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Solar Whitelight with a blank disk - worth it?


Stu

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Having got up early for the GRS Transit, I thought I would leave the scope out, swapping the diagonal for the wedge and try a spot of Solar White light.

With it being around solar minimum, there are no active regions visible at the moment, so, is it worth observing in Whitelight at the moment?

For me, although I would not spend hours at the scope as I might when there is a major AR on show, I still find it interesting to spend ten minute periods through the day having a look. When the seeing steadies, the granulation can be wonderful and it is fun to try to catch tiny pores forming in the denser areas. You can usually also spot small areas of faculae around the limb.

Today, for example, earlier I saw a small group of around 8 or 9 tiny spots in an area of granulation which had a distinct swirling pattern to it. They may be little more than very tight granulation cells, but are definitely there. They come and go with the seeing but wait for for the steady spells and the views are excellent. About half an hour ago there was just one slightly larger pore, and I'm sure it will change again later.

For some it will be like watching paint dry, but I love trying to tease out the tiny details at high power. The seeing is only allowing around x90 at the moment, would be nice to get up to over x150 to get pull out a bit more.

I popped the additional half pillar on my tripod this morning to help me see Jupiter in the mornings, means I now need to stand on my case to view but it helps to clear the trees a little more :) 

Note the counterweight hanging down under the scope at the front. This offsets the binoviewers so that the rig stays balanced with clutches loose even at the zenith. Very handy. Need to paint my counterweight though ;) 

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I am just setting up a WL scope at the moment. I have had a morning playing with my Ha scope but like you I always try to view the sun when it shows, since that has not been too often recently. I too like searching for pores. It reminds me of my working days when I spent hours searching for viruses with an Electron Microscope lol.

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19 minutes ago, laudropb said:

I am just setting up a WL scope at the moment. I have had a morning playing with my Ha scope but like you I always try to view the sun when it shows, since that has not been too often recently. I too like searching for pores. It reminds me of my working days when I spent hours searching for viruses with an Electron Microscope lol.

There is definitely one above right of centre in an area of swirling granulation John. Could see lighter lanes above it, looked a little like faculae but not. Some small areas of faculae around the limb too.

Having just had a look in Ha, This pore seems to match up with a lighter area near a small filament. There is also a lovely arcing prom at around 8 O'clock PST view, really nice.

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  • 1 month later...

@Stu should I use any additional filter in addition to Baader folie on 100mm aperture to kill brightness and improve contrast? Tried solar today for 5 min but it was a wash, wondering if increased aperture plays a role in it (used 70mm until now).

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On 25/02/2018 at 15:57, laudropb said:

What magnification do you use to see surface detail Stu ?

Sorry John, I somehow missed this post!

If the seeing allows, I use up to around x200, with the binoviewers. I find that allows you to start to see the granulation cells (which are tiny features) and you can watch them change over a period of minutes (I believe they last around 10 to 20 minutes) Many people talk about seeing granulation, but I believe at lower power you are just seeing the overall effect (macro granulation if you like) rather than the individual cells.

It takes a fair amount to shock me at a scope these days but when the seeing becomes excellent and the sun is high the detail is really quite staggering. I’ve been known to mutter a choice word or two when this happens!! :)

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6 hours ago, BGazing said:

@Stu should I use any additional filter in addition to Baader folie on 100mm aperture to kill brightness and improve contrast? Tried solar today for 5 min but it was a wash, wondering if increased aperture plays a role in it (used 70mm until now).

Hi,

Yes it is useful to add a filter to improve the contrast. You can try a variable polarising filter, putting one part on the diagonal and the other on the eyepiece so you can rotate the eyepiece to tune the brightness.

The other option is to try a UHC or OIII filter if you have one. These narrowband filters can help to bring out features like faculae. I use a continuum filter which does a similar but better job, but which is expensive unless you spend a lot of time observing the sun, and I think becomes worth it with a wedge and good quality frac.

I would start with the polarising filter, then try others as and when you get them. Even a green filter can help tighten things up a little.

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Hm. I have a nice Astronomik OIII, perhaps that would be a good start. or DGM UHC, though it has some ghosting on bright stars...Or simply a ND moon filter?

This hobby is a a string of problems in search of solutions. Occasionally the solutions are free...:icon_biggrin:

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Thanks for the reply Stu. I have found much the same myself. I use a mag of 190x  to see the granulation but the seeing very seldom allows this. I agree most people are seeing supergranulation and mistaking that for granulation.

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26 minutes ago, BGazing said:

Hm. I have a nice Astronomik OIII, perhaps that would be a good start. or DGM UHC, though it has some ghosting on bright stars...Or simply a ND moon filter?

This hobby is a a string of problems in search of solutions. Occasionally the solutions are free...:icon_biggrin:

Well now you have your FC100DC, you absolutely NEED a Baader Cool Wedge ;). The high power views are amazing. I do always use a continuum which came with mine, I leave it in all the time.

Give the OIII a go with your solar film, might give good results.

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Should have checked the online picture today...zero spots, as I have learned after setting up. :)

Another thing I have learned is that focusing Baader zoom with its barlow brings a ton of problems in FC 100 DF. 

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1 hour ago, BGazing said:

Should have checked the online picture today...zero spots, as I have learned after setting up. :)

Another thing I have learned is that focusing Baader zoom with its barlow brings a ton of problems in FC 100 DF. 

What problems do you have with the Baader?

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Well, using it in 1,25 mode and on T2 prism means that I do not have enough in-travel if I use the extension. If I do not use it, I do not have enough out travel.

When I tried it with the complementary barlow, I did not have enough out travel, even with that massive extension. Will double check. I guess that is why powermates are so popular, no change of focus point...

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