I have been having no end of problems achieving a decent polar alignment of my HEQ5 mount. I've had it for three months and I still haven't got it to point anywhere near what I want to be imaging. Can somebody please help figure out what I am stuffing up?
My ideal process would be as follows:
1. Point northern leg of tripod toward SCP. Make sure tripod is level in all directions. Attach accessory tray, mount, telescope, etc.
2. Go through three-star alignment process. This typically is done with Sirius, Achernar and Alpha Centauri.
3. Hand controller then reports error margins in elevation and azimuth.
4. I manually correct the errors using the azimuth and elevation control knobs.
5. I do a second three-star alignment with the same stars to get new error margins and make any corrections as needed until within acceptable alignment (for me, ideally less than a minute in both elevation and azimuth - my effective focal length when imaging is 5400mm once I attach the barlow, teleconverter and camera).
(When doing the alignment, I'm just using a standard 1.25" illuminated reticule eyepiece, so the focal length during alignment is effectively 600mm - i.e. just the telescope).
Instead, what happened last night is a good example of what typically happens...
1. First three-star alignment reports 22 degrees out in azimuth and ten minutes out in elevation (don't know how elevation was so precise on initial setup!).
2. Was happy with elevation, so left that alone. Moved the azimuth to the west as far as Azimuth control knobs would go (I am using the longer upgrade bolts for Az, not the stock-standard ones as I found they were useless). I could only get 15 turns of the knobs done, so I wasn't expecting azimuth to be close enough... but for the purposes of testing the mount I wasn't going to bother packing it all up and moving the tripod.
3. I then did a second three-star alignment, but the error margins changed unexpectedly:
Azimuth moved in the correct direction (now only 11 degrees out in the same direction). BUT
The elevation was then suddenly out by 4 degrees!
Is it normal for the mount to have moved in elevation despite my only changing the azimuth knobs?
Another story from last week, I was trying my first-ever drift alignment.
I started with elevation at 44deg.
When doing the first star (to align the elevation), I managed to get it so that there was no drift in five minutes. This was at elevation of 20deg! (I'm in Melbourne!)
But as it was a practice run, I decided to see how good I could get it, so I moved the elevation down three more degrees, and suddenly the star drifted across the entire eyepiece in 30 seconds! What the?!
So as you can perhaps understand, I have been banging my head against the wall trying to figure this all out. Can anyone please advise where I am going wrong?
I have been having no end of problems achieving a decent polar alignment of my HEQ5 mount. I've had it for three months and I still haven't got it to point anywhere near what I want to be imaging. Can somebody please help figure out what I am stuffing up?
My ideal process would be as follows:
1. Point northern leg of tripod toward SCP. Make sure tripod is level in all directions. Attach accessory tray, mount, telescope, etc.
2. Go through three-star alignment process. This typically is done with Sirius, Achernar and Alpha Centauri.
3. Hand controller then reports error margins in elevation and azimuth.
4. I manually correct the errors using the azimuth and elevation control knobs.
5. I do a second three-star alignment with the same stars to get new error margins and make any corrections as needed until within acceptable alignment (for me, ideally less than a minute in both elevation and azimuth - my effective focal length when imaging is 5400mm once I attach the barlow, teleconverter and camera).
(When doing the alignment, I'm just using a standard 1.25" illuminated reticule eyepiece, so the focal length during alignment is effectively 600mm - i.e. just the telescope).
Instead, what happened last night is a good example of what typically happens...
1. First three-star alignment reports 22 degrees out in azimuth and ten minutes out in elevation (don't know how elevation was so precise on initial setup!).
2. Was happy with elevation, so left that alone. Moved the azimuth to the west as far as Azimuth control knobs would go (I am using the longer upgrade bolts for Az, not the stock-standard ones as I found they were useless). I could only get 15 turns of the knobs done, so I wasn't expecting azimuth to be close enough... but for the purposes of testing the mount I wasn't going to bother packing it all up and moving the tripod.
3. I then did a second three-star alignment, but the error margins changed unexpectedly:
Azimuth moved in the correct direction (now only 11 degrees out in the same direction). BUT
The elevation was then suddenly out by 4 degrees!
Is it normal for the mount to have moved in elevation despite my only changing the azimuth knobs?
Another story from last week, I was trying my first-ever drift alignment.
I started with elevation at 44deg.
When doing the first star (to align the elevation), I managed to get it so that there was no drift in five minutes. This was at elevation of 20deg! (I'm in Melbourne!)
But as it was a practice run, I decided to see how good I could get it, so I moved the elevation down three more degrees, and suddenly the star drifted across the entire eyepiece in 30 seconds! What the?!
So as you can perhaps understand, I have been banging my head against the wall trying to figure this all out. Can anyone please advise where I am going wrong?
I also spent a long time getting my HEQ5 polar aligned. My first advice is to always drift align - especially if your imaging at 5.4M focal length!
Any slight misalignment will show dramatically at that focal length.
A few things i found:
Get a digitial inclonometer from Ebay. They are a few dollars.
Use your GPS to get your lat/long then use the inclonometer to get altitude set as precice as you can.
Then use a campers compass to get true south on the mount (in QLD thats roughly 10deg east from south).
I used to drift align. Three star method is not reliable and i do not suggest you use it. Best place to start with drift aligning is this guide: http://www.iceinspace.com.au/63-405-0-0-1-0.html
Nowdays i simply use AlignMaster. A piece of software that requires your computer to be hooked up to the scope (EQMOD needed).
It will choose some stars to align on then move your scope for you to the stars. You align the star as precisely as possible then say next. It will slew to a second star and then you need to use the scope controls to move the scope to point straight on. It will then tell you how far off you are in mins/deg. It will ask if you wish to align. Say yes and it will then move the scope slightly in Azimuth. You then turn the azimuth screws to get the scope to center the star again. It will do the same with altitude.
You will then be very close to polar aligned.
Many people do two, three or more passes of the program to get as close as possible.
Its very quick to do and beats drift aligning and can be more accurate.
Of course its not free, but it doesn't cost too much and you need the mount to be connected to a PC.
If that is not an option then drift alignment it is. The guide above explains its better than i can.
One quick question - are you using a compass to get the polar scope axis initially NEAR True South (Mag South MINUS mag declination seeing you are Melbourne)? If you use a compass or mobile phone app,make sure it is at LEAST a metre away from the mount (I solidly mount a good compass in an aluminium bar attached to the head) otherwise they will be afflicted by the magnetic influence of the mounts motors, circuitry etc.
I had been aligning pretty spot on for ages. Moved it to my dark courtyard, and CONSISTENTLY 11° out in azimuth - no matter WHAT I tried, including a new motor board! And you know what it was? Steel reinforcement / rebar in the slab underneath me, couple with the steel house frame and steel roof etc etc etc I was SURROUNDED by magnetic fields, causing all mayhem with the compass and mobile phone app (which are pretty dodgy anyway in my experience)!
Also, which version of the Synscan software are you using? The latest version is USELESS for Southern Hemisphere realignment - sends incorrect adjustments (it sends you the WRONG way). 3.27 is the last semi-usable Synscan software. DO NOT USE THE LATEST RELEASE!
One quick question - are you using a compass to get the polar scope axis initially NEAR True South (Mag South MINUS mag declination seeing you are Melbourne)? If you use a compass or mobile phone app,make sure it is at LEAST a metre away from the mount (I solidly mount a good compass in an aluminium bar attached to the head) otherwise they will be afflicted by the magnetic influence of the mounts motors, circuitry etc.
I had been aligning pretty spot on for ages. Moved it to my dark courtyard, and CONSISTENTLY 11° out in azimuth - no matter WHAT I tried, including a new motor board! And you know what it was? Steel reinforcement / rebar in the slab underneath me, couple with the steel house frame and steel roof etc etc etc I was SURROUNDED by magnetic fields, causing all mayhem with the compass and mobile phone app (which are pretty dodgy anyway in my experience)!
Also, which version of the Synscan software are you using? The latest version is USELESS for Southern Hemisphere realignment - sends incorrect adjustments (it sends you the WRONG way). 3.27 is the last semi-usable Synscan software. DO NOT USE THE LATEST RELEASE!
Nope- I have a big power sub-station in my backyard, so huge magnetic fields here! I just use the pointers and the Southern Cross to determine where SCP is, and then point the tripod in that direction.
Using v3.34. I was excited about 3.32's PA correction function, so upgraded, then found it was useless, so then upgraded to 3.34.
Do you know if it is possible to download v3.27 from anywhere? I've been aware of this firmware issue. When I got the mount, It had FW v3.01, hence I upgraded it to the then-latest (which was 3.32)... D'oh.
Quote:
Originally Posted by whzzz28
I also spent a long time getting my HEQ5 polar aligned. My first advice is to always drift align - especially if your imaging at 5.4M focal length!
Any slight misalignment will show dramatically at that focal length.
A few things i found:
Get a digitial inclonometer from Ebay. They are a few dollars.
Use your GPS to get your lat/long then use the inclonometer to get altitude set as precice as you can.
Then use a campers compass to get true south on the mount (in QLD thats roughly 10deg east from south).
I used to drift align. Three star method is not reliable and i do not suggest you use it. Best place to start with drift aligning is this guide: http://www.iceinspace.com.au/63-405-0-0-1-0.html
Nowdays i simply use AlignMaster. A piece of software that requires your computer to be hooked up to the scope (EQMOD needed).
It will choose some stars to align on then move your scope for you to the stars. You align the star as precisely as possible then say next. It will slew to a second star and then you need to use the scope controls to move the scope to point straight on. It will then tell you how far off you are in mins/deg. It will ask if you wish to align. Say yes and it will then move the scope slightly in Azimuth. You then turn the azimuth screws to get the scope to center the star again. It will do the same with altitude.
You will then be very close to polar aligned.
Many people do two, three or more passes of the program to get as close as possible.
Its very quick to do and beats drift aligning and can be more accurate.
Of course its not free, but it doesn't cost too much and you need the mount to be connected to a PC.
If that is not an option then drift alignment it is. The guide above explains its better than i can.
Good luck.
I'll try out a dedicated inclinometer. My astronomy lecturer used an iPhone with an inclinometer app (on his HEQ5), and that was OK because his iPhone is newer and has a flat, straight edge. My 3GS has a curved surface so is useless for that. :/
I don't have a problem controlling the mount with the computer (although have never gone down that path). If that's easier and better than a drift alignment, I don't care about the cost -- just want something to work!
If you are using a regular spot in your yard to setup then do a solar noon alignment to get your Nth-Sth axis correct and mark it out on the ground with a paint line maybe. Then square it off to get your E-W axis. Your tripod legs will be aligned on these.
As my driveway had a slight incline I made a leveller board so I could leave the tripod legs all fully closed up. Builders level and a 4 x 2 or whatever with spacers to level the lowest two points with the highest point ( mine were the E-W but it could be the North and East or West). As long as you have a consistent start point so once you've got the tripod and the mount head all aligned next time it just drops into place. Then all you have to do is get the DEC right. A bit of stop start drift aligning using a DSLR camera will give you any E-W error and once you've corrected it all next time you should just about be able to put the tripod down on the board and spots and be up and running. My little yellow paint spots are still visible on the driveway.
Compasses are notoriously inaccurate but the sun .... you can't beat it.
Google 'Solar Noon' to get a site which will tell you a time for your location. Mine was always 17 mins past the hour.
If you are using a regular spot in your yard to setup then do a solar noon alignment to get your Nth-Sth axis correct and mark it out on the ground with a paint line maybe. Then square it off to get your E-W axis. Your tripod legs will be aligned on these.
As my driveway had a slight incline I made a leveller board so I could leave the tripod legs all fully closed up. Builders level and a 4 x 2 or whatever with spacers to level the lowest two points with the highest point ( mine were the E-W but it could be the North and East or West). As long as you have a consistent start point so once you've got the tripod and the mount head all aligned next time it just drops into place. Then all you have to do is get the DEC right. A bit of stop start drift aligning using a DSLR camera will give you any E-W error and once you've corrected it all next time you should just about be able to put the tripod down on the board and spots and be up and running. My little yellow paint spots are still visible on the driveway.
Compasses are notoriously inaccurate but the sun .... you can't beat it.
Google 'Solar Noon' to get a site which will tell you a time for your location. Mine was always 17 mins past the hour.
Thanks for your suggestions. I don't have a problem with balancing the tripod itself, thankfully. It's more the elevation and azimuth knobs on the mount itself. But certainly once I get the alignment right, I'll put out some timber boards with paint dots on them.
Sadly, my backyard is very poorly light-polluted, so I usually drive for an hour or so to get to a good spot. So my setup needs to be pretty mobile. Thankfully, I've got enough batteries to sink a ship.
Hopefully synta will get it right - I use the Celestron Polar alignment routine, and it works a treat. Certainly good enough for unguided exposures of around a minute, with my Megrez 90.
David,
I oped for the KISS principle.
2 mtr length of 2x1 - straight. Lay it on the ground EAST/WEST. Using a compass and adjusting declination for Melb which is -11 deg, line the timber up at 259 deg not 270 deg. Peg timber to the ground. Place both rear legs against timber - front left now point to true south. This gets me within 1 deg error margin.
To do my alignment, I use alignmaster with the laptop. I do this 2-3 times and can consistantly get within 1-2 min or better.
Software can be found here: http://www.alignmaster.de/en_alignmaster.html
Cost is about $19AU.
Total alignment takes about 15 to 20 mins.
The last couple of photo sessions using PHD to guide were spot on.
Catch is you have to use a computer (with ASCOM drivers) to control the scope in order to run alignmaster and to guide.
If AZ is out by a huge amount (like 20+ degrees as you have described) then you probably wont be able to make the required adjustment with the AZ bolts (with the stock bolts I think you have about +/- 10 degrees of movement max). In this case you'll need to rotate the entire tripod and mount setup and start the alignment routine again. When I was starting out, I was able to do this with the whole mount loaded up with telescope and counterweights. As others have said, using the solar noon method of finding south is an easy way to get the mount lined up fairly close to south.
I can also vouch for Alignmaster. After a couple of iterations of the Alignmaster software routine I typically have my error down to less than 1 arcmin (and often less than 20-30 arcsecs). Painless and only takes 15-20mins or so.
Once you have completed your setup the first time, it helps if you can mark the ground so that you can place your tripod in the ballpark next time. I have set a few pavers into my lawn, and use texta marks to align the tripod legs (see attached). By doing this i find that I can place the mount on the ground to within about 20arcmins in AZ and 5 arcmins in ALT before i even get started with the alignment procedure. certainly helps to speed things up.
btw, re your observation that moving the mount in AZ also moved the ALT by 4 degrees, if this is the case then your mount wasn't level in the first place.
Thanks everyone for the suggestions. I downloaded AlignMaster and look forward to testing that out in the next few nights (it just clouded over here!). I also found PEMPro which is similar in purpose but more complex... not necessarily more precise, but it has a few other extra features that may be handy. I'll test them both out and let you know which I think is better (although PEMPro is substantially higher in cost!).
Thankfully, both have trial periods.
Richard - that idea of having a pre-marked position on pavers is certainly something I intend to do... especially given that initial precision you claim!
Regarding the alt. moving by 4degrees... the tripod itself was most definitely perfectly level when I started. I checked it with a spirit level. Is that what you meant was out of level? Or is there something else that I haven't leveled? (I was suspecting it was an issue with the HC firmware, erroneously reporting error margins!)
Regarding the alt. moving by 4degrees... the tripod itself was most definitely perfectly level when I started. I checked it with a spirit level. Is that what you meant was out of level? Or is there something else that I haven't leveled? (I was suspecting it was an issue with the HC firmware, erroneously reporting error margins!)
yes that was what I meant. if the tripod wasn't level then moving in az by 20 degrees would easily result in a few degrees of offset in alt as well. However if you had already checked that with a spirit level (which is what I would have suggested) then my next thought would have been a HC issue, as you have said. so all good
have you tried the polar scope - quick and easy. Getting the octans group roughly aligned to the reticle will get you plenty close enough for planetary if that is what you are doing at long focal length
yes that was what I meant. if the tripod wasn't level then moving in az by 20 degrees would easily result in a few degrees of offset in alt as well. However if you had already checked that with a spirit level (which is what I would have suggested) then my next thought would have been a HC issue, as you have said. so all good
Ok, cool. As long as we're on the same wavelength. Ta.
Got any local people willing to help. Makes all the difference. Try with polar scope first, get that covered, become real familiar and with Octans as a result, then move to something like Alignmaster. Great software. I found the illuminated polar scope on my EQ6 quite good to work with, so EQ5 should be the same. Good luck!
MAJOR polar alignment issues - HEQ5 Pro
(I'm in Melbourne!)
