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Old 21-09-2008, 01:56 PM
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Matty P (Matt)
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Talking Finally, No more problems with finding a Guidestar!

Even since I started autoguiding, I've always had problems with finding a suitable guidestar to guide on, creating never ending problems.

So yesterday, after a long day working on my Observatory. The sky stayed clear, so I setup the scope and mount anticipating a great night for imaging. It was, the seeing was average but the transparency was excellent. The Milkly Way was stunning, the best I have seen from my location. I went through the normal procedure of Drift aligning, Star alignment, then setting up the lappy and thousands of cables. Once completed, I collimated my C8 and setup the camera. Focused both scopes and now I was ready to start imaging.

At first I wanted to image the Sculpter Galaxy but after about 20-30mins of trying to find a guidestar.... I gave up and decided to image an object with many bright stars. The Tarantula Nebula.

I got the Tarantula Nebula centered in both scopes and went to see if the guidescope had a star in the FOV. Nothing...... absolutely nothing....... I knew something was wrong as there was thousands of suitable guidestars in that area of sky. I started brainstorming what could be wrong so I went through a checklist. Is the cable connected? YES. Is the cap off the scope? YES. Is the guidecamera focused? YES.

From there I couldn't work out what was wrong. So as a last resort, I decided to start changing some settings on PHD. I clicked on Cam Dialog and changed the Gamma from 100 to 150. Nothing. I changed the Brightness. Nothing. Then I found the exposure setting which was set on -4 as default. I changed it to 2 from -4 and returned back to the main menu. I clicked on the live view button and waited. The first image appeared and I was blown away. About 50 stars appeared on the screen with the Tarantula off to the left. I collected a total of 60 minutes of data on the Tarantula Nebula using 6 minute subs. PHD performed flawlessly and gave me perfectly round stars.

So at the end of it all, I had to laugh that one setting had caused so many problems and I shouldn't have blamed the guidescope and software for not working.

Phew!!! What a night!

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Old 21-09-2008, 02:01 PM
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Well Matty sounds like your night turned out pretty well in the end, now this setting you speak of, I must check it out as well maybe that is some of my problems stem from.

Once I have a guide star it locks on pretty well and goes from there, however as you say, it is sometimes difficult to find one in certain areas of the sky, I will give this a go tonight and see what happens.

How we learn from others, many thanks.

leon
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Old 21-09-2008, 02:08 PM
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Just had a look at the PHD stuff Matty, I presume you mean that you changed the number in the drop down box giving you different values, well I just realized that I already do that, and run PHD at 1.5 usually.

Or have I missed something here.

leon
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Old 21-09-2008, 02:10 PM
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Matty P (Matt)
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Quote:
Originally Posted by leon View Post
Well Matty sounds like your night turned out pretty well in the end, now this setting you speak of, I must check it out as well maybe that is some of my problems stem from.

Once I have a guide star it locks on pretty well and goes from there, however as you say, it is sometimes difficult to find one in certain areas of the sky, I will give this a go tonight and see what happens.

How we learn from others, many thanks.

leon
Yes, you should definitely check that setting because all CCD cameras are really quite sensitive and they should easily pick up a star anywhere in the sky.

I forgot to mention that with only a 0.5 sec expsoure my guidecamera (DMK) captured a lot of nebulosity after I changed exposure setting. I could easily make out the outer arm structure, no problem.

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Old 21-09-2008, 02:21 PM
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Matty P (Matt)
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Quote:
Originally Posted by leon View Post
Just had a look at the PHD stuff Matty, I presume you mean that you changed the number in the drop down box giving you different values, well I just realized that I already do that, and run PHD at 1.5 usually.

Or have I missed something here.

leon
No, I changed the setting in the "Cam Dialog" section under expsoure.

Have a look at the attached image.

Click the Cam Dialog box at the bottom right and then the exposure setting in the window that pops up.

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Old 21-09-2008, 02:32 PM
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Opp's wrong area, will check it out Matty, thanks.

leon
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Old 21-09-2008, 02:41 PM
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Well Matty, I just went out and fired up PHD, all is connected and it is capturing however that cam dialog box fails to light up and stays grayed out, I can't access it at all.

Now how do I go about that one.

leon
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Old 21-09-2008, 03:18 PM
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Matty P (Matt)
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Quote:
Originally Posted by leon View Post
Well Matty, I just went out and fired up PHD, all is connected and it is capturing however that cam dialog box fails to light up and stays grayed out, I can't access it at all.

Now how do I go about that one.

leon
What type of guide-camera are you using?

Does a message come up when you connect the camera saying "Cannot directly control duration of exposure"?

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Old 21-09-2008, 05:12 PM
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That is the box you get if you are using a DMK Matty. If you use a ToUcam then you get the ToUcam settings box. What you get depends on the camera you are using.

BTW do your exposures always show whole numbers (+/-). If so then you need to go to the TIS website and download and install the driver that is there for your camera. Then you will get normal exposure settings. I had issues with that myself. Check this thread out.
http://www.theimagingsourceforums.co...1151#post26085
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