Alignmaster + GPS dongle

[pritc]

OK,so tonight I started from scratch again regarding Alignmaster.

In total I aligned to Eight different sets of stars:

Capella - Dubhe

Mirphak - Dubhe

Aldebaran - Dubhe

Betelguese - Dubhe

Algol - Dubhe

Mirphak - Mizar

Algol - Mizar

From trying to align the other night ,I was quite surprised how close each sync of tonight's alignments were...

In my AZ sync adjustment early on ,I only had to slightly adjust the SE facing pier adaptor bolt.

Best result I could achieve was:

Error in Alt 00 00'01" deg

Error in AZ 00 00'50" deg

Very happy with my Alt setting

But I could not get my AZ setting any lower

Wayne

[malc-c]

I had similar issue, but was limited to the stars I could use, and think that I slightly over-did the adjustment on one of the adapter bolts, as it would centre correctly on one set of stars, but then was out again on the next.

I'm giving up for a while... so long as the mount is close enough aligned for PHD to work that's all that matters to me now....

[pritc]

I'm giving up for a while... so long as the mount is close enough aligned for PHD to work that's all that matters to me now....

Now that I have sorted my cone error and polar alignment.

Sorting out my PHD calibration is next up.........

Wayne

[blinky]

I had similar issue, but was limited to the stars I could use, and think that I slightly over-did the adjustment on one of the adapter bolts, as it would centre correctly on one set of stars, but then was out again on the next.

I'm giving up for a while... so long as the mount is close enough aligned for PHD to work that's all that matters to me now....

Thast why I now use WCS - it really is much more flexible

[malc-c]

You know you get those days where you wish you had left things well alone.... last night was one of them.

I came in at around 9:30pm as the mist was causing dew issues and seeing was poor. I then spent a few hours processing the webcam captures of Jupiter and done the silly thing of poking my head out the door to see how bad the fog was.... it had cleared up a fair bit !

Rolled the roof back and slewed to M42... now way off target. Corrected and launched PHD.... It tracked, but the graph was all over the place. Having taken half a dozen subs of M42 I thought I would try an experiment... I slewed the scope to Alnitak, just above.... even in that short distance the goto was out !

Then at 2am I booted up Alignmaster and tried again, this time using Sirius and Dubhe (the latter now clear of the obsy roof) - the result... miles out and no mater how much or little I adjusted the adapter bolts it still wouldn't give as good an accuracy as before.

I'm going to remove the OTA, and Mount and re-level the adapter again, using my trusty old spirit level, then run through the cone error procedure again, polar align with EQMOD and then either try again with Alignmaster, or revert back to the DARV method that worked well enough for me in the past....

Back to basics !

Glad to hear you have nailed your alignment.... fancy popping down here and doing mine !!

[malc-c]

Its good, I have it but TBH dont use it - I found that with my house behind me I really toiled to find a pair of stars. I use WCS which is like an autmated drift alignment and prefer that. It is good software just that I prefer WCS

Do you have any links for a download

[pritc]

Do you have any links for a download

Polar Alignment - WCS - Fast and accurate polaralignment for astronomical mounts, using a CCD / webcam and drift alignment

Wayne

[malc-c]

Ahhh that one. Yeah, seen that some time ago... possibly worth a punt... can't screw my set up any worse than what it is now

I thought having a permanent set up was going to be better !!

[Earl]

Ill be having a play with this for sure.

[malc-c]

Just looked at the WCS site, and it seems to follow the same principle of other methods... my problem is that I have poor elevations East and West from the observatory, so need something that can overcome this issue...

Anyway, suns out and the fog has gone... still cold out there at 6c but time to strip down and level the mount

[malc-c]

I'm thinking of getting one of these

£25 inc postage.... resolution to 0.1 degree - should be good enough to ensure the adapter is as near perfectly level in all directions

[pritc]

I'm thinking of getting one of these

£25 inc postage.... resolution to 0.1 degree - should be good enough to ensure the adapter is as near perfectly level in all directions

A lot of money to spend for a one time levelling!!

[malc-c]

I'm sure it will come in handy for something else.... er... probably.... yeah maybe your right

[Earl]

Downloaded, paid for, clear skies, no registration key yet :|

[malc-c]

OK, I'm really getting miffed now. Following on from this fiasco I re-leveled my mount, then polar aligned (roughly) and tested for cone error visually by centering Polaris in a high powered eyepiece, and then re-polar aligned using EQMOD and reset to the home position.

Cleared all data points and then targeted Jupiter... the goto was way off, with Jupiter right on the edge of the finder. Positioned Jupiter in the middle of the FOV of the eyepiece and synced it. Next point was M45 (not too far off) and again the goto was off, about half the radius of the finder's FOV. Positioned it in the center of the finder and synced. Then did the same with M42... again it was off by 1/3 the radius of the finders FOV, corrected the position and synced. Then went back to Jupiter and this time it did a pier flip and Jupiter was again almost at the edge of the finders FOV !

If I can't get the scope performing basic goto with some degree of accuracy then there's no point in trying to hone the alignment using Alignmaster etc... This was the first time I considered questioning spending all this money on equipment and thoughts of turning the observatory into a workshop or something equally diverse crossed my mind.

Maybe I need to sleep on it, walk away from the hobby for a few months until I get the urge to try and resolve this. Either that or pay someone to come and sort this out for me.... shame most of your guys who have nailed this are miles away...

[/rant over ]

[MG1]

Deep breaths Malcolm, deep breaths... One.....two....one....two....

We all have nights/weeks/months like this.

I spent the only clear night I've have the scope out in four weeks collecting guider log data to put into PECprep only to realise that the almost three hours of data was useless because I forgot to turn off guider output. For me the problem is I just don't have enough free nights and so I'm forever having to re-learn everything.

I do find however that sometimes in the rush to test something out I completely forget a stage in the process. Now I have a checklist I follow...and it's all the more tedious now I'm fixing cone error too...which owing to having a mobile setup has to be tweaked every time!

1- Level tripod as best as I can with level then attach mount roughly pointing north and in approx home position.

2- Centre Polaris in Polar scope using alt/az adjustments.

2- Correct for cone error by:

i: Level RA and centre Polaris using Dec and Azi-bolts.

ii: Flip RA and get Polaris as close to centre using only Dec.

iii: If Polaris won't go to centre then correct half of error with shims under end of tube.

Then centre using Azi-bolts.

(repeat ii & iii until no adjustment needed)

3- Re position to approx home and switch on mount and Camera.

4- Start software up in this order:

i: Device manager (chk com port assignments)

ii: EQMod setup (assign correct comm and input site coord from GPS test connect/disconnect)

iii: EQMod

iv: EQASCOMpad

v: Stellarium scope (auto launches Stellarium...set stellarium location to match EQMod)

vi: PHD (connect to lodestar, connect to mount, show graph)

vii: APT

5- Start EQMod polar align tool and set polar home by:

i: Recenter Polaris in polar scope then adjust alt bolts until it intersects larger reticule circle at 6 o'clock.

ii: adjust RA so Polaris is in centre of small circle at 6 o'clock position

iii: click set polar home

6- Click Align polarscope (after checking mount won't cause gear crash)

7- Rough polar align by positioning Polaris in small circle.

8- Park mount horizontal (alt/az coords at 0:0:0, 0:0:0

9- Loosen clutches and level dec and RA axis with digital level.

10- Park to home.

Then if I want to double check my polar alignment I will either Drift align or use DARV in APT.

This is where I would probably use Alignmaster.

Once aligned to whatever degree of accuracy I feel necessary for the session it's then a case of checking to GOTo alignment with a few triangulated 'N-alignment' points in different sectors of the sky.

I think that's about it for me... Although I'm tired and on my phone so may very well have forgotten something!

As normally happens in the field.

Anyway, hope u get it all sorted....

Clear skies

Michael

[Earl]

Nice and simple to use, im impressed.

I need to build a frsh alignment model which can wait for another night now.

[martin_h]

Positioned Jupiter in the middle of the FOV of the eyepiece and synced it.

I personaly wouldn't use a planet for a sync point...better of using stars.

And for the first one....from the home position, slew to the first star, undo the clutches and manualy push the mount until the star is centred, re-do the clutches and go on to the second star, you will find that it is much closer to centre that way.

By undoing the clutches and moving the mount by hand you are fooling the electronics into thinking it got the first star spot on first time.

[dmahon]

When we experimented with the original EQMOD polar alignment routine (now hidden) we compensated for a non level mounts but this significantly added to the complication of the overall process. Six alignment points were needed, three points triangulating the positions actually used for the alignment calculations.

Will this every be unhidden again?

It would be nice to be able to do a perfect polar alignment using any points in the sky, and with a CCD and plate solving software it's a matter of only a minute or two to get 6 points into EQMOD. When I start an evenings imaging I usually put 6-12 random points spread about the compas into EQMOD anyway.

[richardcav]

Hey guys, I have bought Alignmaster and also a GPS dongle - this one...

http://www.holux.com/JCore/en/products/products_content.jsp?pno=342

...however even though the GPS works great with its own software (on whichever COMM port the USB dongle is assigned to) it doesnt work with Alignmaster, I receive a runtime error 8020 from the Alignmaster software.  I have tried to email Alignmaster a few times over a couple of weeks and have simply had no response, any ideas - starting to wish i had never paid for their software now!