eqmod guide rates

[libraryman]

Hi all, is it o.k to set eqmod to run different dec and RA rates or simply unwise?

i tend to run 0.3x on both DEC and RA but i find i have a slow oscillation in RA that would be resolved with a higher rate but  dec is o.k so why change it.

PHD gives a warning after calibration when i apply different rates,is it safe to ignore this?

Ray

[Xplode]

Oscillation on a EQ8...you're not only one. I have decided to sell my mount because of the backlash problems.

You won't damage anything so the easiest way to find out is try and see how it works out.

[jsmoraes]

I am working with EQMOD there are much time, and I love it. It has an excellent performance with my set.

If you are talking about the speed rate for DEC and RA (percentual of intensity of the movement) , I can say that:

1) my set is very heavy. The mount is an NEQ6 and the scope is GSO 305 mm (dobsonian without all parts that isn't necessary. It is clean, only OTA and focuser). The camera is Canon, with Filter Wheel, OAG and coma corrector.

2) NEQ6 has long backlash for DEC

Therefore I use 0.6x for RA and 0.8x for DEC.
Some position of OTA, e.g. vertical toward zenith, I need increment the pulse for DEC backlash

Because I prefer to have small pulse correction I use the default minum pulse width 20 ms for both movements: RA and DEC

PHD gives warning perhaps because at the calibration task the movement of DEC or RA was very small, and this is adjusted in PHD: time for pulse of calibration. With my set, very heavy, the PHD does the calibration with 10 to 15 steps for RA and 8 to 10 for DEC. Remenber, I need strong movements because my weight.

For DEC issues, the best solution is adjust very well the polar alignment.
For RA issues, the balance of the set (OTA with all acessories) is the key.

note: it is very important you do PHD calibration with the EQMOD slides for RA and DEC at 100 %  (in EQMOD tab for control guiding pulses). As my polar alignment is very good I reduce DEC to 15 % after that calibration. As the minimum pulse is 20 ms this adjust reduce the false correction for DEC: refraction of the star that PHD think to be drift.
And so, the backlash issues because of invertion Noth/South. Some positions of OTA needs reduction in these sliders for RA, too. Around 70 to 80 %.