View Single Post
  #2  
Old 16-04-2006, 12:06 PM
astro_south's Avatar
astro_south (Andrew)
No GOTO..I enjoy the hunt

astro_south is offline
 
Join Date: Jan 2005
Location: Brisbane
Posts: 1,094
OK - guess I will kick this off

Here are some raw shots from last night (15/04/06 from 10:22pm to 10:34pm - according to my camera). All I have done is crop out the image of Jupiter from the larger image to fit the forum guidelines on file sizes. I tried to get some shots of the Europa shadow transit after Jupiter had cleared my rooftop, but the seeing was very poor. Visually it would snap for fractions of a second and then blur again. Therefore it was hard to get a single shot timed right and hence all these shots are pretty poor. There was also some cloud around and during the shadow transit which indicated the upper turbulence.

When the shadow transit of Europa was over the seeing steadied down a bit and the view through the eyepiece had crisp views for a number of seconds, before going blurry and then snapping back to clear. When the blurriness occurred it was difficult to pick out the GRS, when it was crisp it was easy to see festoons and white ovals and detail within the red spot. This is the period that the attached shots are taken from. The seeing was no where near the quality when these shots were taken : http://www.iceinspace.com.au/forum/s...ead.php?t=9093 , and it was harder to get everything to work together (clear seeing and steady hands).

Later I tried to get Europa's egress and the seeing had deteriorated again and there was significant cloud around. To top that off the batteries ran out in the camera when I finally got a gap in the clouds - so no good shots of Europa next to Jove

Anyway, the details of the 4 attached raw shots (pick of the bunch) are below
Scope: 12.5" F6 truss dob - no tracking at all
Eyepiece / barlow : 8mm Radian + Shorty Plus 2x (472x)
Camera / settings : Canon A40, Macro, no flash, everything else auto point and shoot, maximum optical zoom. Checking the properties of the original files indicates the camera settings of 1/8 of a sec exposure, focal length of 16mm, f-number of 4.8

I have saved the quality of these jpegs @ 95% as they are over the 100Kb size limit at 100%

I used Irfanview with the "890" (3rd Raw image) below to play around with getting more detail out of it. I know nothing about wavelets and deconvolution and a few other terms I have read on this site, so I just went into the "enhance colours" section and reduced the brightness to -37 and increased the contrast to 59. I then sharpened the image once with the built in sharpen tool, and finally I resized it by half (532x504 to 266x252 pixels). I know there are a lot more technical processing that can be done, however I think with these single shots you are limited by what you can 'bring out', though I am open to other suggestions for processing and I wait to be impressed by others.

Kudos to Dave (and Asi) for coming up with the idea and supplying prizes. I have certainly been amazed by what I have done (given the setup), and I am sure there are a heap of other unsuspecting observers that will be equally amazed at what can be achieved with some experimentation and having a go . I will be trying again soon and hopefully things will go a bit smoother and I can capture some moon events with great seeing. Feel free to go crazy with any or all of the 4 raw images - I look forward to learning more.
Attached Thumbnails
Click for full-size image (20060415_jove_875_crop_95%q.jpg)
64.6 KB15 views
Click for full-size image (20060415_jove_886_crop_95%q.jpg)
64.7 KB9 views
Click for full-size image (20060415_jove_890_crop_95%q.jpg)
62.3 KB16 views
Click for full-size image (20060415_jove_900_crop_95%q.jpg)
63.2 KB13 views
Click for full-size image (20060415_jove_890_crop _bright_cont_sharp_resize50%.jpg)
40.1 KB35 views
Reply With Quote