Looking for cause of dropped frames

[Moonstruck]

Hi Robin,
I was imaging IC405 (the flaming star nebula) last night, taking 5 min exposures at a gain of 120 with my Esprit 100 scope and ZWO asi 294 camera. Sharpcap captured two frames successfully but then started dropping them. I am curious why that happened so I can hopefully prevent it from happening again. Any idea why this typically happens? It was a clear night. I included my capture log below if that helps. If you see a setting or something I did wrong can you please let me know?

Note - when I first centered on the target I did a few live stack frames to make sure I could see the nebula, but I couldn't, and the stars looked unusually dim in the display. I am sure I was on-target because I did a successful plate solve. Not sure if that helps diagnose the problem but thought I'd mention it. Also this target was very low on the horizon- mot sure if that played into it.

Thanks,
John

[ZWO ASI294MC Pro]
FrameType=Light
Debayer Preview=On
Pan=528
Tilt=0
Output Format=FITS files (*.fits)
Binning=1
Capture Area=3104x2822
Colour Space=RAW16
High Speed Mode=On
Turbo USB=80(Auto)
Flip=None
Frame Rate Limit=Maximum
Gain=120
Exposure=305.356s
Timestamp Frames=Off
White Bal (B)=67
White Bal (R)=58
Brightness=19
Cooler Power=30
Temperature=-10
Target Temperature=-10
Cooler=On
Auto Exp Max Gain=0
Auto Exp Max Exp M S=30000
Auto Exp Target Brightness=100
Mono Bin=Off
Trail Width=3
Minimum Trail Length=100
Trail Detection Sensitivity=9
Remove Satellite Trails=Off
Background Subtraction=Off
Planet/Disk Stabilization=Off
Banding Threshold=10
Banding Suppression=0
Apply Flat=None
Hot Pixel Sensitivity=5
Subtract Dark=None
NegativeDisplay=0
Display Black Point=0.01953125
Display MidTone Point=0.0314472000693481
Display White Point=0.17041489684466
Notes=
EQMOD ASCOM HEQ5/6=RA=05:17:55,Dec=+34:25:23 (JNOW)
TimeStamp=2023-05-07T01:30:32.7653825Z
SharpCapVersion=4.0.9538.0
StartCapture=2023-05-07T01:33:26.8761648Z
MidCapture=2023-05-07T01:43:38.2581648Z
EndCapture=2023-05-07T01:53:49.6403525Z
Duration=1222.764s
FrameCount=3
ActualFrameRate=0.0025fps
TimeZone=-4.00

[admin]

Hi,

for the first issue with the dropped frames, the answer is usually in the SharpCap log - it will record at least some info on what caused the frames to be dropped. I suspect given the circumstances that it will turn out to have recorded that the dropped frames were reported by the ZWO SDK, which probably means issues with communicating with the camera. It might be worth turning the 'Turbo USB' setting to manual then setting it to minimum for longer exposure imaging to help avoid this sort if issue.

On the other point - since the target was low, is it possible that it was partly obscured by trees/buildings/etc? If only part of the telescope aperture was able to see the target then you will get a darker than usual image - you may not notice much else apart from that...

cheers,

Robin

[Moonstruck]

Thanks. Do you think turning off “high speed” may also help?

[admin]

Hi,

I *think* that high speed only has any effect in 8 bit modes, so it probably will do nothing, but it might be worth trying just in case I'm wrong. It certainly will not do any harm to turn it off

cheers,

Robin