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Mount with easiest polar alignment routine?

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#1 Domerman

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Posted 04 March 2013 - 11:42 PM

I'm looking for a high end mount in the future around 5k used or new. Portability will be a major concern, as I will be setting up and tearing down every time I use the mount. I will mainly use the mount for AP, thus accurate polar alignment is paramount for me. Which mount in this class offers the easiest and most accurate alignment procedure? I really want to avoid drift align as much as possible. I understand the Taks have awesome polar alignment scopes, but the Mach1GTO appeals to me greatly since it can handle a bit more capacity than the EM-200 and handles cold better...however, my understanding is that the polar alignment routine with Mach1GTO stinks in comparison.

#2 orlyandico

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Posted 05 March 2013 - 12:06 AM

I have never tried the polar alignment routine in the Mach1. The best one is supposed to be the "Quick Drift Align" which reduces a drift alignment to a 5-minute job. It requires you to select a star that is close to zenith AND close to zero declination, then align on that star on both sides of the pier. (if the mount is polar aligned there will be no declination offset when you meridian-flip)

Of course in order for the star to be visible from both sides of the pier, it must be close to zenith so the mount doesn't bang into something.

PEMPro can polar align most any mount via semi-automated drift alignment quite quickly.

Or you can look into the new AP right-angle polar finder, which is allegedly as good (or almost as good) as the Tak polar finder. I just can't use it because I can't see Polaris...

I'd say the best polar alignment routine I've used is the one in the CGEM (the ASPA). So you might as well throw the CGE Pro into the mix. It costs exactly 5k.. but is extremely heavy, and the corrected PE is still 3" range - about the same as the raw PE of a Mach1.

#3 tjugo

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Posted 05 March 2013 - 01:05 AM

Hi Steve,

I agree that the Tak polar finder is very good, I own an EM200.

However when the Atlas was my main mount, I used a software called alignmaster, in my experience alignmaster is as accurate as Celestron ASPA and more accurate than the Tak PAS, so I still use it to set up my EM200.

How do I know that alignmaster is as good as ASPA, well I owned a CGE and I tested both procedures and the residual drift was more or less the same.

The downside of alignmaster is the selection of alignment stars, sometimes they are too low. In that regard ASPA is better, but ASPA only works with celestron's mounts.

Cheers,

Jose

#4 orlyandico

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Posted 05 March 2013 - 01:33 AM

Hmmm. This alignmaster looks good.

However I have a very limited selection of stars from my balcony. ASPA works fine with that. I wonder if it's possible to add stars to alignmaster...

#5 Sean13

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Posted 05 March 2013 - 02:35 AM

I've had great luck with Alignmaster. Simple, quick, easy, and cheaper then a polar scope.

#6 andysea

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Posted 05 March 2013 - 02:41 AM

I have used the Atlas, the Mach1 and the NJP and the skymemo. The Tak polar scope is the most accurate. There might be software routines that get you accurately aligned too but with the tak scope you are ready to image in the 5 minutes that it takes to polar align. The nice thing about the tak scope is that the RA axis is the scope itself and it's factory aligned. Believe or not my humble sky memo has a very similar polar scope and it's very accurate.

That being said I use the Mach1 with the losmandy polar scope. I got it centered as best as I could. My polar alignment typically doesn't take more than a few minutes.
So even tho the Tak get me better polar aligned, in reality I don't see any difference when doing guided astrophotography.
I have not used the new right angle polar scope and I will not for two reasons: 1) The mount needs to be perfectly level in order to polar align. 2) you need to drift align the first time in order to calibrate the polar scope.

Why are you so concerned about perfect polar alignment? Are you planning to do unguided photography?

#7 orlyandico

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Posted 05 March 2013 - 03:14 AM

andy, if the polar alignment is more than a couple degrees out, dec drift will be so rapid that the guider can't keep up.

now you wonder, what sort of incompetent could be more than a couple degrees out... and the answer would be.. me! because i can't see polaris, so i have to guess-timate the polar alignment every darn time. and then drift-align with PHD and watch the declination drift on the graph.

will try alignmaster when i next get the chance. sounds like the answer to my woes.

#8 Paul G

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Posted 05 March 2013 - 06:26 AM

I have not used the new right angle polar scope and I will not for two reasons: 1) The mount needs to be perfectly level in order to polar align.


This is not correct. N-S leveling has no effect on the polar scope, and E-W leveling would have to be "really really off to make much of a difference" per Roland in a recent thread on the subject on ap-gto.

#9 dawziecat

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Posted 05 March 2013 - 07:28 AM

will try alignmaster when i next get the chance. sounds like the answer to my woes.


Good luck with it.
I found myself too treebound for Alignmaster.

#10 andysea

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Posted 05 March 2013 - 09:02 AM

Paul, I still prefer the Takahashi system with the bubble level built into the polar scope, to me that seems a lot easier than leveling the mount.
I understand that N-S leveling is inconsequential

#11 JMW

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Posted 05 March 2013 - 11:43 PM

I use Alignmaster on my AT900GTO. It sit on a concrete pier except for one or two multi night start party trips such as the Golden State or Oregon star parties. I use it on the first night of the star party and once again when the mount go on my concrete pier at home.

One lesson I have learned is to use one of my refractors with Alignmaster. I get very good results. After the 3rd iteration I cannot detect any thing to correct. When I tried to use Alignmaster with an SCT, the mirror movement as the scope has moved from one alignment star to the other would create enough of a change that I could not converge perfectly even after several iterations. This was with my mirror locks engaged.

I use Alignmaster with a camera and an on laptop screen bull eye display. This is much more precise than trying to detect perfect centering with your cross hair eye piece. The 2nd advantage is that you can look at the laptop and see the star relative to the bullseye while you are adjusting the Altitude or Azimuth adjusters.

My last comment regarding ease of polar alignment relates to the precise fine movements of the altitude or azimuth adjusters. My AP900GTO has adjustments that are vastly superior to the adjustments on my old Atlas mount. You should evaluate the alt/az adjustment controls on any mount you consider.

#12 orlyandico

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Posted 06 March 2013 - 12:03 AM

Jeff, so you don't use Roland's favorite QCD?

#13 JMW

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Posted 06 March 2013 - 12:45 AM

I like Alignmaster and started using it before I had the AstroPhysics mount. I haven't seen a reason to change. If I did polar alignments more than 2-3 times are year I might consider other options. To be honest, I have read the procedure but didn't think it was any faster or more accurate than Alignmaster so I haven't actually tried it. Since I am setting up for imaging anyway, the camera and laptop are already available as tools to use so I may as well use them.

One iteration of Alignmaster takes me to a few arc-minutes of polar alignment. The second iteration take it to a fraction of an arc-minute. The 3rd iteration just confirms that I can't see anything else to adjust, unless I wanted to increase focal length for additional magnification.


#14 Raginar

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Posted 06 March 2013 - 02:05 AM

Orly, don't forget PoleAlignMax. It requires MaximDL, but it's user friendly. It doesn't do Jnow but from what I've found it was close enough.

I use the PAM in PemPro now. Super easy.

#15 orlyandico

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Posted 06 March 2013 - 02:21 AM

well i do have pempro... so that would work. haven't actually tried it, maybe i should since i paid for it.. thing is on my balcony i have a very limited view and am pretty sure pempro won't work.

#16 psu_13

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Posted 06 March 2013 - 10:07 AM

Polar aligning a Mach-1 is mostly easy IMHO.

You have three basic choices.

1. Spend money for the new right angle polar scope. Get it calibrated. Then you just put polaris in the right spot and you are done. Takes 5 to 10min at the most. This is just about like using the Tak scope, except you have to get the scope calibrated with your mount first, which is a bit tedious.

2. Do the "quick drift" alignment. This seems complicated, but is certainly easier than the 4+2+polar align dance that people do with the Celestron mounts. You need 2 stars, both near the meridian. You use one near zenith to align altitude via a clever meridian flip scheme and one in the south to align azimuth using a fairly standard iterative scheme. All you need for this is a nice right angle finder. I've done this for months and it works well every time once you get the hang of it.

3. Use some sort of software. If you have a camera your best bet is to get close using 1 or 2 above and then just run your software. I've taken to using a combination of pempro and this:

http://www.observato...ent_CCDv1-1.pdf

[side note]

I just got the new AP polar scope. The other night I was calibrating it. I spent 2min putting polaris in it. Then another 5 doing a single pass of the quick drift scheme. Then I checked the alignment with PemPro. Was off by a knob turn to the West and essentially right on in altitude. After that small adjustment I had almost no drift over a 5min window, which is good enough for me. So even uncalibrated the new scope was pretty close. I spent some time aligning it to the mount axis some more. But I bet it didn't really improve things since I'm a clutz.

In the future I'll probably do polar scope + pempro. Since I bought the software I might as well use it. But if you don't have it just use the CCD scheme above. It's basically the same thing, but you have to calculate where to slew your telescope by hand.

#17 HowardK

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Posted 06 March 2013 - 10:14 AM



2. Do the "quick drift" alignment. This seems complicated, but is certainly easier than the 4+2+polar align dance that people do with the Celestron


Come on....the Celestron routine takes no time...AND.....COMING SOON.....STARSENSE......this AUTOMATICALLY does the 2+4 routine for you...with its own widefield camera...in 3 minutes

#18 psu_13

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Posted 06 March 2013 - 10:25 AM

I had a CG-5 before I got my Mach-1. The 4+2+polar used to take me about 10-15min. The AP quick drift takes about the same amount of time. but the AP scheme is a bit easier because you only need 2 stars. And you can do it with your finder scope rather than the main optics. And you didn't have to worry about things like remembering to always finish centering the stars from the same direction, etc.

#19 Whichwayisnorth

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Posted 06 March 2013 - 10:43 AM

If you happen to have Astroplanner there is a drift alignment helper in there that I've found helpful. Depending on location and time of night it finds and makes a list of the best stars to align with. Then you pick the stars that are visible to you. Basically slews to one star, has you sync it, slews off and back, asks you to physically center, slews to second star, repeat. Shows you the corrections you are making. Very cool feature. I used this back before ASPA.

#20 orlyandico

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Posted 06 March 2013 - 11:00 AM

the reason I don't use the QCD is because you need to orthogonal-ize your finder scope, and I can't wrap my brain around that concept... :tonofbricks:

#21 ahopp

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Posted 06 March 2013 - 01:35 PM

Also, using a DSLR, you can polar align a mount in about 10-15 minutes. It is quite easy to do, and you do not need a computer or a fancy mount...

Tony

#22 psu_13

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Posted 06 March 2013 - 02:26 PM

the reason I don't use the QCD is because you need to orthogonal-ize your finder scope, and I can't wrap my brain around that concept... :tonofbricks:


This is not too bad. The trick is to first make sure that the reticle in your finder is align N-S one way and E-W the other. Then you put the zenith star in the finder and center it. Then flip the mount. The star will have some E-W error and some N-S error. The N-S error is related to altitude mis-alignment in the mount. The E-W error is orthogonality of the finder. Adjust out half of the E-W error using the little screws in the finder mount and then the rest with the hand controller. Flip over again and repeat until the error is gone. After that you don't have to worry too much about it.

#23 Footbag

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Posted 06 March 2013 - 06:16 PM

I had a CG-5 before I got my Mach-1. The 4+2+polar used to take me about 10-15min. The AP quick drift takes about the same amount of time. but the AP scheme is a bit easier because you only need 2 stars. And you can do it with your finder scope rather than the main optics. And you didn't have to worry about things like remembering to always finish centering the stars from the same direction, etc.


I had a wedge mounted cpc-800 and ASPA would be done in 5m, but it wasn't good enough for long exposures at f10. I finished with a phd drift alignment. This would take 15m.

With the Mach 1, I'm thinking the quickest may just be to use the polar scope and finish with a PHD drift alignment.

I haven't bern crazy about the meridian flip method. If orthogonality want a concern, and I didn't have to touch the finder, it would be great. But, aligning, adjusting and readjusting the finder just get tooconfusing and time consuming. At least for me.

#24 Peter in Reno

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Posted 06 March 2013 - 08:07 PM

the reason I don't use the QCD is because you need to orthogonal-ize your finder scope, and I can't wrap my brain around that concept... :tonofbricks:


You never know until you try it. When I first read the A-P QDA instructions I was intimidated at first but the more I read it the more it became so much easier. I could not believe how simple and dead accurate QDA polar alignment is. The orthogonality is about getting the finderscope orthogonal with the mount which greatly aids polar alignment. It's so easy. So when you flip the mount back and forth until the star is dead center, this tells you the finderscope is well orthogonal with the mount. Plus it's super fast. A-P Meridian Delay feature is so cool and simple. Do not get intimidated and give it a try. The only drawback is you need a right angle finderscope for altitude adjustment since the scope points to near Zenith. If your neck and back flex like a rubber band, then don't bother getting RA finderscope.

I find A-P QDA much quicker and more accurate than my previous Celestron NexStar star alignments PLUS ASPA. I have imaged as long as 30 minutes per sub at 2000mm focal length using A-P QDA polar alignment.

Peter

#25 helgeras

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Posted 07 March 2013 - 03:25 AM

Regarding the amount of stars in alignmaster:
You can add more stars by editing the file "Sterne.txt"

My file looks like this:

RA: 01h 37m 42.8s Dek: -57 14 13 Achernar
RA: 12h 26m 35.9s Dek: -63 05 57 Acrux
RA: 19h 30m 45.4s Dek: +27 57 55 Albireo
RA: 21h 28m 39.6s Dek: +70 33 39 Alfirk
RA: 14h 03m 49.4s Dek: -60 22 10 Agena,Hadar
RA: 04h 35m 55.2s Dek: +16 30 33 Aldebaran
RA: 21h 18m 34.9s Dek: +62 35 09 Alderamin
RA: 00h 13m 14.2s Dek: +15 11 01 Algenib
RA: 10h 19m 58.2s Dek: +19 50 31 Algieba
RA: 06h 37m 42.7s Dek: +16 23 56 Alhena
RA: 12h 54m 01.9s Dek: +55 57 35 Alioth
RA: 13h 47m 32.2s Dek: +49 18 48 Alkaid
RA: 02h 03m 54.1s Dek: +42 19 46 Almach
RA: 05h 40m 46.0s Dek: -01 56 33 Alnitak
RA: 09h 27m 35.2s Dek: -08 39 31 Alphard
RA: 15h 34m 41.2s Dek: +26 42 54 Alphekka
RA: 00h 08m 23.2s Dek: +29 05 27 Alpheratz
RA: 03h 08m 10.1s Dek: +40 57 20 Algol
RA: 19h 50m 47.0s Dek: +08 52 06 Altair
RA: 16h 29m 24.3s Dek: -26 25 55 Antares
RA: 14h 15m 39.7s Dek: +19 10 56 Arcturus
RA: 05h 25m 08.0s Dek: +06 20 59 Bellatrix
RA: 05h 55m 10.3s Dek: +07 24 25 Betelgeuse
RA: 01h 09m 43.9s Dek: +35 37 14 Beta_And (Mirach)
RA: 06h 23m 57.1s Dek: -52 41 44 Canopus
RA: 05h 16m 41.3s Dek: +45 59 53 Capella
RA: 00h 09m 10.7s Dek: +59 08 59 Caph
RA: 07h 34m 35.9s Dek: +31 53 18 Castor
Ra: 11h 14m 14.4s Dek: +15 25 45 Chort
RA: 11h 49m 03.6s Dek: +14 34 19 Denebola
RA: 20h 41m 25.9s Dek: +45 16 49 Deneb
RA: 00h 43m 35.2s Dek: -17 59 12 Diphda
RA: 11h 03m 43.7s Dek: +61 45 03 Dubhe
RA: 22h 57m 39.1s Dek: -29 37 20 Fomalhaut
RA: 02h 07m 10.4s Dek: +23 27 44 Hamal(El Nath)
RA: 14h 44m 59.2s Dek: +27 04 27 Izar
RA: 23h 04m 45.7s Dek: +15 12 19 Markab
RA: 12h 15m 25.7s Dek: +57 01 58 Megrez
RA: 11h 01m 50.6s Dek: +56 22 57 Merak
RA: 12h 47m 43.2s Dek: -59 41 19 Mimosa
RA: 02h 19m 20.7s Dek: -02 58 40 Mira
RA: 03h 24m 19.4s Dek: +49 51 40 Mirfak
RA: 13h 23m 55.5s Dek: +54 55 31 Mizar
RA: 06h 43m 55.9s Dek: +25 07 52 Mebsuta
RA: 15h 01m 56.7s Dek: +40 23 26 Nekkar
RA: 00h 56m 42.5s Dek: +60 43 00 Gamma Cas
RA: 17h 53m 31.8s Dek: +56 52 22 Grumium
RA: 20h 25m 38.9s Dek: -56 44 06 Peacock
RA: 07h 45m 19.4s Dek: +28 01 35 Pollux
RA: 07h 39m 18.1s Dek: +05 13 29 Procyon
RA: 17h 34m 56.1s Dek: +12 33 36 Rasalhague
RA: 10h 08m 22.3s Dek: +11 58 02 Regulus
RA: 05h 14m 32.3s Dek: -08 12 06 Rigel
RA: 14h 39m 36.5s Dek: -60 50 02 Rigel Kentaurus
RA: 08h 09m 32.0s Dek: -47 20 12 Regor
RA: 17h 30m 25.9s Dek: +52 18 05 Rastaban
RA: 20h 09m 13.7s Dek: +40 15 24 Sadr
RA: 23h 03m 46.5s Dek: +28 04 58 Scheat
RA: 00h 40m 30.5s Dek: +56 32 15 Schedar
RA: 14h 32m 04.6s Dek: +38 18 32 Seginus
RA: 06h 45m 08.9s Dek: -16 42 58 Sirius
RA: 09h 07m 59.8s Dek: -43 25 57 Suhail
RA: 13h 25m 11.6s Dek: -11 09 41 Spica
RA: 19h 46m 15.6s Dek: +10 36 48 Tarazed
RA: 14h 04m 23.2s Dek: +64 22 33 Thuban
RA: 18h 36m 56.3s Dek: +38 47 05 Vega
RA: 07h 20m 07.4s Dek: +21 58 56 Wasat
RA: 11h 14m 06.6s Dek: +20 31 24 Zosma






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