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

Date: January 11, 2007 10:24:06 PM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: connections for long exposures with Pt Greys

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

Hi Tim;

On 11-Jan-07, at 4:54 PM, Tim wrote:

Hi Milton:

If you have the chance, could you look up which pins need to be

connected on the back of the Pt Grey cameras to enable exposures

beyond half a second?

It's Pin 1 and Pin 2.

http://tech.groups.yahoo.com/group/Astro_IIDC/message/613

and

http://tech.groups.yahoo.com/group/Astro_IIDC/message/614

For the short term, I simply swapped the connector I'd already done

this to from my Flea to my Flea2.  The Flea didn't have any wires in

the connector, so I made one with a wire tie I had laying around, and

so it's a really small thingy all buttoned up in the connector.  If I

take it apart, I might not see where I had the wire connected.

Thankfully, the Flea2's connector has 3 inches or so of wires coming

out of it, so simply twisting the right ones together ought to do the

trick, I figure, so long as I do the right ones.

If you look closely on the Rat Tail Wires you'll see that they  

actually have the wires numbered too, which is a nice touch. Or at  

least the one I have here is numbered that way.

Mine too.  Thanks!

So far, the couple nights I tried the fleas out on the Tak mounts,

with the GPUSB plugged in, I was able to get the mount control in

Astro IIDC to link up with the mount famously every time.

But my guiding wasn't too good, even with the guide speed on the mount

set to the slowest rates.  I suspect that faintness of the guide star

might have been a factor, but I don't know for sure.  I should have

tried guiding (without imaging) using the flea2 with the connector set

up for long exposures, I suppose.  But my brain doesn't tend to think

of these obvious things when I'm tired and freezing my...  Well, you

get the idea...

One odd thing i discovered with guiding was that the Guide Scope does  

not need to be a very long focal length at all. Over X-mas I was  

shooting with the C8 at 1000 mm focal length and using 80 mm  

aperture  / 400 mm focal length scope for guiding. The stars were  

nice and round and tracking worked really well, right up until the RA  

gear started sticking and making a "ca chunk" sound. I was using  

either a 0.1 or a 0.3 pixel tracking accuracy with a Mag 6 star and  

133 ms exposures with the Flea 2 in 4x4 binned mode.

I was going..  HUH?... until I got to the 4x4 binning part.  I was

using the flea, not the 2 for guiding, but I think my stars were all

fainter than that.  And unbinned and .513ms on the Megrez 80.

I can't try again until these bloody clouds go away (and probably that

comet, too!), but I hope that's my problem.  It seemed to wander back

and forth in RA, worse than if I didn't guide at all, and after a few

minutes it'd go wild in dec until I shut it off.  Sometimes I got good

round stars for 2 minutes, because a video of M42 with 2minute frames

has about 4 good frames that I was able to coadd in Photoshop.

-Tim.