Trying something new here, the CaK filter receives a f28 beam, while the chip receives a f40 beam following the use of a 2x barlow nosepeice on the camera. I'm not convinced with this shot, other than a hotspot of brightness the quality reading of the image is much lower than I am used to getting. The image looks soft too. Could be the seeing wasn't up to it or more likely the barlow is introducing spherical aberration. I will persevere with this but my gut instinct is that I much prefer images taken at f28.
The sun is still quiet apart from the activity in the cycle 25 northern solar jetstream. Taken with the usual double stacked 50mm travelling scope.
The seeing was being kind and allowed me to get a closeup of the plage region using the 100mm Tal refractor at f28 (using the Airylab 2.79x telecentric. I'm pleased with the level of detail here. Next time conditions allow i'm going try the above setup but with a 1.4x barlow after the filter stack to see if I can get close to f40 to see if this improves detail.
Taken by double stacking the Coronado SM90ii with the Daystar Quark using the Airylab 2.79 x telecentric cuts the contrast and reveals the subtleties of the cycle 25 jetstream that is currently active on our star.
The northern Jet stream of cycle 25 was certainly showing signs of activity, with an area of plage, filaments and bright points. Taken with the 50mm Lunt etalon double stacked with a Daystar Quark.
Using the 100mm Tal refractor, 2.79x telecentric and the Daystar Quark was a little more cooperative with the seeing conditions on Bank Holiday Monday, revealing better detail in the prom than with the larger scope.
It was soft and squishy, but just about passed with the seeing! Taken with the 8" Airylab HaT and a Daystar Quark.
I was fighting the seeing for this image, it was the hottest day of the year so far and the seeing was boiling away late afternoon. The active regions have died down in terms of activity and seem to be decaying away. Taken with the Lunt50 etalon on the 60mm f6 refractor double stacked with a Daystar Quark and using FLIR GH3 U3 916M camera.
It was nice to be able to spend an hour at the scope yesterday, and was pleasantly surprised how much activity there was on the disk. While the new active region is without spots, and currently undesignated it is far from being inactive. The smaller region to the south appears to be decaying away quite quickly. There were also nice proms on display yesterday too. Taken with the Lunt50 etalon double stacked with the Daystar Quark and using the FLIR U3 GH3 916M camera.
The star of the show on Thursday was the large prominence on the approaching limb, with activity expected to round here in the next couple of days it could be this is associated? Taken with the 100mm f10 Tal refractor, 2.7x Airylab telecentric, Daystar Quark and the FLIR IMX174 camera.
Using the 100mm Tal Refractor, 2.7x Airylab telecentric and the Daystar Quark it was nice to see this small and diffuse prom heading over the suns departing limb.
Taken with the 100mm f10 Tal scope stopped down to 60mm to give my f17 at the home brew filter, this has the effect of narrowing the FWHM of the filter, compared to using a shorter focal length optical system and barlowing to achieve the desired focal length. Pleased with how this disk has come out.
The seeing wasn't as good today, and I was pushing it at 100mm aperture, I would have got better results at 80mm despite taking many 4000 frame avis and hoping to net something good. The shrpeness is down on these images. Take with the 100mm f10 with 2.7x telecentric, home brew CaK filter and the FLIR IMX174 camera.
For some time I have given thought to running a CaK filter in a telecentric beam, the benefits should be apparent, the filter will operate closer to its specified FWHM compared to shorter focal ratios, and, in a telecentric beam the FWHM of the filter will not change across the field of view. With CaK and optics comes the caveat of transmission, at shorter wavelengths glass becomes increasingly opaque and coatings on optics are designed to not let UV wavelengths pass through.
I've been impressively pleased recently with the 2,7x Airylab telecentric as the image amplifier on my Quark when used in conjunction with my 100mm Tal refractor. Normally this telecentric would be used with the HaT, but, plagued with poor seeing the scope gets less use than I would like, so lockdown curiosity meant I tried the telecentric on the f10 refractor, figuring it was designed to be used on the f10 HaT. Results have been impressive and the setup has become my preferred setup for imaging prominences.
So when I rigged up the scope with the CaK filter on the back, straight away I was beaming at the view I was getting on the screen, the contrast was some of the best I have seen. The final stacked quality value in AS3 was up in the high 900s, which, is very very good. Sadly after a couple of weeks activity the sun has gone quiet, but I was still impressed in the details I was pulling out in the above images. Looking very much to being able to image more with this setup when activity picks up again. Camera used was the FLIR IMX174.
One of the tests I wanted to do with the faster Airylab telecentric compared to the Quarks 4.2x telecentric was to see if there was any sign of the solar double limb when it was double stacked on the SM90. Despite a higher FWHM of the filter there was no double limb due to continuum leakage. As a bonus the flame prom that was on view came out well in this shot.
Trying the Airylab telecentric on the back of the SM90 and then double stacking with the Quark etalon produces a wider field of view as expected than using the 4.2x telecentric on the Quark, but also reduces exposure time which is always a plus. FWHM while wider is not to a deleterious effect. I think this system will get quite a bit of use when activity picks up a bit more.
Trying a different setup here (of sorts!); the Lunt 50mm etalon on the 60mm f6 scope, the Airylab 2.7x telecentric on the Daystar Quark etalon. This has the benefit of the image fitting on the camera chip without using the Baader solar telecompressor, which, I think adds some softness to the image. The caveat is the system runs at a higher FWHM, so not as much contrast, but the full disk has a more even illumination. This system needs a little more testing to see if I like it, as was difficult to judge the on band position with such a featureless sun, in this instance I concentrated on getting the filaments at their darkest.
Knowing that I was getting away with CaK at 60mm it is reasonable to assume that can get away with Ha at 100mm, as CaK wavelengths have 1.6x the resolution of Ha light. Lucky imaging was needed to get an image, and a large number of 3000 frame avis were recorded before the best could be processed for this final image. This image was taken with 100mm Tal refractor, 2.7x Airylab telecentric and the Daystar Quark along with the FLIR Grasshopper camera with the IMX174 chip.
There is more of a sign of brighter points on light on the disk of the sun now as we slowly drift out of solar minimum and the next solar cycle starts to wake up. Taken with the Lunt 50 etalon double stacked with the Daystar Quark, apart from the bright points and a few small filaments the star of the show was the prominences that were on display.
Seeing really wasn't great later in the afternoon when this image was taken, and using 60mm aperture was a struggle, it would have been a lot easier using the 40mm scope. A lot of post processing was needed to tidy the image up.
It was a joy to view the prominences today using the Coronado SM90ii and the 15mm Televue plossl eyepiece, it was a lot easier to see them rather than image them. This shot was taken with the above scope, 2x Cemax barlow lens and the FLIR U3 GH3 23S6 (IMX174) camera.
It took some stretching to reveal the faint prominence on the suns approaching limb, but this shot shows the small region of activity along with a small filament. Taken with the Coronado SM90ii double stacked with the Daystar Quark to increase contrast by reducing continuum leakage from the solar photosphere.
A small cycle 25 region of activity is visible on the disk, but by far today the features of interest were the prominences. This shot was taken with the Lunt 50 etalon double stacked with the Daystar Quark.
When I first set up this morning I was looking visually in single stack with the LS50C and this prominence really jumped out and looked great. I was only when I double stacked I realised it was actually part of a filaprom. I used the Skywatcher ED80 along with the Daystar Quark and the FLIR GH3 U3 23S6 (IMX174) camera to image it.
Been a while since there has been a decent filaprom, so was pleased to see this one today, brought out well with the double stack setup to increase contrast.
Pushing the resolution of the 50mm aperture at this scale, but still got a nice view of the 2 regions that still remain. The one closest the limb is distinctly showing the foreshortening associated with the Wilson Effect.
Poor weather has prevented me observing for virtually a week, fortunately though, early saturday morning offered clear blue skies and so I was keen to get out and take a look at the active regions before they departed completely over the limb. Taken with a Lunt LS50C etalon double stacked with the Daystar Quark.
