SolarChat!

Bob Yoesle

Ouch! I try to use visually every few weeks and retune if needed. Peter: Can you post the image at the limb that isn't the ubiquitous mixed negative disc/positive prom? I ask because this is typically used to hide the double limb of the photosphere apparent with single stacking, which should disappe...

Bob Yoesle

Hi Doug, Single stacked always seem to give a much more even full disk than double stacked. For the most part the disc evenness with double stacking etalons is highly dependent on the individual etalon parameters and quality. With good uniformity etalons needing minimal tilts to get on-band and remo...

Bob Yoesle

Hello Stu - love the data driven approach! NOAA has a new "experimental" prediction posted here . cycle_update.png Hathaway and Upton have revised their prediction as well. PredictSSN_23_24_25.jpg I wonder how the 'double peak' of this cycle will pan out compared to previous cycles. Mark I...

Bob Yoesle

You're pretty much stuck with paints for small internal surfaces. Some people add carbon black to regular flat black paints. Spray paint fogging with standard flat black can work well; and if applied while paint is still tacky, blowing in a little carbon black (some use back printer toner) can also ...

Bob Yoesle

1) A pressure-tuned internal DS for the 50 would usually use smaller collimating lens optics and another etalon, and might cost as much or more than a front etalon. Internal etalons suffer from more scattered light (more optical surfaces) and increased field angle magnification, reducing the size of...

Bob Yoesle

you may find one of the many modders on here has a gold tube they are happy to sell - you could just swap the objective over then. A great idea! However, since you'd be replacing the rusted ITF coating on your OEM objective with likely a later un-ITF coated objective, you'll also have to get a stan...

Bob Yoesle

Looks nice Stu!

Bob

Bob Yoesle

It's the same nonsense DayStar stated dismissing double stacking etalons.

It revealed either complete ignorance of etalon optical principles and the filter making industry, or was marketing propaganda for fooling the less well informed consumer.

It's buyer beware for either circumstance.

Bob Yoesle

Indeed, the small amount of physical pressure needed to effect a gap spacing change is remarkable.

Bob Yoesle

My first H alpha filter was a 1976 DayStar 0.7 ATM, and it was superb. Mark Wagner (then at DayStar) replaced the failed blockers around the mid 90's. I really regret having sold it. If you check the DayStar website , you can see how they now leave a lot of wiggle room in their warranty. The SE (for...

Bob Yoesle

I believe from reliable sources this is in the works.

Bob Yoesle

So far the Alluxa 1.0 CaK filters appear overall to be the better of the two between the Chroma and Alluxa, with the chroma having less uniformity. And while the 2.2 PST CaK filters also appear very uniform, they have a wider overall bandpass in real world implementation. Double stacking with either...

Bob Yoesle

Question to Christian et al; has the filter from a CaK PST or from a Lunt been scanned with the same resolution etc as the ALluxa 1a? Mark scanned my 2.2 A PST CaK filter and Chroma 1.0 A CaK here: CT v PST CaK filter curves.png Here's the Alluxa 1.0 A CaK filter (no tilt): Alluxa 393.37 1.0 M Wagn...

Bob Yoesle

Awesome Christian, especially the limb prominence image!

Bob Yoesle

I asked Baader about using the RG 0.4 and 0.7 focal reducers intended to be used for the TZ3 focal reducers. They responded: "We actually haven't tried it out yet, as a reducer usually is not necessary for the CaK-filter (which operates at the native f/ratio of the tellescope), and the SolarSpe...

Bob Yoesle

It looks like it might be AR coated. Once you remove the ERF cell and flip it you can reverse the ERF itself to maintain the OEM orientation. Has anyone tried it with PST etalon? See previous post in this thread. The PST is already similarly mechanically pressure tuned, but needs some additional sup...

Bob Yoesle

There are actually two separate issues. Spherochromatism is telescope dependent - some perform very well like the Takahashi TOA 130 & 150 at only f7+. The Synta ED100/900 I have used also seems to perform quite well at f9 with single 2.2 A and double stacked CaK filters (1.4 A) - although I' sur...

Bob Yoesle

The bad one looks clearly like it's a double peak. I guess that means there are effectively two etalons in there (presumably due to some separation in the mica?). Mica is a birefringent crystal , and I wonder if it is possible that one or both of the polaroids are defective (or misaligned) and ther...

Bob Yoesle

Found this video that attempts to explain fundamentals of how SolarQuest works. Anyone else got a detailed explanation? Hmmm... I find video succeeds in explaining the fundamentals of how the SolarQuest works quite well. Surprised that you don't find that video's explanation detailed enough. If you...

Bob Yoesle

Setting up and tuning is quite difficult and I am not very satisfied with the results. FD still isn't the best, although longer focal length images don't look terrible. It'll be another birth before I tune it out. Hello Petr. The image processing by Stu is very good. But as Valery notes, it seems t...

Bob Yoesle

Hi Christian, Mark told me about a new CP that is available with high overall transmission: the Breakthrough X4 CPL . It doesn't look too good for 400 nm or less. But their sales page has a graph which shows the Zeiss T* POL CP having possibly a relatively good transmission below/near 400 nm: X4_CPL...

Bob Yoesle

If you're almost on-band with little tilt then there is really no reason to implement a compression tuning system for an external etalon use. It may also be unnecessary for double stacking with a telecentric arrangement at the focuser side of the optics. In ay event, very little compression is actua...

Bob Yoesle

As Mark stated, the double limb at 0.3 A and as seen in your images is minimal. I think I would be more than satisfied with that, rather than messing with the hassle and reduced image brightness of double stacking. But then again there's only one way to find out - try it and see how the pluses and m...

Bob Yoesle

Noticed the Operating Temp is 97 F (36 C). 97 F is really low for a solid-spaced etalon unless you're in the arctic. The typical operating temp. should be 30 or more degrees F higher (~ 130 F or 55 C) - minimum. The serial number 080807 indicates the filter manufacture date is August 8, 2007 - so th...

Bob Yoesle

Depends on how far off-band the native CWL is. A small amount of compression would likely be OK. If it needs a lot of compression, the etalon gap without central compression will get pretty uneven, and the etalon FWHM will widen considerably.

Bob

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 160 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 ...

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