Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Daystar Quark Chromosphere vs Baader SunDancer II

  • Please log in to reply
38 replies to this topic

#26 eblanken

eblanken

    Ranger 4

  • *****
  • Posts: 302
  • Joined: 21 Mar 2020
  • Loc: Portland Oregon Area NW USA

Posted 26 June 2022 - 04:58 PM

Hello giodic & All,

 

I concur with much of what has been said about "comparing apples to apples" in the sense that f/30 and f/24 are different enough that one should use "the same" barlow with both sides of the comparison: I would use a barlow 4.0x "telecentric" to make the closest approach to the native 4.2 or 4.3 internal to the Quark unit. The "best" approach would have two ERFs and Two "Identical" OTAs mounted on the same Mount, but who has all that ?

 

On another note, The Quark actual oven operation can be "augmented" with a simple meter system. I use a Drok USB Voltage and Current meter inline with the USB "A" port on a USB "A" to USB "Micro" cable. I use an external USB "A" Battery that provides many hours of operation and can supply more than the minimum current to power the Quark (about 1.25 A at 5.1x Volts are "typical" with my several Quarks). With this metered approach, I can monitor and see the oven cycle "on-and-off" and "back off from the full-on" as needed. I have standardized my approach using the meter to show me what power is being drawn at any given moment. I find that this "metered" approach appeals to me as an Engineering Scientist. I don't need to see the actual wattage, but can just pay attention to the Amps drawn, since the Voltage available from my "BIG ENOUGH" battery remains almost constant.

 

The Quark uses a PIC Micro-Controller to estimate the PID settings needed to control the "Oven" that "tunes" the Quark. I find that I can keep a close eye on just the current and know all I want to know about the Quark's heating (or Cooling = lack of heating) in a glance.

 

Perhaps this helps some of you Quark owners ? (My meter was about $10 USD on Amazon).

 

Ed (aka eblanken) Blankenship


Edited by eblanken, 26 June 2022 - 05:11 PM.

  • BYoesle and giodic like this

#27 eblanken

eblanken

    Ranger 4

  • *****
  • Posts: 302
  • Joined: 21 Mar 2020
  • Loc: Portland Oregon Area NW USA

Posted 26 June 2022 - 05:35 PM

 Hello again giodic and Bob,

 

Here's what I glean from what you two said:

 

(1) The Baader was "slightly" better than the Quark in your well presented experience, giodic, right ?

(2) Bob's chart from our French expert's tells me that the experiment is pretty valid, given the "subjective" nature of it.

(3) The Baader would probably perform "better" if it was fed f/30 or f/34 or f/36 light, so #1, would be a bigger delta, right ?

(4) The Quark is an "entry" positioned product and Daystar has other offerings "up-the-ladder" that would be more expensive

      AND perform BETTER, BUT AT A DIFFERENT PRICE POINT, RIGHT ???

(5) I am glad to know more about the Baader offering, but it would not help me as much as owning "another" Quark, right ???

     (I have Na & Mg too). I want to try a Helium next (Grin !?!?!?!?). All need to be available at same time for comparison, right ???

 

Ed

 

 

Hi all.

For some time I have been wondering if one filter was better than the other and to what extent, but it seems to me that no one has yet made comparisons between the two.
Finally, this morning I had the opportunity to make a quick visual comparison between a Baader SunDancer II and my Daystar Quark Chromosphere, on a day of strong solar activity, with various protuberances and active regions simultaneously present on the solar disk.

The two h-alpha filters were used, alternatively, on a 4” f/8 Takahashi refractor (FC-100DZ) equipped with a full aperture frontal ERF, obtaining an f/24 system with the SunDancer (telecentric 3x) and f/34 with the Quark (telecentric 4.3x).
As eyepieces I used a 40mm Vixen LT and a 32mm Baader Plossl, first observing in both filters with the 40mm Vixen, and then using the 40mm with the Quark and the 32mm with the SunDancer obtaining, respectively, with the Quark 86x (40mm), with the SunDancer 60x (40mm) and 75x (32mm).

Having said that, my impressions of use were as follows:
- the SunDancer works at 12V DC, while the Quark works at 5V and therefore can be powered with a small and light powerbank;
- the temperature regulation times of the two filters seemed to me to be comparable, but the SunDancer has an external thermoregulator with display, which seemed more "professional" to me;
- given that, obviously, with both filters it is possible to observe only a portion of the solar disk, the details at the chromosphere and prominences level, which can be seen, are substantially the same, but with the SunDancer it is all a bit brighter (especially the prominences).

In conclusion, the SunDancer seemed to me better overall than the Quark, but the owner of the SunDancer agreed with me that, from a purely visual point of view, the two filters do not show such a difference as to justify an almost triple expense for the purchase of a SunDancer.
Perhaps the situation is different if the main use is instead the photographic one.

 

 

Thanks for the report. To be a more valid comparison, both filters would need to be used at the same effective f ratios and aperture. Such is the nature of mica etalons and telecentric systems.

 

So I'd try and locate a relatively inexpensive 4" f10 + refractor for the SunDancer before making a judgement, or replace the 3x telecentric with a 4x.

 

If you go by the filter curves from Christian Viladrich, and take the SunDancer as advertised to be 0.6A at f30, then at f34 the FWHM would be ~ 0.55 A, while if the Quark looks essentially the same as the SDII at f24, the Quark has a FWHM of ~ 0.75A at f34.

 

attachicon.gifFWHMSDII v Quark.jpg


Edited by eblanken, 26 June 2022 - 05:40 PM.


#28 BYoesle

BYoesle

    Cosmos

  • *****
  • Posts: 7,645
  • Joined: 12 Jun 2004
  • Loc: Washington USA

Posted 26 June 2022 - 06:57 PM

Be acutely aware, that you need to experiment with the temperature dial on the Quark to find the best setting on *your* sample. The best setting varies wildly among them, despite what Daystar claims.

The Quark is an "entry" positioned product and Daystar has other offerings "up-the-ladder" that would be more expensive

      AND perform BETTER, BUT AT A DIFFERENT PRICE POINT, RIGHT ???

There's a lot going on here. So I will be as concise as possible.

 

All etalons have issues with uniformity. The better the etalon, the better the uniformity. The better the uniformity, the more expensive the etalon becomes. Given the nature of mica etalon production and testing (or lack thereof), you can't expect an entry level etalon like the Quark to be very uniform, and if you get one that is, you are just very lucky.

 

You also can't expect mica etalon's tuned by temperature to behave the same way at the same temperature setting. Some might be slightly thicker than others, and therefore have a different on-band temperature point. Some may come from a batch of mica that has a different set of densities than another batch - which is the natural variation of the raw material.

 

And there is more than one correct setting for any one etalon. Besides affecting the bandpass (FWHM), using an etalon in different f-ratios will affect the central wavelength of the etalon. Faster f ratios will blue shift the CWL, and it would require a different temperature setting (higher) to be on-band than when that very same etalon is used in a slower or collimated optical configuration:

 

Julia-Trans-Profile-mica-spaced-07A-telecentric-f-ratio15-collimated.jpg

Christian Viladrich. Note as the f ratio decreases the CWL blueshifts and the FWHM widens.

 

Quarks come with no test reports or temperature setting recommendations, can vary in overall FWHM uniformity, and the temperature settings will vary depending on the individual etalon characteristics, and the particular telescope objective diameter and heat it allows downstream (type of ERF), and effective focal ratio it is used at. So you have to be prepared to experiment to find the best temperature setting for a particular etalon and its particular telescope configuration.

 

Added to this is the fact that most beginners getting an entry level Quark often don't really know what an on-band solar image should look like. Prominences are visible over a wide range of tuning (temperature) settings, and this makes things more complicated for the observer to nail down the correct temperature setting. Those coming to the "day side" from the "night side" are usually unprepared for the complexity of sub-angstrom filter use - and mica etalons are generally the most difficult to configure properly for optimal performance.


  • Starman609 likes this

#29 eblanken

eblanken

    Ranger 4

  • *****
  • Posts: 302
  • Joined: 21 Mar 2020
  • Loc: Portland Oregon Area NW USA

Posted 26 June 2022 - 07:38 PM

Hi Bob,

 

Thanks for your inputs. So do you agree or disagree with the statements you quoted ???

 

So in theory, all mica is a "perfect" crystalline structure, right ??? So if one could just count each layer in the crystal and "cleave" it perfectly to form the two planes that make up the etalon, one would "always" get a "perfect" etalon, right ??? (NOT !!!)

 

But at "What Cost ???" you should say, right ??? The problem is in the manufacturable cost details and the "impurities" in the mica, right ???

 

Oh, but you say, "But Ed there is the telecentric barlow quality too and the Blocking filter too and the Polarizer Quality as well", right ???

 

I once dabbled in Audio Sound Reinforcement and Recording: I had a variety of Microphones. Shure Brothers was well represented in my stable. The SM-58 was a model that not only I owned, but also I saw on Broadcast Television often. I had also the 565 model and it was also seen on TV, but more often it was being used in "less critical" applications or "lower budget" shows. Then there was the Realistic By Shure microphone that was available at the local hobby store for even less money. My point is that ALL THREE MICROPHONES USED THE "SAME" moving coil element. The difference was that the SM-58 had the "best", the 565 had "middle" and the Realistic had the "poorest" moving coil elements from each batch that were made. Noone told the public this fact that (often) cost and performance are (sometimes loosely, but often well) correlated.

 

I expect that things inside Daystar are similar.

 

Ed (aka eblanken) Blankenship

 

P.S. My apologies to geodic if I "hijacked" your fine post.


Edited by eblanken, 26 June 2022 - 08:28 PM.

  • giodic likes this

#30 betacygni

betacygni

    Apollo

  • *****
  • Posts: 1,053
  • Joined: 06 Feb 2011

Posted 26 June 2022 - 10:23 PM

You can with mine, on hot days, because it has such a low operating temperature. Other Quarks may be completely different. I've heard of some that require the dial to be turned way up for best performance.

Verify through experimentation.


Clear skies!
Thomas, Denmark

I’ve noticed the same with mine. Forgot to plug it in and it took me quite a while to realize. The other issue I’ve been running into so far this summer is it’s getting too hot, at least the LED goes back to orange. I hadn’t noticed a significant loss of detail when this happens though, so it must be only slightly off temp (outdoor temp has been in low 90s F). Will have to experiment with unplugging it after I get the green light.

Edited by betacygni, 26 June 2022 - 10:24 PM.

  • Astrojensen likes this

#31 BYoesle

BYoesle

    Cosmos

  • *****
  • Posts: 7,645
  • Joined: 12 Jun 2004
  • Loc: Washington USA

Posted 26 June 2022 - 11:33 PM

Hi Ed,

 

The first statement I quoted notes that one has to find the best temperature setting for "your sample." My point is that even for one's particular sample, it will have different temperature settings based on the telescope's effective focal ratio, and the temperature both from within and outside the system. This is the reality of solid etalons, and their optical positioning and greater susceptibility to temperature induced CWL changes. Even air-spaced etalons will demonstrate subtle changes in CWL with temperature changes of both the air and spacer substrates.

 

The second statement is regarding the higher quality models from DayStar, and they would have a different price point. That is correct. The filter maker evaluates the etalon from the quality of the raw mica received and then throughout the manufacturing process to finished and coated etalon, and then the incorporation of the ancillary filters (soft-coated, hard coated, etc.) Then there is the issue of the actual telecentricity of the final optical elements. So yes, all these things come into play.

 

If by your analogy with microphones you're stating all mica etalons use mica - well yes they do! But there are varying qualities of mica, just like there are varying quality of microphone coils. Mica is more akin to diamonds. Some make for good industrial uses and phonograph needles, some rarer ones with the best clarity, color, and purity make for expensive fine jewelry.

 

However, you should take the DayStar statements regarding Quark specifications with a grain of salt: "As each Quark produced may vary from 0.25 - 0.5 FWHM; and each QUARK produced will vary from SE to PE grade, direct side-by-side comparison of one unit vs a different unit does not constitute a standard by which any unit may be qualified or disqualified."

 

In the "real world," here's what Christian Viladrich measured and observed in a Quark he evaluated: Link.

 

Quark-1-10june2022-Profile-tuned-Ha.jpg

 

I will note the asymmetrical etalon fringes Christian attributes to reflections in the telecentric lens system should not be present - if that is the actual cause. My belief is that there is something amiss with the polaroid filter(s) not blocking the birefringent etalon peaks.

 

The only way to really know the quality of an etalon is evaluation by an experienced visual (qualitative) evaluator, along with a technical measurement (quantitative) evaluation.

 

For comparison, here's Christian's evaluation of a 40 mm air-spaced etalon, and here's his evaluation of a PST etalon.


Edited by BYoesle, 27 June 2022 - 01:20 AM.

  • eblanken likes this

#32 BGazing

BGazing

    Surveyor 1

  • -----
  • Posts: 1,634
  • Joined: 25 Feb 2016
  • Loc: Belgrade, Serbia

Posted 27 June 2022 - 01:57 AM

There's a lot going on here. So I will be as concise as possible.

 

All etalons have issues with uniformity. The better the etalon, the better the uniformity. The better the uniformity, the more expensive the etalon becomes. Given the nature of mica etalon production and testing (or lack thereof), you can't expect an entry level etalon like the Quark to be very uniform, and if you get one that is, you are just very lucky.

 

You also can't expect mica etalon's tuned by temperature to behave the same way at the same temperature setting. Some might be slightly thicker than others, and therefore have a different on-band temperature point. Some may come from a batch of mica that has a different set of densities than another batch - which is the natural variation of the raw material.

 

And there is more than one correct setting for any one etalon. Besides affecting the bandpass (FWHM), using an etalon in different f-ratios will affect the central wavelength of the etalon. Faster f ratios will blue shift the CWL, and it would require a different temperature setting (higher) to be on-band than when that very same etalon is used in a slower or collimated optical configuration:

 

attachicon.gifJulia-Trans-Profile-mica-spaced-07A-telecentric-f-ratio15-collimated.jpg

Christian Viladrich. Note as the f ratio decreases the CWL blueshifts and the FWHM widens.

 

Quarks come with no test reports or temperature setting recommendations, can vary in overall FWHM uniformity, and the temperature settings will vary depending on the individual etalon characteristics, and the particular telescope objective diameter and heat it allows downstream (type of ERF), and effective focal ratio it is used at. So you have to be prepared to experiment to find the best temperature setting for a particular etalon and its particular telescope configuration.

 

Added to this is the fact that most beginners getting an entry level Quark often don't really know what an on-band solar image should look like. Prominences are visible over a wide range of tuning (temperature) settings, and this makes things more complicated for the observer to nail down the correct temperature setting. Those coming to the "day side" from the "night side" are usually unprepared for the complexity of sub-angstrom filter use - and mica etalons are generally the most difficult to configure properly for optimal performance.

Bob, I was under the impression that, if Quark is on-band at 0, CCW is blue wing and CW is red wing, and CCW is lower temp and CW higher.

Wouldn't your diagram suggest that for lower f-ratios Quark would tune into the blue wing as CWL would shift into the blue?



#33 BYoesle

BYoesle

    Cosmos

  • *****
  • Posts: 7,645
  • Joined: 12 Jun 2004
  • Loc: Washington USA

Posted 27 June 2022 - 09:14 AM

Hi BGazing,

 

I don't own a Quark, and therefore don't know which direction is increasing the temperature vs. decreasing the temperature setting.

 

 

Wouldn't your diagram suggest that for lower f-ratios Quark would tune into the blue wing as CWL would shift into the blue?

Yes indeed - faster f-ratios = numerically "lower f-ratios," blue shift the etalon. This is because any increased ray angles - in this case instrument angles - entering the etalon gap blue-shift the CWL based on the formula for the CWL: 

 

λ = 2 n t cos θ

 

λ is the wavelength

n is the etalon gap refractive index

t is the etalon gap thickness

θ is the incident ray angle

 

The blue shift due to faster (numerically lower) f ratios would require higher temperatures to get the etalon on band. A higher temperature increases the etalon gap spacing due to thermal expansion, and red-shifts the CWL.

 

DayStar does not specify a FWHM of the Quark, or what the f ratio or temperature setting for an individual Quark etalon is to obtain its best FWHM setting. You therefore are required to determine this by observation at your telescope's particular f ratio in combination with the built-in telecentric amplifier. As the diagram from Christian demonstrates, the best performance of the etalon will be in a slow (long f ratio) system, and this will have a lower temperature setting than when using the etalon in a faster (lower) f ratio system.

 

For the DayStar Quatum PE filters (and formerly the SE), there is a bandpass specification and a temperature setting. It is not specified at what f ratio this bandpass is achieved at.

 

On the other hand, Solar Spectrum specifies the bandpass for the etalon when used at f30, and indicates the operating temperature for that bandpass when used at f30.


  • eblanken likes this

#34 BGazing

BGazing

    Surveyor 1

  • -----
  • Posts: 1,634
  • Joined: 25 Feb 2016
  • Loc: Belgrade, Serbia

Posted 27 June 2022 - 12:29 PM

Hi BGazing,

 

I don't own a Quark, and therefore don't know which direction is increasing the temperature vs. decreasing the temperature setting.

 

Yes indeed - faster f-ratios = numerically "lower f-ratios," blue shift the etalon. This is because any increased ray angles - in this case instrument angles - entering the etalon gap blue-shift the CWL based on the formula for the CWL: 

 

λ = 2 n t cos θ

 

λ is the wavelength

n is the etalon gap refractive index

t is the etalon gap thickness

θ is the incident ray angle

 

The blue shift due to faster (numerically lower) f ratios would require higher temperatures to get the etalon on band. A higher temperature increases the etalon gap spacing due to thermal expansion, and red-shifts the CWL.

 

DayStar does not specify a FWHM of the Quark, or what the f ratio or temperature setting for an individual Quark etalon is to obtain its best FWHM setting. You therefore are required to determine this by observation at your telescope's particular f ratio in combination with the built-in telecentric amplifier. As the diagram from Christian demonstrates, the best performance of the etalon will be in a slow (long f ratio) system, and this will have a lower temperature setting than when using the etalon in a faster (lower) f ratio system.

 

For the DayStar Quatum PE filters (and formerly the SE), there is a bandpass specification and a temperature setting. It is not specified at what f ratio this bandpass is achieved at.

 

On the other hand, Solar Spectrum specifies the bandpass for the etalon when used at f30, and indicates the operating temperature for that bandpass when used at f30.

Thank you very much. If, as it might be reasonable to assume, going CCW is a lower temperature setting and I have to dial it all the way CCW to get it on band even at f/7.4, it means that a longer f/ ratio scope might fall off the reach of my Quark's dial. 



#35 ch-viladrich

ch-viladrich

    Viking 1

  • -----
  • Posts: 989
  • Joined: 14 Jul 2013
  • Loc: France

Posted 27 June 2022 - 02:14 PM

Thank you very much. If, as it might be reasonable to assume, going CCW is a lower temperature setting and I have to dial it all the way CCW to get it on band even at f/7.4, it means that a longer f/ ratio scope might fall off the reach of my Quark's dial. 

Indeed, on the Quark I tested with the spectro, when you go CW, temperature increases, and the CWL goes to the red.

 

If you have an IR thermometer, you can check the temperature of the filter (through the eyepiece end). It is not very accurate, but it could give you some information.


  • BGazing and eblanken like this

#36 Astrojensen

Astrojensen

    James Webb Space Telescope

  • *****
  • Posts: 15,208
  • Joined: 05 Oct 2008
  • Loc: Bornholm, Denmark

Posted 27 June 2022 - 02:44 PM

Hi Thomas,

 

Is your Quark standard Chromosphere or Combo version?

 

 

Valery

Hi Valery

 

It's an old standard Chromosphere version, one of the earliest ones, I believe. 

 

 

Clear skies!

Thomas, Denmark 



#37 Astrojensen

Astrojensen

    James Webb Space Telescope

  • *****
  • Posts: 15,208
  • Joined: 05 Oct 2008
  • Loc: Bornholm, Denmark

Posted 27 June 2022 - 02:48 PM

I’ve noticed the same with mine. Forgot to plug it in and it took me quite a while to realize. The other issue I’ve been running into so far this summer is it’s getting too hot, at least the LED goes back to orange. I hadn’t noticed a significant loss of detail when this happens though, so it must be only slightly off temp (outdoor temp has been in low 90s F). Will have to experiment with unplugging it after I get the green light.

The LED on mine *never* turns green, no matter how long I leave it on. It shines bright orange, when the heater is on, then begins to blink, when it has reached the operating temperature. I've stopped paying much attention to it and tunes it "by eye", how the Sun looks in the eyepiece. 

 

 

Clear skies!

Thomas, Denmark



#38 eblanken

eblanken

    Ranger 4

  • *****
  • Posts: 302
  • Joined: 21 Mar 2020
  • Loc: Portland Oregon Area NW USA

Posted 27 June 2022 - 03:06 PM

Thank you Christian for your great work. Bob has shared your graphs both here and on other posts.

 

What you say as far as the CW = Red = Higher Temperature and CCW = Blue = Lower Temperature rings true for me.

 

I have done some simple time studies and input power ( approximated by input current) and have found that the quickest way to

get a Green LED is to have the "Cold" Quark (really room temperature) and time how long until the Green LED comes on:

 

CCW = -5 takes the shortest time and CW = +5 takes the longest time. Zero position takes an intermediate time.

 

I conclude that +5 = most Red shift = most expansion of the Mica takes the longest time for the Heater to reach SETPOINT.

 

Qualitatively, one can sense with their hand that the outer barrel of the Quark is hotter at Most Red = +5 = CW  than at Most Blue = -5 = CCW.

This is best done in a cool room in the house on a rainy day when the weather is not cooperative.

 

Using one's body temperature to assist the heating process can get you from room temperature to Blue "faster"

by simply using your hands as a warming device or "blanketing" the Quark's metal outer barrel.

 

I believe that the Quark contains a PIC micro-controller that takes into account the time history in a PID-like manner, so

it is easy to be "fooled" by just the Yellow vs Green LED. One really needs to "study" the oven's power vs time graph.

There is a STEADY Yellow, a Bilnking Yellow, a Blinking Green and a Steady Green, so notice 4 states, not just two.

The Quarks that I've studied  look a little misleading when stepping back down from +5 = Red, because they are

relying on the ambient temperature to "cool" the Mica etalon and not the heating of the oven during "one click CCW" operation.

 

Ed (aka eblanken) Blankenship


Edited by eblanken, 27 June 2022 - 03:15 PM.

  • BGazing likes this

#39 giodic

giodic

    Sputnik

  • -----
  • topic starter
  • Posts: 45
  • Joined: 14 Apr 2019
  • Loc: Roma, Italy

Posted 28 June 2022 - 01:06 PM

 Hello again giodic and Bob,

 

Here's what I glean from what you two said:

 

(1) The Baader was "slightly" better than the Quark in your well presented experience, giodic, right ?

(2) Bob's chart from our French expert's tells me that the experiment is pretty valid, given the "subjective" nature of it.

(3) The Baader would probably perform "better" if it was fed f/30 or f/34 or f/36 light, so #1, would be a bigger delta, right ?

(4) The Quark is an "entry" positioned product and Daystar has other offerings "up-the-ladder" that would be more expensive

      AND perform BETTER, BUT AT A DIFFERENT PRICE POINT, RIGHT ???

(5) I am glad to know more about the Baader offering, but it would not help me as much as owning "another" Quark, right ???

     (I have Na & Mg too). I want to try a Helium next (Grin !?!?!?!?). All need to be available at same time for comparison, right ???

 

Ed

Hello Ed,

(1) Right.

(3) Yes, right. I think the Baader surely performs better than the Quark, if it is fed f/30/34 light. The point is: how much better?

(4) Right.

(5) Yes right. Already having the Quark, it worth upgrade to a Baader, or it is better to go simply to DS with a Lunt 60mm module (plus at lower cost)?


  • eblanken likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics