SolarChat!

Bob Yoesle

My preference it to loosen when not in use, as this will allow the foam ring to "relax" back to "normal" and relieve any stress on the silicone buttons that constrain the the edge of the etalon plates.

Bob Yoesle

Hi James and Alexandra, Unfortunately, Aaron's methodology and equipment was not ideal and suspect for making such sweeping claims - a 70 mm telescope used at 850 nm has at best a resolution of 3 arcsec. I suggested setting up a topic in the experimental part of the forum, the 'prominence and filame...

Bob Yoesle

I'm not trying to be argumentative, and I'm all for curiosity and skeptical inquiry. However, here there is no theory, and just one persons observations. Arron's opening statement is not in line with skeptical inquiry or the scientific method: I have discovered these loop or bow like structures and ...

Bob Yoesle

I think you have processing / stacking artifacts rather than filaments. I would agree. In 50 years of solar observing I have never seen anything resembling these curved structures in continuum. continuum_full_disc.jpg I can if I choose to detect something like them when imaging. Continuum 15 07 201...

Bob Yoesle

Well done!

Bob Yoesle

Sounds like the electronic temperature control module and/or display has a problem and will need to be replaced. Quantums, especially PE versions, are now quite expensive and therefore valuable. I would get the specs off the etalon which will tell you bandpass, the on-band temp. setting, serial no./...

Bob Yoesle

Yes, both are interference filters. But they have different constructions. Etalons are generally much narrower in bandpass but allow multiple harmonics to pass, while bandpass interference filters are wider in bandpass but better blocked for a single filter construction. I'm not sure what the filter...

Bob Yoesle

The LS50 appears to have a rather small sweet spot to begin with, and the LS50 image appears to show it is centered, but slightly off-band, with the periphery of the sun's disc more on-band. The real angular size of the sweet spot is dependent of the ratio of the focal length of the collimator lens ...

Bob Yoesle

The first commercial H alpha solar telescope that I know of was the one I first looked through in 1968. It had been advertised in Sky & Telescope beginning in the late 1960's. Marvin Vann Solar Telescopes 1 (2).jpg I grew up in San Jose California - now known as "Silicon Valley" - wher...

Bob Yoesle

Steve: The link you posted above goes to "Page Not Found."

Bob Yoesle

I don't use a PayPal account - their fees are a rip-off.

Is there a non-PayPal account credit card or debit card method available? I usually see this method of payment alternative on most PayPal payment sites. It does not show this on the link provided above.

: PayPal Options.png (34.86 KiB) Viewed 162 times

Bob Yoesle

You don't need to replace the wedge.

Extract the sheared off bolts and replace them with new ones. If you can't do this, use a high temperature epoxy and glue the heat sink back in place and you be good to go.

Bob

Bob Yoesle

The rusted ITF filter should only be replaced with the Maier ITF replacement filter, the BelOptik ITF replacement filter, or the BelOptik UV/IR block on KG3 filter.

Bob Yoesle

Can't see the original pics you posted, but as Mark states, looks very uniform - good to see the customer service has been good.

Bob Yoesle

Theoretically the Baader Continuum would be a good choice, and would be less affected by poor atmospheric seeing than a bluer wavelength. I have found it gives very good results: Cotinuum filter.jpg Bob Yoesle The better optical performance is theoretically due to the fact that most telescope optics...

Bob Yoesle

The BG38 filter is apparently used mostly for brightness control and some IR blocking only to about 900 nm, and additional IR blocking is needed beyond 900 mm. KG3 can provide this additional blocking out to 2500 + nm. However, the combination of the two would be quite dim at 656 nm: BG38 v KG3 2 mm...

Bob Yoesle

Hi Peter, You don't need a new etalon, the one you have just needs new spacers which are thinner. Getting the correct spacer thickness is as difficult - or can be more difficult - than polishing the etalon plates themselves. The current spacers you have are simply too thick, and the etalon CWL is th...

Bob Yoesle

The Baader Research Grade TZ3 (German language text above) is also pretty good with a 0.8 Strehl at 393 nm, which IS diffraction limited, and likely better than the preceding optical components - and generally better than what the atmosphere allows for ;-)

Bob

Bob Yoesle

Hi Peter, For the links, the "tidier" method is to use an equal sign and paste the link url inside the bracket symbol where you will see the linked word or words highlighted. see this link With regard to the SV50, it looked great in 2016, but the etalon appears to show signs of an increase...

Bob Yoesle

The Feathertouch focuser is one of the options you can get from Lunt. It's a $223 USD upgrade from the helical focuser ($320 vs $97 USD when initially ordered).

Bob Yoesle

Hi David, I have imaged and viewed with a LS152 DS, and it worked fine. What do you see visually when using the DSII? If you're using the same 3.5 x Barlow for both the SS a DS images (they look to have the same image scale), then the DSII is the problem. I note you stated that it had the issue prio...

Bob Yoesle

Hi JohnD, Ditto with the negative (inverted) disc images. IMO they are a fad and horrible for evaluating image quality. If you must blend in prominences to the disc (resulting from parasitic continuum passing through single etalon systems), it is much better to use a negative prominence version, as ...

Bob Yoesle

Hi Christian,

Since AiryLab is no longer making anything, I would be interested in the Baader TZ3 simulation results, as it is specifically designed for both Ha and CaK use.

Best wishes,

Bob

Bob Yoesle

Shouldn't be a problem but don't forget that nobody has used a C6 before for Halpha, so some experimentation my be needed. Not exactly true, as a 6 inch SCT is apparently what Mark Wagner of Solar Spectrum uses with a Baader DERF: M Wagner's H alpha rig SM.jpg Mark should therefore be a good resour...

Bob Yoesle

Front etalons generally offer the best contrast uniformity compared to internal etalon systems, and almost every double stacked filter system will offer much better contrast performance than a single etalon filter system. Another general "rule" is that a double stacked filter system seems ...

Bob Yoesle

I just learned that spectrohelioscope pioneer Fred Veio passed on October 2, 2022. I spoke with Fred on the phone a couple of times many years ago when wanting to get to something beyond my DayStar filter. Fred was very generous with his knowledge and willing to help out with construction if I decid...

Bob Yoesle

For tuning the etalon as proposed in a rear double stack arrangement it would be interesting to see if the DIY mechanical pressure tuning method would be superior to the built-in tilt tuning of the etalon...

Bob Yoesle

- if the f-ratio of the telescope < f-ratio of collimator, then the objective of the telescope is vigneted. This is like having a telescope with a smaller aperture (= D * f-ratio telescope / f-ratio collimator), - if the f-ratio of the telescope > f-ratio of collimator, there is no problem. The onl...

Bob Yoesle

Lack of machine shop capabilities is the root of all solar telescope evil.

Bob Yoesle

BRAVO!

Bob Yoesle

Uncoated Newtonian's are not used for H alpha, but for white light and CaK filter implementations. The Coronado MEADE etalons are now notorious for having a high CWL, which induces the banding you have, especially when double stacked. As noted by Dennis, the Quark (also an entry level filter system)...

Bob Yoesle

Yes, we noticed Bob's AS!3 quality graph as well. We only get graphs like that when AS!3 has found a single bad image and thinks for some reason that it is fantastic ie. sometimes when the camera gets a tear line through the image because the buffer has overflowed. AS!3 really loves these ones :) I...

Bob Yoesle

It's been awhile since I've done any significant amount of imaging, but this thread piqued my curiosity again to do some comparisons between RegiStax 6 and AutoStakkert!3. For a while I've mostly used AS!3 for stacking and RS6 for wavelet sharpening, but have recently tried waveSharp as the updated ...

Bob Yoesle

Thank you Bob. So do you think that the risk of failure is high? I've to spend about 1.900 € Yes, most of the Meade etalons I have seen or heard about are mediocre at best. It's an unfortunate situation with the etalon quality these days from Meade. Honestly, I would not buy a SMII or SMIII etalon ...

Bob Yoesle

The problems with the Richview etalons is that their CWL can be rather high, and when tilt-tuned they suffer from significant banding. When Richview compression tuned, excessive central spacer pressure distorts the etalon gap and the FWHM becomes rather large. A combination of tilt and compression m...

Bob Yoesle

My original comparison of RS6 to AS2 showed RS6 was definitely better for detail on the limb: RS6 v AS2.jpg It appeared AS3 had corrected this problem: RS6 v AS3.jpg Since this seems to have changed back to the AS2 problem rigel123's AS3 images, it seems there could be some setting(s) in AS3 (or a r...

Bob Yoesle

Hello Andrew, Bob is wrong. And people who quote what some manufacturer employee? I am not wrong. I queried and got direct responses from Bill Dean and Brian Stephens, who were not just "employees" - they were who originally designed the PST telescope at Coronado Tucson in the early 2000's...

Bob Yoesle

So sad to learn of this tragedy. I will very much miss his wisdom and expertise.

Best wishes for his wife Patricia, brother, sons, and other family and friends through these difficult times.

Bob

Bob Yoesle

I have no info on the Lunt modules, but is suspect the main narrow element - a clear yellow non-mirrored transmission filter which looks similar to the CaK blocking filters that were used by Coronado might also be a hard-coated dichroic filter. From what I have seen it might be sandwiched with anoth...

Bob Yoesle

I'd assume the LS40 is nearly identical to the LS35 (see first post of this thread), and the LS40 etalon will be supported equally and uniformly around the perimeter of each etalon plate, and the etaon is seated on the same type of silicon foam rubber pad as the PST and other etalons. The ERF is an ...

Bob Yoesle

Assuming you are going to use a telecentric configuration, I would opt to put the etalon with the larger clear diameter first. Theoretically, there should be no difference - real world reflectons may become more problematic with the PST etalon following. Typically the blocking filter incorporates fi...

Bob Yoesle

I just queried Brian Stephens (Tucson Coronado, Lunt Solar) regarding PST tuning:

It is Mechanical compression between a Teflon ring and silicone foam.

Bob Yoesle

Hi Dave, First, I've never owned a Ha PST. My conclusions regarding the PST and compression tuning are based on the following information: I too once thought that tilt-tuning an etalon worked by increasing the light path through the etalon. But this would seem to increase the CWL, which made no sens...

Bob Yoesle

I aimed my PST at the Sun and you can see the Sunlight reflected off the Etalon on the inside of the telescope tube and when I tune it on band the reflection moves because the Etalon is tilting... You can see it yourself by looking down the tube at Etalon as you turn the tuning ring and watch it ti...

Bob Yoesle

It is not compressing the spacers at all , it is deforming the plates around the spacers. That is why the silicone is trimmed to even out etalon while it is crushed. Emphasis added. As an engineer and some one who made optics for 40 years including designing solar instruments you can not get enough...

Bob Yoesle

For the most part Marty is correct, especially if the objectives focal ratio is equal to or larger than the collimator lens. However, if the objective's focal ratio is smaller than the collimators, the effective aperture of the objective will be reduced to effectively what it would be for the collim...

Bob Yoesle

Not sure that the right answer for your purposes, but if it is, that what happens when theory meets reality. There will likely be few if any f24 COTS lens to be found. It's the same situation with large negative collimation lenses as well. But on the other hand you could find a larger lens with the ...

Bob Yoesle

Brilliant idea!

My concern would be that the uniformity, thickness, and length of the silicone for the pressure piston would have to be very uniform. If not, the piston might not compress equally around the etalon periphery. Worth trying to see what happens...

Bob Yoesle

This thread clearly states that the PST etalon is pressure tuned, not pitch tuned. Then, however, the silicone pad, which by its stiffness determines the degree of compression of the etalon, should be homogeneous to avoid tilting. Exactly. I will love to see how well this will work - nice job! I'm ...

Bob Yoesle

That looks great!

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