Archive

Archive for August, 2008

The Sun 30-8-08 At last, some Sun!

August 31, 2008 Leave a comment

Five days of constant depressing grey cloud cover is not good for the solar observer, we tend to show withdrawal symptoms pretty quick! Missed out on two great prominences that put a show on over the last week in the south and north, but plenty of images of them on the CN solar forum to drool over. Forecast didn’t look good for today, but between 2.30 and 6pm it really brightened up and the gaps between clouds got ever larger so I decided to set the scope up and see what was happening up there on our star. The active region we were all tracking over a week back has completeley faded now on the west limb, but another smaller one can be seen at the centre of the disk appearing as two minuscule dots of plage. This will fade quickly and not produce any spots, it was already difficult to find today. There was one obvious filament visible in the north east. The prom in the north had some really nice fine detail and a long arch extending over the limb. DMK41 for whole disk shot and DMK21 for prom/filament/AR detail. PST.





Categories: Solar

The Sun 24-8-08 – Looks quiet, but isn’t !

August 24, 2008 Leave a comment

Solved the problem with files over 1GB being rejected by Registax! Turns out all I need to do is chop the video up into two parts with Virtualdub. First part is 869mb and the second part is 1131mb. Even though the second half is 1.3GB Registax seems to accept it fine!? I then load both parts into Registax for aligning – works a treat!

Anyway, the Sun today…..well it appears quiet with just a few small prominences. When I took the full disk images this morning at 11.05 BST I could not see the active region or any other surface detail. Later on between 4.50 – 5.35 pm BST we had an unexpected clear window and I had a leisurely scan of the surface with the DMK21 and the 2x barlow. The sun was far from quiet! I found the active region nearing the centre of the Sun, some filaments, some nice small proms and a curious black spot in the ‘white light’ area of the PST tuning that isn’t a sunspot, but may be associated with the ‘dark mottle’ background of spicules, fibrils and filaments. So even a fairly dull day on the sun is full of activity !



The active region

Filaments

The curious black spot

Categories: Solar

The Sun 23-8-08 – First light for the DMK41AU02 Camera

August 23, 2008 Leave a comment

The DMK 41AU02 USB camera arrived yesterday. At 1280×960 resolution this should theoretically be able to display the whole disk in IC Capture and allow single videos of the surface and proms to be taken which can be combined without having to laboriously stitch panes together. First light today proved that this is indeed the case. It was great being able to see the whole disk on the screen. Until I zoomed out I was scrolling a lot to see which edge was passing out of frame view first, but zooming out made this easy to judge so that the disk could be centred on the chip for best overall focus.

Having found the optimum settings for prom and surface capture I saved these configurations specifically for the DMK41 as the DMK21 configurations cannot be used and result in an error. A video of 2000 frames produces a file size of 2.28 GB in just over two minutes at the 1/15 sec max capture rate. In Registax 4 I came up against the problem that Registax will only recognise AVI files up to 1GB in size which equals 869 frames. Beyond that Registax throws up a read failure message and the aligning procedure fails. So until registax 5 comes out I may be limited to videos of 869 frames, which isn’t too bad, but I would prefer to be able to stack at least 1000 to reduce noise in the final image. K3CCD Tools may be the answer to my problem but an early attempt to stack in that resulted in confusion – I need to read the manual !

The whole disk view does seem to show up the shortcomings of the PST now though. It appears my PST may be slightly astigmatic with focus better on one half of the sun than the other. This is really obvious now whereas with the smaller DMK21 each pane was capable of being sharpened so that the overall view looked more consistent. Sharpening the whole DMK shots does look OK though and the inconsistent focus may even be due to the chip not being square to the objective in the holder – need to check that!

Today was not exactly the sunny, blue-sky day that was promised by the weather forecasters! We actually got 1 hour of patchy clear sky then thick cloud the rest of the day and rain in the evening. I captured these images at 9.16 UT. Not much to see in terms of proms, but the active region is a little larger and there were some small filaments around. Overall i’m pleased with the speed at which I can create a high resolution full disk now and will be even happier when Registax 5 comes along !



Categories: Astrophotography, Solar

The Sun 22-8-08 8.20UT – New AR getting bigger

August 22, 2008 Leave a comment

Had a brief half hour of blue sky first thing this morning at 9.30am before the cloud rolled in from the west for the rest of the day. Managed to capture the whole disk and proms with the DMK21, PST, low profile adapter. The new AR seems larger today with some nice structure developing. Still no sunspots visible though.

Categories: Solar

The Sun 21-8-08 New Active Region and Tall Prom

August 21, 2008 Leave a comment

A quick look through the PST this morning revealed a new small active region area in the south east consisting of two short linear areas of plage brightening. There were seven main proms active around the limb with a tall spike in the west that had a filaprom at its base. There were two small filaments in the north. By 17.30 BST when I was imaging the active region had developed some small active region filaments and appeared to be trying to divide into a bipolar region, but no sunspots could be seen. Bizarrely, Spaceweather was reporting two clear sunpsots in the same area, but if they were there they must have faded extremely fast. Lets hope the active region lasts over the Bank Holiday and puts on a show! DMK21, PST, low profile adapter. 2x barlow for proms and 2x + 4x barlows used for active region close ups.






Categories: Solar

The Sun 18-8-08 – Low Activity

August 18, 2008 Leave a comment

Managed to get a lucky break in the cloud between 6-7 pm BST although seeing conditions were less than average and cloud interrupted the prom captures on many occasions. Very low activity visible today with only small proms and no surface features. DMK21AU04 and PST. The detailed image of the largest prom is the DMK plus 1.6x barlow lens. Whole disk composited in iMerge and coloured in PSPX.


Categories: Solar

The Sun 17-8-08 Whole disk mosaic

August 17, 2008 Leave a comment

Not an ideal day for imaging anything today and this disk mosaic is a result of about 3 hours (10.59 – 13.55 UT) of chasing separate prom and disk details between clouds. Even so I managed to miss a notch of surface detail, but the overall picture of todays activity is nonetheless complete. The slight blurring effect on the disk is due to the iMerge mosaic software as all original surface panes were pin sharp. This is four surface panes and three prom panes composited in iMerge and coloured in PSPX. DMK 21AU04 with low profile C mount adapter and PST (no barlows).

Categories: Solar