36 replies to this topic

[George9]

This is my experience with the chromosphere Quark, part I. I was going to wait until I had checked it out in the 130mm scope but decided to put that in a part II. Here is a WARNING right up front: I tend to get excited about this stuff, so do not be overly influenced by it. All this stuff costs a lot of money.

(For background, I have several hundred hours experience with a 60mm Coronado ASP60 DS and SS and probably a couple hundred hours with a Lunt LS80 DSII and SS. I have only looked through rear-mounted filters at star parties, but I have been doing it for about 17 years, and I have looked through a 10-inch Lunt and a 7-inch AP with a Solar Spectrum rear-mounted filter. I am strictly visual.)

I used the Quark in an AP155 f/7, a Pronto 70mm f/6.8, and a 30mm f/6.7. I used a Televue 32mm Plossl, Meade 26mm original Super Plossl, Televue 21m Plossl, Denkmeier 21mm eyepiece, and Televue 13mm Ethos. And I used a Denkmeier II binoviewer with the Denk 21 eyepieces and Powerswitch but no OCS.

Bottom line is that I cannot believe how good it is. I am seeing things in the AP155 that I have never seen before. This is the closest I have ever seen to some of the amazing high-magnification images posted on this forum. It is not as good as Harald's, of course, but it is just a big jump above my beloved LS80 DSII. Like going from a 80mm refractor to an 8-inch SCT on the night sky. Take filaments, for example. If you have ever looked at the Veil Nebula in say an 8-inch SCT and then gone to an 18-inch Dob, that is how it felt going from filaments in the LS80 versus the AP155 with the Quark. Very fine details. I had one flare in the AP155, and it had great detail. Fibrils and mottling all over the place. Even sunspots had detail not normally seen in my H-alpha scopes. Spicules were very finely detailed and obvious.

Prominences are spectacular. I did not realize how much very faint prominence activity is going on in addition to the brighter proms. And also the proms have different shades of red. The most detail I have ever seen in a prominence was through a 10-inch at NEAF in 2012 during a giant eruptive prominence. The view was messy (prominence was brighter red on a darker red sky), but amazing resolution. It looked like a rain storm. The Quark was not quite that good, but it tied the 2014 NEAF view through the 7-inch AP scope with a SolarSpectrum filter and slightly surpassed the Lunt LS152 DSII view (but we did not get to tweak that at all). Other than the 10-inch, the Quark on the AP155 was as good as any prominence view I have seen.

In the 30mm scope, the image was similar to a good PST. In the 70mm Pronto, it was very similar to my LS80 and my old ASP60. I actually looked through two Quarks (I think). With the first one I was blown away by the proms and liked the surface details. It seemed equal to a 0.65-0.7A front-mounted filter. I gauged it more contrast than my old ASP60 SS, and the same or just less than my LS80 SS, and they are both in the 0.65 to 0.7 range. But I think that a rear-mounted filter sees bigger angles and so the same nominal bandpass (e.g., 0.5) might look a little wider (e.g., 0.65) mounted in the rear; I am just guessing this. And if you read the DayStar Web site describing the view through different bandpasses on rear-mounted filters, my Quark was about 0.5A or maybe slightly wider. (Worst case, that would mean that the Quark in my AP155 would be equivalent to putting a Coronado 155mm SS filter on the front.) Anyway, I asked Sean of Daystar if my Quark was on the wide side, and he sent back what I think is another Quark that seems narrower, with not quite the same proms, but more obvious surface structure. The great thing, though, was that the detailed filaments, fibrils, spicules, etc., were visible in both filters. So I know that one way that DayStar can afford to offer the filter so cheaply is to not guarantee a bandpass, but the good news is that in the range I saw pretty much everything was visible in both. (The other great thing is DayStar's product support.) Here are some more detailed comments:

Sweet spot: Very good on this front. In my single eyepieces, I did not notice any sweet spot. Only in a binoviewer in one of the scopes did I first notice a large (very good) sweet spot bigger than two-thirds of the total field. I have always found that binoviewers seem to decrease the size of the sweet spot. Probably has something to do with pushing the blocking filter further into the light path, but I am not sure. Anyway, I cannot find a sweet spot at all now, even in the binoviewer. So more or less, no sweet spot issues.

Evenness: Pretty much perfect here. The old T-scanners used to have a lot of blotchiness. The disk would be deeper and lighter red in blotches. There is no sign of this here.

Contrast: As noted above, the contrast with the Quark seemed about the same as a good front-mounted filter rated for 0.65 to 0.7A. I found that it was about as good or better than my old ASP60 SS, and maybe not quite as good but very close to my LS80 SS. The second Quark seems even better than my LS80 SS. It does not have as much contrast as a double-stacked filter. That is not surprising because as David Lunt pointed out, the main gain from double stacking is not narrowing the bandwidth but rather changing the shape of the transmission curve so that the filter lets through less light off band. So my LS80 DSII clearly has higher contrast, but also a dimmer image. I was able to find subtle (i.e., dim and small) active regions in the LS80 DSII that were invisible in all the other filters.

Brightness: It has a very bright view, brighter than either my LS80 SS or my ASP60 SS. I found that to be helpful at the higher powers and not a detriment at the lower ones.

Vignetting: The etalon is 21mm, so any field stop wider than that will not show any more sun. That is about a 25mm Plossl. I like having a 32mm Plossl anyway because sometimes lower power lets you see more subtle features. I find that the disk just fits inside the usable field in my 476mm focal length Pronto, and that the tall proms are cut off when the disk is centered. So for a full-disk view, I would rather pair it with a shorter focal length scope.

Binoviewing: Great for binoviewing. The internal telecentric Barlow acts as an OCS, so you do not need another. No problems with focus in my Denkmeier II binoviewer with a Powerswitch (21 Denk eyepieces). Basically, that is all I do now.

Power need: I like the optional battery. Its blue LEDs are a little confusing (they light up even when it is off if light hits the solar cell) but it works very well. After stepping on the wire and fortunately pulling out the other end of cord (not the Quark end), I decided to play it safe. I got a 6-inch USB to micro USB cord and used a plastic tie to hold it to the narrow waist of the eyepiece. Then I attached an 8-foot USB extension cord to that, and then to a 2.1-amp 120v converter or 12v converter. That way, when I trip over the cord, I do not destroy the Quark's micro-USB port. Eventually my 6-inch cord will break, but I can replace that for $10.

Warm up: It takes about 20 minutes. Not a problem for my AP155 because that takes a while to set up anyway, but it limits the quick look use.

Storage: I am keeping it in a waterproof Pelican case with a tin of desiccant. It does not fit inside its plastic case with the 6-inch cord attached, but I figure the waterproof case should be enough.

ERF: I got the Quark first to see if I liked it, with the plan that I would buy an ERF for my AP155 only if the view was impressive enough. At first, I looked through in quick looks using only the Baader UV/IR cut filter on the 2-inch diagonal to make the call. As noted above, I was impressed and decided to buy an ERF. I got the Baader D-ERF, which costs more than the Quark. The DayStar version costs less than the Quark. For the 70mm Pronto, I just use the UV/IR cut filter.

Tuning: Tuning takes a while to get to the new temperature. But the good news is that it is centered well at the middle position. My LS80 DSII is way easier to move off band. But at least the Quark has the option to move in both directions even if it is slow.

Eyepieces: I found that all the eyepieces I listed above worked pretty well, even the 13mm Ethos. The only problem with the latter is that the exit pupil was so small. But no aberrations.

Price: For only a little more than an Ethos eyepiece, you get a great H-alpha filter. You may need to add an ERF, which could double the cost. But that is still way less than an $11,000 LS152 DSII or even my $5000 LS80 DSII. The savings come from not specifying the bandwidth too precisely and I think also because they can use such a small blocking filter before the telecentric Barlow (if it followed the Barlow, it would have to be 21mm like the etalon). I think it will compete strongly with their own ION line (also 21mm etalon, but you can specify the bandpass and you add your own telecentric Barlow) but their more expensive Quantum filters with their larger etalons are still desirable. The Quark may end up being an entry to their Quantum filters.

In summary, I am somewhat surprised that not everyone is getting one. It seems perfect for someone with a 30-to-100mm Lunt or Coronado who happens to own a larger refractor and always wanted to complement it with a rear-mounted filter. It just works.

As your only H-alpha filter, here are the issues:

1. Limited magnification range. The 4.3x telecentric Barlow, which is driven by the need for a high focal ratio, paired with the 21mm etalon means that you are not going to get an exit pupil much over 1mm (about f/30 divided by 30mm eyepiece). Lower-power eyepieces do not add to the true field because of the etalon. And on the high end, you usually will not benefit from an exit pupil smaller than 0.5mm, especially on a low-contrast object. Therefore, the Quark would make the most sense as your only H-alpha scope if you have a range of refractors to put it in (e.g., 40-60mm and something larger).

2. Warm-up time. I really do not mind needing a power source, especially with the optional battery. But waiting for it to warm up means no quick looks. That is fine for the 155mm, which takes some time to set up. But the 30mm could have been a nice travel scope.

Personally, I will not be giving up my LS80 DSII. Quick looks, portability, and still the best contrast I have ever seen on a full disk in any telescope. But it cannot get to the resolution of the AP155 with the Quark, which shows much that could never be seen in the LS80. They are a perfect combination.

I congratulate DayStar for producing this filter.

George

[tomharri]

How hi-x can you go?
Are you limited to around 150x max like doing white light solar?

[CarlDD]

Hi George
a question if I may.
When binoviewing with the Quark, is the optical train:- telescope, diagonal, Quark then binoviewer ? or is it :- telescope, Quark, diagonal then binoviewer ??
I'm just curious.

Thanks for an excellent write up.
Best Regards
Carl

[George9]

To tomharri, I am using higher powers. 220x is my normal in the AP155 (21 Denks). 146x is the minimum I can go (32 Plossl). And I sometimes use 290x (high power setting on Denk), and that seems a little high. The Ethos was 360x, which is too high. My seeing is not unusual in any way. E.g., I can see the sunspots shimmering, but the power is still useful. Having a bright image helps. In white light with that scope, I am usually in the 118-155x range, but 240x also works well. (I would think that white light would take magnification better than H-alpha.)

Carl, I use ERF, telescope, diagonal, Quark, then binoviewer. I have not tried the other. (If you are using a UV/IR cut filter instead of a front-mounted ERF, then obviously you need that first before anything else.)

George

[bill1234]

George,
Thanks for your excellent review.
I also have questions.
Why did you return your first Quark ?
What is OCS ?
What is the cost of a 155mm erf?
Would you recomend it to someone purchasing there first or only H
Alpha setup?
Looking forward to part II.
Bill

[CarlDD]

Thanks George
Best Regards
Carl

[LarryAlvarez]

Thats pretty exciting from a visual point of view. I looked into them when they came out and was initially turned off by their extensive return policy. It sort of makes pre judgements about the buyer. But its a good thing if they are willing to work with you through any issue with the unit. I look forward to part 2.

[sullij1]

Thanks George, this review answers a lot of questions the visual guys have been posting. Truly an excellent review.

[George9]

Here you go, Bill:

Why did you return your first Quark ?

I was careful not to say "return" because I just asked Sean to check it out. In fact, I literally said I wanted it back. I had never owned a rear-mounted, heated filter before and I was not sure how it should perform. I saw the 0.5A specification and assumed it should look more or less like a double stack. I found that it felt more like a 0.65-0.7A single stack. Only afterwards did I figure out that perhaps it was due to the angles in the rear plus of course the shape of the filter curve (for the DS). I was happy with it because even at 0.65-0.7A, imagine owning a 155mm front-mounted filter. That's what it felt like. Later on, I also found on DayStar's ION page a description of what you should expect in their filters, and the filter was in fact delivering DayStar's description of 0.5 or so (perhaps 0.5-0.6, but clearly better than their description for 0.6). I think Sean sent me back a narrower one just because he knew my interest in the disk details.

What is OCS ?

OCS is an Optical Corrector System used with binoviewers generally to correct for the aberrations that a prism introduces and also to serve as a mild Barlow to push the focal point back so that the binoviewer can come to focus.

What is the cost of a 155mm erf?

$900 from DayStar and $1500 from Baader. The Baader is reputed to be optically superior, but the DayStar can handle different frequencies should you desire to use it for other filters in the future.

Would you recommend it to someone purchasing there first or only H-Alpha setup?

If you own both a 40-60mm refractor (i.e., focal length less than 450mm, and focal ratio less than about 8) and a larger refractor, then it can make sense as an only H-alpha. If the large refractor is 120mm or less and not a Petzval, then you can get away without the ERF. But you'll always have to wait for it to warm up. I guess the Quark could be a first H-alpha and then you could later add an LS60 or similar if you want something for quick looks. Personally, I really like having both (LS80 and Quark).

George

[bill1234]

Thanks again
Bill

[Joves]

Fantastic posts, George.

Thanks for the effort that has clearly gone into compiling this report!

[R Botero]

George
Great post!
I have an AP152 and may follow you down the rabbit hole!
Thanks
Roberto

[George9]

Thanks, all. The AP152 is a great scope and should also be a good match. You'll be stuck with a little higher magnification than my 155, but not by much.

George

[ValeryD]

Thank you, George for so interesting report.

BTW. Can you show us a photo or two of your USB safe solution?


Thanks,

Valery.

[Philip Levine]

thank you George,
Interesting and informative write up.
Phil

[George9]

Valery:

Here are some shots of my electricals. I use a black cable tie to hold a 12-inch (not 6-inch) USB-to-microUSB cable to the Quark. One question is which way to thread the cable under the tie. The way I have done it ensures that the cable never slips, thus protecting the Quark but also putting the most stress on the cable (by bending). Flipping the cable 180 degrees would make it bend less but risk slipping under the tie when it is yanked.

The other image shows what I now use. I have a 10-foot USB extension, the optional battery, a spare 12-inch USB-to-microUSB cable that is also used to charge the battery, a 12-to-5-volt 2A converter, and a 120/240-to-5-volt 2A converter. (I keep the charger that DayStar provides as a spare and also the adapters and cables that came with the battery.)

So the Quark goes to the attached USB-to-microUSB, to the 10-foot extension, and then to one of the battery, the 12v converter, or the 120v converter. And I can be charging the battery simultaneously using the spare 12-inch.

George

Attached Thumbnails

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[George9]

Second photo. George

Attached Thumbnails

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[George9]

PART II

This will be shorter. I tried out the Quark on the AP130EDFGT today. I just used the 2" UV/IR cut filter, but I would add an ERF if I were going to use this extensively. (I may make a converter cell to use my AP155 D-ERF on the 130, but I suspect I won't need it.)

The view was great, about what you would expect, somewhere between the AP155 and the LS80. After going back and forth, I would say the the AP155 had greater wow factor. The AP130 felt more like an impressive LS100.

I was comparing the LS80 DSII at 140x with a cloak versus the AP130 and Quark at 167x. The contrast of the LS80 showed more active areas, but the resolution and brightness of the Quark on the 130 showed more details in most structures, especially the spicules and fibrils.

I have to admit that I was hoping the 155 would beat the 130 to justify the hassle of the 155. If owning a 5" refractor is like owning a bicycle, owning a 6" refractor is like owning a boat. Always something up and a money pit. Need a bigger mount, tripod, weights, case, car, house, etc. Each change causes a bunch of other changes. Putting that bias aside (or trying), I would say that the 6" does have a stronger visual impact, and I am glad that I have it, but I would not suggest that it is necessary to swap the 130 for a 155 for using the Quark. They are sufficiently similar.

By the way, on white light using a Lunt wedge, I see less difference between the 130 and 155.

George

[ValeryD]

By the way, on white light using a Lunt wedge, I see less difference between the 130 and 155.

This is absolutely naturally. If we take a marginal example, when the Sun is just pure blank white disk, then we will see NO difference at all!
So, as less details, as less the difference and vise-versa.

For examples, I see less difference between 100mm and 55mm telescope in CaK than in Ha.

[George9]

That makes sense, Valery.

Wonderful flare this morning, and here is what surprised me on the Quark-AP155. In the LS80, it was a bright, meandering line through the AR, as usual. In the Quark-AP155, it looked more like numerous tiny points of light arranged in a wavy line. Is that normal for a flare? Almost like a tight star cluster, but arranged in a line. Great proms today, too. They are small but detailed.

George

[George9]

Also, the 13 Ethos worked pretty well today in the Quark and AP155. George

[George9]

PART III, based on many more hours of use. Some differences from the first impressions:

 

Quark in the AP155: This has become increasingly impressive, perhaps because I hit some days with a little better seeing. I do not have the right terminology for this, but you actually see the fine plumes in the active areas. I mean it looks like numerous flames alternating dark and light. Not just the fibrils that I see in my LS80, but one level of detail finer. And as I mentioned above, when seeing was very good during a flare, it looked like many fine points of light arranged in a row instead of a single solid line. It feels like a new level of detail, unlike the smaller scopes. (Today seeing is terrible, so it looks nice but not amazing. Proms still great even in worse seeing.)

 

Quark in AP130: This had an excellent view, but did not quite get to the next level like the 155 did. Instead, it looked like a finer and brighter version of what can be seen through a 90 to 100mm scope. Spicules were great and fibrils and mottling were nice. Prominences were also excellent.

 

Quark in 70mm Pronto: I compared it to the LS80 SS stopped down to 70mm. Fairly similar. The Quark was brighter and had better contrast, but the LS80 SS could get down to lower power.

 

Sweet spot: Still very good, but now I understand it. In my single eyepieces, I did not notice any sweet spot; there is a small drop off in contrast only at the very periphery, where you will not notice it. Only in a binoviewer did I see a large (very good) sweet spot about three-quarters of the total field and only on one side. I think the cause is the binoviewer sags a bit in the Quark adapter, increasing the angle and going slightly off band on one side. The non-sweet area is still very close to H-alpha, so filaments are still visible but less dark and prominences are visible but less clear. I actually found an Ellerman bomb because I saw a bright spot at the periphery in the binoviewer that almost disappeared in the center of the field. At one point the sweet spot shrunk to half the field and I realized that I had accidentally detuned the Quark turning the temperature knob one click counterclockwise.

 

My main setup now is having the AP155 side-by-side with the LS80 DS, switching the binoviewer back and forth, usually with the Lunt eyepiece in the other. The LS80 tells me if there is something interesting going on somewhere on the sun, and I zoom in with the AP155.

 

To re-answer Bill's question, I think the Quark could be a great first H-alpha scope. Easy enough to use and good enough view that it won't turn people off. As an only scope, I would rather have the two. I used my LS80 175 different days last year, so quick grab and go is critical for me.

 

George

[bill1234]

I can only push my LS80 to 120x with good seeing. I sometimes 

want more. 

 The cost of an ERF is the only thing holding me back from trying one.

I hope someone has one on a large aperture scope at NEAF next year.

Thanks for update....

 

.

[George9]

I am certainly going to try to be at NEAF with everything. Perhaps we can enlist a few newcomers, too. George

[tornor]

Extraordinarily informative post, thanks.

 

I am considering using a Quark with a TeleVue NP-101 (f/5.4) and a Denkmeier Binotron-27. Therefore magnification issues are critical. To get a full disk view of the Sun, Daystar says that focal length should be below 450 mm. But the Power x Switch on the Denkmeier bino's should actually reduce the focal length when you push in the lower power arm. Have you tried that? Did you reach focus? Full disk? Thanks! //Tor