Home Page    Directory    Specials    My Account    My Wishlist    My Basket  

The main difference between finding objects with your telescope visually and finding them with a CCD is that the camera takes the place of your eye.  Instead of seeing the telescope image in an eyepiece you see it on a computer screen.  The advantage of this system is that CCDs are far more sensitive than the human eye, so you can more easily see faint objects.  There are still some tricks, however, to finding targets and framing them properly in the CCD's field of view.  This section will guide you through the process of using CCDOPS to find and center celestial targets.

Exposure Setup


Begin by clicking on the Focus button on the toolbar, or select Camera > Focus from the main menu.

Above:  The CCDOPS Toolbar.

Resolution should already be set to Auto under the Setup menu from having focused the telescope, but if it is not, click Setup in the toolbar, or select Camera > Setup from the main menu, and make sure Resolution is on Auto.  This bins the CCD chip 3x3 for more sensitivity and faster downloads.


Be sure Frame Size is set to Full so that the entire CCD field of view is displayed.  Update Mode should be Automatic in all cases except large-format, parallel-based CCDs which may require a while to download even in binned mode. In this case it is desirable to use Manual update mode allowing you to take another image only after making an adjustment to the telescope (if necessary).


Getting There

Find your target just as you normally would when observing visually.  Most telescopes used for CCD imaging are computer-controlled, so simply enter the object you wish to image.  While this is vastly easier than having to hunt down the target the old-fashioned way, there are still some tricks necessary to getting the subject properly framed (see below).  If you are finding the object manually, do as you would normally with a finderscope and/or Telrad to hunt down the object.  The hard part is finding the object with a small field of view and a delay between exposures.  While some objects are easy to find, nothing will give you an appreciation for goto telescopes like trying to CCD image without one!


The "Frame" Nebula




You can move the telescope either with the hand controller or by using the direction buttons in the Focus window of CCDOPS (which requires having the telescope control cable hooked up from the CCD camera to the telescope mount).  Which direction the buttons move the object in the image is dependent on the orientation of the CCD, the type of telescope, the type of mount, the position of the mount, whether it is the second Tuesday of the month, and the whims of the Fates.  Okay, actually there is a way to figure it out, but your best bet is to just push a button and see what happens.  Remember (or better yet, write down) which way each button moves the image; assuming your imaging setup is basically the same each time, you will pretty quickly learn what does what.



Okay, What About the Really, Really Faint Stuff?


Take a single exposure using either the Focus mode (in Manual update mode so only a single shot is taken) or using the Grab function.  Set the exposure long enough to see the faint subject you are looking for.


Now, go back to the Focus mode, set the exposure to something of more tolerable duration -- say, a second or so -- and begin taking a continuous sequence of exposures as you would to center a bright target (make sure Focus is back in Automatic update mode).  By moving the stars you noted above to the appropriate positions in the image, you can easily frame a dim subject without even seeing it.




Next, Basic Imaging...

Next Page

Copyright ©2000-2014 Starizona
Adventures In Astronomy & Nature, All rights reserved
Map & Directions -  Return Policy