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Calcium Quark

JB80

By JB80
in Observing - Solar

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JB80

JB80

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Can't say I know a great deal about H line compared to K, I would love to see some examples however.

I have always admired the Cak images that are posted and have wanted to venture that way eventually, this may speed things up.

This may swing me from getting an SCT to a frac.

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Uplooker

Uplooker

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It would be interesting to see what this is like / does perform. CaK is not really a visual "thang" as you are looking at light very close to ultraviolet, as opposed to Ha which is very close to infrared. The human eye looses it sensitivity to ultraviolet after the age of about 10yrs. Thats why Cak is mainly  used for imagaing.

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JB80

JB80

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From reading another Daystar page it says....

Calcium offers TWO strong absorption lines at 393.3nm and at 396.9nm, known as the K and H lines.   Researchers have previously avoided the H line for academic research, as it is very close to the Hydrogen Epsilon line.  For purposes of clarity in isolating Calcium, and because imaging sensors offer similar sensitivity to the K as the H lines of Calcium, the K has to date been the target of choice in Calcium filters.  

However, as the visual spectrum ends at approximately 400nm, the further we venture below this wavelength, the more difficult it is for observers to visually see the image.  The H line for visual observations, is much closer to the visual spectrum and easier to see in high contrast violet color. Some observatories have been imaging in Ca II H line, such as the Dutch Open Telescope with outstanding results.

So I guess the reason it is CaH is more because it is better visually than the K.

Not sure zhat that means from an imagers perspective?

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Uplooker

Uplooker

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Ahh, just read the blurb properly :rolleyes: :rolleyes::-

"Why H-line? 

Many astronomers forget that the Calcium H-line and K-line yield virtually identical views of the Sun.  Solar researchers who only image the Sun with CCD cameras often choose the K-Line for purely research purposes.   Sadly, with Calcium K-line filters, many older astronomers are unable to see the low wavelength and miss out on all the fun.   We offer higher wavelength Calcium H-line filters for visual observers for more clients to enjoy!"

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101nut

101nut

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One thing to remember is that it's apparently a 'combo' design (without the inbuilt barlow) so also needs an off axis primary erf on an sct to get an f30 light cone presented to the etalon for good results. I presume Baader film would work but might reduce image brightness too far. I don't think a Baader D-erf would work as it cuts off to much in the blue ... not sure there's a 'cheap' option unless Lunt have come up with a matching off axis primary filter ... So £1000 for the quark and £xx for the filter ...

AndyG 

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michael.h.f.wilkinson

michael.h.f.wilkinson

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I wonder how easy it would be to focus on it. The human visual system uses the centre wavelengths of the visual spectrum for focusing, so this might be similar to trying to focus on "blacklight" tubes (remember those?). I might well be interested in them, if their passband is within that passed by my tri-band ERF. It could sit behind the Baader TZ-4 I use for Solar H-alpha.

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michael.h.f.wilkinson

michael.h.f.wilkinson

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Just a further note. I got this info from the Daystar site, on their regular (eyewateringly expensive) Calcium filter lines. 

* Note. Calcium H and K-line filters do not require F/30 configurations.  They may be used at F/15 or F/20 or greater.  They also do not use the same RED or Yellow glass Energy Rejection Prefilter.  Rather, we recommend dielectric "hot mirror" UV/IR cut filters introduced prior to focus.  Additionally, we suggest an additional neutral density solar film on apertures above 150mm or for long-term dedicated applications.

This suggests that the Daystar Calcium Quark could be used between F/15-F/20. With the same clear aperture as the regular Quark that should mean I could easily use the 2.5x PowerMate in the 80mm F/6, and see the full disk. Very interesting indeed.

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Luke

Luke

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I found a site taking pre-orders, I think they are in Belgium. Do not know them, but page is:

https://www.astromarket.org/solar-astronomy213747/daystar-quark-h-alpha-filter/quark-h-alpha-eyepiece----chromosphere-03-05367553?language=en

and some of the info stated there - please see link for the fuller info.:

PRE-ORDER NOW (Delivery by the end of november)

NOT COMPATIBLE WITH RED OR YELLOW GLASS ERFS.  RECOMMENDED FOR USE WITH A UV/IR CUT FILTER FOR SAFETY.

  •     Calcium H line (3968.5Å), approx 5Å FWHM.
  •     Integrated 25mm blocking filter, 21mm clear filter aperture.  No barlow or focusing elements included.
  •     Best performance with F/10 - F/30 refractors full aperture, or SCTs and Maks.
  •     Full disk viewing possible on refractors up to ~1800mm focal length
  •     No aperture limitations. May be used on larger refractors for higher magnification views
     

DAYSTAR_CALCIUM_QUARK_2015.png

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Luke

Luke

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This is most interesting! My other half is not into imaging any more but likes the idea of viewing with this, and if I can observe with it, it will definitely get a decent amount of usage over a year. Will we be able to view? Oh I wish I knew!! :laugh:

I'm just imaging in summer now, observing rest of the year, which means I have more time for observing now. The Quark h-alpha imaging took over at times this year when the disc was busy and proms were going off here and there!

But suppose older eyes will struggle, why would Daystar not go for CaK instead and say it's imaging only? Then that doesn't leave open wondering how close the image will be to CaK?

I think my plan is, hang around until we see some first lights and images that for my needs are good enough, like I did with the Quark Chromo. At this price it mainly needs to show me some interesting activity that I won't get with white light and h-alpha.

Certainly some interesting images at high res from the Dutch Open Telescope in CaII H line here, would love to see some full discs:

http://www.staff.science.uu.nl/~rutte101/dot/albums/images/album.html

Also I am thinking, with my F7.5 scope, I may be able to use a 2x or 2.5x Barlow in front of the Quark CaH, then a 0.5x reducer before the camera, to get close to cancelling out the Barlow if needed.

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JB80

JB80

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Well Daystars interpretation of the word 'Cheap' is different to most peoples but I guess it is compared to some of their units. But it is still not overly prohibitive if you already have the right equipment to begin with.

Interesting it says can be used with Maks and SCTs, can you use the Ha version on these?

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