Telescopes

First Light with Daystar Gemini Quark

I have visually observed and imaged the Sun for over 50 years, most of that in White Light with full aperture Solar filters.

About 10 years ago I started imaging in Halpha something made possible by Coronado bringing out the PST. This was something of a revelation to be able to view and image in narrowband, previously the cost had been prohibitive. Suddenly here was a telescope for around £500 that allowed this, and considering that the next model, the Coronado Solarmax2, cost over 3 times more it was a bargain.

It had it’s limitations of course. The Solarmax2 although of the same 40mm aperture had a narrower bandwidth of 0.75 angstrom and a proper focuser. The PST had a bandwidth of 1 angstrom, but this made it perfect for viewing prominences. Surface detail on the chromosphere was possible but limited, until I added a double stack module which narrowed the bandwidth to 0.5 angstrom. Now my little PST was therefore ideal, my imaging sessions started with prominences in single stack mode, and by adding the double stack module I captured a detailed surface. These could then be later combined in image processing.  I was fortunate that I had the PST during the most active phase of the Sun’s 11 year cycle and have 100s of images to show for it. I eventually sold the PST and moved on to first a 60mm Lunt and now a Lunt 80mm double stack.

These have been excellent telescopes but often I felt that a wider bandwidth for prominences may have been better as I had when using the PST.

When the Daystar Quark range was released I eagerly jumped on board and have Chromosphere, Sodium, and Calcium Quarks. I am also testing the recent Magnesium Quark.

As a 365Astronomy Adviser I test all our Daystar products and looked forward to the latest product – the Gemini.

When I first chose my Halpha Quark I decided on the Chromosphere version, after testing both it and the Prominence version, indeed my advice to customers has always been to buy the Chromosphere version unless of course you can afford both!

My reasoning has been that the Chromosphere version allows you to image detail at 0.5 angstrom and below, something that would require an expensive double stack dedicated Solar telescope. It is still possible to image prominences but they are not seen at their best.

So the ideal would be to own both, but even if you pre heat them both so they are “on band” and then swap them over this incurs a risk of knocking the telescope off target and probably having to refocus, also add that to the cost of 2 x £1095!!

Step up the Daystar Gemini.

This is one unit with both Prominence & Chromosphere versions together with the ability to switch between versions on the fly and is now available.

The Gemini comes in a bright well protected yellow case  (Images below)

I was able to test the Gemini on 3rd January 2020 when as luck would have it there was an active region AR 2755 on the surface and a few nice prominences allowing for comparison.

The seeing was however very poor and the Sun low so I set up with my William Optics Zenithstar 61 on a Skywatcher SolarQuest mount. I used a 1.25” diagonal with the recommended IR/UV blocking filter screwed to the diagonal. Next the Gemini and finally my ZWO 174mm camera. I also included a ZWO tilting unit between the camera and Quark as I have suffered from Newton rings in the past. (Note, Daystar also offers a similar tilting usint, called Interference Eliminator.) Using Sharpcap software I took a number of 30 second videos, with the slider set to Chromosphere mode, of the active region AR 2755. I also took a 30 second video of the smaller of the prominences to see how well it coped with it.

I then moved the slider to Prominence mode and took 30 second videos of the larger looped prominence and finally of AR 2755 for comparison.

All videos were later processed with Autostakkert, with 15% of the frames stacked and a small amount of sharpening in Registax. No other processing was done on the comparison images, but some processing was done on the Looped Prominence to bring out more detail.

The resultant images are shown below:

CHROMOSPHERE SETTING

As you can see the small prominence is reasonably well seen and compares well with that taken at the Prominence setting, however slightly more detail was seen when used in Prominence mode.

The Image of AR 2755 below shows good detail despite the poor seeing, the bright ring below the active region will need further investigation when I get the chance to do more imaging, however the disc is fully illuminated and dosen’t appear to suffer from uneven illumination.

The looped prominence shows up well when using the Prominence setting, but the image of AR 2755 in Prominence setting suffers from uneven illumination.

My conclusion is that this unit allows you to get the best out of imaging both prominences and surface detail, the sliding from mode to mode gave no problems and introduced no vibration and was a joy to use. I shall do further testing when conditions and detail allow.

PROMINENCE SETTING

TRANSPORTING CASE FOR GEMINI

A picture containing case

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An excellent strong case for storing and carrying the Quark Gemini.

The case comes with mains power supply and USB connecting cable.

That mains supply was not used as I tested with small portable power pack that provided sufficient power for the Gemini.

John, 365Astronomy Adviser

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Posted on January 15th, 2020.