Meade LPI-G mono low framerate outside of SkyCapture

[Forunke]

Hi,

I bought the Meade LPI-G as a replacement for my previous guidecam. I connected everything during the day and did some testshots through the guidescope with Sharpcap.

Up to that point everything seemed fine. But when I setup my rig at night and tried to do polar alignement in sharpcap I noticed the framerate of the camera was about 1fps with an exposure of 250ms.

Fiddling with the settings I could sometimes reach 4 fps but stil way to low. I tried binning by 2x2, lowering resolution, 8bit / 12bit, Raw / RGB , no real improvements.

I connected via the Ascom drivers I downloaded from meade, aswell as the Meadecam drivers. Both options delivered similar results.

At that pooint it was getting dark and I started to guide with the camera. Same problem here. PHD2 would often skip frames because the camera did not manage to take another frame within 1.5s.

 

At this point I thought my USB connection was maybe to slow, but when I fired up SkyCapture, which came with the camera, I get framerates that sound plausible.

SkyCapture manages 4fps, Sharpcap only does 0.5fps

 

Any idea what could cause such behavior?

 

Edit:

I think I found a workaround: 

You can connect the camera through the "Windows WDM-style webcam camera" option in PHD2 and choose the "MeadeCam" option. This way PHD2 does not connect through Ascom but through the meade driver itself.

Will report back tonight if it improved the framerate.

 

Edit:
Setting the camera as webcam did the job. It required some more settings in PHD2 but I managed to get it to work consistently.

Edited March 23, 2020 by Forunke

[michael8554]

Frame rate is only relevant when shooting AVI video during Planetary Imaging. 

The aim being to get a high frame rate to increase the likelyhood  of capturing some sharp frames amongst the atmospheric distortion. 

Guiding is different, you switch to Long Exposure mode in your software, and expose for 1 to 4 seconds. 

There's probably some latency involved, a 1 second exposure may take say 250mS to download, before the next 1 second exposure starts, but fps isn't really relevant. 

Switch to Long Exposure, set exposure to 1 to 4 seconds, and get guiding!

Michael 

[Forunke]

3 hours ago, michael8554 said:

Frame rate is only relevant when shooting AVI video during Planetary Imaging. 

The aim being to get a high frame rate to increase the likelyhood  of capturing some sharp frames amongst the atmospheric distortion. 

Guiding is different, you switch to Long Exposure mode in your software, and expose for 1 to 4 seconds. 

There's probably some latency involved, a 1 second exposure may take say 250mS to download, before the next 1 second exposure starts, but fps isn't really relevant. 

Switch to Long Exposure, set exposure to 1 to 4 seconds, and get guiding!

Michael 

 

Yeah no need for high fps when guiding but the problem was that even at 1.5s exposures it would skip 2 or 3 frames till the next came in. On top of that PHD would frequently loose the star.

That lead to some big guide pulses which ruined some frames.

But it worked out when using the cam with the webcam settings. 

[michael8554]

Okay, that was a much better description of the problem than saying the frame  rate was poor. 

Good that you found the driver was at fault. 

Unusual for PHD2 to loose the guide star after one missed frame.

Uually it stops guiding, carries on tracking, and picks up the star on the next supplied frame--is your PE or PA that bad, or is the green star selection window too small? 

Michael