HEQ5 Woes.

[raymo]

I have been happily using my "5" for 18 months, 2 star aligning and
typically getting the target within the centre third of a low power EP;
but now I have decided to do longer subs, and therefore need more
accurate PA. I updated to 3.35 in order to use the PA function.
First problem, with 3.35 installed the mount hunts back and forth 7 or
8 times when acquiring a target.
Second problem, the errors shown after PA is done are virtually useless.
Last night I did some 25 PAs. After a PA I adjusted either Alt or AZ,
and the adjusted one would improve, but the untouched one would
change hugely. An example. Error approx. Alt 1.5 degrees, Az 2.2 degrees. After adjusting Alt 0.75 degree, Az 4.7 degrees.
How can this happen when I didn't touch the AZ.
Third problem. I did 8 PAs between the same 2 stars, and got very
different errors each time.[ I used reticle EP].
I think I'll have to find out how to uninstall 3.35 and go back to old
faithful 3.20, and do drift aligns. I remember posts about the hunting
problem months ago, but can't remember if the problem was
explained and/or fixed. It drives me mad trying to use the actual PA
function as I have to wear glasses to read the LCD on the H/Controller, and remove them to position the star in the EP, and then put them on again to find the next step in the manual, remove them to carry out the next step, and so on ad nauseum. It's enough to make me want to go
back to my old Super Polaris. It'll be interesting to see what replies I'll
get; if anyone can be bothered to read all of this one that is.
raymo
P.S. It didn't make any difference which axis I adjusted first.

[Astro_Bot]

You're not alone. I know some people who like and others who don't. I'm in the group that has problems with it (with an NEQ6).

Using the polar scope, I can get within ~5 arcminutes, or so it seems, though that's probably not good enough for long subs - I'm still working up to that myself so can't really comment more.

However, Alignmaster (on a laptop wih ASCOM/EQMOD) is well recommended for better polar alignment.

As for firmware, I'm using v3.27, which I find less troublesome in general - v3.27 is "old faithful", IMHO.


If the tripod is not level, then the axes will not be truly independent and adjusting one will affect the other. But that degree of effect does seem a bit large. Do you level your tripod with a decent bubble level/digital inclinometer? Don't use the little bubble level built into the mount - it's terribly inaccurate. Also, a solid mount footing will help prevent tripod movement from affecting your levelling - I use fence paling offcuts to stop the tripod feet from sinking into soil at different rates, which would ruin levelling and introduce pointing/tracking errors.

As for the variance in your results - I experienced some of that myself, though not as bad as you seem to. That's one reason why I don't use the PA feature.

[raymo]

Thanks for the quick response. The "5" doesn't have a built in level; I use
a level 3 ways before putting the mount on the tripod.
I can't get my old bones down to the polar scope, so I suppose I'll have
to look into EQMOD etc, although I have no idea how to go about it. I'll
google it. The mount is on flagstones and is rock solid.
raymo

[Astro_Bot]

You could try using orthogonal axes instead of three ways - it's both quicker and more accurate.

Put the bubble level across the tripod parallel to two legs and at right angles to the third leg. Level using the two legs adjustments and leave the third leg alone.

Then turn the level 90 degrees so it points to/passes over the third leg and bisects the first two legs (that you've now finished adjusting). Level using only the third leg adjustment.

It takes only about a minute that way and is better than trying to iteratively adjust three legs (which are not independent axes) where adjusting one usually introduces error into the others.


I know what you mean about getting to the polar scope, but I worked out a sure-fire way to get it done in under 5 minutes, and I'm still flexible enough to get down there for that short time. I can provide more if you need it, but it sounds like you really can't use the polar scope at all.

There are plenty of threads on ASCOM/EQMOD/EQDIRECT and Alignmaster, both here on IIS and on other forums like Cloudy Nights. There are a few websites with How To's as well. You shouldn't have any problem finding info.

[raymo]

Thanks again for the info; being as the PAs were all done in the one
night without moving the tripod, and the readings obtained seemed to bear little relation to the adjustments made, I would be surprised if a tiny inaccuracy in levelling was the cause. Oh well, time will tell I hope.
raymo

[billdan]

Gooday Ray,

Dion (Astronomy Shed) has a video tutorial for mounting a webcam onto the polar scope and doing PA on the laptop screen. You will need to put the original webcam lens back in to be effective. However he's looking at Polaris a lot brighter than Octans. I'm not sure if this technique will work in the southern hemisphere.

I use drift alignment with PHD much more accurate.

Regards

Bill

[raymo]

Thanks Bill, I'll have a look at it.
raymo

[guggle]

Have you tried a factory reset of the hand controller?

[raymo]

Hi Michael, I haven't tried a factory reset because I didn't know you can do such a thing. Everything seemed to work fine[ no hunting etc:] with
3.20, so it didn't occur to me that there could be anything amiss with the
hand controller when I switched to 3.35.
raymo