PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!!!

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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by Valery » Tue Jun 03, 2014 7:55 am

While PST shows more relief in filaments, the QUARK shows more details in penumbra and at bright surface areas.

Full comparison. Thanks, JP!


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by smerral » Tue Jun 03, 2014 8:02 am

Excellent comparison JP. As Valery says the details are there in the Quark, but the PST mod is a clear winner when it comes to contrast.


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by swisswalter » Tue Jun 03, 2014 4:01 pm

Hi Valery

thanks for that comparison. The pics tell the story


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by jp-brahic » Tue Jun 03, 2014 5:04 pm

In my opinion it is not because the Quark which shows more detail :)

In fact with the Quark the chromosphérique material is missing, look on the image of the quark small spots behind the proms are perfectly visible while with the PST mod one do not see them because it gets more chromosphérique material Which hides the sunspot behind, this is why there is more contrast with the PST MOD and of effect 3D because it gets more of material

in my opinion with the daystar filter the foot of frontally of wavelenght H-Alpha is not also stiff as a standard etalon with air and thus a loss of contrast


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by eroel » Tue Jun 03, 2014 5:10 pm

J.P:
I have 2 Daystar filters, one is a 0.5Aº T-Scanner and the other is an ATM of 0.4.5Aº that have used for years and I can say, that your PST mod is way lower than the 1Aª you think, I would say it is at least 0.5Aª.
I also have stacked Coronado filters (old type 40mm handpicked and matched by David Lunt and Bill Dean) this set is incredibly contrasty and well tuned for just 40mm aperture. On the other hand I have also stacked 90mm Coronado (Meade) with Rich View both etalons, they were also, both perform very good, but the Daystar´s and the stacked 40mm for sure are on their advertised bandwidth, they are much better than my Solamax 90 double stacked.
Best regards and congratulations for your superb modification.
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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by jp-brahic » Tue Jun 03, 2014 5:28 pm

Thank you Eric :)

also think that daystar is in their wavelenght announced. It is just that their cdesign gives less contrast than the PST MOD because their wavelenght has to bend towards the base of the central peak of H-alpha


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by colmic » Tue Jun 03, 2014 5:37 pm

Hi, JP fabulous images as usual :)

Eric, i have the same conclusion:
- last year i made some full discs with my first SM90 + my PST mod in double stack (about 0.4 or 0.5 A)
- this year i have 2 SM90 and the bandwith is not better than with the PST + SM90.

But the image with both SM90 is beautiful on all the disc, not the PST wich show only a small field :)

PST mod is very good with high magnification, other systems offer better in large field.
We have the choice, JP made the choice for high magnification and i made the choice for the full disc :)
Both are beautiful...


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by sullij1 » Wed Jun 04, 2014 12:41 am

I am wondering if this contrast issue isn't simply a manifestation of the two different technologies to produce the H alpha line.

As I understand it Daystar incorporates the natural/organic mica as the bifringent and SiO2 coupled to the multilayer TiO2/SiO2 filters whereas the Lunt, Coronado use David Lunt's panted TiO2 / SiO2 layer technology only. Right? Wrong?

This suggests the TiO2 / SiO2 layering produces better contrast. Yes? No?

None the less both filters produce the bandpass at the proper wave length, they just have distinctly different characteristics in the final photographic image. Agree? Disagree?


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by Merlin66 » Wed Jun 04, 2014 12:55 am

Hmmmm
I don't know enough about the inner workings of the DayStar "solid" etalon to comment.
The "standard" air spaced etalons - I'm not sure where the TiO2/SiO2 coating would be????
The function of the etalon doesn't require these coatings...just a pair of highly reflective, VERY flat (optically) surfaces....

My original opinion still stands...the quality of the Quark images look very "soft" - there seems to be a lack of "crispness" at all apertures....
If the bandwidth is there (which seems to be the case) then the optical arrangement (x4 Powermate/ etalon) must be contributing to the outcome.
Just my 1.3c (after tax)


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by sullij1 » Wed Jun 04, 2014 1:26 am

Colin Cominski posted the Lunt patents some time ago in other threads. You can look there to see the public patent data.

Mark Wagner has tutored us more than once on the Mica etalons.
Last edited by sullij1 on Wed Jun 04, 2014 1:32 am, edited 1 time in total.


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by Merlin66 » Wed Jun 04, 2014 1:30 am

Joe,
As we found on the "patented" PST etalon tuning....patents are one thing, what's applied to the final commercial solution is another.
(All the known Patents are in the Reference Library - under Technical)


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by sullij1 » Wed Jun 04, 2014 2:01 am

Perhaps you missed a couple of papers or did not feel them important enough to place in the library. From Lunt and others. I assure you my summary is correct. I nave the coating paper in my work computer I will post it later if I remember. I have studied them in my efforts to come up with a cheaper way. right now there isn't one. Here is a paper/patent you may have missed that explains pretty well both technologies.

file:///C:/Documents%20and%20Settings/Joe%20Sullivan/Desktop/patents/Patent%20US7397604%20-%20Narrow%20bandpass%20filter%20assemblies%20for%20solar%20telescopes%20-%20Google%20Patents.htm


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by Merlin66 » Wed Jun 04, 2014 2:34 am

Joe,
I think it may have been missed in the "Lunt/Coronado" patent search as it's not one of these.
http://www.google.com.au/patents/US7397604

You may have to help me here... I couldn't find a direct reference to the TiO2/SiO2 coating ????
Interesting comments however on the construction of ITF filters...


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by sullij1 » Wed Jun 04, 2014 3:42 am

It is not in our database. I will try and recover it tomorrow and post it. Sorry.


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by sullij1 » Wed Jun 04, 2014 3:52 am

Ken. not that it really matters as far as exact coating processes, the real point is that Lunt/Coranado use a different approach to cutting the bandpass than Daystar. I am simply suggesting it is this variance in approach that makes the difference. regardless, the difference does exist. Perhaps there are positives in both approaches than can be exploited to produce successful images, each in their own right. It is the user knowing the difference that will be the deciding factor for the user. Perhaps we should not expect the same thing from two different manufacturers and seek to reveal the best qualities in each product.


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by Merlin66 » Wed Jun 04, 2014 4:18 am

OK, found the reference in one of the Lunt patents.
It talks about the construction of the OSF (order sort filter) what we call the ITF filter (front part of the blocking filter assembly)
'''
The OSF has an optical density of at least OD5 within spectrally rejected regions, thus providing blocking levels of at least 10"5. The OSF is preferably structured to operate as a thin-film interference filter, fabricated with hard, refractory oxides of dielectric materials with very low thermal coefficient (<0.003 nm/°C) and a refractive index (on the order of 1.9) significantly higher than that of typical glass. Titania (titanium oxide), zirconia (zirconium oxide), silica (silicon oxide), and titanium pentoxide are known dielectric materials that exhibit these properties.
""
See the following for more detail:
http://www.google.com.au/patents/WO2005111684A2?cl=en


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by Valery » Wed Jun 04, 2014 4:23 am

Merlin66 wrote:
My original opinion still stands...the quality of the Quark images look very "soft" - there seems to be a lack of "crispness" at all apertures....
If the bandwidth is there (which seems to be the case) then the optical arrangement (x4 Powermate/ etalon) must be contributing to the outcome.
Just my 1.3c (after tax)
I have another opinion about the reason of softness.

1. Images by JP have equal resolution and sharpmess on small details.
2. Filaments have different contrast and looks soft.
3. Filaments look soft and not very contrasty on smaller telescopes.

Conclutions:

1. Too long focal length for smaller telescopes - required longer exposures, makes worser signal/noise (grainy).
2. Bandwide is not between 0.3A and 0.5A - it is wider than that
3. On images with smaller telescopes it seems that diffraction establish the resolution limit and adds "softness" to the image.

The drug:

1. Use slow donor telescope!
This helps to have narrower band wide and Spherical Aberration at 656nm is MUCH less than in fast refractors. Also QUARK's optics itself works better (less aberrations).

2. Use 0.5x reducer (between the QUARK and the camera) for imaging. Makes focusing easier, makes 4x better S/N during image reading, shortens the exposure at 2x - helps to freeze atmosphere, helps to have shorter movies duration - less smearing of details on the sun which move fast.

3. Do not use such large extension (camera collimation adapter) as Joe use. This helps to get rid of Newton rings, but also makes QUARK's barlow lens works at more amplification than was designed for image plane at the eyepiece holder end.

4. Use a maximal contrast gamma settings. This will helps to have more contrast images without to big contrast add in the processing (less noisy images).

5. Downscale your final images to about 0.67x (better S/N, less grainy, better crispness).

6. Use a aluminium foil to protect the QUARK from the sunlight - prevent heat load to the QUARK body - helps to cool when change the CWL to the direction which require colder etalon).

Hope this helps to obtain better final results.


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by zorgdotnl » Wed Jun 04, 2014 10:03 am

In case the BF part of the Quark is not efficient enough, maybe you can try to use a BF between quark and cam (or eyepiece) ?



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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by Valery » Wed Jun 04, 2014 3:13 pm

zorgdotnl wrote:In case the BF part of the Quark is not efficient enough, maybe you can try to use a BF between quark and cam (or eyepiece) ?
May be! Good idea to try.


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by jp-brahic » Wed Jun 04, 2014 3:27 pm

I tried of course :) too dark!!!!!

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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by zorgdotnl » Thu Jun 05, 2014 12:16 pm

So it was too dark to catch some changes in the bandwidth? Too bad if it's the case. I just asked this because we tried some dark stuff too: to doublestack the Lunt 100 (BF34)+Daystar 0.6PE, and yes it was dark visually, but after some night vision adaptation, the surface looked .3A-.4A: black filaments and white 'flares' jumping out the view. :shock: :o



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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by fjabet » Thu Jun 05, 2014 1:25 pm

Valery wrote:
The drug:

1. Use slow donor telescope!
This helps to have narrower band wide and Spherical Aberration at 656nm is MUCH less than in fast refractors. Also QUARK's optics itself works better (less aberrations).

4. Use a maximal contrast gamma settings. This will helps to have more contrast images without to big contrast add in the processing (less noisy images).
Hi Valery, I permited myself to quote you partially.

I do not fully agree with you about relatively fast (ie F/D 6) mid size (up to 130/155mm) refractors working in the Ha band. There is some spherochromatism indeed, but nothing dramatic here if the initial setting was make in the green.
Focus compensates about on third of the 3rd order SA, and the longer wavelegth gives some room to stay in the L/4 area. And a lot of older refractors have been adjusted in the red HENE line at the time, that's the case of AP refractors till early 2000'.
On another hand Petzval design have less spherochromatism than equivalent triplet as power is spreaded between both doublets. An F/5 petzval such as the FSQ will perform better, spherochromatism wise, than a triplet. Especially if there is no degree of freedom on the lens spacing such as for Astrophysics.

Of course the perfect choice would be a long apochromat or achromat, or even better the TOA that shows no spherochromatism at all.

Note that the larger the aperture, the more spherochromatism you have. On a 203mm LZOS triplet apochromat at F/7, it becomes relatively important and a longer F/D would be welcome.

You can have a look on my test database here : http://www.airylab.fr/AirylabUS/index.p ... &Itemid=57

Regarding the gamma setting, it's not a matter of SNR. You loose SNR when pushing gamma on the camera, and you loose the same when streching with curves afterward. The only but great added value of the gamma is to help the morphing of the processing software.
Gain, gamma and all those analog settings that change the reponse curve and that take place in the amplifier and A/D converter do not increase SNR or dynamic, they do not create information : they do just the opposite.

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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by Valery » Thu Jun 05, 2014 1:49 pm

fjabet wrote:
Valery wrote:
The drug:

1. Use slow donor telescope!
This helps to have narrower band wide and Spherical Aberration at 656nm is MUCH less than in fast refractors. Also QUARK's optics itself works better (less aberrations).

4. Use a maximal contrast gamma settings. This will helps to have more contrast images without to big contrast add in the processing (less noisy images).
Hi Valery, I permited myself to quote you partially.

I do not fully agree with you about relatively fast (ie F/D 6) mid size (up to 130/155mm) refractors working in the Ha band. There is some spherochromatism indeed, but nothing dramatic here if the initial setting was make in the green.
Focus compensates about on third of the 3rd order SA, and the longer wavelegth gives some room to stay in the L/4 area. And a lot of older refractors have been adjusted in the red HENE line at the time, that's the case of AP refractors till early 2000'.
On another hand Petzval design have less spherochromatism than equivalent triplet as power is spreaded between both doublets. An F/5 petzval such as the FSQ will perform better, spherochromatism wise, than a triplet. Especially if there is no degree of freedom on the lens spacing such as for Astrophysics.

Of course the perfect choice would be a long apochromat or achromat, or even better the TOA that shows no spherochromatism at all.

Note that the larger the aperture, the more spherochromatism you have. On a 203mm LZOS triplet apochromat at F/7, it becomes relatively important and a longer F/D would be welcome.

You can have a look on my test database here : http://www.airylab.fr/AirylabUS/index.p ... &Itemid=57

Regarding the gamma setting, it's not a matter of SNR. You loose SNR when pushing gamma on the camera, and you loose the same when streching with curves afterward. The only but great added value of the gamma is to help the morphing of the processing software.
Gain, gamma and all those analog settings that change the reponse curve and that take place in the amplifier and A/D converter do not increase SNR or dynamic, they do not create information : they do just the opposite.

Frédéric.
I disagree with you, Fred

1. We do not lower the S/N ratio installing high gamma setting! In fact we increase it as we see better contrast on the monitor. Of course we should take into account the limitation of the dynamic range of the monitors. And within it we INCREASE the S/N.

2. All guys here have used fast refractors which are cheap chinese achromats with poor SA at 656nm.

3. The result is the sum of all errors and all contrast loss from objective to the CCD and from the CCD to the monitor/printed paper. And there is NO SENSE to add the contrast and crispness loss by using fast refractors poorly corrected at 656nm.

You can ask Mark Tawnley and he will confirm that I recommended to use a TOA telescopes for both CaK and Ha imaging.

Longer F/9-10 achromats in 3-4" size range are not that too balky vs shorter F/5-6 ones and no sense to make images softer and less contrasty using the latter ones.


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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by swisswalter » Thu Jun 05, 2014 2:27 pm

[quote="Valery

2. All guys here have used fast refractors which are cheap chinese achromats with poor SA at 656nm.

[/quote]


Hi Valery

I protest very clearly :evil:

Is that chinese, cheap and short ? ;)

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Re: PST MOD VS Quark 0.5A°, Allo Houston we have a problem!!

Post by fjabet » Thu Jun 05, 2014 2:38 pm

There is no magic Valery :)

A camera has several metric that gives its final SNR :
- QE
- Well depth
- read out noise (RON)
- Throughput

Plus some over points that are not related to the SNR but which have there importance but that's another story (sensitivity to fringes for ultra narrow band, PRNU for CMOS, unwanted noise correction, shutter type rolling/global...).

More QE = better SNR (more signal vs RON)
Deeper well depth = better dynamic
lower RON = better dynamic and better SNR
More throughput = better SNR for the same acquisition time

Changing the sensor response curve (gain changes the steepness, gamma changes the low light/high light response) does NOT create SNR or dynamic, it is just a dynamic compression, the very same you do with photoshop :)

For the refractor, I have some values at 635 nm at best focus at hand :

- Equinox 80ED : PTV 118nm / 0,972 Strehl
- SW 80ED : PTV 131nm / 0,934 Strehl
- SW Esprit 150 : PTV 214nm / 0,830 Strehl (had coma, bad alignment. Same issue with a 100mm Esprit as well...)
- Televue 127is : PTV 158nm / 0,936 Strehl
- Televue NP101is : PTV 164nm / 0,915 Strehl (Televue are fine but not amongst the best, the cell is very poor...)
- TOA 130 : PTV 76nm / 0,979 Strehl (!) No spherochromatism/UV friendly !
- TOA 150 : PTV 74nm / 0,967 Strehl (!!) No spherochromatism/UV friendly !
- FSQ 106 : PTV 183nm / 0,850 Strehl (set in blue, looks common for FSQ which are rather deep sky imaging oriented)
- FSQ 85 : PTV 86nm / 0,970 Strehl (!!!)
- TSA 120 : PTV 114nm / 0,967 Strehl
- Secretan 108mm F/15 year 1883 : PTV 105nm / 0,952 Strehl (for the fun, this one is mine)
- CFF 102 oil spaced : PTV 100nm / 0,96 Strehl
- Vixen 81ED : PTV 200nm / 0,86 Strehl
- TEC 110 FL (F/5.6 !!) : PTV 121nm / 0,956 Strehl, it's far worse in the blue obviously!
- LZOS 203mm F/7 : PTV 123nm / 0,930 Strehl (not bad at all for such a large triplet)
- AP130 : PTV 137nm / 0,925 Strehl (recent, set in green)
- AP130 : PTV 86nm / 0,978 Strehl (older, set in yellow)
- AP155 : PTV 55nm / 0,989 Strehl (older, set in yellow, recordman I think)
- 80/480 triplet : PTV 140nm / 0,955 Strehl (very generic lens such as TS, Astrotech...)

As you can see, small fast chinese lenses have pretty good results.

But quite old design (FPL51 doubet) are rather poor. But those are very low end.

Frédéric.


Looking for professional reports about telescopes ?

http://www.airylab.fr/AirylabUS/index.p ... &Itemid=57

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