26 replies to this topic

[Spectrum222]

Well, I have been doing solar for many (nearly 30 now) years, and today was one of those days where I just could not process mentally ALL the details available in my instrument I have owned. Came close with my Baader Solar spectrum in H-alpha on my 80mm ED, and wit my 120mm APM SD Binoculars, but this exceeded those levels of general details by quite a bit - today!

 

Before getting into some of the highlights, here's the basic setup:

 

 

1. TS Optics 152mm f/5.9 RFT doublet (f=900mm)
2. APM 15mm UFF (60X in the scope), and TS 13mm UWAN (69.3X).
3. Lacerta Optics 2" Brewster-angle Herschel wedge (Lac-2s) - modified a bit - more later*
4. Filters after prism surface: 2" Baader ND3.0, B+W Linear polarizer (46mm), Custom** 589nm D-line filter, FWHM ~8nm, ~68%T, 2mm thick x 37mm dia., mounted in custom 37mm cell, adapted to 48mm on back side, 46mm front (for mounting polarizer)
5. Mount: Stellarvue M2C mount (alt-az) on Oberwerk TR3 Walnut tripod.

I had been meaning to try this filter in the RFT for some time, I won't get into why now for brevity, had some mods to do on the mount that were needed. Now good to go.

 

I mounted this D-line filter into a 37mm cell and used adapter rings many years ago, and it does very well in most scopes I have (using mostly wedges - my Baader Mk1 Herschel and APM Wedges, both 2" format), but I generally prefer the full spectrum as a rule. Even the lime-green of the Baader Continuum filter, which works well, was not my ideal - and this 589nm filter shows more, BTW, than the Continuum. With an Achromat, using a narrow filter like these nulls out the CA issues totally. I have ways to use CA reduction, but certainly these DO help noticeably when seeing does go less ideal - for sure... But, not the case today! Seeing was superb!!!

 

It is sort of a perfect storm here; optically, the RFT doublet is optimized coincidently to the Fraunhofer d-line, one of the quirks of this optic. It has best monochromatic Strehl at 589nm. As my "luck" would have it, mates ideally with this filter in the chain. Atmospherically, we had sub-arcsec seeing with the sun near apex and just a light wind, which really steadied the view today. Sol was between 32-36 degrees during my observational window of Sept 17 18:20-19:50 UT. (lunch break basically) If I had NO work to do today, I'd still be out - almost missed my 1pm Teams meeting!

 

So... how did it do, and what was visible?! Let's refer to today's active region HMI view: 

https://www.spacewea...p24/hmi1898.gif

 

I am still honestly reeling from the amount of details - not many times do I get SO much at once that it is hard to fully process, but here are the highlights:

 

First, imaging taking the sun, have it like a ball of yellow colored dough, and rolling it in ultrafine ground pepper! That is sort of the level of granular detail seen today all over the disk - exc. where facular plague and other details were seen over this. Granular cells were alternating DARK and light (in sodium yellow tint of course), which is VERY easy for our eyes to see optically, contrast-wise, one of the better combinations of tints for this. I could NOT not see this even when not specifically looking. It was SO obvious! Seeing had me well below an arc-sec for resolution. I will confirm this later, but I am 99% certain of it (talking like in the 0.85" regime, or possibly slightly lower at best - pretty much near the optical limit or very close for this 152mm optic).

 

Facular Plage details were DEEP - about 2x deeper in estimation than seen in a Baader 538nm CF. Structural details in granulation, over most of the disk, including the mid-disk portions, had excellent visibility. On spot penumbrae, most of the active regions had fine featherlike appearance (esp. the mid spot group, AR 3825), and excellent rendition of fine structure within them, even to >90% of the disk view. Subtle shading and granular depth (read: temperature and size) variances could easily be made out, within and around the plages too. Image sort of a "cross" between a Baader CF and a good Ca-K image, but with yellow and dark tinting instead of green or blue-violet. Best way I can sort of describe this!

 

AR 3828: Besides being amazing, the primary spot had some discernable structure, seen yesterday evening in this scope in white light as it was splitting down the "middle"; it showed last evening as a partial split with a light bridge - The split at the time today has not quite

fully bifurcated the spot yet. penumbrae were "featherlike" surrounding this spot, and superbly deep plage seen throughout this area into AR 3825, and also really nice between it and AR 3827, including some small pores dotted about as well between them. WOW. 

 

AR 3827's penumbral region also was very "featherlike", with ultrafine filamentary details seen in it. read - VERY fine! I even saw a few porelike specks on the S leading edge, just within it, for a bit anyway, before they either merged with the adjacent filament (thickening), or stabilized to nominal average temp...

 

Some variances in tint were seen in AR 3827, 3828 (initiation of another light bridge I suspect), and AR 3825. These showed as spotlike variances in the umbral coloration - since I was basically at one wavelength, this would be a temperature variance within the spot umbra. I have seen these in color before, using my SV/TMB 105 APO, and my APM 120SD Binoculars, showing as a sort of deep mauve-taupe sort of color. That was a few weeks back, and in monochrome, showed as a paler tan-yellow tint, brighter than the deeper umbra region, but within it. This was NOT OOF color, or seeing - seeing was solid. Even when  few times the seeing varied a touch to maybe just above 1 arcsec for a few seconds, this structural feature seen held well, but looked better when stable seeing returned. 

 

The biggest HUGE highlight for me was AR3825: The penumbral area was SO detailed! Again, ultra-featherlike details prevailed. I witnessed what I can only call the "bear claw"; this was an extension of 4-5 darker and longer filaments (better than HV movie shows!) beyond the main border of the penumbra of the main spot, facing east and slightly below (reversed in wedge). I've marked this on a Helioviewer snapshot which does not show this well - it was WAY better in 589 D-line light: 

 

Here's a movie of this over 6h, most of the structure was in my window I think: https://helioviewer.org/?movieId=9kKW5

 

 

You can see in the above snap a bit of this "claw-like" structure - but it was WAY more detailed and changed in the range of 5-10 minute timeframe. VERY neat to witness this!

 

So... in a nutshell, I have a new favorite: my 152RFT w/Lacerta wedge and 589 d-line filter. The Lacerta Wedge gives a wider brightness range than my Baader or APM wedges, and I suspect part of the reason WHY this was so good, as well as having full polarization in the light coming off the wedge surface. 

 

If time had allowed, I wanted badly to go to 100X. I just was having a ball at ~70X, and time was precious. Will d more with this as conditions allow. This level of detail reminded me of a "live" movie or fast changing photograph. I will look into adapting my camera to shoot this sometime, but not a priority - I just got this running, and it is NOT on a tracked mount - that's on my next list for a mount to handle this 23lb. scope. 

 

*the mods to the Lacerta Lac-2s are basically removal of the stock EP/cam mount, which has M54 threads to mate to the wedge body. I added a 15mm extension tube, and a ZWO 4mm thick M54m-M48f ring to mount my 48mm Baader ND3.0 in the unit similar to the Baader wedges. I then use a clicklock and CL 1.25" adapter, and used 3mm extension to the d-line housing to clear any 1.25" EPs I put into the upper section - will fit APM UFFs, TS UWANs, Nagler T6s also. The ring acts as a "stop" to prevent any filters from hitting the ND3.0 filter at the wedge entrance. So I know when I am full length for the 2" filtering.

 

**the d-line filter was a surplus (one-of, probably a cancelled order) It is an Omega Optical interference filter, 34mm x 2mm, in 37mm OD ring assembly mount (round). FWHM 8nm, outside of passband blocking of OD 2.0 over 400-1200nm, just ~1/9.2 wave (1/10 wave at 632nm) at 589nm. Mounted 37mm ring Inside a cell (43mm) using graphite epoxy and used step up rings to mate to 48mm (m) and 46mm (f - to mate to B+W Pol filter). Checked alignment during mounting using a He laser I had in 2008 when I got it.

 

I am looking at options for other d-line filtering and will update when information presents itself. Also, I may look into a He-line Quark down the road - that might be FUN! The 589nm allowed the BEST this scope can deliver and it did so in SPADES! 

________________________________________

 

Clear skies, and good solar - I hope this post was informative... 

 

Darren

Edited by Spectrum222, 17 September 2024 - 10:08 PM.

[Spectrum222]

FYI - I edited this post - I forgot to mention that my filter was by Omega Optical

 

Darren

 

Any questions? 

[Spectrum222]

Sorry, I do NOT know why CN posts off my iPhone shots show up sideways all the time!

 

Makes viewing harder, sorry about it!

 

Darren

[BYoesle]

Perhaps because you have not actually re-oriented them with a photo editing program or app from landscape to portrait?

[Spectrum222]

Tried that with several, still posts sideways! 

 

But orients correctly when clicked on...

 

D

Edited by Spectrum222, 19 September 2024 - 12:19 AM.

[Spectrum222]

UPDATE: I GOT IT!!!

 

Okay - that "bear claw feature - from 17 Sept. of AR 3825's lower spot penumbral extensions... I ran the HMI magnetogram (instead) with AIA 1700 layer and it shows MUCH better (contrasted):

 

 

WOW - and y'all thought I was making this stuff up (maybe not... lol)

 

Not the ideal rendition of what I saw in 589nm light, but at least it shows the EXTENSIONS to the penumbral filaments! 

 

Whew... So - more research to be had here, but it LOOKS like I may have stumbled onto something in 589nm D-line observing w/Brewster wedges.

 

If the light is fully polarized, and filtered narrow enough, perhaps I caught a magnetic polarity change, or some form of doppler effect with the filter acting as an edge filter (?) - not sure, but this IS supremely intriguing! 

 

Movie run of the previous 6h to show structural change: HV w/AIA1700 full, HMI Magnetogram at 45%, layered...

 

https://helioviewer.org/?movieId=zVKW5

 

Shows these changes over time, with filaments elongating and reducing, and temperature changes, which is basically (sort of, but looked different in He/Na light) what I was observing. 

 

more work to be done! I may be onto something new (?)

 

Darren

Edited by Spectrum222, 19 September 2024 - 12:11 AM.

[steveward53]

A picture's worth a thousand or two words ... 

[gstrumol]

For what it's worth, here's the evolution of AR3825 over time:

 

(click to enlarge)

 

I'm still having trouble visualizing the "bear claw" however 

[ch-viladrich]

Nice move Darren !

 

Indeed, the resolution of a 150 mm refractor is sure much larger than a 100 mm refractor. Pushing to 100x or more should revel even more exciting details.

On my side, the best view of the photosphere I ever had was with my Taka TOA 150 mm and a G-band filter. Granulation was impressive.

In fact, the best view have ever had was with a 450 mm f/15 refractor (450 mm is indeed its aperture) but it is a bit out of league ...

 

I have some questions :

 

1) Could you clarify what you mean by "Facular Plage details were DEEP - about 2x deeper in estimation than seen in a Baader 538nm CF".

Does "deep" mean something like contrast or luminosity ?

 

 

2) I am not sure in this part whether you are refering to white light observations or to observations with the Na I filter ?

"Some variances in tint were seen in AR 3827, 3828 (initiation of another light bridge I suspect), and AR 3825. These showed as spotlike variances in the umbral coloration - since I was basically at one wavelength, this would be a temperature variance within the spot umbra. I have seen these in color before, using my SV/TMB 105 APO, and my APM 120SD Binoculars, showing as a sort of deep mauve-taupe sort of color. That was a few weeks back, and in monochrome, showed as a paler tan-yellow tint, brighter than the deeper umbra region, but within it. This was NOT OOF color, or seeing - seeing was solid. Even when  few times the seeing varied a touch to maybe just above 1 arcsec for a few seconds, this structural feature seen held well, but looked better when stable seeing returned."

 

There is of course no way to observe a variations of color within a 8 nm bandpass. Or "tint" means "luminosity" in this context ?

 

 

3) The solar light (photophere) is not polarized. This is some amounts of polarization (linear and circular) in sunspot ombrae (magnetic field => Zeeman effect => polarization).

What do you mean by this :

"If the light is fully polarized, and filtered narrow enough, perhaps I caught a magnetic polarity change, or some form of doppler effect with the filter acting as an edge filter (?) - not sure, but this IS supremely intriguing!"

 

Do you mean a change of polarization of a given region during the observing time, or a change of polarization between two adjacent areas ?

 

Christian

[BYoesle]

An additional point or two that might be of interest.

 

Most refractors have their best correction at the e line at 546 nm (hence the design of the Baader Continuum filter). From there, spherochromatic aberration usually increases the farther away from 546 nm you get, and is generally not as good in the blue G band at 436 nm (and even less so at the CaK line at 393 nm):

 

telescope-optics.net

 

The exception would be the Takahashi TOA series (number 20 above), which has the best spherochromatic aberration control of just about any refractor design at most all optical wavelengths, and as Christian notes "the best view of the photosphere I ever had was with my Taka TOA 150 mm and a G-band filter" - and considering whether the atmospheric seeing conditions allow for it due to the shorter wavelength usually being more affected by turbulence.

[Spectrum222]

Hi Christian, thanks for the input and comments!

 

I appreciate your request for clarification here, as in hindsight, some of my descriptions could be read a bit unclearly - first off my apologies for my overt use of more "colloquial" terminology instead of perhaps more correctly-phrased scientific or technical terms. I will endeavor in the future to use more "correct" terminology when and where I can. 

 

Sometimes, my enthusiasm gets the best of me in an attempt to share information rapidly!

 

To answer your questions:

 

1. My use of DEEP here refers to contrast predominantly. So in this example above, what I refer to is slightly deeper contrast showing in facular plage, certainly compared to full spectrum WL (but my binocular observations we spoke of were pretty good there!). View is similar to the Baader Continuum Filter (used CF for this 538nm "green" filter), but the plage details seem more contrasty, and also some extra details surrounding them are visible - show as fine shading with granulation on the edges in some areas - I am still working on this as it is a bit more pronounced and some features surrounding the plage bordering more active regions also have heavier granulation/pore or maybe micropore (?) structure in the edge areas and some in between these too. More work on this is needed as I have only had this system out twice so far.
2. I should apologize again for the term "tint" - hard to break the WL habit! What is seen in this narrower band monochrome light is definitely better described as intensity or brightness (luminosity) differences. The structures are similar to those seen in WL in my 105 APO and 120-SD binoculars, but in this case are really monochromatic differences, instead of the "colored" tinting seen in earlier reports we have discussed on a few occasions. Admittedly, it has been quite some time since I viewed solar in monochrome using this filter, and was trying to "correlate" those features with what was seen before in more full spectral views. We can read this "brightness" difference as a temperature difference in these cases of umbral "internal" shade detection, where the view has a more "yellow, or yellowish-deep tan" appearance to it. I hope that clarifies it better.
3. I guess I was speculating as to whether the more complete polarization of the light due to the Brewster wedge (when used with a narrower band filter here) was also affecting some of the surrounding penumbral features, more, because the described "bear claw" feature on the penumbral filamentary extensions seen on Sept. 17 for the trailing spot in AR 3825 were better seen in this wavelength, but I was able to enhance it using some layering in HV's SDO channels, as shown. It did not show very well in the HMI continuum standard channel, but the magnetogram channel with the 1700A AIA underlay seemed to show it better, but still not as much as I could make out in Na 589nm light at that time. The apparent temperature changes in this area seen in the (zoomed in) movie seem to correlate with much of what I could make out at the time. It is difficult to describe the level of VERY fine filamentary structure seen now in this filter, as I recall us having some private discussion on penumbral and limb appearance awhile back when I was observing at 78X in my 120mm binoculars and 105mm APO in full spectrum. Some of this "new" detail is admittedly novel to me in 589 light, and I am still trying to process and understand this. The mating of the 152RFT with the "Na I wedge" was not entirely an accident, more serendipitous, and since doing so is allowing about the best resolution this optic is capable of. I am admittedly in uncharted ground a bit here - which is certainly FUN!

Having said all this, referring to the last (#3) comment on polarization, magnetic effects, etc., it may well be that eye position may be creating an "edge effect" in the filter, allowing hints of more contrasty structures which would be seen if this were in a narrower, pure, "spectral line" filter. Since I NOW have this filter stack as a sort of "integrated module", I also have a twin 1.25" Baader Clicklock insert for this wedge to enable me to use an identical twin focal length EP with a Baader Continuum filter and experiment with switching these during longer sessions to evaluate the differences, between these narrower filters, and even advantages using one over the other, comparing even using WL as a reference as well.  I just have not yet done this as I JUST got started with the Na I filter, as mentioned. I may even look into a true line filter later after playing more with this system for now. I do not know of many (if barely a handful around) using 589nm filtering. If you know of any in your circles, I'd love to compare notes and possibly learn from them! 

 

Even after 50 years at the EP, I admittedly was overloaded by the details hitting my retina and my "wetware" (visual cortex) had a bit of a difficult time trying to process the sheer volume of information! As time permits (life and -for me still- work sometimes gets in the way of science, unfortunately!) still working on doing this - and, I DO have a narrower 3nm filter set coming, which I plan to employ and compare to the current system since I have a LOT of dynamic range in the illumination of these filters and still retain a significant safety margin (for VIS and NIR). It may show more yet! I am admittedly excited regardless. 

 

I also lately have been doing a LOT of reading to refresh my knowledge, and learn newer updated theories on, solar dynamics as it is a fascinating subject. Some of the exciting observations by many this solar cycle has really opened up some interesting novel phenomenon, or at least made these more regularly seen so far. Great times to be doing this! Future plans, as mentioned in other posts, are a heftier tracking mount (for my larger scopes), I also wish to eventually finish re-collimating my 165mm Maksutov, which with my Baader AS ND3.8 full aperture filter would allow me to use my wedge (sans ND3) similar to your Mewlon setup (but smaller), and there might later be an Antlia G-band in the plans for that scope.

 

I cannot imagine your view in that 450mm scope! Must have been stunning! And I thought I was overwhelmed in my recent views - that is awesome - a sunspot as big as "life"; WOW!

 

Anyway, sorry for the rambling! I hope that this clarifies some of these descriptions for you, Christian! I truly appreciate your interest in my recent solar observations in general, and may I go so far to say that I am admittedly honored that I am able to possibly contribute in a small, but hopefully novel way to some of the exceptional work that you and your group in Europe have been doing for solar investigation and research. I have been reviewing your book a lot over the past 2 months since getting it, and it has enhanced my knowledge on solar observing, certainly, and I will likely have to return to doing solar AP after a 15 year hiatus, which will have a bit of a learning curve to it again! 

 

Cheers and good solar - more to come with better descriptive language!!

 

Darren

Edited by Spectrum222, 19 September 2024 - 10:02 AM.

[Spectrum222]

Good points, Bob! Thanks for the reminder to all of us - and also illustrates that results for these filter systems is highly dependent upon the optical system used with them! 

 

 

In MY 152 RFT case, my BEST crossing is at the Helium d-line (showing above in the diagram as the dark red-brown line), at 588nm, so for THAT scope, I suspect the main reasons this D-line filter works so well here is that it is technically AT the optimal line for this doublet. Combined with the shallow focal error at this wavelength in the 152 RFT, and using narrow (<10nm FWHM) pass band, also contributes to offsetting and compensating for minor seeing effects here as well, allowing it to perform more "APO-like" (if I can loosely use that term - lol) at THAT wavelength. Part of the reason I wished to try it in the first place!

 

The next best line in my RFT is the green e line at 546nm, so I suspect my views in a Baader CF at 538nm will be not quite as good, but probably pretty decent still since that green line curve is pretty flat over a wide range, before deviating. TBD.

 

Good points all around! 

 

FYI - I do find the "presentation" with the mid-yellow of the D-line filter to be quite pleasant for my eyes, and the contrast in this system on solar features I find exceptional - whether it has to do with a sort of "dark on yellow" vs "dark on lime-green" having visual perception difference (which I suspect as well) not sure. I DO know that it is amazingly comfortable to view - almost natural in a way - in the 589nm wavelength's tint - for me anyway. A very "warm" view to the tint.

 

Cheers, 

 

Darren 

Edited by Spectrum222, 19 September 2024 - 11:04 AM.

[Spectrum222]

Christian, 

 

You probably have this link, but:

 

http://jsoc.stanford...mi/images/2024/

 

In the "/08" directory, I grabbed the 2045 UT shot on 11 August:

 

http://jsoc.stanford...04500_Ic_4k.jpg

 

the intensity-gram shows a distinct structure of hot or hotter regions within that central complex that we saw that I reported to you last month.

 

Also, found the FLAT 4k on 17 Sept for the central spot where I saw that "bear claw" in Na I light a few days back, and looking over the 15 minute-spaced 4k images on 17 Sept. window from ~1700-1815, you can see penumbral extensions/changes showing pretty well, though NOT nearly as detailed or as finely resolved as I saw then in the RFT on first light in D-line observing. 

 

Just some FYI here. Thanks!

 

Darren

[Spectrum222]

UPDATE on some Na-I D-line finer points:

 

So, I found some interesting things looking more into this setup (more so on the wedge/filter)...

 

It turns out I may have found out why my Lacerta Wedge does SO well with this filter in the optical chain, compared to use with other Wedges I have (APM and Baader Mk1): single polarization! I covered this earlier on a post but worth reviewing before moving on:

 

The fact is that while most "standard" wedges have ~75% polarization at the 45^o angle, the Lacerta, at the 56.6^o Brewster angle, has COMPLETELY single polarization (100% s-polarized light) - the Brewster angle for BK7 glass is at this angle, for the wedge:

 

 

Polarization, then, is impacted by reflection off a surface at the Brewster Angle:

 

 

And as such, this s and p light polarization is mixed a bit at 45^o, and exclusively s-pol at 56.6^o.

 

Note also, that the overall surface reflectance has GONE UP to over 8% (OD~1.07), for the Brewster wedge, versus a "normal" wedge, %R off the surface is in the 4.5% regime (OD~1.3) and a mix of polarizations, with s-pol being predominant, but looks to be maybe 65-35% mix at that angle. This translates to both higher average light throughput in Brewster angle solar wedges, or a wider dynamic range of brightness overall, and single polarization...

 

So, why might this be a potential benefit or change over using a standard (45^o) wedge? 

 

Well, I am still looking into this, but it appears as if F-P filters shift wavelength also based on polarity as well as AOI (angle of incidence). S-polarization often shifts the cut off to the blue a bit more than p-polarization, so the peak shifts blueward and slightly narrows as well. Wider BW is less sensitive to this and so with my 8nm not an issue. But if I start getting closer to 2-3nm, I won't be wanting to have mixed polarizations. It might even have some phase implications as well. 

 

It is also probable (not sure, looking into this) that the single polarized nature of the light coming off the wedge may also benefit with these substrates as p-pol light could potentially scatter in the filter, reducing its contrast, since my scope I am using currently using has an AOI 1/2 angle for the f/5.9 optic and it is ~4.8^o; this is probably non-trivial for < 10nm filters. Even with my 105 f/6.2 Apo, and Baader Mk 1 wedge I did not see nearly as much fine structure even this spring, so I suspect something like this may also be in play - certainly having one less "variable" to worry about does help. Could be just predominantly a blue-shifted cut off, which would maybe give it more of an "edge filter" response... TBD - I will and should check this again

 

Again, somewhat speculatory, admittedly, but looking into this a bit more. I also had a CN member pass on a 2nm 97%+ 589.25nm filter option, and i have asked them about this, so hopefully more info from a source. 

 

I have my new 6nm KO filters coming in, and will be mount those 25mm OD cells into 1.25" empty filter cells. Will share details on that shortly... I'll also shoot a few pics as I make them. 

 

Darren

[gstrumol]

I gather that all of your discussion on the "Lacerta vs the world"   is focused on visual observations you've made.

 

Do you have any images made with the Lacerta vs a 'standard' wedge of your choice so we can see for ourselves the difference?

[hornjs]

Darren, that animation in #6 is awesome!

[Spectrum222]

Thanks Jeff! Yeah that movie mode in HV is pretty fun to play with - very educational. The AIA 1700nm channel is as follows:

 

https://sdo.gsfc.nas...ta/channels.php

 

 

The Log T is 3.7 = 10^3.7 K, or ~5000K. Since this is midway between standard hot ~5700-6000K, and cool minimum Umbra at 4000K, I think it is a good channel to use layered with the HMI channel in general - I usually do 95%HMI:100%AIA1700 as the plage shows better and is more representative in general (when I use WL/Continuum) with Wedges. It also can allow for showing hot areas as you see in that video, and hot edge penumbral and umbral features, which (especially now, using my Na-I filter) correlate better when I use the Magnetogram with it, adjusting to just show the spots well.

 

Gary - Since I have only currently for this scope an AA mount it may not be as easy to do. Also, it admittedly has been ages since I shot solar through ANY of my scopes, to be honest. I moved back to Edmonton 16 months ago and still have some of my cam adapters for my M3 and M1 mirrorless DSLRs to dig through (boxes still sealed). May get to do this sometime. 

 

To be fair, I HAVE not tried the new stack module w/589+BW-Lpol filter in my Baader, so when I get a good decent seeing window, I will change those out and try and be as fair to both during testing. Not knocking my Baader, but I have to say the Lac-2s is REALLY good with this setup. 

 

I had planned to use my 120mm w/Baader+CF and compare with the RFT+Lac2s+589stack. Since the 120 would favor use in mid-Vis, that would be at least a 8nm vs 8nm optimized side by side.  I will also try the Baader again w/589 stack on the RFT as well. 

 

Stay tuned. If I do find those camera adapters, which I sort of hap-hazardly packed I'll see about getting some fast shots. 

 

Darren

Edited by Spectrum222, 23 September 2024 - 09:39 PM.

[Spectrum222]

Darren, that animation in #6 is awesome!

Hey Jeff,

 

Since I am doing things with my "natural camera" I have to make sure I can find a detail or two just not quite showing well or barley on the HMI channel alone. This helps me to SEE what has happened over the window, or understand this observed detail a bit better. Helioviewer is a great resource for some things I find. I have to be a bit careful not to over do the layering, unless for strictly curious reasons, to NOT find things that I did not see. So far have avoided this, as most of that AIA channel stuff only shows some of this detail (and others I did not) - esp. now with using Na-I. 

 

side note: My daughter has two degrees: industrial and architectural drafting/CADD technologist and a biological Sciences degree she's just finishing this year... (don't ask me how she's combining somehow those two!! Must be a bit of a crazy, like her ol' dad... lol); anyway - I have asked her to do up a series of transparent overlays that I can use as Stonyhurst disk templates to overlay with HMI/GONG images for reference. When we're done, I'll be happy to share them when she's done them up for me. I used to be pretty good with graphics, but rusty with GIMP, etc. She'll likely bash these off this week, if her studies are not to heavy. 

 

Bob Y recently suggested to a budding new astronomer about a good book - a field observer's guide. I just ordered it off Amazon.com (I have both accts w/Amazon, as some US site stuff does NOT even show on a CDN search... lol). Looks to have some good stuff too, and never showed initially during a search. Weird. I think Google is losing it! 

 

https://www.amazon.c...0?ie=UTF8&psc=1

 

Looks to be a handy reference as well.

 

Darren

[Spectrum222]

I gather that all of your discussion on the "Lacerta vs the world"   is focused on visual observations you've made.

 

Do you have any images made with the Lacerta vs a 'standard' wedge of your choice so we can see for ourselves the difference?

Gary, one of the things that was NOT my intent was "Lacerta vs world", btw.

 

I DO recall that when using my Baader w/ my 105mm APO, the Na-I 589nm filter was sort of maxed out for brightness at moderate powers. That likely has most to do with it. Now, with 152mm aperture, I should have 2X the light gathering over the 105, and that should help. Incidentally, the Lacerta has (OD4.07-4.3 = ~70%) light gain again, over a standard or Baader Wedge - when running max brightness, so if I combine the difference from what I had before, it IS substantial. 

 

In fairness I will run the Baader Mk1 I have with my stack again and see how it looks, I think that is a fair test. In this situation, with the NB wedge utilization, having the extra optical throughput will likely allow me to run to much higher magnifications with it than alternatives, but I will re-confirm this. BTW, MY Lacerta uses a Baader ND3.0 in it. So it should be a more "even" test in this case. I covered the modifications I did over the "stock" unit in a few other posts as well. 

 

I DO find it interesting though... mostly a curious thing: When I read reports of visual observers using EPs in their setups and mention things like EP #1 looked just a bit sharper than EP #2, I do not see requests for shooting images in a EP projection test to "confirm" results. It IS easier to do this type of testing, using wedges though

 

There are other Lacerta wedge owners out there; and in fact, I was a bit skeptical myself, given how VERY well my Baader Mk1 has done over the years to provide exceptionally contrasty and detailed solar views. I've said before that it is for the most part like splitting fine hairs, as they are VERY close. I think that the Lacerta's key advantages are more pure polarization of the incoming light (as to how/if this impacts the final view in some way is still under investigation), and also the extra potential dynamic range of the design given its additional nominal light throughput (OD1.07 vs ~1.35OD before post-ND3.0 filtering); That last one can be adjusted for with different ND post/pre-filtering choices, so not as big an advantage for sure. Mostly more convenient and handy IMO. 

 

 I DO wish to finishing up on this one post by saying again that my intent was never a "Lacerta vs "the others", or "the world". It is possible that my combination I am using hit a sweet spot in performance with the combination of all optical  elements. Before I do that testing, I wish to do up the new 6nm 589.3nm filters I have coming in as I can not only evaluate that to the current one, but also see if the narrower spectral window is somehow at its near limit with both my current Lacerta and the Baader Nk1 Wedges, and whether this shows these differences using them as well. 

 

I am hoping that conditions will sometime in the next few days allow for this. new Knight Optical filters are due in tomorrow. If all goes well, I can have this done up on Wednesday evening (with some photos of the assembly).

 

Darren

Edited by Spectrum222, 24 September 2024 - 08:54 AM.

[gstrumol]

Gary, one of the things that was NOT my intent was "Lacerta vs world", btw.

 

I DO recall that when using my Baader w/ my 105mm APO, the Na-I 589nm filter was sort of maxed out for brightness at moderate powers. That likely has most to do with it. Now, with 152mm aperture, I should have 2X the light gathering over the 105, and that should help. Incidentally, the Lacerta has (OD4.07-4.3 = ~70%) light gain again, over a standard or Baader Wedge - when running max brightness, so if I combine the difference from what I had before, it IS substantial. 

 

In fairness I will run the Baader Mk1 I have with my stack and see how it looks, I think that is a fair test. In this situation, with the NB wedge utilization, having the extra optical throughput will likely allow me to run to much higher magnifications with it than alternatives, but I will re-confirm this. BTW, MY Lacerta uses a Baader ND3.0 in it. So it should be a more "even" test in this case. I covered the modifications I did over the "stock" unit in a few other posts as well. 

 

I DO find it interesting though... mostly a curious thing: When I read reports of visual observers using EPs in their setups and mention things like EP #1 looked just a bit sharper than EP #2, I do not see requests for shooting images in a EP projection test to "confirm" results. It IS easier to do this type of testing, using wedges though

 

There are other Lacerta wedge owners out there; and in fact, I was a bit skeptical myself, given how VERY well my Baader Mk1 has done over the years to provide exceptionally contrasty and detailed solar views. I've said before that it is for the most part like splitting fine hairs, as they are VERY close. I think that the Lacerta's key advantages are more pure polarization of the incoming light (as to how/if this impacts the final view in some way is still under investigation), and also the extra potential dynamic range of the design given its additional nominal light throughput (OD1.07 vs ~1.35OD before post-ND3.0 filtering); That last one can be adjusted for with different ND post/pre-filtering choices, so not as big an advantage for sure.

 

 I DO wish to finishing up on this one post by saying again that my intent was never a "Lacerta vs "the others", or "the world". It is possible that my combination I am using hit a sweet spot in performance with the combination of all optical  elements. Before I do that testing, I wish to do up the new 6nm 589.3nm filters I have coming in as I can not only evaluate that to the current one, but also see if the narrower spectral window is somehow at its near limit with both my current Lacerta and the Baader Nk1 Wedges, and whether this shows these differences using them as well. 

 

I am hoping that conditions will sometime in the next few days allow for this. new Knight Optical filters are due in tomorrow. If all goes well, I can have this done up on Wednesday evening (with some photos of the assembly).

 

Darren

The "Lacerta vs the world" was a tongue-in-cheek comment because of your fervent advocacy of it (nothing wrong with that, mind you) - hence the added  ! I hope you didn't take offence, as none was intended.

 

And I asked about images not for any confirmation of what you reported but merely because I'm curious and there's no other way for me to 'experience' the difference, short of getting one myself  . But since I already have 2 wedges (a Lunt and an Antlia 393nm, which isn't for visual) and a Baader film, I don't think a third wedge is in the cards 

 

I like your scientific approach to these discussions - keep them coming! 

[Spectrum222]

Hey Gary, no worries, and big thanks for the comments. 

 

I did initially sort of feel like it was a cynical jibe at first (a little, not a lot) until I re-read the post

 

I KNOW exactly what you mean though - this stuff can add up VERY quickly - my CCs prove that!

 

I am also happy to help where I can. I am glad this has been of general interest with folks here, and also being able to chat with fine folks on here like yourself, is a lot of fun. My philosophy is we learn together, and in my case with this setup it is in sort of "uncharted waters"; I feel a bit like Magellan - no detailed exact maps to follow here, unless I'd spend $8k plus for a Na-Quark. (which I MIGHT later do if this feels "worth it")

 

Likely would just get a nice big CERF for it and add my H-alpha Solar Spectrum 0.22A instead. Have been mulling over that! I am not sure whether the red line is tight enough but both the 633 line and 656 lines curve sort of closely to the 588 line in this RFT, so maybe okay afterall (with just a focus shift only):

 

 

That would be fun to have a 6" H-a setup for sure! Likely next big purchase after PERHAPs (based on my results with the KO filters) getting one more, slightly tighter, 2nm 589.2 one ($800, so I will have to see a lot MORE with those over my current filter to justify getting that 2nm one. 

 

Anyway - I am happy to share this with you, as almost NO one is doing any D-line observing or shooting that I have found so far - only one fellow had a Sodium Quark and posted last year in May. That is all. Hoping I'll hear from him, sent a PM a few days ago when I finally found his post. HE's doing visual with his, but hasn't posted anything since on that setup. Here's his post in case your are curious:

 

https://www.cloudyni...sodium-d-quark/

 

I found this AFTER I started on this new path. Fun stuff to be sure...

 

Have a super day and will see what we can see soon!

 

Cheers, Gary! Thanks again for keeping me sane! 

 

Darren

 

 

 

[Spectrum222]

Okay, here's a brief follow-up on the 45-minute solar observations taken at lunchtime!

 

24 Sept 2024, 1855-1942 UT:

 

Darren's pretty nifty 152mm SST (Sodium-I Solar Telescope  ) at ~70X...(13mm NT6)

 

• Wedge tests: As suspected, confirmed that the difference IS noticeable, not so much in detail, but BRIGHTNESS. I was able to set to pretty much max throughput on the Baader Wedge, but had more light still available in the Lacerta - this is more of a reference when transparency drops, but esp. for >90X observations, where a bit more light MIGHT be needed. I was not able to test this today - seeing was variable with only short (10-15s at a time) steady periods. 7/10 average, but did hit 9/10 at times. (hence the 70X limit)
• IMO, both showed excellent details when seeing steadied. I did a ~15 minute run with each, and left the Lacerta in to finish the session. Not a fully comprehensive comparison, admittedly, but that was all I had for lunch window, and seeing dropped around 1935 to getting pretty turbulent - enough to affect most of the finer structural stuff... Likely would have settled, later I am sure, but oh well...
• One thing I forgot to mention, which during testing between the wedges was notable (thanks Gary S!), was that at certain intensity levels, the view begins to "saturate" a bit - one sees this also with WL observing, but the fine structure "window" of settings affects shadings/granulation more significantly, and it starts to drop - likely a contrast/brightness issue; if run on the high side of this but not maximum quite yet, (say 80% to maximum), the central plage starts to wash out a bit. granulation still holds, but the lesser developed plage, visible at lower levels of illumination, start to become harder to resolve. I noticed this during the testing, because I was playing with intensities to evaluate differences between the wedges. I did not check this yet (will next time), but I suspect that under higher powers, say 90-100+, that this would drop back to more nominal and permit finely resolved viewing. I did see this on Saturday when I trimmed the polarizer axis over ~8-10^o but left it when an optimal level was reached. Today this was easier to see, given seeing changes as well. Under ideal, nearly perfect seeing, this may be present to a lesser degree, but since i have only had this "SST" out for several days so far, I need more "data" in that regard to be certain how sensitive these settings really are to the overall view. I think I could run THIS filter with the Baader sans polarizer  like I did on my 105, and get good results. Will check when I have a chance. 
• The best seeing just happened to be during the Lacerta phase. Not by design, but I suspect equilibration may not have been achieved fully during the Baader wedge test. I had planned to re-check until seeing and time constraints decided for me. Now, onto the goodies seen mostly in both - just the interesting top three highlights:
• For brevity, I saw three very interesting things despite the variable seeing:

 

• (1) - two hot spots and significant visible plage structure further north than I usually notice when doing solar prior to this SST view. I estimate closer to 60^o north; I verified this with HV's angular tool: 331-333^o @ 0.875 R_sol. For reference 1.0 R_sol is limb edge, 0 = disk center. North on sun is 0^o:

 

 

(AIA 1700 enhanced for better view of details not as easy to see in HMI channel alone: HMI@60%, AIA1700@100%)

 

• (2) - A central disk region of facular plage that looked a bit like a 3-toed "Cat's Claw"; had nearly-parallel arches and plage-edge shadings which were rather prominent during better/best seeing:

 

(AIA1700 enhanced image again to show structure better).

 

• (3) - Eastern Limb edge - +/- 40^o or so: Facular plage during session was evident to over 1/2 way to the disk center, or at least from 1 < R_sol < ~0.60. A lot of the western structures connected heavily with AR 3836, the new region rotating into view, plage common though AR 3835, and some plage with very interesting shaded edges nearer AR 3834, too. The edge-shaded plage boundary looked like someone with charcoal had lightly brushed the disk accidently with a finger. Really neat!  I could also JUST make out (seeing affected this) a bright region on the leading umbra of AR 3834, on the northern side, approx. size was maybe... ~30% of the umbral area - hard to make out as seeing made it a challenge to see this as well as I have seen on the past Saturday. May have been better later today, but partial cloud has plagued our skies. No joy for a rematch today!

Still, some interesting results, and nifty views, which are rather unique to observing the sun in 589nm NB light. The 152 SST wins again! 

 

Cheers and CS,

 

Darren

[Spectrum222]

Making a 1.25" Narrowband filter:

 

Hi all, 

 

Well my Knight Optical 3nm wide 589.6nm filters came in today. At lunch, since it was cloudy and windy at the time, I began to assemble the unit from the parts:

 

• Actual Filter - 25mm OD x 6mm deep
• 1.5mm(d) x 23mm (id) x 27mm (od) copper washer (to insert and secure the smaller cell)
• 1.25" filter cell - mine were Astronomik empty ones

 

 

These are the filter cells and the actual filters, after unpacking - for some reason my iPhone rotates these images geez...

 

 

The above are the copper washer inserts painted with ultraflat black acrylic these will "hold" the actual filter cells and prevent them from falling through the rear aperture, which is larger than 25mm. These act as a "stop".

 

 

Used 5-minute epoxy and lock-lube ultrafine graphite as adhesive. This is mixed 1R:1G:1H, or 1:1 all parts hardener:resin:graphite, though you CAN easily go 0.5 Graphite ratio and have this work well on larger amounts of resin. The graphite does several things:

 

First, it changes the viscosity of the mixture, making it much less viscous - like honey instead of mustard, when mixed. This allows the composite resin to "flow" slowly into a gap and smooth out better.

 

It also changes the "set-point", and delays it by ~1 minute, and then becomes very tacky/stringy near curing. During curing, it gets very warm, but not hot enough to damage anything. This gives a bit more time to generally apply this composite resin and fill into cracks etc.

 

It also TINTS the mixture a dark black, which for astro applications, is ideal! We want black/dark things surrounding our optics to reduce stray light. The surface after curing can be coated with any decnt paint to flatten further, as the cured surface does have a bit of sheen. That is to taste/application. 

 

It sticks to just about everything, so it makes an excellent, fairly non-toxic choice for adhesive as well.

 

Finally, it has a bit of a better overall bond, and is less brittle over long periods; many epoxies cure and ultimately become rather brittle. This can lead to failure and debonding over very long times. My current 589nm filter being used was done up 16 years ago, and still is going strong with no issues. Graphite-epoxies (G-Es) also handle temperature swings better. Here in Central Western Canada, we get pretty cool temperature over parts of the year, and big swings sometimes too. This resin composite seems to fare extremely well in this regard. I have yet to have ANYTHING I have done up/made, as far as astro accessories using this, fail yet! It can be also easier to wipe during application with IPA used to clean before final cure. 

 

 

After setting the cell on the copper ring, I used 3 "dabs" of G-E resin to affix them to the ring so I could then have the whole assembly inserted into the cell. Time - ~8min curing, after 10 set into ring, applied more with toothpick into gaps between filter cell and 1.25" main cell. In my case today, my little Persian feline "pal" (forgot to close door before starting!) decided to say hello and disrupted my final application a bit, soit was NOT quite as "clean" as I normally do it.

 

Once tested, I will likely add a small overlay to finish the "finished" look a bit. TBD

 

The filter, once done up, can be stored in those nice boxes you can get off Amazon for putting knick-knacks in. Keeps them protected when storing. I added a 1:1 mix of lemon yellow: yellow orchre (Vallejo modelling acrylic paint) and placed a paint dot onto the cells to remind me they are 589nm filters at a glance. 

 

Have not tested yet - but make sure if you try this for yourself, even with alternate bands, watch the ARROW - the carat or point is in the direction of light througput. Many are bi-directional, but not all - this one is optimized to have the main optical cavities in the front. So Arrow points towards the EP.

 

Stay tuned - the cells are very centered, flat/square to the optical path. I am looking forward to comparing these to my current filter. Should be fun! I may first try on my 120mm binoculars - should work well to 70X or so! 

 

Darren

[Spectrum222]

Semi finished for testing:

 

 

Darren

[Spectrum222]

So these are DONE!

 

I added some extra graphite epoxy to form a meniscus on the edge of the filter front, makes it look more "finished". That's why I love using that stuff, as it flows into itself, and fills any voids and smooths out rougher portions. Once you get used to it, very easy to work with. Does a not too bad job I think...

 

Also (not shown as I am awaiting drying) hit the front there carefully with flat black to darken/flatten the frontal outside edge to minimize any reflections:

 

 

Another "sideways" photo - I will get to why this happens ASAP! Sorry - clocking should show it normal though...

 

You can see on the finished filter on the EP, for allowing rotating while applying resin, that the smooth cured finish after 10-15 minutes is a bit "shiny". So, a hit of flat black paint (Vallejo modelling flat black) darkens and flattens the surface reflectance to make it as good as the filter cell it is mounted in, for flatness. This shot is BEFORE application of the paint, BTW. 

 

Here's the FINAL product - looks... decent?!

 

 

All ready to try out next good sky! Wish me luck!

 

Darren

Edited by Spectrum222, 26 September 2024 - 01:13 AM.