MaximDL Question?

[beamer3.6m]

Hi

I have just installed MaximDL and it appears to be an all in one wonder solution for someone like me.

I guide with ED80 and a QHY5 and image through my Explorer 200p with the Canon 400D.

All these seem to be supported and I want to use the Focus help so that my images are spot on, but how does this actually work. I have seen the simulator results in a graph but what is the graph supposed to look like when you achieved perfect focus?

Also, I have a skywatcher motorised focuser which works with a hand controller but can this be attached to the PC by any means so that the PC can control it - is that even possible.

Ideally, it would be great if you could take a shot, get the PC to consider it and then adjust the focus itself - can that be done?

Stupid questions huh!

Cheers.

[brendant]

The Shywatcher Accufocus unit can be controlled from your computer using a Shoestring FCUSB unit, you will also need to get the cable to connect onto the motor from the FCUSB unit. Then download a free copy of FocusMAX, then autofocusing is possible. It works reasonably well once you have run a series of setup focusing runs called V-curves. Takes a while to get working correctly but worth it in the end.

Brend

[beamer3.6m]

I have MaxinDL suite which appears to have the autofocus built in but so it appears that I can use the Skywatcher focuser with it which is excellent.

I am unsure how I do the autofocus but what does the graph show on the readout?

[brendant]

I have not used Maxim's own focusing routine but it looks very similar to FocusMAX. FocusMAX is pretty much the software of choice for automated focusing and is widely supported and integrates seamlessly into Maxim, it's free which is another bonus. There is a Yahoo user group which is also a great source of help and advice as well.

Essentially you require to run a series of focusing runs called V-Curves where the software will select a star then proceed to take a series of images (assuming your camera is connected up for full shutter control / image download with Maxim), ranging from out of focus to focus and back out of focus again. It measures the (FWHM) size of the star if the size is increasing after a move command it can tell that it needs to reverse, it then proceeds to move in increments until the star is at minimum size (Focused) and then continues for period to defocus the star. It is measuring the star shape each side of focus and determining the linearity of the system response, you need at least 10-15 good "V" profile runs so the software can understand the focusing characteristics of the scope and understand the response of focuser.

From this info it is then able to quickly determine the correct position for correct focus on subsequent runs, it knows if the star is "X" size it roughly needs to move the focuser "Y" to reach focus. Note, it will still verify this focus by measuring the FWHM of the star to ensure it is in focus and correct if required before issuing a success dialog.

The initial setup can take some time to do (a night typically) but once done correctly subsequent focusing will take a couple of minutes max.

If you have different scope / camera configurations then you need different "V" curves for each one. If your focuser has excessive backlash or unpredictable non linear movements the software will understandably struggle to make sense of it all. There is no question when it works and it does the results are spot on and it makes the work of refocusing at regular intervals easy and if unattended imaging is a goal an essential piece of the puzzle.

Hope this helps.

Brendan