 1% of the chip with a rapid update on the rear  
LCD. I can see at least down to mag 8 stars in this mode. Just turn  
the focus on your scope until the centered star becomes the smallest  
image. Brighter stars tend to be blobs and fainter stars are closer  
to points.

This is not as deterministic as FWHM on a computer display but I  
haven't had anything I could call a focus failure so far.

There's also a separate timer-controller that lets you set the  
exposure time from 1 sec to 99 hours, time between exposures, and  
number of exposures up to 99. The TC battery is supposed to be good  
for 3 years. There's no on/off switch. :-)

I don't know if the camera battery pack would last all night but  
there is an AC adapter that supplies the required 3 VDC. It would not  
be hard to modify the cable to accept a 2 D-cell battery pack.

Using the Pleiades for an example, I focused first, then set up as  
for any film exposure. I set the TC to 18 exposures, 10 minutes long,  
and I use 15 seconds between exposures. Then I went to bed for 3  
hours. :-) This does not allow for image dithering which is another  
discussion probably not appropriate here.

Chuck

--------------------------------------------


> Hey Chuck.
>
> --- Chuck Vaughn <aa6g@aa6g.org> wrote:
>
>> You don't even have to have a computer connected at
>> the scope if you don't want to.
>>
>
> Now this sentence caught my attention. I thought a computer was
> mandatory. I know you've been answering a lot of questions and
> comments, but, can you give us a quick run down of your setup  
> procedure
> and image capture process. How do you focus?
>
> This may have swung me back to the digital side. In the future of
> course. 8-)
>
> Thanks,
> Alan
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