Help w/ ST4

I recently aquired a used ST4 and have been having trouble getting the thing to work. Last night (since it was warm here) I was bound and determined to get it to work since I had all night if I needed to. I read the manual again and was going to use Wil Milan's article as my step by step guide. Got everything hooked up and plugged in the camera to start the cool down process. According to Milan's guide the head is cooled down when the X and Y values flash zeros. After a few minutes, only zeroes flashed. After 10 mimutes, random numbers were starting to appear in those X & Y values although not all the time. The entire time the guider head was capped and in a black bag so I don't think (or know how) light could have reached the head. There is where I stopped for the night. Is this normal for the X&Y values to display those random numbers?

Chris

I'm not familiar with the flashing zero method and have not heard of it before so I can't make a comment on that.

The proceedure I use when setting up is to get everything hooked up. As soon as I plug in the ST-4 I hit the "Interrupt" key so that the "Hello" message is displayed. I then go about other things that need to be done for 10-15 minutes, then I set some of the general settings including a exposure time I think I will use. By this time the camera has cooled and I can take my dark frame and then start the procedure for getting my guide star centered and doing calibration. If I have to change the exposure or something else I just cover the scope and take another dark frame.

I don't know if my proceedure is the "correct" way of doing it but it works for me and I hope it helps in some way.


Robert W.

Hi Chris,
Here is the best refrence article out there.
http://www.abmedia.com/astro/articles/st4.html
I recently bought an ST-4 myself and have taken quite a few notes on what adjustments have worked for me. I would be glad to pass on anything and everything I have learned. If you wanr, you can email me...
Don Spencer

Chris,

I went back and reread the article by Milan. It is good.

Did you take a dark frame? Was the temperature of the camera and the ambient temperature stable?

If you are getting CHANGING readings (with a covered ST-4), that may indicate the temperature is changing, either because the evening is getting cooler, or because the cooler in the camera has changed the camera's temperature.

If you are covered up and are getting unchanging non-zero readings that may indicate that the cap is not light-tight (hard to believe), or you forgot to subtract the random noise of the hot pixels that--i.e., you forgot the dark frame.

From your description of what happened, I would simply assume you either forgot to take the dark frame or the temperature was continuing to change after you took the dark frame. At any rate, just take another dark frame and continue climbing that old learning curve.

Alex

The numbers displayed by the ST-4 show the value and the location of the brightest pixel, even if the brightest pixel would barely show up on an image. Regular, random noise is common and actually expected especially if you haven't taken any dark frames. It is most likely causing the numbers you're seeing, I see them every time I power my ST-4 up. The "all zeroes" method means nothing to me. The only time I ever got all zeroes was when my battery was nearly dead. In my opinion if you didn't take a dark frame and the values are all zeroes there is a problem.

Read the article Don posted a link to. It is a fantastic one especially since the user manual is just about worthless. I've read the thing many, many times and the article is what made learning the ST-4 so easy for me.

When you power the unit up immediately push interrupt. The camera will cool down by itself and shouldn't need monitoring. I would hardly call it a "process" as well. I can, and have, power it up and begin tracking within just a few minutes. The ST-4 seems intimidating but it is actually very easy to use once you get use to the simple interface. I've had great success with my ST-4. My first really long-exposure photos were taken after the second time I had even touched one.

The biggest piece of advice about the ST-4:

"When in doubt, take a dark frame."

Daniel
http://home.earthlink.net/~dreyna14/astro.htm