#1  
Old 26-12-2012, 10:52 PM
h0ughy's Avatar
h0ughy (David)
DOGHOUSE REBORN

h0ughy is offline
 
Join Date: Apr 2005
Location: NEWCASTLE NSW Australia
Posts: 31,228
question for planetary imaging

with a mono camera and filter set - what is the preferred or best way to image a subject like Jupiter for example? say you have a RGBIC filter set and a manual filter wheel? how long do you run the image capture for?
Reply With Quote
  #2  
Old 27-12-2012, 02:07 AM
Tandum's Avatar
Tandum (Robin)
Registered User

Tandum is offline
 
Join Date: Apr 2008
Location: Carindale, Brisbane.
Posts: 4,124
Hey Dave, I got a new video camera and have been looking at Mike's article for tips -> http://www.iceinspace.com.au/63-468-0-0-1-0.html

I've been controlling the wheel from the PC.
Reply With Quote
  #3  
Old 27-12-2012, 08:27 AM
Shiraz's Avatar
Shiraz (Ray)
Registered User

Shiraz is offline
 
Join Date: Apr 2010
Location: ardrossan south australia
Posts: 4,820
hi Dave

main trick is to ensure that the AVIs are short enough that the target does not blur too much due to target planet rotation. You can easily work out the maximum exposure times for your system from the planet rotation rates (eg Jupiter features move at about .25 arc sec/minute on the meridian) - with typical systems, a good starting point would be to use a Jupiter limit of about 60 seconds per colour and Saturn about 120 seconds. I use RGB (60Hz all) on Jupiter and LRGB (60,30,30,15Hz) on Saturn, with L taken at higher frame rate to beat seeing. Set your exposure time/gain to get about 75-80% histograms - leave a bit of headroom to ensure that the final result does not end up with any saturation, particularly on Saturn.

Often you will throw away most of the frames in an AVI, using AS!2 to stack say 25% (or less) of them unless the seeing is very good, so signal to noise can suffer with such short imaging times. If the seeing is very stable, consider reducing the framerate to reduce read noise. You can improve SNR by taking multiple short R, G, B AVIs and then combining the stacked results in WINJUPOS, which derotates the stacked images by cylindrical projection before RGB combining. WINJUPOS also allows you to take longer AVIs and derotate each frame before you stack in AS!2 or Registax - this removes rotation blurring from quite long sequences. Haven't had much success with that yet, probably because seeing has not been good enough.

I usually take multiple RGB (or LRGB) sequences with no delay between them and then it is possible to choose an RGB, GBR or BRG sequence that has the best combination of seeing in the channels. Its also possible to compile RGBs from non-sequential R G and B images, provided they are not separated by more than about 10+ minutes, by combining them using frame derotation in WINJUPOS. You really do need to battle your way through WINJUPOS - nothing about it is particularly intuitive, but it works exceptionally well in getting the best from your RGB data.

regards Ray

Last edited by Shiraz; 27-12-2012 at 09:50 AM.
Reply With Quote
  #4  
Old 27-12-2012, 09:19 AM
h0ughy's Avatar
h0ughy (David)
DOGHOUSE REBORN

h0ughy is offline
 
Join Date: Apr 2005
Location: NEWCASTLE NSW Australia
Posts: 31,228
thanks guys - thats been a big help. I forgot that that info was available. Ray sounds like there needs to be some WINJUPOS videos made on how you use it
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 12:29 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Advertisement
Bintel
Advertisement
Lunatico Astronomical
Advertisement
Astromechanics
Advertisement
Testar
Advertisement
Astronomy and Electronics Centre
Advertisement