Heq5pro Pointing Accuracy

[pjphilli (Peter)]

Hi
I am located in Sydney and I have been trying out my new HEQ5PRO mount the past few nights. I am having trouble with its pointing accuracy especially on initial two or three star alignment. For instance after choosing
the first star Alpha Centauri I find that the mount stope slewing way off - almost 3/4 of the way to Beta Centauri, which is a long hike to correct with the movement keys. However, the coordinates shown on the paddle are correct for Alpha Centauri.
I have checked my initial setups carefully eg location,timezone, date, time etc but these are OK. Also I have carefully polar aligned the mount.
Do you have to start alignment with the scope in the parked position? Should the RA shaft be vertical and the DEC pointing due South for this to be correct? The scope seems to park with the RA shaft noticeably off vertical. I have followed the instruction book carefully but I cannot fault my
procedures as instructed.
How close can I reasonably expect the mount to point? - I would hope to be able to see it within the field of my 25mm crosshair eyepiece in my 80mm f6 finderscope.
Is there a preferred way of setting up for star alignment?- I seem to be
missing something!
Cheers Peter

[marki]

G'day

Level and point the mount and scope south. Set the mount to the correct lattitude for your site. Make sure the two mounting bolts that hold the dovetail are on the right hand side as you look towards the front of the scope and that the RA is vertical and the scope is lined up with the mount as you look down. If you can see the pole use the polar scope otherwise use a compass to get reasonably close (not essential for visual observing but does help with tracking and pointing over a period of time). Make sure you get the date right, it goes month, day, year and make sure you enter the correct coordinates for your site. Use google earth to find these or a good map. Do a three star align. The first star will be out but the other two should be in the FOV of a 25mm eyepiece. Your pointing accuracy should now be good with most targets falling in the FOV.

Good luck

[Tandum (Robin)]

Mine puts the object in the field of my camera everytime.

Read this first -> http://www.iceinspace.com.au/index.p...63,405,0,0,1,0

You need to do a 1 star alignment to start it tracking.
You will need an illuminated eyepiece to drift align and an $8 bullseye level from bunnings helps to level the tripod.

Once you have it aligned so it can track for about 30 minutes or whatever you think is enough, mark where the legs are so you can just plonk it back in the same spot later.

After doing all that, I now just do a 2 star alignment but I align on the side of the mount I'm going to use. So if I'll be looking east, I'll align on 2 eastern stars or at least on stars that are on that side of the meridian. If I flip the mount to the other side of the meridian, I'll do a 2 star alignment on that side.

I normally have a camera plugged in and swapping meridians means retraining the guide scope program anyway so I normally plan what I want to look at.

[marki]

3 star allignment compensates for cone error (scope not perfectly parralell to polar axis) and rough polar alignment. It is far more forgiving then the 1 and 2 star alignment methods and does a fair job on my mount at least. It depends on what you intend to do? Visual star gazing or astrophotography. At this point it sounds like you just want to get the thing working? Visual only requires a rough setup which takes about 5 - 10 mins (depends on how far you need to lug your gear). Astrophotography requires you to drift align and can take a lot longer to get right. Either way these mounts are very capable.

[Starkler (Geoff)]

I have been advised not to use alignment stars anywhere close to the pole, eg acrux, hadar et-al are not good choices for an eq mount as small errors in centering get magnified.

Same deal with an alt-az mount except in that case its zenith that you want to avoid.

[marki]

Thats what I thought. I always try to use stars on both sides of the meridian during set setup to give the software a better map but I guess its just a case of whatever works best for you.

[pjphilli (Peter)]

Thanks All for your help. I tried your suggestions out last night and my HEQ5PRO is now working and point fine. Cheers Peter