Sunday, June 17, 2012

Venus. Done. Now give me some deep sky!

With eclipses, transits, and other astronomical events of note behind us I'm returning to my first love.  Wide field deep sky imaging.  But I really should post at least one picture of the transit before continuing.  I'm still going to work on assembling the time-lapse but haven't had time for the frame by frame alignment required.

Venus in mid-transit.  One of 298 frames.  Movie adaptation to be released...later.

It has been too long since I've really adorned the hair-shirt.  I've missed the unique pain of sleepless nights with endless hours fighting optics, weather, and electronics problems, followed by more hours of processing.  I'm not the most efficient (far from it), accomplished (light years away), or clever imager but I hope some other poor soul starting off can gain some measure of assistance by reading of my accounts.  Or at least a chuckle at my multitude of travails.

I always seem to bite off more than I can chew and this upcoming project will be no different.  The benefit of wide field is the variety of objects that can be captured.  It allows for greater creativity with framing.  But sometimes even a single wide frame isn't enough and that's where a multipanel mosaic comes in.  I've only attempted one two panel mosaic previously so why not make it harder by going for six?

A close friend encouraged me to post progress along way.  Too much focus on the finished product he says.  He's right ... accomplished imagers already know what is involved.  If things work out well you end up with a nice image with no one is the wiser of the struggles to get there.  As the title of of the blog implies - imaging is hard work.  Don't let anyone tell you otherwise.  The pros only make it look easy.  A tribute to their skill honed from thousands of hours of focus.  The rest of us need to bumble along ... but oh what fun!

So.  Posts to follow will chart the journey of this mosaic.  Warts and all.

Taken in my backyard in San Jose, CA  Jun 5, 2012 7:00pm PST
Canon T2i (stock), Canon EF 200mm f/2.8L + Extender EF 2X III @ f8, Baader solar filter

AP900 mount
1/800 sec exposure @ ISO100
post-processed in Lightroom 4, Pixinsight (colorized to my taste)

Sunday, June 3, 2012

Goodbye Venus ... till Tuesday

After yesterday's successful capture of the crescent Venus I decided to try one last time.  Planetarium software shows Venus about 3.75 degrees away from the Sun this morning - and should be safe to image.    After making absolutely sure the sun was outside of the frame I removed the Baader filter and snapped off a sequence of exposures.  The keeper was at 1/3200sec ... a little faster than yesterday.

Goodbye Venus ... see you in silhouette on Tuesday

You can readily see the large gradient from being so near the Sun.  If there were a second frame adjacent on the right side the Sun would be in about the middle.  I think we can safely say that Venus is lost in the glare now ... we'll have to wait until Tuesday when she does her once a century glide across the solar disk.

Taken in my backyard in San Jose, CA Jun 3, 2012, 10:51am PST
Canon T2i (stock), Canon EF 200mm f/2.8L + Extender EF 2X III @ f8
AP900 mount
1/3200 sec exposure @ ISO100
post-processed in Lightroom 4 and PS5

Saturday, June 2, 2012

Venus revealed: T-3days

This morning I took a couple more images of the sun to verify exposure conditions and then thought about Venus, unseen in the glare of the Sun, racing towards her date.  But is she really unseen?  

I checked planetarium software and it shows Venus is currently about 5 degrees away from the Sun.  The field of view of my camera with 200mm and 2x telextender is about half that in the long direction so in theory the Sun should be outside the field.  Could a picture be had?

Keeping the solar filter on ... I slewed to the position of Venus and verified that no part of the Sun was visible in the frame.  Then off with the filter and took an exposure series all the way to 1/4000 which is the limit of the T2i.  Focus was kept the same as when I was imaging the Sun so if Venus was in the frame I should see it.  In the glare of daytime I couldn't see anything on the camera back but once inside I could see Venus quite clearly in the fast exposure frames. 

Three days before "new" Venus

Since we are only 3 days before transit when Venus will be directly between Earth and Sun only a slight sliver of a crescent is visible.  Pretty neat!  

Tomorrow, exactly 24hrs after this image Venus will be 3.75 degrees from the Sun.  The apparent motion is now about 1.75 deg/day (about 3.5 moon diameters).  With care it might be possible to get another picture tomorrow morning.  After that it will be too close and lost in the glare of the Sun ... at least for my gear.  Still it is pretty neat to see her one last time before she reappears against the disk of the Sun on Tuesday afternoon.

Taken in my backyard in San Jose, CA  Jun 2, 2012 10:30am PST
Canon T2i (stock), Canon EF 200mm f/2.8L + Extender EF 2X III @ f8

AP900 mount
1/2500 sec exposure @ ISO100
post-processed in Lightroom 4

Friday, June 1, 2012

Transit Practice

With excitement for the coming Venus transit this coming Tuesday (June 5) I ordered me up a Canon Extender EF 2X III to double the focal length of the 200mm lens.  As I learned from the annular eclipse the image scale (for the sun) with the 200mm is pretty meager.

I took the following picture yesterday and while the sun still doesn't fill much of the frame it is more than  adequate for my transit purposes.  All I really want is a record of having lived through it and if all goes well assemble an image sequence into a movie.

Here is the full frame with the T2i.

Ol' Sol

I took that image, brought it into Pixinsight for enhancement and colorization.  Here is the result after a heavy crop.

Detail visible after processing in Pixinsight.  Please click for larger size - it's much nicer.

Focusing is a challenge ... in full daylight it is difficult to see the camera screen.  Autofocus does work but I'm not absolutely certain if I could improve on that with manual focus or not.  The above was focused manually using the buttons on the control box for the robofocus.  While it was the best of the lot it a moment of good seeing could easily account for the improvement.

Taken in my backyard in San Jose, CA  May 31, 2012
Canon T2i (stock), Canon EF 200mm f/2.8L + Extender EF 2X III @ f8

Baader solar film over lens cap
AP900 mount
1/640 sec exposure @ ISO100
post-processed in PixInsight