Finally, after a few months without a DSLR, I am now the excited new owner of a Canon EOS 550D! I just picked it up yesterday and I must say, so far, I am EXTREMELY surprised at the power and capabilities of this camera! This is going to be a fun summer!
Occultation (wiki): An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer.
On June 30 we will have the opportunity to observe the Moon cover and uncover the planet Venus in the early morning sky. The phenomenon begins with the Moon slowly passing in front of Venus at 09:06 Local Time (06:06 UT) and reappearing at 10:28 LT (07:28 UT). Due to the phenomenon's close proximity with the Sun (approx. 13 degrees to the east) anyone who attempts to view or photograph it should be EXTREMELY CAREFUL not to accidentally point a telescope at the Sun while looking for the objects. The Sun's intense luminosity amplified through a telescope will cause severe injury to the careless individual.
Click the image below to view how Anthony Ayiomamitis captured a similar event on June 18, 2007 as well as his
collection of occultations!
It was a thriller! Here in Nicosia we lost the phenomenon up to totality due to thick clouds & fog, occasionally getting glimpses through holes in the clouds. Halfway through the event the skies gradually opened and we got to witness the exit from totality all the way to the end!
I had arranged to meet with Pampos & the others at Akropolis Park so we could set up our joined equipment: My CG5 mount with Pampos's Vixen ED81S & 450D. Due to the clouds we were unable to get a decent polar alignment or even get the focus right which resulted in mostly soft images up to mid-totality. Once the skies opened I was able to fix the focus and we enjoyed the end of the eclipse with decent results!
On June 15 we will have the opportunity to observe a Total Lunar Eclipse which will be fully visible from Cyprus! The fact that it occurs in mid-June promises great weather conditions (although this year the weather has been unpredictable!).
The Moon will start its pass through the Earth's penumbral shadow at 17:23 UT (20:23 Local Time) although this part will not be visible to the naked eye. At 18:22 UT (21:22 Local Time) the Moon will begin to darken as it enters the Earth's umbral shadow thus marking the beginning of the visible part of the eclipse. Greatest eclipse occurs at 20:12 UT (23:12 Local Time) and at this stage the Moon is expected to have darkened considerably as it will now be passing through the center of the Earth's shadow. At 21:03 UT (00:03 Local Time) the whole process goes backwards with the Moon beginning to exit the Earth's shadow marking the end of the visible part of the phenomenon at 22:02 UT (01:02 Local Time). The entire phenomenon ends at 23:02 UT (02:02 Local Time).
So to sum up, here's the local times for the visible part of the event:
Partial Eclipse begins: 21:22
Maximum Eclipse: 23:12
Partial Eclipse ends: 01:02
Here you can find all the relevant info for the phenomenon.
Below are the images from the March 3rd 2007 Total Lunar Eclipse.
Reaching the end of the data from April 13, I was able to put together this 12-frame animation spanning between 19:48 - 21:26 UT, all shot at f/30 and resized 150%. I don't normally resize that much but in this case there is a very slight hint of some southern hemisphere detail seen transiting across the disk.
Also, here's a view at f/30 from 20:48UT.
I had been watching the forecasts all day. It looked like I would get a break in the clouds and possibly some *fair* seeing conditions. Nothing to get all excited about in good weather patterns but with the conditions I've been experiencing this year, this looked like a worthwhile night. Once I pointed the C9,25 at the first alignment star I was stunned at the stillness of the atmosphere and a few minutes later I was collimating with metaguide and getting a uniform crisp airy disk. Haven't seen that since late summer! Here's a preview at f/22 with Rhea in the FOV (had to enhance the moon a little bit).
You capture nothing if you don't try. I read this somewhere on CN and it was playing in my head all day yesterday while I was trying to decide if the slowly improving conditions were worth setting up the scope and capturing Saturn. The weather has been unusually bad this year with my last window being a month back! The chilly temperatures were not encouraging either! Never the less I decided that whoever said that is propably right so around 23:00 (March 11) the C9,25 was set up and cooling!
After the obligatory collimation check & touch up, I pointed the scope at Saturn and began capturing, this time experimenting with longer capture times (up to 240 seconds). I'm currently sifting through the data which seem promising but, yet again, I must pay more attention to the collimation as it is evident that we are not quite there yet.
Here's a preview of the data quality. I'm crossing my fingers hoping it will turn out good.
P.S. it's b/w because I didn't use debayering!
A reprocessing of some of the data from February 10. Slightly different color balance & 150% resizing.
Saturn 10 February 2011 - reprocessed
Below you will find the single best image from the data set of February 10 aswell as a 17-frame animation compiled from stacked images spanning 36 minutes apart. Despite the poor data quality there is a hint of the storm moving across the Saturnian atmosphere. This is the first time I've had data good enough for something like this!
The skies finally cleared and settled well enough for the C9,25 to venture out again and have another shot at Saturn. Following up on the f/issues I was experiencing I decided to test both the Ultima 2x and the GSO 2.5x with the focuser on 0-10-20mm positions accordingly (all the way in, half way and all the way out). I opened up the scope at 00:30 UTC and with the cold breeze freezing my fingers I touched up the collimation which had shifted considerably since last time. I shot avi's at 30fps for 3mins (dont ask why, I hadn't done this since the 19th of January and I was half asleep!) ending up with ~5000 frame vids which I trimmed to 600 frames with Virtual Dub as I wasn't interested in image quality but target size only.
I ran the avi's through Registax with the same parameters and measured Saturn's disc size in Photoshop averaging the result with both X and Y axis pixel count in the formula. Here are the results of the test runs:
C9,25+Ultima 2x @ 0mm = f/21,8
C9,25+Ultima 2x @ 10mm = f/22,4
C9,25+Ultima 2x @ 20mm = f/22,45 (...which is odd!)
C9,25+GSO 2.5x @ 0mm = f/21,1
C9,25+GSO 2.5x @ 0mm = f/21,7
C9,25+GSO 2.5x @ 0mm = f/21,5 (...which is even more odd!)
Conclusion? ...well it seems that the GSO 2.5x Barlow doesnt seem to add that .5x extra to the Ultima. This might mean that the Ultima is a bit more powerful or the GSO is weaker than advertised, at least in my scope. I'm not sure what happened at the 20mm position for both barlows as I wasn't swapping them between runs instead I ran the Ultima at 0-10-20mm and then the GSO in the same way. After I was done with the testing I put the Ultima back in the focuser and shot a few avi's of Saturn which I will begin to process shortly. I guess the GSO will be up for sale as I can't justify keeping it & besides, I wouldn't give up on my Ultima just yet!
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