Hi,
When I use PHD2 I can guide on comets throu a star by relative guiding (as long it fit in the guide window). But now I use the internal guider in Ekos (Astroberry), I can't see that there is something like that built in.

I can change the speed of the RA and DEC motors to match the speed of a comet but then it can not autoguide. What is the best way to change the speed of the motors, change standard setting or is it a way to add a relative extra speed (dRA, dDEC) ?

/Lars

Lars

As far as I know, there's no equivalent in the internal Ekos guider to the PHD2 feature called comet tracking openphdguiding.org/man-dev/Tools.htm#Comet_Tracking. I have taken reasonable comet images in the past using Ekos by just using stacks of relatively short exposures that are both registered to the comet and the stars, and by keeping the comet in the frame by moving my pointing after a while, but clearly this would be a nice addition to the Ekos guider for those folks imaging comets.

Hy

Hi Hy,
Thanks for the answer. Next time I have a comet visible from my balcony I will do a test with only alter the speed of the RA and DEC motors. My comet images so far I have taken with 30 seconds expsure and with my HEQ5 there is not necessary to guide, but if I could do it's fine.

/Lars

I started a topic on this same idea about a year ago. There was some interest, but it did not progress from there.
My recommendation is to stick with PHD2 for comet tracking mode. You can get the dRa and dDec rates calculated from www.minorplanetcenter.net/iau/MPEph/MPEph.html
You will want to choose these options:
Ephemeris interval: Hours (especially for fast moving comets)
Separate R.A. and Decl. sky motions
Display motion as: "/hr
When the HTML tables are generated you will be interested in the values under Sky Motion.
Ensure Sticky lock position of OFF in PHD2. Because eventually the guide star will be lost, and a new one will have to be selected elsewhere.

Carte du Ciel can also calculate and send the rates to PHD2 and is INDI compatible.
It certainly would be nice if EKOS could make the same ephemerides calculations and send the values to PHD2 and internal guider as well.

Hi Andrew,
That's almost exact how I did with PHD2 when it was installed in my old Windows server. I wrote a turorial abut it, maybe outdated now:

www.astrofriend.eu/astronomy/tutorials/t...met-autoguiding.html

Today I changed to Astroberry setup on Raspberry. But the problem I got this season is that PHD2 doesn't work anymore in my Astroberry, see my thread:

www.astrofriend.eu/astronomy/tutorials/t...met-autoguiding.html

When I couldn't get the PHD2 work anymore I shifted to Ekos internal guider and it worked very well now with the last update. So I felt it could be good to only use that guider. Very happy with it. But still, it could be a very good alternative to have the PHD2 auto guide to work again.

/Lars

Great tutorial!
I found your thread regarding your PHD2 issues. I left some troubleshooting advice there.