Exposure times less than 1 second.

[gcfboulder]

On your website, there are 10-year old posts saying how set exposure times to less than 1 second. These posts tell me to "go to the bulb pull down and pull it down." I can't find the bulb pull-down. Where is it, or is there now a different way to set exposure less than 1 second?

Imaging Mode.pdf Planetary Mode.pdf

[gcfboulder]

Well, this is embarrassing! I just figured out what my problem was. I didn't have my camera set to manual. DUH! Now it works.

[astroman133]

It is the Shutter column dropdown in the Capture Plan area of the Imaging panel. Bulb is just one entry there are many other entries down to the minimum value supported by the camera model.

[s3igell]

Usually, inquiries about Short Exposure Times such as sub-1sec lead to the discussion of Planetary/Solar Imaging.  Planetary Imaging via a DSLR is much better done via the BYE/BYN Planetary Imaging Mode.  This mode uses the 5x LiveView image feed to generate an uncompressed video stream of 1:1 Sensor Resolution (the best a camera can do).  It also avoids several other issues of DSLR Planetary Imaging - repeated fast actuation of the mechanical Shutter Box causing wear/Tear on that component and Vibration on the Camera / Optics /  Mount; difficulties triggering Shutter Lock-up Mode (to avoid the previous issue); larger than necessary image downloads (the Planetary region of interest is much less than the DSLR field of view unless extreme long focal length); slow download throughput of full-size RAW Image Files (even on USB3 based DSLRs the LiveView mode FPS rates significantly higher than individual frames).

If your usage is instead to produce Bias Frames, it is much simpler to trigger the Camera manually with the Shutter Speed set to the minimum and simply hold down the Shutter Button until the Buffer has Filled.  There are no concerns about vibrations induced by manually pressing the Shutter, as one usually does this with the Body Cap on the Camera dismounted from the OTA.

If your usage is to produce Flat Frames, the above Bias guidance can apply.  However, the observation would be that sub- 1-second Flats indicate you have a truly over-bright light source.

[gcfboulder]

My problem is still not solved, since I would very much prefer to use BYE to control the shutter speed. I used to be able to do that in the past (prior to installing BYE v3.2 on a new computer this week). In neither the Planetary mode or the Imaging Mode, does the bulb drop down menu (under shutter) give me the option to set shutter speed less than 1 second. This is very important for imaging the moon. The attached files shows this in the screen shots. I'm at a loss on how to solve this.

Imaging Mode.pdf Planetary Mode.pdf

[astroman133]

Thanks for letting us know.

Good Luck.

[bdrelling@yahoo.com]

Same problem here.  I have used BYE for almost 10 years and it always had the sub 1s shutter speeds in the dropdown menu.  At a star party in October, those options suddenly disappeared. I had not updated the software nor changed any settings, so I can't figure out why those shutter speeds went away.

[astroman133]

First, when you report a problem, always report the BYE version number, like 3.2.3, and the camera model.

Try this: Put the camera in Manual mode and go into the Advanced Settings and click on Delete Cache Data. Then disconnect, shut down, and restart BYE.

You should now see the sub-second Tv exposure options.

This is the workaround for your issue. It seems like a bug in the Canon SDK.

[bdrelling@yahoo.com]

On 11/16/2025 at 2:34 PM, astroman133 said:

Try this: Put the camera in Manual mode and go into the Advanced Settings and click on Delete Cache Data. Then disconnect, shut down, and restart BYE.

Thanks.  Turns out it was operator error.  Somehow, at O'dark-thirty, the settings on my camera changed.  It went from Manual to one of the "CA" settings on the camera dial.

I was on BYE 3.1.7, which worked great with my 5D Mk II, but have since updated BYE to the current edition.  Thanks again for your quick reply and help!

All the best,

Bill Drelling

[astroman133]

Bill,

Thanks for letting us know that you are working.