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AVX alignment help

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#1 bjgiii

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Posted 23 January 2019 - 11:11 AM

I recently acquired an AVX  and I'm having a little issue getting the alignment right. After doing the 2 star alignment I then proceed to the 4 calibration stars. The alignment does not improve as I go through the calibration stars. The alignment stars will be in the FOV of the 50 mm finderscope as I go through the alignment process, but does not put the alignment star closer to the finder scope crosshairs as I go through the calibration stars. I've owned an AVX years ago and I remember after a calibration star or two that my old mount would center the stars perfectly in the finder and EP. I'm currently using a C8 with the mount. I have done the following to the mount to find the issues.

 

Checked the time, date, lat/long, time zone and daylight savings time.

Factory reset the mount

Check that all clutches are tight

Performed the ASPA then turned the mount off and performed a new alignment routine 

Made sure the saddle was tight ( ADM DV saddle is installed on mount). I also double checked that the Dec clutch was not hitting the motor cover.

I'm using a 9mm crosshair EP.

 

The only thing I've haven't tried is installing the latest firmware. I'm currently using firmware version 5.29.7137

 

I'm also using the factory DC power plug with a 5v DC inverter  plugged into an extension cord. I do have a splitter powering the mount and a dew heater. I'm going to just power the mount with the power inverter to double check power issue, but the mount does seem to have good power. 

 

Any help would be awesome. Thanks.



#2 agflit

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Posted 23 January 2019 - 11:26 AM

Finderscope alignment with the OTA must be dead on....I simply go thru the following with my AVX AR102 & 60mm raci combo..

 

 

Set up, rough polar align thru mount base, balance assembly...I than power up mount, and using a 34mm, center first star in both ota and finderscope fov.

 

Change to 5mm eyepiece, center finderscope and ota ...power down mount

 

Now your finderscope is close to ota...

 

Power up mount, do an initial star alignment (  2 + 1 )....THAN run ASPA.

 

Whats important here is that the target is dead center in eyepiece. Once you have that set, you can always tweak your finderscope positioning to reflect actual OTA alignment.

 

It gets easier as you go...and I never trust the finderscope thruout the night...the mount tracks very well, but the finderscope may move around at times...doesn't matter. The targets dead center at the scope.



#3 mbechtel

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Posted 23 January 2019 - 12:28 PM

I have found that as I do the alignment stars, you are right, they do not appreciably change as selected and aligned. However, when I then start using the goto, they are then good. So, my experience is you do not see the improvement, but it does happen.



#4 mclewis1

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Posted 23 January 2019 - 12:54 PM

Bobby,  It sounds like you're doing all the right things. You're right in that you should be seeing the change in accuracy as you add calibration stars. The times I've seen similar behavior a Factory Setting reset has fixed things.

 

I'd try three additional things (they are long shorts but they are something to try) ... 

 

a) use different alignment stars. Start out selecting two very different alignment stars and see if there's any difference.

b) use a different 12v power source and check the DC power socket on the mount (do the split pin trick). 

c) plug the hand controller into the AUX port on the mount instead of the hand controller port  (be careful to use the AUX port and not the Autoguider or DEC port). 



#5 terrypaula

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Posted 23 January 2019 - 04:24 PM

Honestly, from what I seen you are doing everything right with your PA's.  My alignments got a lot better after I aligned my RA.  After using my mount  and scope this way for a couple months I added the use of an inexpensive AP camera and plate solving to align my mount.  My alignment's, with the use of this type of alignment technique, improved a great deal and it tracked quite well.  But that still wasn't good enough for me so I added a guide scope and mini guide scope camera into the mix and with the proper setup and use of the guide scope everything improved exponentially. I not kidding either.  You can really get dialed in on the CNP using plate solving, so be patient with a little practice everything will improve a great deal.  So if you can acquire an inexpensive AP camera, color or monochrome, about $150 new, with the use of several free programs that will run from a PC, Mac or Linux computer and your will slowly see your alignment woes start to disappear with a little practice and use any simulators available to you. 

 

Of course, if you have a lot of money to invest and a Celestron mount you can buy a StarSense Auto-Align unit.  It really is a wonderful tool for an average AA.  With minimal configuration your alignment issues will disappear.  I have taken my StarSense to it's extremes.  Mne is setup to use a OAG guide camera through the mount's auto-guide port.  It's a very nice tool for AP no matter what you read online about them don't believe it.  With mine setup with a guide scope I find any issues that I might have diminish to where the are almost invisible. what I do first is I have the StarSense perform an auto-align then use of the StarSense's PA program then another I perform another auto-align and add a couple star aligns in to the mix, with the use of a guide scope and camera and a little practice you won't have any issues tracking anything.  I use mine for AP and I get some pretty stunning images.   With the StarSense on your Celestron goto mount you really won't have any more alignment problems.  But the StarSense alone isn't good enough for AP you have to add the things I mentioned to be able to use the Starsense for AP.  Sorry.   I have one and it is configured to center objects in the ep of two totally different sitwo ze telescopes that can use the same ep's.  The 50mm is setup with the camera attached with two filters for AP.  I haven't tried it with the OAG and filter wheel yet.  The 102mm is a different story altogether, with the OAG, filter wheel and the right filter combination,Viola..

 

I decided to go another step, with the purchase of Stellarmate.  After a little studying of the user manual with the use of the simulators, that are transferable to the setups to aid in getting you up and running.  Mine helps me tremendously.  It won't break the bank either at $179.  If your a judicious person you should be able to find everything you'll need online used if your on a budget.  It will interface with the StarSense and use it's tools too if you really want too.



#6 bjgiii

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Posted 23 January 2019 - 05:59 PM

Terrypaula,

Are you using your mount for AP? I don’t see the point in plate solving for visual. That would take forever to go from target to target.

I do understand how the Starsense works which is basically a plate solve for initial alignment.

I went ahead and upgraded the firmware and I’m going to using my power source for just the mount and see if that helps. Hopefully I can get a peek through the clouds tonight to try an alignment.

#7 mclewis1

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Posted 24 January 2019 - 10:02 AM

There's no question that StarSense and such are nice and effective ease of use upgrades, and that being in better polar alignment makes the initial alignment process go a little faster (but if you are setting up from scratch doing a PA before an initial alignment doesn't save you any time) ... but for visual work you should also be able to get highly accurate gotos from just a good initial alignment process using the regular hand controller, assuming the mount is working as it's supposed to.

 

If you can't get good gotos and as described here there is something not right with the basic initial alignment process adding additional features to the setup probably won't help (unless of course the problem actually resides in the original hand controller and you replace it with a StarSense model).



#8 TelescopeGreg

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Posted 26 January 2019 - 12:23 AM

I've never tried using ASPA for polar alignment, but instead I got their Polar Alignment Scope and use that along with an app on my smartphone to tell me where on the circle Polaris should be positioned.  That works really well.  If you have a view of Polaris, I recommend that over ASPA.  Better is reported to be guider-based tools such as SharpCap or PHD2.

 

Once the mount is mechanically polar aligned, I then do the 2+4 alignment to the sky.  I find that things get pretty accurate after about 2+2, so often don't bother with the other two calibration stars.  The finder scope hardly ever gets used.  I got a Telrad for aiming, and a 12mm Meade reticule eyepiece for centering the target stars.  The Telrad is surprisingly useful, way more so than the finder, since it's often hard to get the target star into the finder, and be sure it's actually the star you think it is.  If you're aligning on the wrong star, lots of things get really wonky later on.


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#9 mclewis1

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Posted 26 January 2019 - 10:16 AM

Greg, I fully agree with your second paragraph but have a question about the first one. If you've never used ASPA how can you recommend it over the polar alignment scope?

 

For folks who setup on a tripod the PAS (polar alignment scope) can be a quick accurate solution to getting a good polar alignment ... but you have to practice and really get used to using the scope. ASPA is simpler and cheaper (no extra hardware) but requires that you have already done an initial alignment so for most folks the process ends up being - Initial alignment, ASPA, another initial alignment.


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#10 TelescopeGreg

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Posted 26 January 2019 - 06:01 PM

Greg, I fully agree with your second paragraph but have a question about the first one. If you've never used ASPA how can you recommend it over the polar alignment scope?

 

For folks who setup on a tripod the PAS (polar alignment scope) can be a quick accurate solution to getting a good polar alignment ... but you have to practice and really get used to using the scope. ASPA is simpler and cheaper (no extra hardware) but requires that you have already done an initial alignment so for most folks the process ends up being - Initial alignment, ASPA, another initial alignment.

Hi Mark,

 

Sorry, clumsy wording on my part.  I meant that I prefer using the Polar Alignment Scope to doing ASPA.  The reason is mostly time.  Mostly I do imaging (vs visual), and about half of my imaging is "at home", which is actually across the street on my neighbor's driveway, so I can't take my time to set the rig up and let it run for the night.  The other half of the imaging is at the club's mostly-monthly star party.  Both situations mean that I need to get aligned and running quickly.  I've read the procedure for ASPA, and it basically doubles (or more) the alignment time, where the PAS is just a matter of looking at Polaris and fussing with the two knobs.  Done. 

 

Others also report that an ASPA alignment isn't generally as precise as one using other methods; it's chief benefit is not needing a view of the celestial pole.  Precise polar alignment is necessary for deep sky astrophotography, especially since the AVX mount's Dec motor and bearing is not intended for being used when tracking.



#11 mclewis1

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Posted 26 January 2019 - 06:58 PM

Greg, No problem, I figured something like that. 

 

Time is the issue. You can get very accurate polar alignments using ASPA but this usually means multiple iterations of both the polar alignment and initial alignment routines.

 

The folks that are good at using a PAS can do a good setup and be imaging very quickly ... but I know a few folks who continue to stumble with using one (personally I'm on the fence as I don't get to practice with mine very often). PoleMaster and the routines built into SharpCap and PHDGuide do work well and for most folks seem to offer the best accuracy. Like the PAS there are also folks who can do a good drift alignment relatively quickly and practically with their eyes closed ... but like using a PAS there are others who continue to struggle with this method.

 

The good thing for all of us is that there are lots of different choices for doing accurate polar alignments, some are easy, some take time, and some are even free.



#12 bjgiii

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Posted 29 January 2019 - 08:55 AM

Thanks everyone. I was able to get my self straightened out. I was just rushing a bit and not setting up properly.




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