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LX90 Drive Training OTA Angle

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#1 imk

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Posted 22 March 2019 - 11:43 PM

Hello,

I am having a RA tracking issue and wondering is it is due to me training the drives with the OTA horizontal?.

 

I have a new audiostar hbx with firmware A4S1 and have been thru the setup/training/motor calibration three time now and still the same problem.

So i was reading the book again and it says "Use a terrestrial object such as telephone pole/lamp post" .which are generally upwards.

Well I used a tall factory chimney about a mile away that is in the valley hence my OTA was horizontal.

Should i have the OTA point upwards during Drive Training say at 45 deg?

 

Many thanks imk

 

 



#2 OzAndrewJ

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Posted 23 March 2019 - 12:08 AM

gday imk

 

For DEC training,you can use any OTA angle.

For RA training, the DEC tube should be as close to DEC/Alt = zero as you can ( ie 90deg to RA axle ).

Meade completely changed the way tracking gets done in the later firmwares

which is one of the reasons i suggest staying with A1F7 for the LX90s.

 

Andrew Johansen Melbourne Australia



#3 imk

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Posted 23 March 2019 - 12:24 AM

Andrew,

Many thanks for the posts, it is couple of days before next clear sky here so will be then before i have new test results.

BTW is down or has moved? http://www.stargps.ca/downloads.htm

 

Thanks again for your help



#4 OzAndrewJ

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Posted 23 March 2019 - 01:36 AM

Gday imk

No idea re his site

I have emailed him to let him know, so will wait and see.

 

Andrew Johansen Melbourne Australia



#5 Piet Le Roux

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Posted 23 March 2019 - 02:02 AM

Hello,

I am having a RA tracking issue and wondering is it is due to me training the drives with the OTA horizontal?.

 

I have a new audiostar hbx with firmware A4S1 and have been thru the setup/training/motor calibration three time now and still the same problem.

So i was reading the book again and it says "Use a terrestrial object such as telephone pole/lamp post" .which are generally upwards.

Well I used a tall factory chimney about a mile away that is in the valley hence my OTA was horizontal.

Should i have the OTA point upwards during Drive Training say at 45 deg?

 

Many thanks imk

Hi imk I take it that you have decided to upgrade to a wedge?



#6 imk

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Posted 23 March 2019 - 04:18 AM

Hi imk I take it that you have decided to upgrade to a wedge?

Piet,

Yes I am considering a wedge, but have a strange RA tracking problem at this time, detail of which you can find in another thread.

As you will see i had/have an older flaky AutoStar hbx and from memory i think it RA tracked was better than this new AudioStar.

But last time i had a clear sky, i did not have presence of mind to re-test with the AutoStar and when i thought of it the skies clouded up.

Hence, plan is to get up at 0300 sunday morning to re-test with the old autostar and if tracking is better then it must be issue with way i have setup this new audiostar.

 

I have read much in several astro forum in past week and it seems like these meade hdx's have a few undocumented features that may have caused my audiostar not to RA track at all.

So when i have the basics all working as expected i'll go wedge shopping.

 

We await some stars, wish me luck imk :-)



#7 OzAndrewJ

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Posted 23 March 2019 - 04:45 AM

Gday imk

 

I have read much in several astro forum in past week and it seems like these meade hdx's have a few undocumented features that may have caused my audiostar not to RA track at all.

Just for info, there are 2 ways to track in polar and 2 ways in AltAz

ie In Polar, you can track using a std sidereal rate, or you can work out the now vs Now + 30second positions

and work out a tracking rate from that. ( ie a pseudo king rate calc )

For AltAz its the same, you can create differential equations to convert polar tracking

to equivalent Alt/Az rates, or use the now vs 30 seconds from now to come up with rates.

A1F7 in polar just uses a std tracking rate

The later firmwares use the delta Alt/Az rates, so can give different results, esp if they use the wrong motor commands to apply the speeds ( as the LX600s do )

All good fun

Andrew Johansen Melbourne Australia



#8 Piet Le Roux

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Posted 23 March 2019 - 06:15 AM

To prevent confusion : When using Azimuth mode your two drives are the Azimuth and Altitude drives (Az/Alt) and in Polar mode with a wedge, your two drives are the Right ascension and Declination drives (Ra/Dec).


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