jerky framerate

[darknight]

i realise this is something that I think is down to me, but not sure how to fix, hopefully ill explain properly.
I'm new to sharpcap sooooo, gpcam 2 in a oriaon st80, the image on screen is really black, so I up the gain to maximum and the exposure time, only then do I see the really bright Jupiter.
I never find any stars, and Jupiter can never get in focus very blurry, I guess due to high gain and longer exp time, but if I decrease these then Jupiter becomes a small spot, the capture window is very jerky, like its only taking a screen shot every 2-5 seconds?
what is going wrong?
thanks guys for help, I'm using s.c version 3 paid.

[admin]

Hi,

the usual cause for jerky frame rates is USB issues. Things to try are

* Start by connecting the camera direct to the PC using the supplied USB cable - no hubs, extensions etc
* Set an exposure of 0.1s - you should get about 10fps at that exposure if everything is working well
* Adjust the USB speed control (try higher and lower values) to find out which gives the best rate

If you manage to get 9-10fps by this approach then start adding back any hubs, USB extenders, etc testing each time that the problem doesn't re-appear.

If you can't get 9-10fps in this basic setup then

* Try a different (short) USB cable in case you have a faulty cable
* Try different USB ports on your computer - sometimes different physical ports have a different controller and might work better
* Try using an ROI of about 1024x768 - sometimes the reduced image size - particularly the vertical reduction - helps.

cheers,

Robin

[darknight]

thanks Robin for the info, ill try those, one thing I have done is try today in daylight, its fine? only jerky at night

[cuivenion]

Just a suggestion, do you have the Av (auto exposure) box ticked? If you do it would explain why you have fast frame rates during the day and low framerates at night. You need to choose your own exposure. Jupiter will be very small with an ST80, you will need to use a 2x or 3x barlow to get a bigger image scale. Even then it will pretty small. Try using this site to get an idea of how large your targets will be in your scope:

http://astronomy.tools/calculators/field_of_view/

[darknight]

hi cuivenion,
no that's all off, I know how big stuff is in what scope, I was more trying to illustrate what was happening but thanks for input, ill try all the above in the next few days and report back

[cuivenion]

No probs, good luck.

[admin]

I would have suggested the same (auto exposure as a likely cause) for cameras that are afraid of the dark! Check all the camera settings used in both tests (day and night) and look for anything different - also any physical differences (USB cables, laptop on battery, things like that). Once you find the trigger it will be easy enough to avoid it hopefully.

cheers,

Robin