computer controled focusing

Joshua Bunn (Joshua) · #1 12-12-2011, 01:43 AM

Hi Everyone,

Im looking into getting a SCT crayford style focuser and am assesing my options. in order to use focus max, do i need to focus the scope through the computer (using the computer to control it) or will focus max work by only using the hand controler to focus the telescope?

The main contenders at the moment are moonlite and starlight instruments.

thanks
Josh

cfranks (Charles) · #2 12-12-2011, 11:59 AM

FocusMax uses the computer to focus and is (usually) connected via a Serial (RS232) port. There are a few USB to RS232 convertors available but, like everything in this hobby, some work and some don't. To start its initial calibration run, FM needs the scope to be close to focus so you could use the hand controller or FM for that.

Charles

cventer · #3 12-12-2011, 02:51 PM

Optec TCF-S is also a good option to consider

or even FLI-PDF

Joshua Bunn (Joshua) · #4 12-12-2011, 03:41 PM

thanks for the replies.
I should clarify that i realise focus max uses the computer, but could i change the focus with a hand controler while focus max is working on the computer to guage best focus?

also, will @focus work with a moonlite focuser?

thanks
josh

Poita (Peter) · #5 14-12-2011, 11:47 AM

I can loan you a Optec TCF-S if you want to have a play and see how it all works.

Joshua Bunn (Joshua) · #6 15-12-2011, 02:19 AM

Thanks for your kind offer Peter, I have sent you a private message.

Josh

Brundah1 (David) · #7 15-12-2011, 05:58 AM

Joshua,

Depending on which scopes you have, I can highly recommend the Moonlites with their own HR stepper motors and mini-controller.

I have the 2.5 inch CFL on my 127EDT and the 2 inch CS Tall focuser on both C8 and C11. That's just one CS focuser with two lower flanges that stay on the respective scopes.

For C9HD, C11, C14, some RCs and large refractors, the 2.5 inch focusers have an option of 68mm threaded Drawtubes and various adapters - I chose this option and its highly recommended. You may need some custom threaded adapters, depending on your image train.

The Moonlite Mini Controller has no DRO (Digital Read Out) or stand alone manual focusing, but its half the price of the Moonlite DRO stand alone controller.

Both controllers are very well made and come with a USB RS-232 adapter that works. Moonlite controllers work with Robofocus and most other focus software - see the Moonlite website for details.

Besides Ron Newman's service & support is Platinum Standard

(no commercial affiliation - just a

customer)

Poita (Peter) · #8 15-12-2011, 10:07 AM

Take a look here and you can peruse the manual and grab the relevant drivers/software.
http://www.optecinc.com/astronomy/downloads/tcf-s.htm

TheDecepticon · #9 15-12-2011, 11:18 AM

Quote:

Originally Posted by Brundah1

Joshua,

Depending on which scopes you have, I can highly recommend the Moonlites with their own HR stepper motors and mini-controller.

I have the 2.5 inch CFL on my 127EDT and the 2 inch CS Tall focuser on both C8 and C11. That's just one CS focuser with two lower flanges that stay on the respective scopes.

For C9HD, C11, C14, some RCs and large refractors, the 2.5 inch focusers have an option of 68mm threaded Drawtubes and various adapters - I chose this option and its highly recommended. You may need some custom threaded adapters, depending on your image train.

The Moonlite Mini Controller has no DRO (Digital Read Out) or stand alone manual focusing, but its half the price of the Moonlite DRO stand alone controller.

Both controllers are very well made and come with a USB RS-232 adapter that works. Moonlite controllers work with Robofocus and most other focus software - see the Moonlite website for details.

Besides Ron Newman's service & support is Platinum Standard

(no commercial affiliation - just a

customer)

I second this. This is the set up for my refractor and is very smooth in operation. It can run with the Robofocus unit and in CCDSoft with @focus or MaxIm, Focusmax as well as with CCDAutopilot, I think.

If you want to use Focusmax for automated focussing runs, you may need to invest in Pinpoint full edition so you can aquire the right magnitude stars for filter changes etc.

There is a few solutions out there, you just need to decide which one you want to go with. My set up cost around AU$1200.00 delivered with the focuser and the Robofocus unit, which gave me a spare motor to put onto another scope if I want to.

Poita (Peter) · #10 15-12-2011, 12:23 PM

Focus Max overview here:
http://www.flemingastrophotography.com/focusmax.html

Joshua Bunn (Joshua) · #11 15-12-2011, 11:32 PM

Thankyou everyone for your advice. Im currently leaning towards the optec TCF-S, I think I can even get it slightly cheaper than the equivalent equipment by moonlite or starlights' feathertouch .

BTW David, It will be going on a 12"ACF OTA.

regards
Josh

Poita (Peter) · #12 16-12-2011, 01:01 AM

Bassnut has owned an optec for ages, you could ask him what he thinks of it.
Check out his stuff here:
http://fredsastro.smugmug.com/

Joshua Bunn (Joshua) · #13 16-12-2011, 01:04 AM

PM sent Bassnut.

higginsdj · #14 19-12-2011, 12:12 PM

Focusmax compares the focus of the current image to it's predefined focus curve. It does this by making adjustments and calculating the FWHM. It looks at the chaneg sin the FWHM after making those adjustments to determine where the best point of focus should be then drives the focuser to that point. It doesn't care if you make small changes to the focus manually.

Cheers