Fast frame ASI 174MM??

[Merlin66 (Ken)]

While I wait to sort out a computer with the necessary USB3/ SSD configuration - has anyone tried the ASI 174MM at high frame rates???
I'm interested in feedback re rates above 400fps.

[pdalek (Patrick)]

I have a ASI174MM-Cool but should be much the same.
Only used SharpCap 2.7beta at high frame rates.
For 320x240
16bit mode (12 from camera) gives ~220fps using USB2.0
8bit mode ~ 400fps USB2.0
16bit mode ~ 572fps USB3.0
8 bit mode ~ 730fps USB3.0

These values roughly agree with specs.
USB2.0 speeds measured Qosmio F60, USB3.0 on Alienware M11XR3.
Using the 174MM on USB2.0 is much more reliable and faster than the old 120MM. However there were some dropped frames.

Note: .ser file type was selected for both 16 and 8 bit modes, using .avi roughly halves frame rate.

This is more a test of software and not the camera. What information are you looking for?

[Merlin66 (Ken)]

Patrick,
Thanks for that....
I hope to use a ROI of 24 (or 32) wide by full height 1936, and pull AVI files at 12 bit(?) at maximum frame rates (>600fps?)
(The software I'm using for the spectrograph image reconstruction works with deconstructed AVI files - need to get a better understanding of the .SER file structure)

[pdalek (Patrick)]

I can try a custom ROI if you wish.
SharpCap does poorly with .avi output at high frame rates, but it is a beta version.
PIPP will convert .ser to .avi, just turn off all its processing and select .avi output file type.

[pdalek (Patrick)]

I tried it out with custom ROI
At very high fps things get a bit confusing.

First the ADC switches from 12 to 10 bit.
Sharpcap has a high speed check box.

With high speed on
1936x64 10bit .ser 625 fps
1936x32 10bit .ser 851 fps with many dropped frames

With high speed off
1936x64 10bit .ser 804 fps with some dropped frames
1936x32 10bit .ser 986 fps with many dropped frames

High speed of is faster????

These were all done with the minimum possible exposure time.

Beta software can't really be trusted but I think you should get > 600 fps
without any problem - would guess ~ 800 fps

Tried SharpCap mono8 .avi mode and it was a total failure with 120 fps and many more frames dropped than recorded. Forget .avi with this version of SharpCap.

I have not tried Firecapture yet because it has no cooler support yet, at least when I last looked.

[Merlin66 (Ken)]

Patrick,
Interesting....
Firecapture was the "recommended" Hi-speed software.
Appreciate you help. I'll try to borrow a PC with USB3 to establish the "parameters"
I would anticipate that the AVI duration for a full solar scan would be approximately 4 sec duration. Any dropped frames will impact on the re-constructed image....

[Maurice]

Originally Posted by Merlin66

Patrick,
.........
I would anticipate that the AVI duration for a full solar scan would be approximately 4 sec duration. Any dropped frames will impact on the re-constructed image....

Hi Ken
If you're talking about letting the sun drift across the slit, then isn't it about 1arcmin/4sec (15arcsec/sec).
The sun is about 30arcmin across, so doesn't that make it about a 120s AVI? Maybe I've got it wrong...its been a big day..

cheers
Maurice

[Merlin66 (Ken)]

Maurice,
You are 100% correct, and that is the current problem!
By significantly increasing the frame rate capture you can then speed up the acquisition...
Normally there's 2000 frames collected during the scan , to give a good resolution; if this is done at 500 fps, the necessary scan is only 2000/500 = 4 sec.
This scanning speed can be a achieved with a "nodding mirror" arrangement.

[Maurice]

I see.
So its better temporal resolution that you're after rather than spacial resolution...is that correct?

[Merlin66 (Ken)]

Maurice,
Hmmm
Both.
The resolution comes from the plate scale and pixel size, the ability to re-constitute the image from the individual "slices" from the spectral image.
By varying the pixel "slice" we can vary the waveband width - from 0.2A to whatever, but each frame of the AVI collected forms the basis of the image.