From: Phil Houston <pkh111@knology.net>

Date: July 7, 2007 2:58:50 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: guiding with Astro IIDC


Milton,


The discussion about auto-guiding has raised a question about using Astro IIDC for guiding my scope.  I use a small 90 mm scope and a  210 mm f/5.6 zoom camera lens attached to a DMK camera for auto-guiding through a GPUSB to an ST-4 compatible connection.  Past attempts to use Astro IIDC resulted in a failure to calibrate possibly because of the short focal length of the guide scope and slow speed of the telescope drive. This may have caused the program to either time out or think the drive was not functioning, I don't know.  It is possible to move the scope using the manual controls in Astro IIDC.  I tried using PHD for guiding and initially had the same results (calibration failed) until I found a setting to increase the length of time the drive signal was sent to the scope.  Calibration was then successful  and I can finally auto-guide using my Mac.


My question is,  does Astro IIDC have a way to increase the length of time the drive signal is sent to the scope?  I do enjoy the capabilities and ease of use of your program and hope I can use it for imaging DSO's as well as the Moon and planets.  My apologies in advance if I have missed a reference to this in the manual.


Last month I tested the auto-guiding capabilities of the system and produced the images linked below.  For imaging DSO's I used a first generation  MacBook and Parallels to run AstroArt 2.0 in order to capture images with an old StarlightXpress MX916 camera (Nebulosity doesn't work with the oldies).  No filters were used for the luminance and I kinda skimped on the color.  Guiding is done on the Mac side with PHD right now and hopefully with Astro IIDC someday.  I used to image with a  500 MHz G3 iBook using Virtual PC for the PC stuff but did not have a Mac program to guide with back then so I don't know if the G3 could handle it all.


I noticed that even with my small guide scope, there was a slow misaligning taking place during the exposures evident by the shifting frames when stacked.  I can't believe tube flexure is the cause.  More likely loose components in the the cheap camera lens or the single 1/4 20 mounting screw slipping.  The effect has been cropped out in the images below but the stars show the slight drift.



m3_6407cm.jpg


m16m.jpg


m20_07.jpg



Phil


Oh, and since I haven't bothered the Group much recently,  here is a link to the guide scope window showing M3 at the top and the star I used to guide with on the right.  I used a .5 sec exposure to guide with but this image is a 5 sec. integration.


http://www.knology.net/~pkh111/m3_guide.jpg


And a Jupiter shot this year. ;-)


q6_61607.jpg