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New Quark Chromosphere, is it flawed?


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So after a lot of back and forth, I purchased a new Quark Chromosphere and the initial impression left me wondering if it is one of the "bad ones". So out of the box the most obvious feature was some creasing over one of the filters, visible as distorted reflection when a bright light is being shinned from the eyepiece end. It affects about 1/3 of the total area (and it looks like a pie graph sector) while the remaining 2/3 have nothing out of the ordinary. In the telescope, 80mm F6, the same area has a few small "bubbles" when looked at without an eyepiece in place (telescope pointed towards the sun of course). These "features" do not seem to affect the view in some dramatic way BUT the field of view appears to be split in half, roughly, with the affected half having obviously less contrast. That being said, a couple of counterclockwise clicks of the adjustment knob seems to improve things a bit, yet still the unaffected area performs better. For this test I moved across the FOV a plague and observed how visible or contrasty it remained. With the knob set at 0, essentially the plague was invisible over almost half of the FOV. Unfortunately, I am located too far north and the sun barely makes it above the horizon at best, so a more rigorous test is rather difficult if not impossible. I would really appreciate if some of you Quark owners could give me some feedback based on how your samples look/perform.

Thanks in advance! 

 

P.S. I am purely visual observer, and for this test I used 25mm and 40mm plossls. 

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With hydrogen alpha you do sometimes get sweet spots depending on the etalon quality where areas will be on band better than others. Your description however sounds extreme and I wouldn't expect such quality. Some vendors test their quarks because of quality issues, id suggest you speak to the vendor. Fast scopes also are not ideal for good contrast variation but I don't find too much of an issue in my f5.9.

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Many thanks for your reply Elp! A lot of quality issues have been reported in the past for this device, so I did not expect perfection. However, I cannot accept that any quality is "good enough", there must a reasonable baseline. The seller seemed willing to sort out the situation when I expressed my concerns following my first impression. I am leaning towards returning it, so your opinion helps me a lot!

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I was a bit hesitant getting a quark myself for the same reason and first opted for a Coronado pst because at least I could repair it if needed. The quark however does produce a magnitude better views and you have the benefit of using it easily with other scopes. I hope you get it sorted.

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When I decided I had 'outgrown' my PST, I considered a Quark.
The large number of issues reported (about 4 years ago) did not tempt me to spend.
I could see possible arguments with the dealer about my scope letting down the quark, etc.
The idea of heating and cooling the etalon didn't quite sit right with me.
At the end of the day I bought a Lunt LS60. A known product with few complaints.

After purchasing, I attended an astro show. Taking the opportunity to talk to some retailers, without letting on that my wallet was already empty.😄
Specifically I asked about how they could sell complete Daystar solar scopes for less than the cost of a quark. Was it etalon quality?
'No idea' was one retailers response. Another said they are £100 off today - show price - you should buy.
The honest dealer said it is a lot of money to spend and needs thinking about.

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Daystar use their lowest quality etalons for their quarks, this is known though not advertised. It depends how much one wants to spend, Lunt's are very expensive and very good. Coronado were the first in this field to mass produce and made the pst so more people could enjoy ha solar viewing, their Solarmaxs are also pricey. As an individual you'd have to weigh up the options of what you want to do and how much you're willing to spend. I bought my quark for a good price so I figured if it needed to be sent back to Daystar for repair it'd still be cheaper than getting another solar scope.

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Daystar etalons and Lunt/Coronado etalons are completely different items.  The latter are specially coated glass plates separated by a very thin air gap and the tuning is either by pressure or tilting of the etalon.  The Daystar etalon is a cleaved mica chip which performs a similar Ha effect and is adjusted by heating.

Daystar have little or no control over the quality of each chip, it is what it it is when cleaved.  Daystar then grade the chips, the best go into research level instruments and the rest go into those of descending cost down to a level that Daystar judge to be acceptable.  No doubt many are discarded completely.

Unfortunately the parameters for acceptance seem quite wide, hence the variation in performance reports.     🙂

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Many thanks Carbon Brush and Peter Drew (same goes for Elp who I thanked already), your feedback and insight is valuable to me! I need to share some updates from today's noon that muddy the waters a lot. Today we got clear skies and I manage to test my sample for about 2 hours. The test was held indoors due to the prohibitively low temperatures through a double glass door (of the float glass kind) and the sun at 5-8 degrees elevation. The setup was 80mm f6, 1.25'' UV/IR cut filter positioned about 70mm ahead of the Quark and 40mm NPL, 25mm Celestron Plossl and 18mm BCO.  

I went through, initially, the following temperature tuner settings CCW 5,  CCW 3, 0, CW 3 (didn't try CW 5 since it was already worse at CW 3). In short, roughly half of the FOV is on band from CCW 5 until CW1, the other half from CCW 4 until CW3, room temperature about 23 Deg.  From CCW 3 to CCW 1 the contrast was pretty even visually.  

Now I should make a short stop and provide some background, I have only viewed through a PST before (not mine), which was BAD (!), like much worse than plain white light. As such, I do not have hands on experience regarding what is (well except from my BAD PST one) good, decent or great. My reasoning is very much aligned with Elp about H-Alpha equipment. For my case (cost, space, availability e.t.c.) it was (and is) Quark or nothing, so either a usable Quark or nothing.  

Parenthesis closed. 

I saw a lot of sun features, practically everything that can be seen in the following image from: gong2.nso.edu/HA (hopefully I am not breaking any rules here): 

20221216101212Lh.jpg

The CME at the upper left corner, even appeared (I believe) blue shifted since contrast was better with a couple CCW (colder?) tuner positions. I estimated that most contrasty and even FOV is at 2-3 CCW tuner positions. When looking at the Etalon without an eyepiece, there are some slightly brighter/darker spots... which cause some brightness variation throughout the eyepiece's FOV, but only apparent in a picture, like the attached one (let me apologize in advance for the horrible picture quality, handheld mobile phone camera and no processing, but should be sufficient for representing what I mentioned above), visually nothing sticking.   

To sum it up: if I was a seller I would have many points for promoting this sample. As a buyer without a good past experience as a reference, I am having a hard time faulting my sample based on what I saw today and also considering that I will be using it only for visual. Therefore, I am leaning towards keeping this Quark as is, because it does seem within what Daystar promises to deliver and the view is certainly pleasing (also considering that if already good enough, an exchange might return a worse sample). 

I would love to hear your thoughts over this (positive) update. 

 

1671197658131 (2).jpeg

Edited by GrAgrK
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Bit hard to say without experiencing it first hand. With the quarks there's generally a sweet spot where it works great on one setting and once you've found it that's it, because it's controlled electrically it relies on the unit maintaining the temperature and hence being on band. I would expect the whole view to be on band though, not half half.

With the PST the etalon is physically deformed until it's on band, once it's on band all visual aspects are on band (sunspots, prominences etc), though I have read some users do experience their views having areas in the fov on band and it tapers off away from the sweet spot. You may be experiencing a similar thing with your quark.

From my experience, solar observation takes some training, not excessively. I sometimes have to sit with my eyes glued to the eyepiece without moving away or catching any light not coming out of the eyepiece and just stare at what you're seeing. Within a minute or two your brain will start to distinguish what it's seeing from the bright and low contrast areas and detail will start to show. Covering your head with a cloth of some sort will also help with not catching any stray light with your eyes (much like night time viewing). Eyepieces make a huge difference, the ones with internal reflections will be poor (you'll know as the area around your fov (internal barrel) will be bright causing your view to bloom), even Televue plossls fail in this regard in my use. I have a 30mm NPL which was okay but similar to the TV. The best I've used is the WO 9mm (the 15mm suffers a little with internal reflections) and a Celestron Xcel LX 12mm, everyone's eyes however are different.

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  • 2 weeks later...

Thanks Elp! I might have some updates to share soon. So far, I have to agree with what has been said above. After further consideration, my view at this point is that this product is not being taken seriously by its manufacturer. Though, for the marketing part they score 5*. On the bright side the seller, to his defense, seems willing to resolve the situation. Either within specification or not, if real world performance is "meh" one cannot light heartedly accept whatever he/she gets. In the meantime, a picture converter from RAW unprocessed. 

20221223_122255_edited.jpg

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I have a Quark built into the Solarscout telescope from Daystar. To say I'm delighted with it would be an understatement. I've had for nearly two years, and it is by far my most used telescope.

However, it is the only HA scope I have looked through, so I don't know if it is good, average or poor.

What @Elp said in the above post is very good. Training your eye/brain to tune in to the view, covering your head, and finding the right eyepiece, is all good advice. I too found that TeleVue eyepieces did not produce the best view. I prefer Baader 32mm plossl or Vixen 30mm NLP.

It does sound like there may be an issue if there is an obvious difference between two halves of the field of view, but you really need to try it outside rather than through a window.

Also, your images (afocal?), look very similar to what I can manage - I'm not an imager at all but sometimes want a visual record of interesting features. A pink circle with bits sticking out is as good  as it gets with my phone!

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As a rough guide, visually a quark view will look like this in terms of detail:

1541490713_BlueMarbleinSunlight-10-10-22-doimg-Copy_034617.thumb.jpg.6f2cfb5507c4fc94306106b1af217a1e.jpg

It will however be very bright and in the red band of spectrum. They'd be more granularity to the surface detail than in the image visually from the above which will scale up slightly by your scopes aperture. The above is from a Coronado PST shot in mono, it's a 40mm aperture scope 400mm focal length.

With the quark when seeing is good and you're using a high power eyepiece it's as if you're near the sun physically and seeing it in detail, a bit like an SCT view of the lunar surface.

I haven't managed to image through my quark yet but many people have done it very well.

Edited by Elp
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