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Mars 26th Nov


neil phillips
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1 hour ago, geoflewis said:

You did it again Neil, another excellent result from this terrible weather. I got fed up fighting clouds and bad seeing last night and shut down early.

I know what you mean. There were moments where it looked really bad. Started doing 12 min captures during those long runs. There was moments it was trying to calm down. Would settle a little bit a few seconds here and there. And then it was off again. But I got good focus. de rotated. And Astrosurface image analyzer did the rest

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24 minutes ago, Space Cowboy said:

Nothing poor about those images Neil. Remarkable detail considering! The 10" newt certainly resolves more of the polar cap.

 

If I had good seeing I just know it would be on another level Stuart. It's really frustrating because a great image is possible i just know it. But as usual the UK weather is playing silly games. Annoying. Keep hoping. It may or may not happen. Wanted good seeing on Syrtis major. So much fine detail possible there

Cheers Stuart

 

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1 minute ago, neil phillips said:

Cheers

I am capturing at 425 frames per second. Its helping to beat the seeing a little.

Oh, that’s way faster than I’ve been trying, more than double. Maybe I need to drop from 5ms to 2-3ms and see what that gives. How many frames in the stack? 

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4 minutes ago, geoflewis said:

Oh, that’s way faster than I’ve been trying, more than double. Maybe I need to drop from 5ms to 2-3ms and see what that gives. How many frames in the stack? 

Lots Geof that stack was about 111000 

 only recently been trying this to beat the bad seeing

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3 minutes ago, neil phillips said:

Lots Geof that stack was about 111000 

 only recently been trying this to beat the bad seeing

Well your results tell me that you’re on to something👏. I need to try that if the seeing doesn’t improve 🤞

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11 minutes ago, geoflewis said:

Well your results tell me that you’re on to something👏. I need to try that if the seeing doesn’t improve 🤞

True i have gone faster recently. But what was i telling you about abandoning 60 fps. And that in UK seeing. Faster frame rates give better results. Still learning myself as i go along Geof, Still experimenting. But yeah we need to speed up. Mars makes it easy because its bright. Told you faster was the way to go. Only the last two or three outings have i started to see how fast is possible. And how much its helping. Always experiment. theory is one thing results are another. Wisdom might suggest i am going too fast. with too many frames. My answer is. In barbados maybe

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I asked Bird what frame rate he’s using with the new QHY5III-200M that he’s started using recently, the same one as Chris Go has been raving about, but he hasn’t replied to me yet. He’s put up some pretty impressive Saturns with it.

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Now I am feeling much better after my battle with flu I might get the motivation to get the C11 out again.

 

I think the fastest I have gone is about 245fps with the QHY5111 462 and following your discussions will see if I can get a faster rate, what sort gain are you using?

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9 minutes ago, geoflewis said:

I asked Bird what frame rate he’s using with the new QHY5III-200M that he’s started using recently, the same one as Chris Go has been raving about, but he hasn’t replied to me yet. He’s put up some pretty impressive Saturns with it.

But again, put him in the UK and see what happens. It's irrelevant really. Great imager though. One of my old school heroes. 

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2 minutes ago, Ibbo! said:

Now I am feeling much better after my battle with flu I might get the motivation to get the C11 out again.

 

I think the fastest I have gone is about 245fps with the QHY5111 462 and following your discussions will see if I can get a faster rate, what sort gain are you using?

Hi Ibbo glad your over it, nasty bug. At 2ms last night I was at about 246 gain. But that's with 245mm optics. At 280mm you're going to be comfortably lower than that. Assuming similar transparency of course.

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Excellent capture and processing. Nice details.

It seems that the high FPS has helped. My last Mars was at 300fps and like you said having a large stack to play with helps.

Talking of exposure, what is the concept of 2 or 5 ms exposure? I know planetary imagers use that . Why not faster? Eg ISS we go down to 0.5ms with a gain of around 200 to freeze the motion. Wouldn't that help us with planetary?

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30 minutes ago, Kon said:

Excellent capture and processing. Nice details.

It seems that the high FPS has helped. My last Mars was at 300fps and like you said having a large stack to play with helps.

Talking of exposure, what is the concept of 2 or 5 ms exposure? I know planetary imagers use that . Why not faster? Eg ISS we go down to 0.5ms with a gain of around 200 to freeze the motion. Wouldn't that help us with planetary?

Cheers Kon with 245mm optics Under reasonable transparency at 2ms I was at 246 Gain on bright mars. So clearly at 0.5ms exposure gain would be horrendously high. (Not desirable)

At 2ms exposure the camera is maxed out to me on ROI box size 300x300 (to allow for wind or drift on my mount)   at 425 frames per second. So, I don't think I can easily go much faster. To warrant going shorter Exposure. And certainly not 0.5ms. For me there would be no benefit.

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1 hour ago, neil phillips said:

Cheers Kon with 245mm optics Under reasonable transparency at 2ms I was at 246 Gain on bright mars. So clearly at 0.5ms exposure gain would be horrendously high. (Not desirable)

At 2ms exposure the camera is maxed out to me on ROI box size 300x300 (to allow for wind or drift on my mount)   at 425 frames per second. So, I don't think I can easily go much faster. To warrant going shorter Exposure. And certainly not 0.5ms. For me there would be no benefit.

Thanks for the explanation. So potentially we could go faster if the gain is not getting too noisy. Trying to get my head around, if I am shooting at 640x480 (I can't reliably go lower ROI on manual) 2 or even 4ms gives me 300fps with a gain of 230 or so. Would you favour the 2 over 4? I am not gaining more images but the 2ms captured ones should be more 'frozen'. Or would the 4 be better since signal to noise will be better? I am just thinking out loud and it will be a nice experiment to try next time I am out, but in case there is an explanation, happy to hear it.

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3 minutes ago, Kon said:

Thanks for the explanation. So potentially we could go faster if the gain is not getting too noisy. Trying to get my head around, if I am shooting at 640x480 (I can't reliably go lower ROI on manual) 2 or even 4ms gives me 300fps with a gain of 230 or so. Would you favour the 2 over 4? I am not gaining more images but the 2ms captured ones should be more 'frozen'. Or would the 4 be better since signal to noise will be better? I am just thinking out loud and it will be a nice experiment to try next time I am out, but in case there is an explanation, happy to hear it.

It can be more frozen but also noisier. Me personally I would like the benefit the faster frame rate gives to counter the extra noise. But i understand your manual. And your considerations will be different. I guess all i can say is it wouldn't hurt to try, as yes likely more frozen under bad seeing. But also, noisier. So, pros and cons. Certainly, advocate experimenting as it teaches you first hand your equipment's different abilities. Then compare later. Easy to make assumptions under different conditions though Kon. So be careful of what you think you learn. As conditions change so can the outcome. As Geof pointed out Some top imagers in Australia get great results at 60 FPS. But likely with great seeing and high elevation. You get the point. Great imagers adjust to conditions perhaps ? 

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