From: "doobisary" <tjp314@pacbell.net>

Date: September 27, 2010 2:39:52 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: Jupiter Image

Milton:

Lots of good info here!

Yes, a sled focuser supports the spider and secondary, so it moves with the focuser sled.  The Celestron Comet Catchers from the 80's had sled focusers.

I've been cogitating about putting one on my 10" f/6 "Delmarvascope", so that I can alternate from DSO imaging with my SBIG ST2000 and also do planetary.  Maybe even swap out secondaries to use as small a secondary for planetary as possible.  ...but by the time I get around to doing that, I might have made me another mirror at the mirror class next March!  ;oD

I'm thinking of a new pt Grey to get something more sensitive for imaging Uranus and Neptune.  On a night of 8/10 seeing week before last, I viewed Uranus and had a razor-sharp edged disk.  Best view of Uranus I've ever had.  And, of course, Jupiter was stunning! (I can't remember if I've posted the images from that night here.  Will check later.)

I'd almost forgot about the hackintosh possibility, since so many PC laptops (all?) seem to lack firewire ports (with power).  But I've been wanting another PC to program my Sidereal Technology drive that I put on my non-goto Tak EM-500 mount.  So a hacked netbook would be ideal, and small enough I could put it in the same case with the G4 Powerbook.

-Tim.

--- In Astro_IIDC@yahoogroups.com, Milton Aupperle <milton@...> wrote:

Hi Tim;

On 27-Sep-10, at 12:30 PM, doobisary wrote:

Hi Milton:

Yep, it's infocus.  I could certainly move the mirror forward, but  

to do that without modifying the otherwise-original Cave OTA, I'd  

have to make brackets to support the mirror cell.  Then, of course,  

I'd have to recollimate.  Alternatively, I could swap out the  

focuser for a lower profile version.

I think for my future Newtonian builds, I'll use a sled focuser, so  

I can give it as much in or out focus as I could possibly want!

Cool. I take the Diagonal is attached tot he Sled / Focuser too so  

they both move at the same time?

24fps isn't good!  Guess I'll save for the Flea3 at the outset.  I  

wish they had an exhad option that offered a little more real estate  

than that 1/4" chip, though!

The Chameleon (1280x960 pixels) are 1/3" EXHAD CCDs (3.75 microns per  

pixel). The  Flea 3 come with 1/4" to 2/3" CCD's, so you do have choice.

The FireFly MV might be interesting too, at least for bright field  

imaging.

http://www.ptgrey.com/products/fireflymv/index.asp

They now have a couple of models there. It appears they have increased  

the Exposure time to 0.5 seconds for the smaller sensor and up to 8  

seconds with the Larger sensor models.

And since they are CMOS sensor, ROI allows you to run at much higher  

frame rates than CCD. Basically with a CCD an entire sensor line has  

to be read out, so ROI does not gain much at all from shortening the  

horizontal, just the vertical.

The problem with the USB 2 (and 3) is that it sucks for providing  

power over the Bus. Maximum allowed is 0.5 amps and 5.25 volts for USB  

2 and the Chameleon when imaging draws 0.375 amps and ~ 0.15 amps when  

idle. So it's basically one camera per Bus.

Another things is that with Astro IIDC supporting USB 2 cameras, it  

likely is possible to create a Net Book Hackintosh system now for  

Imaging and Guiding.

TTYL..

Milton Aupperle