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 Post subject: Re: SUN in PST
PostPosted: Tue Feb 17, 2015 3:58 pm 
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. Hello Cliff,
My tape measure was not long enough, so I take your measurement as correct.

Best wishes, David


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 Post subject: Re: SUN in PST
PostPosted: Wed Feb 18, 2015 8:56 pm 
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Dear David
I based my Sun feature measurement on the Sun being 1,392,000 km diameter (although one "Sun book" I possess says 1,391,980Km diameter and "The Cambridge Encyclopedia of the Sun published 2001" says the Sun is 6,955 x 10 to 8th metres RADIUS).
I made my measurement of the Sun's apparent diameter on BrianS's super image using an A4 sheet of lined writing paper and just counted the number of spaces between the lines (actually my laptop's BrianS Sun image diameter was bigger than the A4 paper). I then counted the spaces from one end of the long feature to the other, to obtain an estimate of the features overall length.
ie Feature's number of paper line spaces; DIVIDED BY Sun diameter number of paper line spaces; MULTIPLIED BY 1,392,000; EQUALS the features length in Km. I then made an adjustment to allow for the curvature of the Sun's visible surface.
BUT I didn't go to the trouble of measuring round all the feature(s)' squiggles so I think my assessment of 1.094,000km for the feature(s) overall length is if anything on the short side ?????
I would be very happy if someone would check the length.
However, there might be a possibly more contentious matter, which relates to the overall continuous nature of the feature(s) ?
I did say previously I am not an expert at assessing the Sun's features.
Perhaps BBC TV's "Pointless" programme could provide a definitive answer.
Best wishes from Cliff


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 Post subject: Re: SUN in PST
PostPosted: Sat Apr 11, 2015 1:26 pm 
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. Yesterday, 2015 April 10 0831 UTC PST 32 times very sunny slight haze contrast a bit low. The air is apparently polluted April 10.

There was a large bright pyramid prominence at the 4 o'clock position inverted AZ view.
At the 7 o'clock position there was a very long creeping prominence which was bright.
At the 9 o'clock position there was a small pyramid prominence.

There were a few filaments on the disc.

There was a large white area left of centre, which may correspond with the sunspots seen in white light.

1221 UTC approximately in the Street.
White light.
10×25 filtered binocular not braced.
Through some cloud an elongated sunspot was seen at the 5 o'clock position normal binocular view midway between centre disc and the limb. Medium-size.

At 1154 UTC the previous day, 2015 April 9 the elongated sunspot was fairly similar and medium-size as seen in the filtered 10x25 binocular.

Today 2015 April 11 at 1121 UTC approximately in the Street, this sunspot was very diffuse and quite difficult. At the 0430 position much nearer the limb than previously. Seen with 10×25 filtered binocular in fairly good conditions.


2015 April 10 08 50 UTC wind 130° 7 kn visibility 5000 m in haze cloud few 14,000 feet scattered 22,000 feet 15°C TDP 6°C 1019 Hector pascals.

1212 UTC wind 170° 7 kn visibility 15 km cloud few 6000 feet broken 10,000 feet broken 22,000 feet 19°C TDP 3°C 1016 Hector pascals.

1350 UTC wind 190° 9 kn visibility 20 km cloud few 6000 feet broken 15,000 feet broken 22,000 feet 21°C TDP 4°C 1015 Hector pascals.

Regards, David


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 Post subject: Re: SUN in PST
PostPosted: Tue Apr 14, 2015 3:47 pm 
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Location: Lancashire
For solar 'scope-users there's a huge prom showing on the SDO ( Solar Dynamics Observatory ) site today: http://sdo.gsfc.nasa.gov/assets/img/lat ... 4_0304.jpg .

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 Post subject: Re: SUN in PST
PostPosted: Wed Apr 15, 2015 2:56 pm 
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.White light only, but maybe the source of the huge prominence Brian mentioned yesterday.

2015 April 15 1128 UTC in the Street. Beautiful cloudless sunny day and very warm.
Welders glass 13 unaided eyes and Astro specs.
Surprisingly difficult, but I saw a sunspot possibly elongated at the 10 o'clock position.
I estimated this as 47 arc seconds penumbral size.
The sun was too bright really and at a difficult high elevation.
It may be that the sunspot was difficult because its component parts were well separated.

1129 UTC
10×25 filtered binocular partly braced.
There was a long line of three large sunspots and one small sunspot the third one along from the left normal binocular view. This was at upper left.
Fairly near the limb at the 10 o'clock position there was a large elongated sunspot and at about the 9.30 position even nearer the limb was a further sunspot. Perhaps this latter sunspot was responsible for the prominence yesterday?
Most of the sunspots seen were hard black. The Sun was very bright and the sky cloudless.

2015 April 14 1252 UTC approximately in the Street.
welders glass 13 unaided eyes and Astro specs.
A difficult sunspot seen at the 11 o'clock position that was affected by limb crowding.
Estimated 44 arc seconds penumbral size.

1254 UTC approximately.
10×25 filtered binocular partly braced.
The Sun was high and very bright.
There were three sunspots roughly in line at the 11 o'clock position quite a way from the limb.
There was an elongated sunspot at the 11 o'clock position very near the limb.

2015 April 13, 1806 UTC.
10×25 filtered binocular not braced.
The sky eventually cleared and although the Sun was low I saw a line of three sunspots at about the 12 o'clock position somewhat away from the limb.

2015 April 15 1150 UTC wind 260° 11 kn visibility 35 km cloud few 25,000 feet 22°C TDP 3°C 1016 Hector pascals.

Regards, David


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 Post subject: Re: SUN in PST
PostPosted: Thu Apr 16, 2015 2:50 pm 
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Location: Portslade, Sussex Lat 50deg 51min Long 0deg 13mins West
Hello David, Hector pascals ? ...regards mike


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 Post subject: Re: SUN in PST
PostPosted: Thu Apr 16, 2015 4:05 pm 
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.Hi Mike,
According to the Dragon they have been Hector pascals for a very long time.
I tell him to stand in the corner, but it doesn't seem to do any good. I long ago gave up trying to correct it, although occasionally the about correct hectoPascals appears.
To me they are still Miliband's (that is what the Dragon just wrote) or actually minibars, no millibars. The Dragon is having a bad day.

Actually my pilot friend tells me that hectoPascals have been used for years. But now the weather people use them, even though in the, I think, SI units there are no hectos officially allowed. It is a made up unit as far as I can see. So I might as well make up my own Hector pascals.

Regards, David

P.S.
Seems they are called Hectopascals or hectopascals or hPa.
But they break SI rules by using hecto to equal a millibar. A fudge.


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 Post subject: Re: SUN in PST
PostPosted: Mon Apr 27, 2015 9:57 am 
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Location: Lancashire
A distinct and spectacular filaprom was observed in the DS/PST yesterday afternoon. The feature looked like a a curtain, five times taller than the Earth and twenty-five times longer, ending at the solar limb in a spiked prominence.
See this feature on today's http://www.spaceweather.com . Thanks to the cold, clear, Arctic air that's descended over the UK in recent days, the Sun was pin-sharp during yesterday's observation.

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 Post subject: Re: SUN in PST
PostPosted: Tue Apr 28, 2015 3:40 pm 
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Further DS/PST observations of the filaprom yesterday seemed to indicate that the structure is beginning to collapse or dissipate.
Another fine image of the feature taken with a Lunt 80LS on www.spaceweather.com .

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 Post subject: Re: SUN in PST
PostPosted: Tue Apr 28, 2015 7:38 pm 
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. What was strange today, 2015 April 28 13.19 UTC in the street, was that I could see no sunspots at all with the filtered 10×25 binocular. Possibly suspected something upper left, but maybe imagining it.
Basically a featureless Sun in white light with a filtered 10x25 binocular.

Not a bad day, a bit cool with 5/8 cumulus cloud, some Cirrus cloud and some other high cloud, may be called alto something.

It has been very clear sometimes in the last few days.

Regards, David


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 Post subject: Re: SUN in PST
PostPosted: Wed Apr 29, 2015 1:57 pm 
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The featureless Sun David is discussed on today's www.spaceweather.com .

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 Post subject: Re: SUN in PST
PostPosted: Thu Apr 30, 2015 3:11 pm 
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2015 April 30 07 20 until 07 22 UTC, 1/8 high cloud, PST 32 times transparency very good seeing good.

A few small prominences. At the 7 o'clock position inverted AZ view there were three small spikes.
At about the 1.30 position there was a very small spike prominence emanating from a white area on the limb.

A few filaments leading from the centre disc to the upper right near the limb.

A small white area above and to the right of the centre disc.

But really not much happening.

White light
1234 UTC approximately in the Street.
Nothing seen with filtered partially braced 10×25 binocular in good conditions. 5/8 large cumulus but sky quite transparent about 14°C.

1150 UTC wind 270° 15 kn visibility 50 km cloud scattered 4800 feet 14°C TDP 2°C 1010 Hector pascals.

Regards David


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 Post subject: Re: SUN in PST
PostPosted: Thu May 28, 2015 2:39 pm 
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. White light.

2015 May 26, 27, and 28.
At about midday UTC on these three days in good skies I could not find any sunspots with the filtered 10×25 binocular.

It was difficult, because the Sun was very high and the angle was uncomfortable, but I could not see any sunspots.

Perhaps the Sun is very quiet?

Regards, David


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 Post subject: Re: SUN in PST
PostPosted: Thu May 28, 2015 3:35 pm 
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Quiet for spots David, but a vast filament hovers over the Sun: http://www.spaceweather.com .

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 Post subject: Re: SUN in PST
PostPosted: Thu Jun 25, 2015 4:13 pm 
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2015 June 25 0921 UTC PST 32 times. A considerable amount of cloud.

There was an enormous double flare about the 7 o'clock position inverted AZ view a long way from the limb.
There was a largish sunspot below this and prominences along the limb around the 7 o'clock position. However the prominences were faint through the cloud. There may have been other prominences and disc detail but I couldn't really see through the cloud.

There was at least one filament above centre disc.

1150 UTC approximately in the Street.
White light
10×25 filtered binocular. I saw the two sunspots at the 3 o'clock position that are nearing the limb. They look smaller than in previous days although yesterday they were smaller than the days before that.
Today the sunspots looked more prominent in white light than in H Alpha.

0850 UTC wind 240° 6 kn visibility 30 km cloud few 3500 feet scattered 15,000 feet broken 25,000 feet 21°C TDP 11°C 1021.5 Hector pascals.

1350 UTC wind 220° 7 kn visibility 40 km cloud scattered 4500 feet broken 12,000 feet broken 25,000 feet 24°C TDP 13°C 1021 Hector pascals.

Regards, David


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