Baader Coolwedge Mark II

[Stu]

12 hours ago, JeremyS said:

Glad it’s arrived - there was I thinking you’d kicked the idea into the long grass.

Very good Jeremy, enjoyed that one 🤣🤣

I nearly did, having just bought the Tak but would have regretted it I’m sure. Will be interesting to see if there is much improvement.

While we are here, any views on whether I should be brave/foolish enough to use the FS-128 for Solar? I use my FC100DC all the time, so in theory it should be ok??

[Stu]

14 hours ago, Highburymark said:

Lovely Stu. Really hope it delivers. Bet someone at the printers copped it from Baader HQ when that consignment of manuals first arrived 🤬
I’ve been playing around with an alternative polarising option with my Ha scope and binoviewers. This followed a thread on CN which suggested two polarising filters on top of the eyepieces produced good results (for Ha that is). I’ve never been impressed with polarisers for any solar viewing, but I concocted makeshift adapters for my TV 32mm Plossls (see pics) as I had a few polarisers lying around, and I must say it does highlight background Ha surface detail slightly better. 
Back to WL - it will be interesting to hear how the new Continuum performs. Perhaps it might show more of a difference on faster scopes (your Vixen?) or achromats than the FC-100? Look forward to hearing your views. 

Yes, I bet that didn’t go down well. It was the same in the first unit I got so clearly it happened to a whole batch 🤪

Interested to hear how the polarisers with Ha works. The second picture looks good, I imagine that works well with the long eye relief on the Plossls. I’ve read about people experimenting with either and filters or polarisers to enhance the surface detail, though it think it was @Peter Drew who said a layer of thin cloud actually works as well or better than any filter; I must say I agree with that. Daft question, I know the light through wedge is polarised but is it also through an Ha scope? Will you post up about the results you get, would be interesting to read.

BTW, the Vixen is f8.8, so even slower than the Tak.

[Alan White]

Why not use it Stu?  
Mind you I would say that wouldn't I, its not my scope.

Honestly, is the 128 any more special in glass terms over the 100? Not as in what it will reveal, but actual glass.
This comment is not meant in anyway be disresepcting to any scope maker.

I would use any scope on solar WL observing with correct filtration of course, why not.

[MalcolmM]

3 minutes ago, Stu said:

layer of thin cloud

That's my experience too. Also observing early morning or late afternoon when the sun is low helps Ha surface detail. Evening is particularly good when bizarrely, I'm observing over the smog of Belfast! 

Malcolm 

[Stu]

7 minutes ago, Alan White said:

Why not use it Stu?  
Mind you I would say that wouldn't I, its not my scope.

Honestly, is the 128 any more special in glass terms over the 100? Not as in what it will reveal, but actual glass.
This comment is not meant in anyway be disresepcting to any scope maker.

I would use any scope on solar WL observing with correct filtration of course, why not.

Very true Alan. Nothing plastic inside and the glass is no different to anything else I’ve used. I’ve viewed with the Vixen Fluorite too and that was fine, so I’ll probably brave it sometime soon 👍

[Alan White]

Stu, I imagine the extra resolving power will notice.
If it was my scope it would be used allround, but I fully understand any reticence on this step.
 

[Paz]

I'm interested to hear how the 7.5nm continuum filter performs. I've just received  one but first light with it was observing through constantly changing thin cloud so I haven't got reliable observations to draw conclusions from yet.

[Paz]

14 hours ago, Highburymark said:

I’ve been playing around with an alternative polarising option with my Ha scope and binoviewers. This followed a thread on CN which suggested two polarising filters on top of the eyepieces produced good results (for Ha that is). I’ve never been impressed with polarisers for any solar viewing, but I concocted makeshift adapters for my TV 32mm Plossls (see pics) as I had a few polarisers lying around, and I must say it does highlight background Ha surface detail slightly better. 

That is interesting and sounds worth giving a go, is that better as in better than not using a polarising filter or better than if using a polarising filter in front of the eyepieces or binoviewer?

[Telescope40]

Hello Stu. Since having mine, I've done WL solar viewing with no issues if this helps with your decision. Best views have so far been with a solar continuum filter in the light path. 

ATB  John 

[Alan White]

2 hours ago, Paz said:

I'm interested to hear how the 7.5nm continuum filter performs. I've just received  one but first light with it was observing through constantly changing thin cloud so I haven't got reliable observations to draw conclusions from yet.

Have I missed something here?
Is the 7.5nm different to the previous Baader Solar Continuum filter?
 

[Stu]

15 minutes ago, Alan White said:

Have I missed something here?
Is the 7.5nm different to the previous Baader Solar Continuum filter?
 

Hi Alan,

Yes. The main differences between Mark I and Mark II as far as I’m aware are:

7.5nm Continuum vs 10nm Continuum

Brightness adjustment via rotating polarising filter

Ability to shorten the light path by 30mm to help with Binoviewing.

The 7.5nm vs 10nm is obviously a relatively small difference so will likely be a small incremental improvement.

I think the main reason I bought it is the brightness adjustment which is tricky to achieve with binoviewers with the original wedge.

I’ve actually managed to shorten the light path by probably 20mm and give myself a T2 fitting on the original wedge by using a couple of adaptors I had lying around.

One frustrating part is that the Wedge itself is quite pricey, but you still need to buy the 2” polarising filter to enable the brightness control, and an adaptor to give you the shortened light path and T2  thread. Best part of £100 on top of the base price, so not cheap. I think these should be included in the product as standard as they are marketed features. To be fair, they are described as optional but I don’t think I picked up on this when I ordered.

 

 

[Highburymark]

I’d definitely use the 128 for white light Stu, though I’ve found I have fewer satisfying sessions with the TSA-120 than my old 100 DC because of sensitivity to seeing. But of course in good seeing the resolution is even better with the bigger scope. 
The double polariser on top of the eyepiece idea was linked to an academic study suggesting they could work better at the end of the chain. You do need two filters per eyepiece, as the light isn’t polarised with my set up at least. The CN poster said he was getting spectacular results with a Quark through this technique. My own earlier experiences with polarising Ha have been disappointing, but this time I did see a difference - not that it turned a double stacked scope into a triple stacked-type view, but it does replicate the ‘thin cloud’ effect that we see so often with Ha and referenced above - improved background contrast of the orange peel surface. As you say Stu, it’s useful with long eye relief EPs like the TV 32s, but problematic with shorter ER eyepieces, and high powers when the view can also get too dim (certainly with binoviewers). So I’d recommend trying it - polarisers can be bought very cheaply - but not to expect anything transformational. 
The issue with the new Continuum filter is that in a well corrected telescope, 10nm or 7nm should make no difference. It may have an advantage in scopes with poor CA control. There’s a thread on Solarchat about it titled ‘Baader new 7.5nm continuum marketing guff’ (!) which assesses the effects of spectral lines at narrower bandpaths. The author of the amazing Solar Astronomy book suggests that an Oiii filter may be more effective.    
Having said all that, the three or four reports I’ve seen from 7.5nm owners have all been positive - with particularly good granulation. So who knows?

[Highburymark]

One caveat - isn’t the fluorite element at the front with the FS-128? I’m no expert but it’s worth checking with Tak that it’s safe for WL.

[jetstream]

10 minutes ago, Highburymark said:

The CN poster said he was getting spectacular results with a Quark through this technique.

Years ago I did this with a Baader single variable polariser with excellent results and posted on solarchat. The views with a Quark are superb with one.

 

11 minutes ago, Highburymark said:

though I’ve found I have fewer satisfying sessions with the TSA-120 than my old 100 DC because of sensitivity to seeing.

I find the same thing Mark- strange how 20mm of aperture can cause seeing issues but for solar it sure can IMHO. My 90mm SV Raptor is my most used solar scope.

[Stu]

Thanks Mark for the info. Yes, it’s quite possible the 7.5mm is not so much of an improvement but time will tell.

I’ve just had a first cloudy light, not enough to judge the quality but enough to discover an unwanted effect when using binoviewers. With a single eyepiece, the brightness adjustment works fine, though time will tell whether the dimmer settings are any better than full beams.

The problem I’ve discovered with the binoviewer is that it appears the polarisation is in different directions in each channel, so, when one channel is bright, the other is dim, and vice versa. It defeats the object and feels quite weird and unbalanced 😭. I guess another polariser on one of the eyepieces may correct this but it seems a bit of an oversight. Perhaps even one on each eyepiece then rotate them until they are balanced? Need to give that a go, but am a bit frustrated I must say.

[Highburymark]

16 minutes ago, Stu said:

Thanks Mark for the info. Yes, it’s quite possible the 7.5mm is not so much of an improvement but time will tell.

I’ve just had a first cloudy light, not enough to judge the quality but enough to discover an unwanted effect when using binoviewers. With a single eyepiece, the brightness adjustment works fine, though time will tell whether the dimmer settings are any better than full beams.

The problem I’ve discovered with the binoviewer is that it appears the polarisation is in different directions in each channel, so, when one channel is bright, the other is dim, and vice versa. It defeats the object and feels quite weird and unbalanced 😭. I guess another polariser on one of the eyepieces may correct this but it seems a bit of an oversight. Perhaps even one on each eyepiece then rotate them until they are balanced? Need to give that a go, but am a bit frustrated I must say.

All prism binoviewers are polarised to some degree, so I remember the same issue cropping up with Quarks and binoviewers Stu - the Quark has internal polarisers. I think rotating the Quark itself tended to equalise the brightness through each channel - at least to a level where the brain compensated and views were decent. I’d be surprised if something similar isn’t possible with the new wedge as a lot of people prefer to binoview white light, and both the current Baader BVs on sale show quite strong polarisation. Worth checking the manual, even if it means brushing up on your German. Otherwise, a mirrored binoviewer would obviously solve the problem 💰💰💰

[Stu]

Some positive progress. You can move the peg on the brightness adjustment so that the brightness varies from dark to bright through the range (the starting point varies depending on the position of the polariser). Once I set that to a better position, the channels match more closely in brightness through the range. Not exactly but certainly to an acceptable degree.

What I’m not sure about is the benefit of dimming the image. I keep wondering if it is helping with visibility of faculae near the limb but then I think it’s actually just a different presentation, they are visible in all brightnesses and I probably prefer the brightest so far! 🤪 Perhaps with a larger scope it will help more. Somehow I like it being there but am not totally convinced 🤣

Unfortunately the seeing is pretty atrocious today so the views aren’t that great, hard to make a judgement on it because I normally see much more than this.

Maybe tomorrow will be better 🤞

[Highburymark]

8 hours ago, Paz said:

That is interesting and sounds worth giving a go, is that better as in better than not using a polarising filter or better than if using a polarising filter in front of the eyepieces or binoviewer?

I thought it was definitely better than previous polarising set ups I tried Paz, but I never found them effective before. I notice a couple of posters on CN have reported no improvement, so no guarantees!

[Stu]

@Highburymark I notice the 35nm Ha filter has been replaced by a 20nm. Do you know if these are still suitable as mini ERFs? I’m wondering about trying to set my Tak FS60Q up as a PST mod for travel, with a filter ahead of the optics in the extender Q module to give them some protection. Any ideas if this will work with the new filter? Apologies to myself for the thread drift 🤣

[Highburymark]

40 minutes ago, Stu said:

Some positive progress. You can move the peg on the brightness adjustment so that the brightness varies from dark to bright through the range (the starting point varies depending on the position of the polariser). Once I set that to a better position, the channels match more closely in brightness through the range. Not exactly but certainly to an acceptable degree.

What I’m not sure about is the benefit of dimming the image. I keep wondering if it is helping with visibility of faculae near the limb but then I think it’s actually just a different presentation, they are visible in all brightnesses and I probably prefer the brightest so far! 🤪 Perhaos with a larger scope it will help more. Somehow I like it being there but am not totally convinced 🤣

Unfortunately the see is pretty atrocious today so the views aren’t that great, hard to make a judgement on it because I normally see much more than this.

Maybe tomorrow will be better 🤞

Glad there’s some progress. I’d absolutely agree that it’s not needed at higher magnifications with binoviewers. 

[Highburymark]

10 minutes ago, Stu said:

@Highburymark I notice the 35nm Ha filter has been replaced by a 20nm. Do you know if these are still suitable as mini ERFs? I’m wondering about trying to set my Tak FS60Q up as a PST mod for travel, with a filter ahead of the optics in the extender Q module to give them some protection. Any ideas if this will work with the new filter? Apologies to myself for the thread drift 🤣

I don’t see why not. It might even be more effective at managing heat issues. But as always with technical solar questions on a public forum I will happily admit my lack of expertise and advise checking with the manufacturer.  
You’ve certainly got some amazing options for solar now Stu - looking forward to hearing about the bigger scope that Peter built.   

[Louis D]

I vaguely recall Denis offering an astro version of a Zeiss microscope binoviewer that almost entirely uses mirrors, so it might not have the differential dimming effects of a prism based BV.  It still uses a prism beamsplitter, so differential polarization may be unavoidable even with it.

[Stu]

I managed a bit of a comparison with the Mark I yesterday. I just had the Tak out so was switching between Wedges, and conditions were quite variable so hard to tell what was the kit and what was the seeing.

I THINK the 7.5nm Continuum gives a small but noticeable increase in contrast and visibility of faculae, they seemed a little brighter and better defined but more comparison needed here.

I had been thinking that the brightness control via the rotating polariser was a white elephant, but have changed my mind here. For faculae full brightness seems better, but I found the granulation became easier to see with the setting at around half way. Lower than that wasn’t useful in this sized scope with binoviewers, though it may well be in a larger scope and more with a single eyepiece I think.

So, overall a positive I think. As said, more comparisons would be useful under better conditions but I’m happy with the new wedge now I’ve got these niggles sorted.

[Stu]

This image shows the comparison with the new Mark II CoolWedge in terms of path length. My modded Mark I is about four or five mm longer to the T2 fitting, so still a decent shortening vs standard. Mark II is on the right.