Jetstream, what jetstream? - Jupiter 14 Oct 2022

[geoflewis]

There is a strong body of opinion that high resolution planetary imaging isn't possible with a fast jetstream parked overhead. Whilst experience indicates that is a reasonable general rule, there have been several occasions when that has not been proved true. Take last night as an example......

My wife and I had been binge watching the David Tenent 4 part series "Inside Man" and were heading for bed around midnight, but as usual I popped my head outside first and to my surprise there was a clear sky. I checked a couple of weather sites, including the jetstream forecast and thought, NO, I'll be wasting my time, then thought again, well why not give it a go. FYI here are 2 jetstream forecast for midnight 14 October and 1am 15 October - different sites, but essentially the same with a fast jetstream parked over the UK.

So how did I capture this?

Ok, so maybe not fully hi res, but far better than I saw a few nights ago with the jetsream out of the way. I managed 5 x 6 min SERs over about 45 mins, the above image comprising best 6000 frames from 3 of the de-rotated and quality graded SERs, so 18000 frames in total.

After Jupiter, I thought I'd try Mars for the first time this year, however, by the time I got Mars on the sensor and defined capture settings in FireCapture, fog had rolled in so quickly that Mars was no longer visible naked eye, and the nearby waning Moon had dimmed considerably, so I called it a wrap. It seems that if the jetstream doesn't always get you, then fog definitely will.

So back to imaging through a fast jetstream; it's something that I've discussed a few times with my mentor, Dave Tyler, who suggests that it's not just the jetstream, but whether it comprises a steady laminar flow, or there is turbulant mixing going on. My location in south Norfolk was right in the middle of the flow last night and I suspect that whilst the atmosphere was fast moving, it was doing so at a stable rate, not mixing as much as it might do at the edges of the stream. It's just a contention, but nevertheless, not for the first time I was able to image fairly successfully through the jetstream.

I'm interest to learn what others think about this.

 

Edited October 15, 2022 by geoflewis

[bob-c]

3 minutes ago, geoflewis said:

There is a strong body of opinion that high resolution planetary imaging isn't possible with a fast jetstream parked overhead. Whilst experience indicates that is a reasonable general rule, there have been several occasions when that has not been proved true. Take last night as an example......

My wife and I had been binge watching the David Tenent 4 part series "Inside Man" and were heading for bed around midnight, but as usual I popped my head outside first and to my surprise there was a clear sky. I checked a couple of weather sites, including the jetstream forecast and thought, NO, I'll be wasting my time, then thought again, well why not give it a go. FYI here are 2 jetstream forecast for midnight 14 October and 1am 15 October - different sites, but essentially the same with a fast jetstream parked over the UK.

So how did I capture this?

Ok, so maybe not fully hi res, but far better than I saw a few nights ago with the jetsream out of the way. I managed 5 x 6 min SERs over about 45 mins, the above image comprising best 6000 frames from 3 of the de-rotated and quality graded SERs, so 18000 frames in total.

After Jupiter, I thought I'd try Mars for the first time this year, however, by the time I got Mars on the sensor and defined capture settings in FireCapture, fog had rolled in so quickly that Mars was no longer visible naked eye, and the nearby waning moon had dimmed considerably, so I called it a wrap. It seems that if the jetstream doesn't always get you, then fog definitely will.

So back to imaging through a fast jetstream; it's something that I've discussed a few times with my mentor, Dave Tyler, who suggests that it's not just the jetstream, but whether it comprises a steady laminar flow, or there is turbulant mixing going on. My location in south Norfolk was right in the middle of the flow last night and I suspect that whilst the atmosphere was fast moving, it was doing so at a stable rate, not mixing as much as it might do at the edges of the stream. It's just a contention, but nevertheless, not for the first time I was able to image fairly successfully through the jetstream.

I'm interest to learn what others think about this.

 

Don't know much about the Jet stream Jeff, but it looks a fine image to me. 

 

Bob.

[geoflewis]

1 minute ago, bob-c said:

Don't know much about the Jet stream Jeff, but it looks a fine image to me. 

 

Bob.

Thanks Bob

[Space Cowboy]

Very nice image Geoff. Any kind of weather forecast is only a guide at the end of the day 🙂

[Nik271]

A light mist is always a good sign, especially for targets higher up in the sky. Some of my best views of planets and double stars have been on nights when can't see near horizon from fog, but near the zenith the stars are still showing.

[geoflewis]

23 minutes ago, Space Cowboy said:

Very nice image Geoff. Any kind of weather forecast is only a guide at the end of the day 🙂

Thanks Stuart, yes we only now for sure when we get out there and try......

[geoflewis]

7 minutes ago, Nik271 said:

A light mist is always a good sign, especially for targets higher up in the sky. Some of my best views of planets and double stars have been on nights when can't see near horizon from fog, but near the zenith the stars are still showing.

Thanks and yes, I've experienced the same. I suspect that I was imaging Jupiter through some mist, as I had to set the gain a tad higher than I've been doing recently and my last capture before trying Mars was fading fast, no doubt as the mist/fog thickened.

[geoflewis]

Anotated version....

[neil phillips]

You have convinced me to pay less attention to a jet stream. Thats a lovely result Geof. Your location really seems to deliver, No matter forecast of a jet stream

[geoflewis]

12 minutes ago, neil phillips said:

You have convinced me to pay less attention to a jet stream. Thats a lovely result Geof. Your location really seems to deliver, No matter forecast of a jet stream

Thanks Neil. I still think that most (80%, 90% 🤷‍♂️) of the time the jetstream is a killer, but I've experienced this a few times, so there's definitely something at play. Of course the jetstream forecast is just that and at best updated every 4 hours I think, so things change. I'm fortunate to have an observatory, so setting up is pretty quick and the tube fans help to stabalise the OTA fairly quickly.

[neil phillips]

16 minutes ago, geoflewis said:

Thanks Neil. I still think that most (80%, 90% 🤷‍♂️) of the time the jetstream is a killer, but I've experienced this a few times, so there's definitely something at play. Of course the jetstream forecast is just that and at best updated every 4 hours I think, so things change. I'm fortunate to have an observatory, so setting up is pretty quick and the tube fans help to stabalise the OTA fairly quickly.

One reason i am a bit coy about ignoring the jetstream. Is the 1-hour setup Geof it's a lot of messing. For nothing otherwise. But in your case its a win win. 

[Kon]

Great image. It was the same for me last night but the dew on secondary killed my session.

[geoflewis]

1 minute ago, Kon said:

Great image. It was the same for me last night but the dew on secondary killed my session.

Thanks Kon, yes, there was a lot of dew formimg on the OTA, mount, finder scope and telrad, but the dew strap kept the corrector plate of the C14 clear.

[dweller25]

@geoflewis

Which software/apps are you using for the jet stream forecasts please ? They look very useful 

Edited October 19, 2022 by dweller25

[geoflewis]

4 minutes ago, dweller25 said:

@geoflewis

Which software/apps are you using for the jet stream forecasts please ? They look very useful 

These two which are really just different versions from the same source. The graphics on the 2nd one are a bit more interactive....

https://www.netweather.tv/charts-and-data/jetstream

https://www.netweather.tv/charts-and-data/global-jetstream#2022/10/19/0600Z/jetstream/surface/level/overlay=jetstream/orthographic=-6.72,57.59,712

[dweller25]

Thanks Geof

[Pete Presland]

Given how the weather is in the UK, you certainly cannot afford to only image when the Jetstream is out of the way. I always feel a little more confident when it is not present, but as your image shows it is certainly possible to produce fine images with it over the country.

[geoflewis]

11 hours ago, Pete Presland said:

Given how the weather is in the UK, you certainly cannot afford to only image when the Jetstream is out of the way. I always feel a little more confident when it is not present, but as your image shows it is certainly possible to produce fine images with it over the country.

Thanks Pete, yes, if it’s clear in the U.K. then it’s a go, Jetstream or not