Jupiter 29/30 Oct 2023 - doing some testing....

[geoflewis]

As the title indicated, the session on night of 29 Oct was me experimenting a bit. I've never really automated any of my planetary imaging sessions as for years I've used a mono camera with RGB, etc. filters in a manual filter wheel, so I've always sat at the scope to start individual captures and manually cycle through the filters between each capture or group of captures. Now that I'm using a colour camera, I don't need to touch the filter wheel unless I want to shoot IR or CH4 data, so I started to look at the Autorun feature in FireCapture. Also after running out of HD space on my laptop SSD during my last long session, I want to test using different capture speeds. Unfortunately, by the time I'd worked out how to set up Autorun, I only got to do a couple of speed tests before clouds shut me down.

However, I've processed the two sets of data and put them in my usual fully annotated format to submit to the BAA.

I'd be interested to know what difference, if any, anyone can detect in their comparative image quality. I won't say which is which yet, but one was from SERs captured at 100fps (10ms) and the other at 124 fps (8ms). I was intending to capture at some other speeds, so maybe that's for another session. Also one of these images is from a stack of 10x1m SERs, the other from 13x1m SERs. So what do you all think?

Aside from the speed test, the Autorun feature was great success. Whilst the seeing was fairly good, it was decidely breezy, which not only was shaking the scope quite abit, but the wind chill on my body was something else 🥶. I therefore reconfigured where I'd set up my table and laptop in the observatory, so that I had easier access to the observatory warm room, meaning that once I set Autorun going, I could retreat out of the wind to a much more comfortable location for several minutes at a time.

[MartianHill]

I think the left one is slightly better at the poles and the right one at the equator.

Overall, I prefer the one on the right, but that could have been due to seeing ?

Both are good 👍

Edited October 31, 2023 by MartianHill

[geoflewis]

26 minutes ago, MartianHill said:

I think the left one is better at the poles and the right one at the equator.

Overall, I prefer the one on the right, but that could have been due to seeing ?

Both are good 👍

Thanks, I agree with all your points, will be interested to see if others view differently. Of course Jupiter was very slightly higher elevation, but really both were close to max so I thought it a good test. I also wonder whether the more central GRS of the one on the right, influences opinions. Maybe a test when the GRS isn't present might be less subjective.....🤔

[Space Cowboy]

Not much difference in those shutter speeds 🙂 Have you tried FC's cropping feature to save HDD space? FC locks onto the planet only recording that area of the ROI. Think it's called "cut out".

[geoflewis]

3 minutes ago, Space Cowboy said:

Not much difference in those shutter speeds 🙂 Have you tried FC's cropping feature to save HDD space? FC locks onto the planet only recording that area of the ROI. Think it's called "cut out".

I agree, not much difference in speed, but a 20% reduction in file size, which is a significant win I think. Yes, I use a combination of FireCapture's ROI and Cut Out features to reduce file sizes. I could probably go a bit tighter, but I'm not using auto guidimg, so the target does drift within the ROI a bit, requiring me to nudge the mount with the HC every few minutes. I guess my next experiment might be to try autoguiding, though currently I don't know what I need for that with planetary imaging....

[John_D]

They both look great to me. If I had to choose I'd probably pick the one on the right but, as you mentioned, the GRS is more prominent in that one. Just looking at the cloud bands towards the top I can't see much difference at all.

Is the processing of the raw data automated or is there room there for image variations?

( Also I'm glad you've thawed out after the previous post 😁 )

[Space Cowboy]

58 minutes ago, geoflewis said:

I agree, not much difference in speed, but a 20% reduction in file size, which is a significant win I think. Yes, I use a combination of FireCapture's ROI and Cut Out features to reduce file sizes. I could probably go a bit tighter, but I'm not using auto guidimg, so the target does drift within the ROI a bit, requiring me to nudge the mount with the HC every few minutes. I guess my next experiment might be to try autoguiding, though currently I don't know what I need for that with planetary imaging....

Very true 20% extra disk space is a lot. My tracking is not good enough to use the crop feature so I use the auto centre of ROI but have to watch the planet doesn't eventually slide off the sensor.

Have you tried a NVMe  SSD for fast data transfer? I can transfer 100 gigs from my laptop in 5 mins.

Edited October 31, 2023 by Space Cowboy

[Pete Presland]

Not sure there is any huge difference between the two images, both are very good with plenty of detail visible. 

Difficult to be 100% certain as the centre is always going to look sharper as the features rotate into it.

[geoflewis]

4 minutes ago, Space Cowboy said:

Very true 20% extra disk space is a lot. My tracking is not good enough to use the crop feature so I use the auto centre of ROI but have to watch the planet doesn't eventually slide off the sensor.

Have you tried a NVMe  SSD for fast data transfer?

I also use auto center ROI, but as you say, still have to watch that it doesn't drift off the sensor. That become even more of an issue if/when I add a barlow into the imaging train, which of course also leads to bigger file sizes. Sorry, I don't know what an NVMe SSD is, but it's not the speed of transfer that's an issue, just the size of the SSD.

[geoflewis]

Just now, Pete Presland said:

Not sure there is any huge difference between the two images, both are very good with plenty of detail visible. 

Difficult to be 100% certain as the centre is always going to look sharper as the features rotate into it.

Thanks Pete, I think the concensus is that there is no material gain in quality for shooting at the fast speed, at least during that session. That was my initial conclusion and indeed if anything I think the the additional signal per frame from the slower speed may have been a slight advantage. It was certainly worth experimenting and I appreciate the feedback received from you and others.

[Pete Presland]

regarding space, i bought an 2tb SSD external hard drive to transfer data on to temporally when disc space is getting low and my SSD hard drive is 2TB. 

[geoflewis]

Just now, Pete Presland said:

regarding space, i bought an 2tb SSD external hard drive to transfer data on to temporally when disc space is getting low and my SSD hard drive is 2TB. 

I have a few 4TB HDs that I use for archiving data as well as uploading to the cloud. Are you ripping data from your laptop to the external HD on the fly whilst imaging, as I have wondered about doing that?

[Space Cowboy]

6 minutes ago, geoflewis said:

I also use auto center ROI, but as you say, still have to watch that it doesn't drift off the sensor. That become even more of an issue if/when I add a barlow into the imaging train, which of course also leads to bigger file sizes. Sorry, I don't know what an NVMe SSD is, but it's not the speed of transfer that's an issue, just the size of the SSD.

NVMe works as an external SSD plugged into the USB port so you can quickly transfer data if the lappy gets full. £50 for a good quality 1tb. There are cheaper makes but they can slow up as they get full.

[Pete Presland]

2 minutes ago, geoflewis said:

I have a few 4TB HDs that I use for archiving data as well as uploading to the cloud. Are you ripping data from your laptop to the external HD on the fly whilst imaging, as I have wondered about doing that?

I haven't done that, I was a little concerned about transfer speeds even with USB 3. I don't think it should be a problem though, just to change the storage location in Firecapture. Something to try next time i think.

[Space Cowboy]

Obviously speed is effected by the quality of your laptop but these things are lightening fast :

Samsung 980 1 TB PCIe 3.0 (up to 3.500 MB/s) NVMe M.2 Internal Solid State Drive (SSD) (MZ-V8V1T0BW) https://amzn.eu/d/5ppknqC

[geoflewis]

15 minutes ago, Space Cowboy said:

Obviously speed is effected by the quality of your laptop but these things are lightening fast :

Samsung 980 1 TB PCIe 3.0 (up to 3.500 MB/s) NVMe M.2 Internal Solid State Drive (SSD) (MZ-V8V1T0BW) https://amzn.eu/d/5ppknqC

Thanks Stuart,

That link is to an internal drive, but I do have a few 1Tb, 2TB and 4TB My Passport external USB drives, which I believe are NVMe, so I could use one of those, which is what I was considering using in my reply to @Pete Presland

[Space Cowboy]

8 minutes ago, geoflewis said:

Thanks Stuart,

That link is to an internal drive, but I do have a few 1Tb, 2TB and 4TB My Passport external USB drives, which I believe are NVMe, so I could use one of those, which is what I was considering using in my reply to @Pete Presland

Yep, they fit in an external case but if you already have something similar thats great!

[Kon]

Nice images but no much difference between 8 and 10ms. You have a marginal 24fps better at 8 but a better comparison is to go down to 4-5ms and 290fps . I remember you did a similar comparison with Mars last year. I used to shoot at 5ms but my latest are at 10ms and I am finding the noise to be better managed and I can push wavelets a bit more.

Regarding captures, I capture at an external SSD at max FPS of my camera, not sure if it's a Mac thing but no frames are dropped either. Regarding storage I am terrible and I delete most of them after posting but I want to start archiving a bit better.

[geoflewis]

28 minutes ago, Kon said:

Nice images but no much difference between 8 and 10ms. You have a marginal 24fps better at 8 but a better comparison is to go down to 4-5ms and 290fps . I remember you did a similar comparison with Mars last year. I used to shoot at 5ms but my latest are at 10ms and I am finding the noise to be better managed and I can push wavelets a bit more.

Regarding captures, I capture at an external SSD at max FPS of my camera, not sure if it's a Mac thing but no frames are dropped either. Regarding storage I am terrible and I delete most of them after posting but I want to start archiving a bit better.

Thanks Kostas,

Yes, I tried down to 3ms on Mars last year and also 5ms on Jupiter this year. I remain unconvinced about the benefits of capturing at those speeds, as the loss of signal in each frame is pretty significant, plus if the seeing is that bad, that I need those speeds to freeze it, then I'm probably not going to be imaging anyway. As we discussed my 'normal' used to be what my Aussie friend uses which 13ms (76fps). I definitely feel that faster than that has it's benefits here in the UK, hence I upped it to 8ms, but am now thinking that 10ms might be fast enough, so very interest to know where you're currently at. It's not too many years ago when my old ImagingSource colour camera's max speed was 30fps and I achieved some pretty good results with that. In those days,I was imaging Saturn at 5-8 fps...