Thursday, 29 December 2016
I've been messing around with a PST for some time now since the summer, first double stacking it with a Lunt 50 etalon, the BF5 has been replaced with my BF10, as IMHO, this particular filter offers better contrast. I've also shortened the eyepiece holder on the PST, so that all the usual issues of cameras not coming to focus without a barlow etc are a thing of the past. Today, in my new found hour long winter season viewing window I tried a different experiment, which barlow offered the best view. I had 2 to choose from, my astro engineering magnimate and a bog standard Skywatcher 2x barlow. The PGR Chameleon 3 with its 2048x1536 pixel sensor offers plenty of real estate for such an exercise. After taking numerous images the results kinda didn't surprise me, the best image was the one without a barlow at prime focus, it was noticeably sharper, with more contrast and more fine detail. It gives a 1200 pixel wide disk, which, for displaying via the web is ample. I still need to get the perfect tilt with the Daystar Interference Eliminator, I feel some index marks coming on. Next steps may have to be to lose the PST Black Box (and it's potentially astigmatic) penta prism assembly and have a focuser directly on the back of the etalon. With the correct spacings it should work well!
With my new found gap in the trees i've now over an hour to pass solar imaging in the winter season around solar noon, and, after messing around with some full disks still had some time to spare. Seeing wasn't good with the low sun as you would expect, but I decided to crack out the Skywatcher ED80, and stopping it down to 60mm I took a closer look at some of the plage that is currently visible in Calcium wavelengths. Viewing the image full size there is the smallest of pores visible in this relic active region. Taken with the homebrew CaK filter and the PGR Chameleon 3 camera in conjunction with the Daystar Interference Eliminator to tame Newtons rings that can be a problem.
Another clear and frosty day here in Brierley Hills, and with my new found 'gap between the trees' available for a full hour around midday it would be foolish of me not to try and exploit it for a bit of solar. Our sun is very quiet at the moment, with only a few areas of white plage visible on the disk, indicative of slightly higher magnetic fields, alas no strong enough to form any sunspots. The air was very clear, and, it is possible by clicking on the image to view it full size to see the spicule ring around the limb, along with ghostly pale views of todays prominences. Also, at 9 o'clock on the limb a small surge is visible. Taken with the 40mm scope at around 500mm focal length with the PGR Chameleon 3 camera.
Tuesday, 27 December 2016
A pretty blank quarter of sun all bar a few filaments and small areas of plage. There are a few smudges which are the result of a couple of chips on the glasswork of my el-cheapo 2x barlow which was used for this pic 😶 - time for a new year barlow lens me thinks! Despite this i'm pleased with the way this image came out given the low altitude of the sun and the poor seeing that this presents. The focus feature in the Genika capture software really helps with this. The image was taken with a PST double stacked with a Lunt 50 etalon and a PGR Chameleon 3 camera, along with the very effective Daystar Interference Eliminator to tame the issue of Newtons Rings easily with minimal tilt to affect focus across the frame.
Posted by Mark Townley at Tuesday, December 27, 2016
Monday, 26 December 2016
It's days like today when a double stacked scope is really needed to see the smaller and finer details on our star. Double stacking reduces continuum leakage from the wings of the Ha line at 656.28nm, and the consequence of this is increased contrast, making delicate filaments and filaproms easier to see, in a single stacked scope these tangible details are just washed out. While very little was visible on todays sun, the double stacked PST did a good job of showing these more subtle features. My favourite in this shot is the small filament and the hazy filaprom. Also working very well was the Daystar Interference Eliminator in doing a great job of applying just the right amount of tilt to get rid of the annoying Newtons rings!
My new found 'gap in the trees' around midday in the winter season has given me a bit more time to image. I tried zooming in a bit with the 40mm scope as realistically this is all the seeing would allow with such a low sun, alas, there was not much to see at all! It really did need a much bigger scope to zoom in on some of the plage regions to close in on the smaller scale detail. Either way, nice to be able to image this late in the year!
Boxing day dawned bright and clear, and despite the low sun I was determined to make the most of the day. The sun is devoid of spots at the moment, but, looking in Calcium light at 393nm it was possible to see several small areas of brighter, white plage - these magnetically frothy regions hint at very low levels of activity, maybe, deeper within out star. I was testing out some new technology today too: Firstly the focus assistant in the Genika capture software allowed an empirical measure that the focus was as sharp as the conditions allowed, which, with a north westerly air stream and a low sun wasn't as good as I know is possible with this setup. Secondly the Daystar Interference Eliminator allowed me to easily apply the minimal tilt needed to get rid of Newtons Rings yet retain a sharp focus, this is a piece of equipment that I feel is going to be invaluable in imaging with other setups in the future. This full disk was taken with the 40mm scope at ~500mm focal length with the homebrew CaK filter and the PGR Chameleon 3 camera.
The weather turned from the storms of Christmas day to building high pressure and clear skies on Boxing Day. I was keen to try out my Daystar Interference Eliminator as a means for getting rid of Newtons Rings that afflict my imaging with the PST and PGR Chameleon 3 camera. I'm pleased to report this is a very effective solution that allows the user to very quickly and easily adjust to a minimum tilt (required) position to give minimal affect on focal shift across the image frame. I'm looking forward to being able to do more testing with this great little device as the sun climbs higher and higher in the sky now we are past the winter solstice. Wish there was a bit more to see on the sun though! Merry Christmas to all! 😃
Thursday, 22 December 2016
I would have liked to get an image on the 21st December to mark the winter solstice, alas, UK weather was not in my favour, so, i'll have to settle for the day after! At an altitude of less than 10 degrees in the sky when this image was taken it was a race to get the sun in between the branches as it passed amongst the trees on the urban skyline. With so many branches passing in and out of the field of view it can be a challenge to actually get a decent focus on our star. The sun is remarkably quiet at the moment with only a few brighter areas of inactive plage, there are several smaller areas of filaments, and also some smaller prominences on the limb. Taken with a PST double stacked with a Lunt 50 etalon, running at just over 500mm focal length with a PGR Chameleon 3 camera. I'm pleased to get an image of the sun at this time of year, at least now with each passing day it is getting that bit higher in the sky!
Posted by Mark Townley at Thursday, December 22, 2016
Sunday, 4 December 2016
The sun was low in the sky this afternoon, and was a waiting game for it to pass between the gaps in the trees so that I could image it. AR12516 is a nice active region, that while not strongly active is active none the less. It would have been nice to be able to get a close up of this area, but, the seeing was not playing. This shot was taken with the 40mm scope at ~500mm focal length with the homebrew CaK filter and the PGR Chameleon 3 USB3 camera.
The sun really is low now as we're only just over 2 weeks away from the winter solstice, where, for observers in the northern hemisphere the sun is at it's lowest in the sky. From that point onward the sun climbs higher and higher in the sky with each passing day. I'm severely limited at this time of year with the low sun and it being blocked by the urban skyline of trees and rooftops, but luckily was able to find a gap to observe just after midday. Considering we are heading towards solar minimum there was plenty of nice activity including nice prominences and filaments, but also in the form of largish AE12615 which has been crackling away with minor B and C class flare activity since it rounded the limb a week or so ago. This image was taken with the PST double stacked with a Lunt 50 etalon, and with a barlow to take the focal length to ~500mm it nicely filled the frame of the PGR Chameleon 3 camera that was used. This is a stack of the best 100 images from a 1000 frame avi.