From: Mark Gaffney <markgaffney@me.com>
Date: August 29, 2010 8:27:46 PM MDT
To: Astro_IIDC@yahoogroups.com
Subject: Re: [Astro_IIDC] Re: guiding last night...
My father tells me 7AH should be 1 amp for 7 hours..I`m guessing the power is used at a greater rate when slewing than just tracking...
Mark.
On 30/08/2010, at 12:20 PM, Mark Gaffney wrote:
Hi Milton,
The settings for Azm & Dec, both positive & negative were all at noughts so I`ve left them there.
You`re right there was some play in the mount afterwards. It was a rocking of the mount on the tripod in both directions but this was easily fixed by doing up the mounting knob underneath a little more tightly.
I should get 7 hours of use out of my 7AH Celestron Battery tank isn`t this right fully charged? It seems to give out after 1 & 1/2 to 2 hours powering my dew strap.
I should be ordering a new AC-12 volt adapter on Wednesday. I`ve heard from York Optical to say they have the 240 volt Australian one for $25 + $12 postage..
I`ll get out tonight hopefully & try the slew test with the HC on a star & perhaps do another 4 star (at least) alignment then Hibernate the mount. I`ll have to look at my Planetarium apps to see when it`s best to do these.
With the HC I haven`t noticed that start & stop times are particularly difficult. I usually use a speed of 7 when doing all but finest adjustments with the direction buttons. 6 is usually a little to slow to get where you`re going..
The mount has never been altered with respect to backlash before..(it`s still pretty much "out of the box" though about 6 years old now..)
Thanks for the help..!
Mark.
On 30/08/2010, at 8:28 AM, milton_aupperle wrote:
Hi Mark;
After zeroing the internal backlash with the Hand Controller, I'm pretty sure your going to find out the mount is loose on the RA and probably Dec axis.
You can see if the mount is got slop just with your hand by rocking the scope gently back and forth on both axis. If you can feel the scope shifting, then you will have backlash.
To measure it visually, all you need to do is put a camera or an eyepiece on the scope (prime focus is best with the C 9.25 at 2350 mm), center it on a bright star and then use the hand controller Left / Right or Up / Down buttons. Press a button and count how long it takes for the object to start moving. Then release the button and see if it keeps moving after being released. The Reticule in Astro IIDC works really well for checking this.
If the mount is perfectly in synch with no backlash it starts when you press and stops when you release, no delay at all. If there is any delay in either case, then you have backlash.
I've also done that test in daylight if you have a distant object say 500 m to 1+ kilometers away. You just turn of the sidereal tracking and move the scope with the hand controller. Things should stop / starts immediately - just as I described before.
HTH..
PS: Also check to make sure that Periodic Error correction is not being performed and is off by default.
Milton Aupperle
--- In Astro_IIDC@yahoogroups.com, Mark Gaffney <markgaffney@...> wrote:
>
> Milton,
> Attached is the backlash adjustment section from my Manual (It`s for a
> C9.25 SGT scope, which mine is effectively with the C9.25 OTA & CG-5
> mount..)
> I`ll try tomorrow, weather permitting to set these backlash settings
> to zero as you suggest..
> As for testing whether this has any effect we`ll see..
>
> Mark.
>
>
>
>
> On 30/08/2010, at 3:44 AM, milton_aupperle wrote:
>
> > Mark;
> >
> > --- In Astro_IIDC@yahoogroups.com, Mark Gaffney <markgaffney@>
> > wrote:
> > >
> > > Milton,
> > > Some of those fluctuations in the guiding graph may be accounted for
> > > by my turning on the desklamp I have at the site so I can add
> > items to
> > > & from the scope without balancing a torch in one hand.
> >
> > I seriously doubt that has any affect unless the light is pointing
> > in the guide scope.
> >
> > > The
> > > callibrations were done in the dark though (I`m pretty sure..?).
> > > Would the settings you described for your 1100 mm FL (with an f6.3
> > > reducer I presume) be OK..i.e. 7 seconds for start time & min
> > > distances of 25 for RA & 20 for Dec..? Or should I be trying
> > something
> > > a little different?
> >
> > I can tell you all the settings in the world mark, but it will not
> > make a bit of difference. You have mechanical issues with the mount
> > and nothing will fix that until you resolve them.
> >
> > > You`ve got to realise I`m yet to familiarise myself with the
> > > significance of the figures in the log..! These pixel distances
> > etc.,
> > > measurements, I take it are how far Astro IIDC is moving the mount
> > > when guiding..
> >
> > Read the previous message I sent about the Log results wher eI
> > describe in detail what they measn.
> >
> > > I may try to adjust the backlash settings on the HC & mount using
> > > power from my battery tank (it`s not much chop running for long
> > times
> > > though, especially running just a dew strap which I usually use it
> > > for)..
> > > My readings for the FL etc. of the Kwiq & the Scorpion combination,
> > > seem to tally with yours..as far as I can see..?!
> >
> > Why not read what I wrote and think about it. Both the last message
> > and the other one described in detail how to interpret the
> > calibration log and what it is telling you.
> >
> > Your ignoring the actual problem that your mount is mechanically out
> > of whack. Until you solve that problem, which is screwing up not
> > only the guiding but your GOTO repeatability, your wasting your time
> > imaging DSO's.
> >
> > Best of luck..
> >
> > Milton Aupperle
> >
> >
> >
>