Surface Granulation with Baader White Light Filter ?

[Northern Soul man]

Hi To All, been out the last couple of mornings set up is a 127 Celestron Mak (F11), Baader Solar filter (Astrozap) - sunspots - very nice Umbra/Penumbra detail very nice.

Been trying too see some surface granulation - not really had much luck - I've read more than a few posts saying that surface granulation was visible using the Baader solar filter - is it just down to atmospherics - I've tried different colour filters #58 Green, Variable polarising - will the Baader Continuum be any better for this or am I missing something ?

Thanks

Paul

[Floater]

Been a while since I used the film but I don't remember seeing granulation.

I had a Herschel wedge on the sun today and didn't see any granulation with that either. Mind you, I was concentrating on the one AR that was worth looking at in detail and not paying much attention to looking for anything else.

Willing to be corrected (as ever) but I would say no, you won't see surface granulation with the film filter.

[Stu]

I believe it is visible with solar film, but clearer in a wedge. It is also highly dependent upon seeing conditions, and whilst I didn't observe today, I don't think from what I've read elsewhere, that the seeing was good today.

I would not invest in a Continuum at this stage, your Wratten #58 should help a bit.

Try with a low magnification as this can often help. Which eyepieces are you using?

[Northern Soul man]

Gordon, Stu - Thanks for the quick replies - I've done a lot of reading on the net and I know that Solar becomes very expensive - don't get me wrong the sunspot detail has been very nice and even the smaller spot above the larger spot today (using the Mak with a diagonal gives right way - up but reversed left/right) gave me very detailed views with a comma like structure visible to the side of this much smaller spot - with overall very good contrast between Umbra/penumbra regions.

Stu the EP's I was using was a basic 40mm Celestron plossl for getting the disk centred, then changing to a Baader Zoom - even at the narrow 24mm's I had the complete disk in view - not sure that at F11 I would get much more contrast using the Panoptic/Delos - what do you guys think ?.

Paul.

[Moonshane]

You may be seeing it and not realising it. At low power eg under 100x it's basically a fine peppering on the surface sometimes a associated with faculae (white channels within the peppering). Only at very high powers will it be obvious cells and seen in very rare seeing quality, in the UK anyway. I used to regularly see it with film and my 6" newts at around 50x my most used mag for solar.

[Stu]

Gordon, Stu - Thanks for the quick replies - I've done a lot of reading on the net and I know that Solar becomes very expensive - don't get me wrong the sunspot detail has been very nice and even the smaller spot above the larger spot today (using the Mak with a diagonal gives right way - up but reversed left/right) gave me very detailed views with a comma like structure visible to the side of this much smaller spot - with overall very good contrast between Umbra/penumbra regions.

Stu the EP's I was using was a basic 40mm Celestron plossl for getting the disk centred, then changing to a Baader Zoom - even at the narrow 24mm's I had the complete disk in view - not sure that at F11 I would get much more contrast using the Panoptic/Delos - what do you guys think ?.

Paul.

Hi Paul,

I think I'm correct in assuming your scope has a 1500mm focal length? This means the 40mm gives x37 and the zoom at 24mm gives x62. I would perhaps spend some more time observing with the 40mm under good conditions to see how you go. A 32mm Plossl might also be worth trying; not that expensive and would give you a nice x46.

Simpler eyepiece designs such as plossls or orthos tend to give better results for solar and they have good throughput and low scatter so I probably wouldn't bother with the Panoptic or Delos.

Shane's advice is spot on, at low power it is a very fine effect. I've only managed clear views with very high power under excellent conditions using the Baader Wedge. Looked lovely!

Keep at it, I'm sure the conditions will play ball sooner or later

[Floater]

Paul, this has been a good thread for me, too. Thanks Stu and Shane.

Looks like my report card will read "could pay more attention". I'll sit at the bottom of the class for a while ...

[Merlin66]

The average size of the granulation is only 1- 2 arc sec.

This means an aperture =>100mm and very steady seeing conditions.

As the eye can resolve about 2 arc min a minimum magnification of x60+ is required.

[Stu]

Do you mean for resolving the individual granules Ken?

I clearly see it with the Docter 12.5mm in the Tak at x59, and it is visible below this I'm sure, it seems to vary depending on transparency/seeing conditions.

I agree that high power is needed to resolve the granules properly but this does need good seeing in my experience.

[Mark at Beaufort]

Paul I know this is more expense but I have found using binoviewers shows granulation very well. I have a 4" f6.95 APO Frac and use a Herschel Wedge and Badder Continuum Filter. In my binoviewers I use 25mm Antares Plossls (not expensive) and a 1.5X barlow (to gain focus). I estimate that the extra focal length of binoviewers gives me a mag of 85X.

With this arrangement I get the whole Sun and it looks 3D.

OK this does cost extra funds but its worth it IMHO.

[Macavity]

I sense it's a resolution & seeing thing. Maybe even eyesight?

A local guy (professional landscape gardener) was working on my

"yard". I had my (then) PST out... He was really interested though.

"WOW! Look at those enormous "flames" (spots!) and "mottling",

he said. Me? I found, even a PST, "underwhelming". But I do wish

I hadn't sold it, before I had my *video* imaging cams though...

Me? I just hope to see as many things as possible - Even in quite

modest ways. (Video Imaging has rather taken over there). But

whatever works? So much to *do* - At my age, rather less time!

I am back to working on my "white light" setup now though. I am

going to try a CaK filter (they seem rarer now!) to augment this.

I never got much extra from the Baader Solar Continuum filter?

But I am moved to try an O(III) maybe... even a DSO "H-alpha".

[Northern Soul man]

Great Guys, thanks very much for all your advice recommendations, had a brief spell this morning and things are certainly looking up (pardon the pun!!) experimented with different EP's again and tried a few more colour filters - I don't usually use these but thought I would give it a go.  The #80A blue and the #58 green worked very well - picking out what I think are called "plage" brighter linear features( advice on nomenclature needed here!) toward the E - NE and N areas of the disk near to the limb, the blue filter especially helped these features stand out more - funny enough I was using the 24mm Hyperion - worked very well - got the full disk in.

I think the Granulation is going to need a lot more observing though - I think I was getting "hints" of this - you know when your searching the FOV for that Galaxy which is on the limit of visibility - is it there? maybe not - yes - no - I think its that sort of a moment - at times definitely not a uniform colour over the whole disk - if you guys know what I mean?

Thanks again for all the replies - oh I tried the Bino's - but its been that sort of a morning when cloud makes up more of the sky - so sort of in between clear spells with high cloud passing over the solar disk - I've put some plastic screws in the diagonal - so the Binoviewers felt a little insecure to say the least - so I need more time - the 40mm in the Binos are my next solar adventure.

Must say though the actual sun spot detail Umbra/Penumbra is just breathtaking - I've been watching the same spot for a couple of days - there's also another spot just above and to the left ( reversed Left Right with the Mak and Diagonal) which is much smaller but just as active - the white solar filter I think really does do these features justice though.

Thanks again all

Paul.

[Stu]

Glad you are having some better views Paul. I suspect the brighter features you are seeing are faculae rather than plages.

Stu

[Northern Soul man]

Hi again Stu - Thanks for correcting me - I've had a look on the net regarding the correct names for the features - I've just thought I have a pair of Meade 26mm Super Plossl's, so I think they will go nicely in the Binoviewer, also a pair of 40mm Meades - so can have a go next time I'm out - thanks again and regards to all for the replies.

Paul.

[Stu]

No probs Paul.

I had a shortish session on the sun today, battling high haze and full cloud!

Despite this, I had one or two moments of cracking seeing when the detail on the main active region was stunning. A nice light bridge running across the umbra and I'm pretty sure I saw the bright ring around the penumbra. Lovely detail (filaments?) also visible in the penumbra. Can you tell I've been reading my 'Observing the sun' book?

I checked for granulation, which was nice at x59 in the Docter, but also visible down at x40 in the zoom. At higher mags it just washed out because of the hazy conditions.

Hopefully Ken will come back on this one, but my view is that the granulation is visible as the kind of peppering effect Shane mentions at low powers, and can be easier to see as the contrast is higher.

At low power though, you don't resolve the granules themselves as they are very small features, so high power and good to excellent seeing conditions are needed for this.

[Highburymark]

Sounds like you're getting some decent views Paul - must say I've not seen granulation through my ETX105/baader film/continuum combination. But that's from city location - maybe there's a better chance elsewhere.

[Merlin66]

Stu/ Paul,

The detail in the penumbra are fibrils, streams of hydrogen following the magnetic field.

The peppery look I think is an artefact of "joining the dots" and represents the macro granulation structure but not the granulation elements themselves.

[jetstream]

The average size of the granulation is only 1- 2 arc sec.

This means an aperture =>100mm and very steady seeing conditions.

As the eye can resolve about 2 arc min a minimum magnification of x60+ is required.

Hi Ken, back to resolving questions  What calculation did you use to figure out the 60x minimum?

[jetstream]

I find that to really see the granulation "open up" that a goodly amount of mag is needed and the seeing to support it. The 120ED works well for this starting @ about 150x and only gets better the higher you go-up to the seeing limit, which at times here is 200x+. The granulation takes on a cell like look to it at these mags. My highest is 240x, under excellent seeing- this is quite a sight.

The 90mm does show the "cell" structure but not as well and the mag is limited to 150x-170x it seems in this scope.

[Merlin66]

Gerry,

It was the necessary magnification of 2 arc sec to achieve the eye resolution of 2 arc min which is = 60 x sec.

[Stu]

Stu/ Paul,

The detail in the penumbra are fibrils, streams of hydrogen following the magnetic field.

The peppery look I think is an artefact of "joining the dots" and represents the macro granulation structure but not the granulation elements themselves.

Thanks Ken, that makes sense and firms up my understanding of what I'm actually seeing.

I suppose it's still the effect of the unresolved granulation which is being seen at the low powers, so I'll continue to describe it as this when I see it. I do need to spend more time trying to catch the early morning good seeing to use high power to resolve the cells though. I think my best view was probably the first time I used the Baader Wedge at x247, the seeing was excellent that day!!

[Stu]

Just to add, what an excellent thread, really good info in here, always something to learn

[Tonynexevo925]

I very much agree Stu. So much to learn and even more to try and understand fully.

The seeing does make such a difference viewing the sun and no two days seem to give me consistency in my results. Clouds don't help much!

[Stub Mandrel]

20/20 vision is 1 arc minute, and many people can do better than this.

https://books.google.co.uk/books?id=u43MTFr7-m8C&pg=PA54&lpg=PA54&dq=eye+angular+resolution&source=bl&ots=6viDz9IWx0&sig=BSJGlb04L2_DSt-YPI82LMc1emw&hl=en&sa=X&ved=0CEcQ6AEwBzgKahUKEwimpOHYi4_HAhXTB9sKHW_FAxk#v=onepage&q=eye%20angular%20resolution&f=false

Naturally this assumes excellent contrast...

[Northern Soul man]

Excellent Guys - Thanks so much - been out this morning and had literally only a couple of minutes worth of the Sun under near total cloud cover, but I must say I've had the BV's out - had to re - balance and put a tape mark on the dovetail waiting for the clouds to part (yeah I know, NOT) had the 40mm and 26mm Meade 4000 Super Plossl's in, but have found exactly the same when comparing mono to BV on Planetary/Luna - so much more relaxed - I think its a little different in the day - you have a very bright surrounding once your at the EP, but being able to get both eyes inside the rubber eye guards really does help - the detail has only got better day after day - the simple EP design works very well here, a lot more Faculae visible just in from the Eastern limb, also, the two sunspots I've been watching are showing more and more detail - very different from day to day - not sue whether this is the BV "effect" or not but I think its going to be the way forward now with 2 eyes on the Sun - just got to wait for clearer skies.

The Plossl's work much better than the Baader Zooms - they're ok in the 1100 - but way too much for the little Mak - I was worried about heat build up and tube currents during the day, but the seeing has been really nice - as you would expect the actual limb of the Sun shows this much more than detail and structure in the spots - and again fleeting glimpses of peppering more so than the uniform colour the Sun gives us from the Baader Solar Film.

Yeah and all from just a couple of minutes between cloud cover - Great!!

Paul.