Showing posts with label Solar. Show all posts
Showing posts with label Solar. Show all posts

Sunday, May 20, 2012

Annular Eclipse 2012

On Sunday, May 20, 2012 most everyone in the western US had a great opportunity to see the Annular Eclipse or Ring of Fire.  For a few weeks prior to the eclipse I have been busy preparing for the big event, finding a good location, equipment (new solar filter), inviting friends and family, test runs......   For the first 45 minutes we were treated to some nice views of the eclipse. Just before the maximum, mother nature threw some clouds at us which pretty much broke up the party.  We were lucky enough to get a few glimpses of the eclipse at maximum as it broke through the clouds for a few brief moments. Overall, it was still a great time with a lot of oooh's and ahhh's to be had.  Dave Brown also brought his telescope which he was able to project images of the eclipse onto a white piece of paper.  The extra scope came in real handy with the large crowd we had.

Technical Details:

Annular Eclipse, May 20, 2012
Pocatello, Idaho

Equipment:  Meade LX90  8" SCT Telescope, Thousand Oaks Optical White Light R-G Solar Filter,  Nikon D300s Camera.

For more information on Eclipses

Set up and ready for an eclipse. 

 We had a nice turnout with about 35-40 people showing up to take a look at the eclipse.
 Dave set up his scope with a nice image projected onto a white piece of paper.  This was great for "mass" viewing while I was trying to get a few images.
A brief break in the clouds gave us some great looks right around the peak of the eclipse.  Notice the clouds drifting through the image.

Image taken a few minutes before first contact.
Image taken about 5 minutes after first contact
Image taken about 36 minutes after first contact

I was able to get a quick view of the Eclipse maybe a minute after maximum.  I was having a hard time getting the focus correct due to the clouds continuously passing through the image and the lack of a sunspot achieving the fine focus.
When it was all over, the clouds that caused so much grief provided a great sunset! Note the cloud at the top half of the image started out as a small whiff barley covering the sun.  It just kept growing and growing and growing......



These images can be viewed in full resolution on my Flickr account

Sunday, May 13, 2012

First Solar Image


I recently purchased a Thousand Oaks Optical White Light R-G Filter in preparation for the May 20, 2012 Annular Eclipse.  Above is my first attempt at "Solar Imaging".   I was pretty happy with the results and hope to post more pictures of our nearest star over the next few months.  It should be fun since the sun is heading into a more active period.

The above picture was taken during a "dry run" in preparation of the annular eclipse on May 20th.  I used a Nikon D300s (Prime Focus) with an LX90 (Classic) Telescope.

A few things learned from this dry run were:

1) Needed to review telescope tracking and figure out how to initialize my telescope in a daytime setting.  I think I have resolved this issue by just approximating true north (get the telescope in home position) and doing an (autostar) easy align without looking at the guide stars to ensure they are in centered (just hit enter).  I then target the sun and let it track (using keypad, direction arrows).  With this approximation, it is calibrated well enough to keep the sun in the eyepiece for 5-10 minutes before an adjustment is needed.  Close enough for the sun!  In the future, I will look to optimize daytime calibration for better results.

2) I was able to take a variety of exposures and settled on some settings I know will work for the sun.  ISO 200 and exposures between 1/640 to 1/250 will work best.

3) Focusing may be the most difficult.  I found that using the sunspots may be the most effective way to focus the image. Using the outer edges of the sun to focus does not yield positive results.  Sunspots have a lighter outer section called the penumbra, and a darker middle region named the umbra. When the lighter details of the penumbra become visible in my camera view finder sharpen up, I stop.....  It is really hard to see detail through your view finder so I'm constantly adjusting focus and shooting......   You can always throw away the worst of the lot.  Taking lots of frames over a short period of time is also required to get that "clear" patch of sky.

4) Overall picture quality will go down when the sun starts nearing about 30 degrees from the horizon.

5) Mirror lock up before the image is not as critical as when taking pictures of the night sky.

6) For now single exposures seem to be sufficient.  I will work on multiple frames and stacking later when I get other kinks worked out.

7) Will need to get a focal reducer to capture the "entire" sun in one image!

8) Its a lot warmer to observe in the middle of the day or late afternoon.  I'm used to chilly nighttime high desert temperatures.

BRING ON THE ECLIPSE...............

WORD OF CAUTION:  Do not observe the sun through ANY optical aid unless it is properly filtered.  Sunglasses do not count!