David's Astronomy Pages CCD Imaging Observatory Use   Home Page   Computer Control

See also
- CCD Imaging Performance 2001-09 to 2002-01 describing my first 4 months of CCD Imaging.  
- Imaging Sessions for latest CCD Images look at my page. 
- Scripting for information about my Telescope/CCD Image Scripting 

CCD Camera

My CCD Camera is a ST-7E manufactured by SBIG (USA) and supplied via BCF in London. (picture of ST-7)

The ST-7 camera uses the KAF-400E CCD chip (765 x 510 pixels, with pixel dimension of 9 x 9 microns).  A non-ABG camera was ordered, but it is currently suspected that the camera supplied is actually an ABG camera (details)

Camera control is performed via CCDSoft v5 program written by Software Bisque. The software was supplied with the camera.

[ Technical specification of ST-7 camera (at SBIG Website) ]
[ Technical specification of CCDSoft v5 program (at Software Bisque Website) ]

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First Images

Some of the first pictures taken with my ST7 camera are shown below. They don't really to justice to the capabilities of the ST7 camera, but they show my first achievements.  For more recent images look at my Imaging Sessions page.

	First night - stellar imaging (images 2001-09-25) Double-Double in Lyra 2001-09-25,  23:16h UT (#2014) 8 secs exposure Due to poor focusing and/or poor seeing the binary components of each of the 2 main stars could not be resolved Previously I've been able to resolve the binary components (See previous Visual View through eyepiece 1996). Subsequently,  deconvolution was used to process the image and just resolve the pair of close binaries (notes 2001-09-25)
	Second night - lunar imaging (images 2001-09-29) 2001-09-29,  21:36h UT 0.5 secs exposure (#4030) Due to high brightness of the near full  moon, the aperture of telescope was stopped down to less than 2 inch. This limited the resolution achieved.
	Third night - lunar imaging (images 2001-10-03) 2001-10-03, 23:01h UT 0.2 sec  exposure (#5037)
	Fourth night - deep sky imaging NGC 7331, Spiral galaxy in Deer Lick Group 2001-10-11, 20:49h UT 60 sec  exposure (#6002) Stars imaged down to at least Mag +14.8 in this  60 second exposure.   (previously Mag +12 was my visual limiting magnitude) Longer exposures started to show trailing/Pec wobble (I'm waiting on a replacement RC Adapter from SBIG to enable PEC training & autoguiding)
	Fifth night - low resolution planetary imaging, Jupiter & Saturn 2001-10-31/2001-11-01 0.05 & 0.1 sec  exposures,  Unsharp masked  (#8080 & 8043) Saturn - various exposures, various unsharp-mask processing

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Initial Teething Problems

Initial Teething problems and solutions are listed below

• Problem :  Focus control and @Focus not working from within CCDSoft although focus control working from within TheSky

Solution :  Telescope / Server Settings modified in the TheSky to allow remote connections/allow focus control   (solution originally provided to me by Software Bisque technical support )

• Open TheSky. 

• Open menu item Telescope |  Server Settings. 

• Click on  'Allow remote connections'

• Then within the 'Remote client capabilities' section, click on 'Allow focus control'

• Finally click on Ok

• After this you small window that comes up called 'TheSky Server' which
  contains a note indicating that Sky is 'Listening on port 9032'

• Problem :  Telescope running away in Declination when ST7 is connected to LX200, making it impossible to keep a star image stationary on the CCD chip
  Temporary Workaround: Remove cable (Autoguider consequently not available)
  Solution:  SBIG diagnosed a probable reverse wiring problem with the RC-Adapter and sent a replacement by Airmail.  This new adapter fixed the problem.

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Experience and comments using ST-7

CCDSoft
CCDSoft appears to be fully capable for acquiring CCD images using the ST-7.

Some bugs noticed in 5.00.041
a) Problem : Offset time field on the FITS Modifier form will not accept '-1'. Error given as soon as '-' is entered. Workaround : Enter '1' first, then left arrow and then enter '-'

Autosave/Image numbering
I use the Autosave facility in CCDSoft, with an image numbering system with format, sssssnnn, where sssss records the imaging session number and nnn records the consecutive images taken during the session. eg 00006001 is the 1st image taken during the 6th observing session.

At the start of each session I set the Autosave Starting number to  sssss001 (eg 6001) and the autosave folder to ../Ccd Imaging/New/yyyy-mm-dd/  where yyyy-mm-dd is the observing date.

Mechanical Connection to Scope
The standard connection provided with ST-7 is a 1.1/4" nose piece. When connected into a 1.1/4" eyepiece holder with a single thumb-screw, the ST-7 is in danger of falling out and/or slop.

I've now bought a #62 T-Adapter, which allows the ST-7 to be screwed securely to a T-Thread. In practice I connect the ST-7 and T-Adapter to a Thread to 2" nose adapter, which I insert into a JMI-NGF-S focusser and tighten with a pair of thumb-screws.

An assessment of CCD Imaging Performance from my first 4 months use of the camera is documented. (CCD Imaging Performance 2001-09 to 2002-01)

CCD Operating Temperature

Graph showing CCD Operating Temperatures used in SBIG through year.
(note SBIG 7e camera cools up o ~ 30 deg below ambient)

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Accessories

The principal accessories associated with the CCD camera are
- 3D Counter Weight system 
- JMI NGF-S focusser controlled via CCDSoft and TheSky

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Books

Books that I own and have read on the subject are as follows

• Choosing and Using a CCD Camera
  by Richard Berry  (Willmann-Bell, Inc, 1992)
  A practical, nuts and bolts kind of book with aim of helping the reader decide if CCDs are for them, and then help them plan and execute successful imaging sessions. This was my first book on the subject and helped me to decide that I needed to get into CCD imaging one day.

• The Art and Science of CCD Astronomy, 
  edited by David Ratledge (Springer-Verlag London Ltd, 1996)
  Describes the equipment, techniques and solutions of 12 amateur astronomers with various CCD targets. One of the chapters is by David Strange who belongs to the Wessex Astronomy Society.

• A Practical Guide to CCD Astronomy
  by Patrick Martinez and Alain Klotz (Cambridge University Press, 1997)
  Gives a clear description about how CCD cameras work and what factors determine their performance. I  found Chapters 4 and 5 (Display and image analysis functions, Image Processing functions ) very useful and helped clarify to me how image processing works. 

• The New Astronomy
  by Ron Wodaski  (2001) ( http://www.newastro.com/)
  A practical, up to the minute description of modern amateur CCD imaging.  Most useful if you own a SBIG camera and use CCDSoft.

I've also borrowed and read the following book 

• Handbook of CCD Astronomy 
  by Steve B. Howell (Cambridge University Press, 2000)
  Describes the electronic workings of Charge-Couple Devices (CCDs). Chapter 5 on photometry and astrometry useful. Last chapter about use of CCDs in Space.  More of a book for university students than the CCD amateur.

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UT/BST Times

BST times are 1 hour greater than UT times

To analyse FITS images for a minor planet using CCDSoft/TheSky, times (TIME-OBS, DATE-OBS) must be in UT times.

CCDSoft's | Research | Analyse Folder of Images | FITS modifier | can be used to correct BST times to UT times.    Use Offset Time (hours) of -1 
(Need to be careful to apply change only once)

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Imaging / Analysis Practice

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