solarnutcase (solarnutcase) wrote,

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Testing the dial settings on a Daystar Quark Chromosphere

I have wanted to do this since I bought the Quark but having the time in the Sun to do this test was a million to one chance. Considering this year I have not had more than a 30 minute run of blue sky the chances of getting 2 hrs was slim. However, Saturday 8th August 2015 I had 4 hours of pure blue before it clouded up and so was able to do this test.

Here is a picture of AR12396 on the best setting (which I discovered later). This image was very popular after being posted on Flickr Explore and managed 7,500 views, I was quite proud of that :)

080815_093711 Sunspot group in the Sun's chromosphere

So, now for the testing, the Quark is a temperature controlled etalon made from mineral mica crystals. So, to achieve hydrogen alpha centre-line we need to get the temperature exactly right. To start I set the Quark on zero point which is 12 o'clock on the dial (middle) and bagged some images of the AR and filament and prominence, although like previously I really struggled with the prom exposure. I then started turning the dial clockwise to +01 and waited for the green light to come on (about 5-10 minutes). Now I knew this position was better (more on band) the last time I had used it but this is all I had managed. I then kept imaging the same 3 objects on the same exposure (no flats) for every point on the dial clockwise to +05. I then turned the dial all the way back to -05 counterclockwise and took the same images again each click until I got back to centre point again. So here are the results, I think the best overall contrast, flatness of field, and prom exposure was +04 clockwise. You can see that 'on band' comes in from the bottom right, passes through the middle then leaves top left, just like a tilt tuned etalon, this surprised me, somehow I expected it to be like a pressure tuner with an even field. Now I know why I had been struggling with the prominence on the first two outings. I think it is very important for each Quark user to try this out at some point if they can, especially if you have a problem with uneven field or struggling to see prominences. If you spend a lot of money it is worth getting to know the beast you bought.

Here are 3 image series - active region, filament and prominence to show the different dial settings. The setting -05 is clearly in the blue wing.

2015-08-08 AR12396

2015-08-08 Filament

2015-08-08 Prominence

As an aside to the testing it was very interesting to study these regions in the blue wing of hydrogen alpha line (-05). I could tell it was the blue wing due to the spicule 'twinning' which is only seen in the blue wing.

080815_100547 -05 crop

Bright Arch filament footpoints - not to be confused with Ellerman bombs!

080815_100829 -05 Bright footpoints

Ellerman bombs (only distinguished from footpoints if you take a series of images)

2015-08-08 Ellerman bombs

A prominence showing the blue shifted parts and blue shifted spicules (blue shift=moving quickly towards you).

080815_095413 +05 & -05 Blue shift combo

So plenty of fun can be had using any of the dial settings but it is seriously worth knowing where hydrogen alpha centre-line is on your model of the Quark. All will vary because of the natural mica that the etalon is made from and the temperature and pressure at your location.
Tags: daystar quark
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