Alignmaster problem

[Demonperformer]

I had my first go with Alignmaster last night and to say that I did not get the mount well-aligned would be an understatement - some trial 10-second shots showed trailing, but at least it was consistent trailing, rather than the 'blobby' jumping around trailing that I tend to get on the SE with longer exposures, so I guess that is a positive (any other nearby straws I can try grasping?).

I was using Mizar and Albireo, and there were two issues.

Firstly, because of the streetlights, it took me some time to get Albireo lined up during the process (wish I could have used Deneb or Altair instead) due to finding it hard to see it in the telrad. I would have thought that the prog would take that into account, but it is worth asking for confirmation on that from people who use it.

The program duly issued errors of about 1/2^o in both AZ and ALT (which I thought was a bit on the large side, having lined Polaris up in the telrad before I started, using the position from EQMOD [as described here: http://stargazerslounge.com/topic/254175-using-the-telrad-as-a-polarscope/]).

But the main problem was that it was simply not possible to get Mizar back into the centre of the reticle using ONLY the directional bolts I was supposed to use (i.e. only the AZ bolts first time and only the ALT bolts second time). I therefore had to compromise and put the star in the middle of the double line, when that line was perpendicular to the direction of movement. I'm guessing that's not right, and this is why I ended up trailing.

OK, things I know I got right:

* the computer time was accurately matched to the time from the GPS dongle.

* my longitude and latitude were entered correctly, copied directly from EQMOD.

* I was lining up on the right stars (both were clearly bright doubles in the eyepiece).

* each star (the brighter component) was well within the central square of the reticle during the first half of the alignment process (when I was using the EQ controls).

So, has anyone who uses Alignmaster ever had these problems?

Can anyone see anything stupid I might have done to cause this?

Thanks.

[Goes without saying that the plan to image asteroid 86666, did not come to fruition!]

[RobRob]

You have to go through the process a couple of times to get it closer and closer. Did you tick the Daylight Saving Time checkbox (when appropriate for your location), unfortunately this checkbox is "forgotten" when restarting this handy app.

[Demonperformer]

Thanks, Rob. Yes, DST was ticked.

[Astroboffin]

Yes as stated above, you may not get it close the first or even second time, the idea is just to get closer each time, the first time I used I had to do 4 times and then it was spot on, but after the first run, I could not get any where near.

I have heard some people having to do 5 or 6 runs before being bang on.

So stick with it and all will be well

AB

[Davey-T]

Gave up on Alignmaster as it gave too small a choice of stars and I'm too old to bend double to try and see Albireo or anything else when it's at a high dec. 

Could eventually achieve reasonable alignment after a few contortions

Dave

[Demonperformer]

Thanks for the replies. Guess I will just have to keep plugging away.

Do you just keep using the same pair of stars for each iteration, or do you have to come up with something different? With the obstructions caused by buildings and streetlights, my options are limited.

Dave, when you gave up on Alignmaster, what did you move onto? I don't want to give up on it just yet, but knowing what someone who used to use it moved onto (which is presumably better) would be good to know.

Thanks.

[RobRob]

I used the same stars each time and eventually was able to reach an acceptable polar alignment. 5 or 6 iterations was sufficient...

[de0s]

DP, I had (actually still do) the same problems with Alignmaster not being able to center the star with only the ALT or AZ bolts. I did some digging and read somewhere that also cone error could be causing this, so now I've fixed that (to a certain degree) during daytime, using a distant antena. I've yet to test this during the night as the weather is not very friendly atm.

Clear skies,

Andrei

[r3i]

I've had mixed results with AlignMaster though I'm quite happy to accept that operator may have been involved.

However the last time that I used it which was a couple of weeks ago, I checked the outcome by checking the drift alignment with PHD2. It turned out that AlignMaster had been spot on so I think it's worth persevering with.

[Davey-T]

Dave, when you gave up on Alignmaster, what did you move onto? I don't want to give up on it just yet, but knowing what someone who used to use it moved onto (which is presumably better) would be good to know.

Thanks.

Just recently been using PHD drift aligning tool, ok once you get the hang of it.

Dave

[Demonperformer]

Thanks for the responses.

@Andrei - thanks for pointing me in this direction. I will have to do a little investigation and see (1) if I have it, and (2) how to fix it.

@Mike - it's good to know that it will produce good results when I get the hang of it

but ...

@AB & Rob - 5-6 iterations sounds a painful way to start an evening's imaging ... will have to keep an eye on this and maybe look elsewhere

@Dave - I did have a brief look through the instructions for this a few days ago - something to do with deciding when a line is horizontal or not, I believe? - but I will investigate further, in case the problems with Alignmaster don't "go away".

Thanks

[StuartJPP]

I haven't had much luck with Alignmaster...despite trying it multiple times and using many iterations.

You seem to make tiny adjustments to correct, then all of a sudden on the next iteration you need to make a massive correction as you see the target star whizz past.

To me it depends too much on the accuracy of your GOTO system as well as any backlash.

From most of my imaging locations I can't drift align either because the view to the south is obscured.

[Tinker1947]

I have never used any of the above App's, I disconnect EQMod do a 2 star align, this give a Polar Align option, i do this, run through it all again on different stars, remove  the handset, reattach EQMod, in EQMod i choose a star in stellarium and click slew to with the clutches undone, when it stops slewing i manually move the scope to the same star, align with the Telrad then centre it with the CCD screen 1 second loops synq when centered , Autosave unticked, slew to another star with the motors moving the scope , centre it and sync, thats it PA sorted 20 minute subs with round stars on a NEQ6, 250mm Reflector, ST-80 Guide scope, i do this every 4th or 5th omagine session, which can be months apart in the UK.....

NGC 891, Atik 414EX, 1200 seconds, single image

[Demonperformer]

Thanks, for the input.

@Stuart - the NEQ6 is (supposed to be ) pretty good as regards GOTO accuracy, but backlash is an issue I hadn't considered. What do you use instead?

@Tinker - I suppose that could be a possibility, but I would view it as a last resort - the £325 price tag of upgrading to the GOTO version is something I would rather avoid .

Thanks

[AllanJ]

Alignmaster needs the mount to be totally level. See Bizibilder's posts here:

http://stargazerslounge.com/topic/189752-alignmaster-altaz-step/

I think of alignment as a three stage depending on how good you need it and how long you want to spend on it - (1)  through the polarscope, (2) Alignmaster, (3) PhD drift aligning

Allan

[StuartJPP]

@Stuart - the NEQ6 is (supposed to be ) pretty good as regards GOTO accuracy, but backlash is an issue I hadn't considered. What do you use instead?

Don't laugh...I just use my well collimated polar scope on my Avalon M-Zero...until I can find something better (drift alignment is usually out of the question from the usual places I image from).

[redtail]

There is a tick box to enable you to use both axis and when you have done one run tick the box again and use each axis .

•  

[Demonperformer]

Thanks for the replies.

@Allan - I wasn't aware that the mount had to be level, but it is something that I am almost compulsive about anyway. I think this partly comes from habit (many years on an altaz mount) and partly because I thought it would minimise the alterations to the alt bolts as I set it up (and so have to realign) every time.

@Stuart - I won't laugh. Whatever is easiest for you, if it gives the results you require, is the best thing to use.

@redtail - thanks for that. I was not aware of this and will have to go looking.

Thanks.

[daz]

Hi DP

I always find that using AM, I can never get the object star in the centre using the bolts. Mind you, I generally run one, maybe two iterations. I get frustrated and give up...

I think I was expecting that it would take no more than two iterations, but reading this thread is interesting...

I need to redo polar alignment anyway, having disassembled the obsy recently, so I might well do:

1. EQMOD Polar Align

2. AlignMaster align - multiple iterations as needed

3. PHD Drift align

Will have to see how long that takes and if the time is acceptable for in-the-field...

[Psychobilly]

Will have to see how long that takes and if the time is acceptable for in-the-field...

And then the tripod settles a bit again..... Unless you use decent sized spreader plates under each foot... which IIRC I think you do....

Peter...

[Astroboffin]

Thanks for the responses.

@Andrei - thanks for pointing me in this direction. I will have to do a little investigation and see (1) if I have it, and (2) how to fix it.

@Mike - it's good to know that it will produce good results when I get the hang of it

but ...

@AB & Rob - 5-6 iterations sounds a painful way to start an evening's imaging ... will have to keep an eye on this and maybe look elsewhere

@Dave - I did have a brief look through the instructions for this a few days ago - something to do with deciding when a line is horizontal or not, I believe? - but I will investigate further, in case the problems with Alignmaster don't "go away".

Thanks

Yes I understand you would not want to do that every session, I have a pier with a permanent wedge fitted for my fork mounted Meade LX90 so only have to do once, and then just check once a year, and always spot on.

AB

[Demonperformer]

Bit of a cross-over from my other thread (http://stargazerslounge.com/topic/254724-what-dp-wants-from-a-pa-prog/ ) here, but I wonder if this would work:

1. For the first half of the exercise, put the camera on and let Astrotortilla do the work [there is a box to tick to allow syncing of the results, so presumably if that box is left unticked, it doesn't sync the results and so doesn't mess up alignmaster's routine]. Not sure if "within 1'" would be good enough, but that figure could be amended based on experience.

2. When ready to do the adjustments, replace camera with reticle eyepiece, as easier to make those adjustments at the eyepiece rather than the computer screen. Would need to make sure that the star is in the centre of the reticle before I do that bit, to allow for any misalignment between camera and eyepiece.

I think that, as both of the EQ bits are done using the same procedure, and both the ALTAZ bits are done using the same procedure (even though the two procedures are different), this might make it a little easier.

But then ... you know how dangerous it can be when I start "thinking" ...