Re: [APML] OT: Pleiades

["D. Kodama" <kodama@alumni.caltech.edu>]

Chuck,

Very nice shots!  You are getting up to speed very quickly.  No doubt your
film processing experience gives you a leg up on others just going
directly to DSLR imaging.  I take it that you find the blue-green balance
for OIII emission acceptable?

I also am biased towards taking a computer out of the loop, especially out
on field trips where the extra power consumption, weight, and complication
should be avoided.  You can also still use a knife-edge focuser for
focusing, and instead of just getting a huge memory card, you can get
special battery-operated portable disk drives with 20+ GB of storage.  I
have an X-Drive unit that reads virtually all types of camera memory
cards.  Just stick a card in and press 'copy' and the contents of the card
get copied to the hard disk drive.  The card can then be cleared and
re-used on the camera.  At home, just plug a USB cable into the drive to
retrieve all the images.

Dave Kodama


> 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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