Advice on frame rate please

[assouptro]

Hi solar imagers! 

I have never posted before in this thread but I have just bought my first solar scope. The Daystar solar scout 60mm 

I am looking for a suitable camera and it looks like the zwo asi174 is the one i should be looking at. 

I am possibly buying an FLIR Blackfly usb 3 which apparently has the same sensor as the 174 but it’s max frame rate (at full resolution) is 41. It obviously gets faster when doing ROI cropped imaging. 
My question is, will it be ok @ 41fps for solar imaging? 

Many thanks in advance for any advice. 
 

Bryan

Blackfly USB3

MODEL: BFLY-U3-23S6M-C: 2.3 MP, 41 FPS, SONY IMX249, MONO

[Craney]

 

This has interested me as well.   A lot of column inches on image scale and pixel size etc , but  'fps'  is not discussed as much.

My gut feeling is the faster the better.  But.....  if you zap 200 fps during a  short period of bad seeing,  will that end up as a  poorer image than that  of 40 fps over a longer time of good seeing ??

hmmmm???

Anybody manufacture a 'good-seeing-predict-o-meter'   ??

[assouptro]

10 minutes ago, Craney said:

 

This has interested me as well.   A lot of column inches on image scale and pixel size etc , but  'fps'  is not discussed as much.

My gut feeling is the faster the better.  But.....  if you zap 200 fps during a  short period of bad seeing,  will that end up as a  poorer image than that  of 40 fps over a longer time of good seeing ??

hmmmm???

Anybody manufacture a 'good-seeing-predict-o-meter'   ??

Thanks for the reply! 
I understand it is some sort of trade off, I guess what I need to know is will it work at 40fps? Or will the sun be over exposed? 
 

cheers 

Bryan 

[Owmuchonomy]

When competing with UK daylight 'seeing' conditions then you need a good frame rate. If you are happy to mosaic then you have that option to get your frame rate up.  There are no rules for frame rate but I would be throwing a lot of video away with less than 80fps achieved.  To some extent, it will also depend upon what you can deliver to and receive at your storage device.  Now that I have SSD storage, things have improved.

[Ibbo!]

My Chameleon delivers 56fps at full frame size at about 18ms double stack and 3ms single stack.

I have installed a PCIe SSD as I got buffering over 20 secs of capture.

I have stacked small number of frames ie 51 on my last image and got a resonable image, I am starting believe with solar we tend to try and stack too many.

For planetary I can get over 160fps with ROI.

[symmetal]

49 minutes ago, assouptro said:

Thanks for the reply! 
I understand it is some sort of trade off, I guess what I need to know is will it work at 40fps? Or will the sun be over exposed? 
 

cheers 

Bryan 

Whether the sun is overexposed depends on your exposure time. The max theoretical frame rate is just the resultant reciprocal of the exposure time.

If you expose for say 5mS then the maximum frame rate possible is just how many 5mS exposures can I take in 1 second. This is 1 second / 5 mS or 1/0.005 = 200. Unless you go for a small region of interest you'll never achieve that frame rate as the hardware (camera hardware, PC processor speed, memory, USB link) will limit what's achieveable.

Your camera saying 41fps is the maximum framerate is it's hardware limit at full frame recording. If you expose at 1mS you'll still get 41fps. Likewise if you expose at 10mS you'll still get 41fps. Theoretically the maximum exposure time you can achieve at 41fps is 1/41 seconds = 24mS. So don't worry too much about the fps figure. It just sets how fast you collect your images. If your fps is say 20 then recording a video for 30s duration will give the same number of frames as recording at 41fps for 15 seconds.

The downside of a longer video recording is clouds getting in the way or the subject detail changing throughout the video causing blurring when stacked. Using my ASI174MM I manage 30fps at full frame and get 900 frames in 30 seconds which is fine for stacking. The spec says it's 60fps at full frame but it never achieves anywhere near that even using a fast PC. I doubt whether your camera would actually give 41fps in reality.

So whether the sun is overexposed depends on exposure time and camera gain setting, not the fps. 🙂

Alan 

 

Edited June 12, 2020 by symmetal

[assouptro]

Thanks guys for your replies.

i think I have enough information and confidence to have a punt at the Blackfly! 
 

Solar Imaging, here I come! (I think the clouds heard me!)

Bryan 
 

[Freddie]

50 minutes ago, symmetal said:

Whether the sun is overexposed depends on your exposure time. The max theoretical frame rate is just the resultant reciprocal of the exposure time.

If you expose for say 5mS then the maximum frame rate possible is just how many 5mS exposures can I take in 1 second. This is 1 second / 5 mS or 1/0.005 = 200. Unless you go for a small region of interest you'll never achieve that frame rate as the hardware (camera hardware, PC processor speed, memory, USB link) will limit what's achieveable.

Your camera saying 41fps is the maximum framerate is it's hardware limit at full frame recording. If you expose at 1mS you'll still get 41fps. Likewise if you expose at 10mS you'll still get 41fps. Theoretically the maximum exposure time you can achieve at 41fps is 1/41 seconds = 24mS. So don't worry too much about the fps figure. It just sets how fast you collect your images. If your fps is say 20 then recording a video for 30s duration will give the same number of frames as recording at 41fps for 15 seconds.

The downside of a longer video recording is clouds getting in the way or the subject detail changing throughout the video causing blurring when stacked. Using my ASI174MM I manage 30fps at full frame and get 900 frames in 30 seconds which is fine for stacking. The spec says it's 60fps at full frame but it never achieves anywhere near that even using a fast PC. I doubt whether your camera would actually give 41fps in reality.

So whether the sun is overexposed depends on exposure time and camera gain setting, not the fps. 🙂

Alan 

 

There is something wrong somewhere in your system if you are not getting 60fps as per the spec. My 174 achieves the spec. at full frame and down through any ROI.

[symmetal]

6 hours ago, Freddie said:

There is something wrong somewhere in your system if you are not getting 60fps as per the spec. My 174 achieves the spec. at full frame and down through any ROI.

I didn't have 'high speed' enabled in the camera setup and 30fps is the maximum in the spec. without it. As I only record in 8-bit I may as well use high speed mode (10 bit ADC vs 14 bit ADC). I do get 50fps full frame in high speed mode. That's at USB speed 80. At USB 90 I get 55fps but above that it starts dropping some frames. 😀

Alan

Edited June 12, 2020 by symmetal

[assouptro]

All very helpful info!

I just want to thank you all. This forum is awesome and full of helpful folk that will share their hard earned knowledge willingly.

Thanks 

Bryan

[Pete Presland]

On 12/06/2020 at 16:15, assouptro said:

Thanks guys for your replies.

i think I have enough information and confidence to have a punt at the Blackfly! 
 

Solar Imaging, here I come! (I think the clouds heard me!)

Bryan 
 

Looking forward to seeing your results with this camera

[richard ashbee]

anyone any photos with the Solar scout 60mm and the various cameras

[assouptro]

Hi Rich 

I bought this camera 

MODEL: BFLY-U3-23S6M-C: 2.3 MP, 41 FPS, SONY IMX249, MONO

And used it with the solar scout 60 to get some images 

 

I then used the rear end of the solar scout, the quark, and adapted it to fit other telescopes, mainly my ed100 to get closer

 

(not without its challenges and should a daystar quark have come up at the right price it may have been a better option)

Cheers 

Bryan 

Edited December 6, 2020 by assouptro

[Luke]

Very nice images, Bryan!

re: frame rate, in general, the faster the better, but I think it also depends on the camera's other properties.

I slightly preferred my Grasshopper 3 ICX687 (26FPS) to my ZWO ASI 174 (120FPS) for solar h-alpha, but I felt they were very close, and if doing it again, I would probably have chosen the ZWO, as it cost far less, and was less of a headache to get working.

I found movies recorded at 16FPS with the ICX687 were very usable too, though faster was preferable.

Edited December 7, 2020 by Luke

[assouptro]

1 hour ago, Luke said:

Very nice images, Bryan!

re: frame rate, in general, the faster the better, but I think it also depends on the camera's other properties.

I slightly preferred my Grasshopper 3 ICX687 (26FPS) to my ZWO ASI 174 (120FPS) for solar h-alpha, but I felt they were very close, and if doing it again, I would probably have chosen the ZWO, as it cost far less, and was less of a headache to get working.

I found movies recorded at 16FPS with the ICX687 were very usable too, though faster was preferable.

Thanks for the input Luke! 
I bought the Blackfly camera second hand and I have to admit I would buy FLI cameras again.

They are compact and sensitive, once I got to grips with the software I was more than happy with my purchase. 
I have since bought a zwo colour camera to try and capture Mars but the clouds have prevented me getting any meaningful results for months now so I cannot really compare..

I have persued this hobby for many years and although my passion is deep sky I am determined to obtain some decent images of our nearest neighbours and hopefully I will have more years ahead to achieve my goal! 
 

Many Thanks 

Bryan