April 9, 2014: Morning session with HUGE "Λ" prominence

[michael.h.f.wilkinson]

Just had the LS35 out at 8:35 and spotted a strikingly dark filament, just east and below the centre of the disk. To the west a few more filaments can be seen. North of the equator on the western side a huge complex of bright structures surrounding some sunspots can be seen, whereas a new group of big sunspots is appearing on the northwards on the eastern limb. Lower on the western limb a low arc can be seen, but southwards on the eastern limb a HUGE prominence can be seen, shaped more or less like a Greek capital Λ, with one leg of the Λ brighter and thicker than the other. On closer inspection, after switching to 33x, I could see that the fainter leg was actually based on the near side of the disk, whereas the base of the brighter leg disappeared behind the limb. This strongly suggests we are seeing a prom arcing from the far to the near side of the limb. Northwards of this big prom several smaller structures are peeping round the limb, so it looks like a big AR is coming our way.

I hope it stays clear till lunchtime, so I can have another look

[pragmatist]

Yep watching this too. Think that prom may be the remnants of the twin towers from yesterday which has now joined together. Hope my 10mm comes today. Nice dark sunspot on the north west side.

[allcart]

Had  a peek at GONG this morning and saw the same thing. It appears the two towers have joined and the region responsible for this prom is finally coming into view. Exciting times for those who can see it.

I would have placed this on the West limb but it seems we all look at  the sun differently.

[michael.h.f.wilkinson]

Had  a peek at GONG this morning and saw the same thing. It appears the two towers have joined and the region responsible for this prom is finally coming into view. Exciting times for those who can see it.

I would have placed this on the West limb but it seems we all look at  the sun differently.

Always difficult to estimate orientation with respect to celestial coordinates on an alt-az mount. Easier with my GP mount (not used this time)

[Umbraldot]

Allow the solar disk to drift across your field of view; the first limb to exit is the western limb.  Helps with orientation issues.

No Sun so far today.  Hoping for a break in the clouds later.

[pragmatist]

Just learned something there. Thanks Umbraldot.

[pragmatist]

So west on the solar disc is around 11 o clock so am I correct in saying that prom is north?

[pragmatist]

Make that East.

[allcart]

So its clear, spots rise in the east and set in the west.

Then you look through the scope and its all reversed. So confusing sometimes.

[Umbraldot]

So west on the solar disc is around 11 o clock so am I correct in saying that prom is north?

There is no simple answer to solar orientation as it all depends on what type of scope you are using and whether you use a star diagonal or whatever method i.e. projection or direct viewing using a solar filter.  You have to work out the orientation for your set up.  Judge the western limb by the drift method and then work out where north and south are.  The easiest way is to check SOHO and then you know where the main spot groups are located.  Work out how that looks on your set up and make a drawing of the orientation.  Beware of course that this will change dependent on the time of day you do your observing.  If you are projecting the image onto white card, use a 150mm disk behind your drawing marked as a grid with an east/west line clearly drawn (a Porters solar disk is ideal or a Stonyhurst disk).  Allow the solar disk to drift using a small sunspot - when that sunspot drifts exactly along the east/west line (you may have to alter the orientation of your drawing several times) then your drawing will be correctly aligned and you are ready to start marking in the sunspot groups in their correct positions.

This is the greatest hurdle to solar observing.  Once you've worked out orientation the rest is a breeze!

This diagram may help when it comes to PSTs.

[Umbraldot]

Today's image from the GONG H alpha network monitor is below.  The images on this site are always shown with north top and east to the left.  The V shaped image bottom left is therefore on the SE limb.

[pragmatist]

Good info, I am using a Lunt 60 with diagonal so I imagine it's all reversed.

[Peter Drew]

Large prominence lift off during the last hour, missed half of it due to cloud. Well demonstrated on GONG playback video. 

[michael.h.f.wilkinson]

Today's image from the GONG H alpha network monitor is below.  The images on this site are always shown with north top and east to the left.  The V shaped image bottom left is therefore on the SE limb.

That matches my view quite nicely, except mine was a mirror image. In my scope east is right (plus or minus correction for the hour of observation) as on an ordinary map.

[Umbraldot]

That matches my view quite nicely, except mine was a mirror image. In my scope east is right (plus or minus correction for the hour of observation) as on an ordinary map.

Mine is too which always makes comparison with on line image from GONG or SOHO a bit of a test of mental agility!

[michael.h.f.wilkinson]

Mine is too which always makes comparison with on line image from GONG or SOHO a bit of a test of mental agility!

You get used to it.

[pragmatist]

Large prominence lift off during the last hour, missed half of it due to cloud. Well demonstrated on GONG playback video. 

Yep have been watching that, really awesome and with a little patience I could see it changing before my eyes.