DSUSB Check results

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Brad Geisler
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DSUSB Check results

Post by Brad Geisler » Sun Nov 28, 2010 4:23 pm

I received my DSUSB and camera control cord and ran the Check program. The system works for turning on and off the LED as well as changing from green to red. However, the open shutter will not actually expose an image until I close the shutter and then open it again. This is excactly how my Canon RS-60E3 remote switch functions, a two step process. Is this correct or do I need to change a camera setting ? The RS seems to move the mirror, then expose on the second prompt to avoid motion.
Is this the proper function for the DSUSB ?
Thanks in advance,
Brad

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Re: DSUSB Check results

Post by dpanderson » Sun Nov 28, 2010 7:09 pm

It sounds like you have the Mirror Lock function turned on. Mirror lock will flip the mirror up first, then open the shutter. This can be useful for astrophotography because you can put a delay in between when the mirror goes up and when the shutter opens to allow time for vibrations in the telescope and mount to dampen out.
Doug Anderson
Shoestring Astronomy
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Brad Geisler
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Re: DSUSB Check results

Post by Brad Geisler » Sun Nov 28, 2010 11:04 pm

Doug,

Thanks for the reply on a Sunday night !!!

Is this the proper function for it to mate and work with Nebulosity when I access it ?
Does Neb use the two step process to avoid vibrations OR do I need to change the camera settings for proper function with Nebulosity.
I don't see a delay time on the Neb exposure setup. Does it take this into account for DSLR's ?

Sorry, new to me,
Brad

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Re: DSUSB Check results

Post by dpanderson » Mon Nov 29, 2010 8:31 am

I found this in the Nebulosity Help files, under Cameras -> Canon DSLRs:
Mirror lockup
The DIGIC II cameras all support a mirror-lockup mode. When enabled, pressing the shutter button once
lifts the mirror and pressing it a second time triggers the exposure. Enabling this mode involves entering
your camera's Tools menu and finding the appropriate Custom Function (CFn) - usually either 12 or 7,
selecting and enabling this prior to connecting to the camera in Nebulosity. Nebulosity has no way to set
this mode itself, but it can detect if the camera is in mirror-lockup mode and, if so, will send the
appropriate shutter pulse prior to the main exposure.
Unfortunately, if using the onboard "bulb" mode for DIGIC III DSLRs, you cannot use the mirror lockup
mode. There is no way to trigger a lockup over the USB line. Note: For Mirror-Lockup mode to be used,
you must have a long-exposure cable selected and attached. Mirror-lockup cannot be used in USB-only
mode.

Hopefully that helps.
Doug Anderson
Shoestring Astronomy
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Brad Geisler
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Re: DSUSB Check results

Post by Brad Geisler » Mon Nov 29, 2010 2:35 pm

That helps quite a bit.
If I understand correctly, I need a "long exposure cable" in conjunction with the USB to use mirror lock prior to NEB taking exposures.
Do you supply the "long exposure cables". I have not seen them on your site ?

My mirror lockup is enabled in custom functions, but it sounds like I need to actuate the mirror lockup prior to exposing with a separate cable. How
do you get automated, repeat exposures with the 400D.

I think I am missing something, but it would not be the first time.
Brad

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Re: DSUSB Check results

Post by dpanderson » Mon Nov 29, 2010 3:08 pm

Your DSUSB is the 'long exposure cable". If everything is set up and working properly, Nebulosity should pulse the remote shutter signal (i.e. the output of the DSUSB) once to lock the mirror up, then assert it a second time to begin the exposure. Neb will then de-assert the shutter signal when the exposure is complete.

You might also experiment with DSLR Shutter, available free from Stark Labs.
Doug Anderson
Shoestring Astronomy
http://www.ShoestringAstronomy.com

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