Not uniform contrast with my Daystar Quark

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Roman
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Not uniform contrast with my Daystar Quark

Post by Roman » Thu Jun 22, 2017 10:39 am

Hello all,

I am newbie here and also in solar imaging. I have Daystar Quark few weeks and for now I'm using it with GSO Newton 150/750mm (@100mm off axis mask) for testing. Today morning I tried it with small refractor SW 80/400mm. I'm not sure what I'm doing wrong, but I still loosing contrast in the centre of the field. Its most visible on prominences. At the upper left corner they are pretty nice and contrasty, but if I move them to the centre of the field, they loose contrast and become almost invisible. I tried turn the tuning knob, but this is the best I can get. And it doesnt help with contrast in the middle of the field.

As far as I red this forum I assume I have a bad copy. I just want to know opinion of someone with more knowledge than me :).

My temporary setup is: Newton 150/750mm (@100/750mm) + 1.25" Baader H alpha 7nm + Daystar Quark + ZWO ASI 1600 mono.
Today's morning setup: SW 80/400 + 1.25" Baader H alpha 7nm + Daystar Quark + ZWO ASI 1600 mono

There are two images from today morning for comparison. No flats, no tilt (Newton rings ... I know).

Upper left corner:
Image

Center:
Image


Some images I took as a test images:

Image
Image

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Re: Not uniform contrast with my Daystar Quark

Post by solarchat » Thu Jun 22, 2017 11:42 am

Hey Roman,
Welcome to our little forum. We have a lot of pros here and Im sure someone will help you out. Im an air spaced etalon man myself so I don't know.
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Re: Not uniform contrast with my Daystar Quark

Post by marktownley » Thu Jun 22, 2017 5:43 pm

Hi there and welcome to the forum!

A couple of questions - the last 2 shots i'm guessing were taken with the reflector? If so did you use the 2 degree off axis snout that is used with the combo quark when used on SCTs/Maks?

First 2 pics are the 80/400? Top left is vignetting - asi1600 is a huge chip with a diagonal measurement greater than the etalon size in the quark. Regards the uniformity / contrast of the image, I would stop it down to 60mm, get a better f-ratio for which the quark is designed, I would also do away with the 1.25" 7nm Ha filter which i'm guessing is on the end of the Quark? I bet that is giving you some wavefront distortion which won't be helping, a UV/IR filter on the nose of the diagonal would be better.

Give a try and let us know how you get on!

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Re: Not uniform contrast with my Daystar Quark

Post by Roman » Thu Jun 22, 2017 8:39 pm

Yes, the last 2 are the good one I took with Newton. I used flat field to get rid of newton rings (to some level). I ordered (Rowan?) tilting mechanism from TS so I hope it helps to remove them. I'm sorry, I don't know what that "2 degree off axis snout" is. If you mean how I changed the aperture - I just made a 10cm hole in the cartoon :D and put it in front of the Newton instead of cap. Off axis because of secondary mirror obstruction. I'm not using any ERF filter.

Yes, the first two pics are with refractor 80/400. There is a lot of vignetting with ASI 1600. Its just temporary camera for this kind of images, I will use my ASI 290 in future. I wanted to show where is the place with good contrast - in the corner of the image field. I took the second image with Sun in the center to show that filaments are almost invisible in that part of image.

I have also refra 80/600, I think it has better ratio for Quark configuration. That 7nm Ha is on the rear of 1.25" diagonal. Sorry, I forgot to mention it. The light path is: SW 80/400 + 1.25" Baader H alpha 7nm + 1.25" diagonal + Daystar Quark + ZWO ASI 1600 mono. Can I put that Ha filter away? I was afraid, that there will be too much of heat without it. I can try it on Saturday if weather allows. Maybe I can do ~10 second video for test without filter. The UV/IR cut and polarizing filter are on the way, I hope I will test them next week.

Thank you very much for all suggestions, I try them as soon as weather allows.

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Re: Not uniform contrast with my Daystar Quark

Post by Roman » Sat Jun 24, 2017 12:28 pm

Well, I tried that this morning, but with no luck. At least I tested Pierro Astro ADC (primary for planets imaging) to get rid of the Newton rings. I'm convicted that its a banding issue. I think I send it for a repair/replace back to Daystar.

One image from today morning (this time with TS refractor 80/600 and ZWO ASI 290 (and ADC)):

Image

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Re: Not uniform contrast with my Daystar Quark

Post by marktownley » Sun Jun 25, 2017 3:42 am

This last image is off band, but the gradient isn't too bad, nothing a flat won't cure.

If the Quark is being used with your reflector off axis (or SCT or Mak) it needs a special snout that offsets it about 2 degrees to the normal - you can see it in this pic http://www.icstars.com/Store/daystar/qu ... lter2.html
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Re: Not uniform contrast with my Daystar Quark

Post by Roman » Sun Jun 25, 2017 7:52 pm

Thank you marktownley. This image was taken with refractor 80/600mm. Configuration with Newton was just temporary until the refractor arrive. I was tuning the band and this was the best I achieved when the tuning knob was at "+5" position. Looks like the "+7" would be the best, but I cannot turn the know more to the right :). Also, in this image I used Pierro Astro ADC just for test - it cured the Newton rings, but probably because of ADC I have lower left corner more in band, than upper right corner. Im waiting for some nice filaments to capture and compare.

I don't think I have that snout. I have this product exactly: http://www.icstars.com/Store/daystar/quark.html. I can take a photo of my configuration, to make it clear, how it look (I'm sorry, I know my english isn't the best one and I cannot explain everything as clear as I want).

However, thank you all for very helpful information. I'm really glad I find such a good support :).

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Re: Not uniform contrast with my Daystar Quark

Post by marktownley » Sun Jun 25, 2017 9:35 pm

When you are on the +5 position, try rotating the quark in the focuser, see if there is a best position for it.
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Re: Not uniform contrast with my Daystar Quark

Post by Roman » Tue Jun 27, 2017 11:41 am

Thanks for tip. I tried it but without luck. I sent it back today for repair or another copy.

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Re: Not uniform contrast with my Daystar Quark

Post by Bob Yoesle » Fri Jul 07, 2017 6:39 am

The Quark etalons are rejects from SE and PE production runs, and contrast non-uniformity is generally to be expected - that's why they didn't make the grade in the first place. They are "cheap, easy, fun," but don't expect too much at this entry level of cost/performance. You may get lucky, or you may not get any better (or possibly worse).
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Re: Not uniform contrast with my Daystar Quark

Post by Roman » Fri Jul 07, 2017 8:37 pm

I'm not happy to hear this. I know that they are low quality when compared with SE/PE production. But who wants to spend more than 1000 Eur on non functional product??? Sorry, but thats nonsense. If I know I get unusable product I would not buy it. Or I would save money for higher grade product. I hope I get better copy than this one :(.

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Re: Not uniform contrast with my Daystar Quark

Post by Montana » Mon Jul 10, 2017 10:24 am

That is why I got my money back :)
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Re: Not uniform contrast with my Daystar Quark

Post by Astrograph » Thu Aug 03, 2017 12:54 pm

Despite us having parted company with Daystar, I should point out that Quark etalons are not 'rejects'. What they are, are mass produced and subject to minimal testing. Jen Winter actually explained the basics of Quark production in a CN thread. Now whether you believe everything said in a forum is up to you but having been a dealer it sounded plausible to me. I was also told by an ex-employee that the basic mica was graded into the good the bad and the ugly and what worked, what could be made to work and what was for the bin.

In simple terms the Quark is a cheap etalon that is not subject to much in the way of QC. Having learnt what you get when you make filters that way, we eventually decided to sun test every filter we received. We were not looking for perfect uniformity, that's not fair on a budget filter like this but dark shadows through the FOV, scratches and fingerprints etc can't be considered acceptable either. We mutually parted company because Daystar would no longer replace the stock we returned. I don't know of many other dealers who test Quarks so customers get what they get. It could be that something I returned to Daystar as poor would be accepted by an enduser as OK. Looking at your top images, that would have been a fail for me.

In fairness to Daystar. although its a long and frustrating process (as Alexandra knows), they will replace, repair and even refund where applicable. Its just you might end up going through the process a few times before you actually get what you want!

Complain to your dealer about the problem. They should be there to help you.

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Re: Not uniform contrast with my Daystar Quark

Post by Marcus444 » Sun Aug 13, 2017 4:40 pm

Comiserations Roman. Hope you can get a better quark or your money back. I'm a relative newbie on solarchat too, and this thread has categorically dispelled any thoughts I may have had about buying a quark myself.
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Re: Not uniform contrast with my Daystar Quark

Post by Solar B » Sun Aug 13, 2017 8:04 pm

From my perspective I'm amazed at the views Quarks can offer and I'm not a solid etalon fan but from what

I've seen its hard to imagine better views from a solid one (albeit the SE & PE range will be easier to use) , however my

preference is still to use a good air spaced one or two.

Brian
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Re: Not uniform contrast with my Daystar Quark

Post by Roman » Sat Sep 09, 2017 12:28 pm

Hello all,

Sorry for long time no response. I finally managed to have some decent outputs from Daystar Quark. Unfortunatelly not because of good replacement. I sent the Quark chromo version to USA 2 month ago. One month later replacement arrived (new one), but it was even worse that the first one (it just confirmed what other people say about their QC ...). But I was lucky enough, because my retailer sent me another copy (as a compensation while I wait). It was Prominence version of Daystar Quark but perfect one! I decided to keep it for myself insteda of Chromosphere version (and sent back the "good" copy which came back from reclamation).
Maybe third copy would be good, but I think that this should not happen. I hope that there will be much less trouble with quality control in future, because this is absolutelly perfect piece of hardware for imaging Sun in H alpha (if you have a good copy). I never think I will have a chance to have solar telescope (which would cost me about 8000 eur). Now I use Explore Scientific AR127/f6.5 and ZWO ASI 1600mmc and ZWO ASI290m for Sun imaging and its great, plenty of details ... Here are few examples I took from my balcony in average/poor seeing. The first one is in blue wing.

Image
Image
Image
Image
Image
Image
Image
Image

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Re: Not uniform contrast with my Daystar Quark

Post by marktownley » Sun Sep 10, 2017 9:07 pm

Very nice results with that prom quark!
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Re: Not uniform contrast with my Daystar Quark

Post by Montana » Tue Sep 12, 2017 7:17 am

Wow! I see why you kept it :hamster:

Alexandra

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