Go Back   IceInSpace > Beginners Start Here > Beginners Talk

Reply
 
Thread Tools Rate Thread
  #1  
Old 10-08-2008, 02:14 PM
Dennis G
Dennis G

Dennis G is offline
 
Join Date: Jan 2007
Location: Albany West Aust
Posts: 213
Dmk 21 First Luna Recording

After weeks of overcast winter weather the clouds cleared late afternoon August 7 and with the moon directly overhead three days before the first quarter, the DMK imager and the new platform drive and control were put to the test.
Although the remote focus makes it easy to control the focuser, getting it spot on, still remained a very difficult guess. Atmosphere wasn’t good, which didn’t help and of the 15 avi recordings made before cloud closed in, none were dead sharp. Disappointing as it was, I’ve never captured detail with the Toucam as seen in these recordings. Having overcome the initial line problems, which eventually corrected itself with use and is now thought to have been a poor cable contact, and with a better understanding of the camera settings and capture controls, which are a dream compared to the Toucam software, it is now apparent that focus, as the Iceman emphasizes in his planetary article, needs to be better than a guess.
This brings the 2x Barlow used for the recordings into question. Is it the weak link? Comparing these first recordings with those taken with the Toucam, the DMK appears to have a higher magnification, more 3D depth in the pictures, or is it because the mono recording produces more detail? These are questions I’d appreciate members comments.
The new platform drive and control worked as planned and I must have been very close to the SCP, because drift was reduced close to zero. A lot of luck rather than skill!
Thanks to all who assisted with my numerous questions.
Attached Thumbnails
Click for full-size image (Theophilus, Cyrillus, and Catharina Aug 7 c21.jpg)
185.2 KB71 views
Reply With Quote
  #2  
Old 10-08-2008, 02:21 PM
wmzaphod's Avatar
wmzaphod
Optically Obsessed

wmzaphod is offline
 
Join Date: May 2008
Location: Brisbane, Australia
Posts: 83
That pic looks pretty good Dennis - not bad at all

It is a complicated process eh!
Reply With Quote
  #3  
Old 11-08-2008, 12:27 AM
Jen's Avatar
Jen
Moving to Pandora

Jen is offline
 
Join Date: Jan 2008
Location: Swan Hill
Posts: 7,102
nice pic
Reply With Quote
  #4  
Old 11-08-2008, 05:07 AM
iceman's Avatar
iceman (Mike)
Sir Post a Lot!

iceman is offline
 
Join Date: Sep 2004
Location: Gosford, NSW, Australia
Posts: 36,799
Well done, Dennis! A great first light.

Did you use 30 or 60fps?

Did you use the histogram? The bright areas are a little overexposed, just be careful of that next time. Also, sometimes capturing a crater/area right on the terminator can be more difficult due to the very high contrast areas.

Maybe try capturing an area a little further in from the terminator, where there's a little less contrast but still some nice lighting to illuminate the crater and fill the histogram without overexposing or underexposing.

The magnification of the DMK and ToUcam should be the same, if you're using the same barlow and the camera is placed the same distance from the focuser, as they both use the same size CCD and the same pixel size.

Great first light, keep trying!
Reply With Quote
  #5  
Old 11-08-2008, 10:26 AM
Kal's Avatar
Kal (Andrew)
1¼" ñì®våñá

Kal is offline
 
Join Date: Nov 2006
Location: Sydney
Posts: 1,845
Nice first image Dennis, look forward to alot more from your DMK!
Reply With Quote
  #6  
Old 11-08-2008, 11:22 AM
Dennis G
Dennis G

Dennis G is offline
 
Join Date: Jan 2007
Location: Albany West Aust
Posts: 213
Thanks for your comments KMZAPHOD. Complicated may be, but most enjoyable when conditions are right. Something seldom seen here on the Sth Coast. A new high forming today we could be lucky! Its obvious you have an interest with cameras.
A question : What would a U/V filter improve on moon shots? This is just a U/V filter doesn't include I/R.
Reply With Quote
  #7  
Old 11-08-2008, 12:22 PM
Dennis G
Dennis G

Dennis G is offline
 
Join Date: Jan 2007
Location: Albany West Aust
Posts: 213
Number of frames and histogram

I think I used 30 fps and the histogram is something I thought was only used when three RGB filters were used to make a coloured picture. I do try to level out the picture contrast with LEVELS - do you mean levels or histogram that you refer to in your Planetary article? I'd like to know how I could adjust the over bright parts. I discovered this problem with the daylight test runs and wondered how I could over come the difference in contrast. The trunks of the white Melaleuca trees where washed out trying to get the rest of the picture detail. Also I'd like your comments Mr Iceman regarding two filters. Some time ago in my ignorance I purchased a cheap green filter that was advertised as a MOON filter and realising green moon pictures were not aceptable discarded it. I owned a 50 mm U/V filter and cut it down and ground it to fit the 1 1/4 inch holder that accommodated the green filter. While testing the DMK in daylight under poor atmospherics I managed to get two or three clear sharper pictures when using either the green or the U/V filter. Is there an explanation for this? And what I couldn't understand was the green filter didn't make the pictures green. This left me wondering if when you make three RGB pictures do they appear in colour?
Now I've discovered GO Advance I'm attaching one more pic taken at the same session. Owing to the short period of clear sky, I started recording before it was totally dark and the first few recordings weren't stong in contrast. The attached being one of the earlier.
Attached Thumbnails
Click for full-size image (craterRoma, Posidonius, Serpentine Ridge Aug 7 c16.jpg)
141.9 KB32 views
Reply With Quote
  #8  
Old 11-08-2008, 01:11 PM
Lester's Avatar
Lester
Registered User

Lester is offline
 
Join Date: Jan 2006
Location: E.P. S.A.
Posts: 4,963
Very nice images Dennis.
Reply With Quote
  #9  
Old 11-08-2008, 05:25 PM
Matty P's Avatar
Matty P (Matt)
Star Struck

Matty P is offline
 
Join Date: Nov 2007
Location: Canberra
Posts: 2,797
Great first images Dennis.

Keep it up and I'm looking forward to more.

Reply With Quote
  #10  
Old 11-08-2008, 05:48 PM
Dennis G
Dennis G

Dennis G is offline
 
Join Date: Jan 2007
Location: Albany West Aust
Posts: 213
Reducing exposure with the Registax histogram

The Histogram meant little to me Mr Iceman, but as a beginner I accept all the advice given and as the only Histogram as per your planetary articles found, is in Registax, I experimented with an AVI recording with the same over exposed hi-lights as that submitted previous. By increasing the number in the box Io: which moves the red line to the right, I was able to make the O/a of the picture darker thus reducing the hi-lights. Clicking on do all and saving to Photoshop and using the centre slider in levels to lighten the O/a,the end results are as per attached. This then raises the question: Is this how you would have done it? If so, then I’ve learnt something, which will assist in finishing future avi recordings and may also assist other members of IIS.
Attached Thumbnails
Click for full-size image (Theophilus  Aug 7 c19.jpg)
153.7 KB29 views
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 08:51 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Advertisement
Bintel
Advertisement