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Go Back   IceInSpace > Beginners Start Here > Beginners Talk

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  #1  
Old 05-09-2018, 09:45 PM
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Outcast (Carlton)
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Location: Cairns, Qld
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Stunning session with my LX90 8"

After owning my recently acquired LX90 8" SCT for a few weeks now, I was getting a little frustrated at the apparent inaccuracy of the goto's.

I stumbled upon a series of articles regarding the mechanics of the mount & some settings tweaks together with advice on drive training

Link here: http://arksky.org/aso-guides/aso-tel...o-to-telescope

After doing most of the things indicated (not the delving into the drive internals though - not that brave) I was still not getting great goto's.

I took a chance & emailed the author & spent a few days back & forth discussing how I was setting up, the precision of my alignment process & so forth. The results tonight speak volumes to Dr Clay Sherrod's knowledge & patience in working through a good setup & precision star alignment process. I am grateful to him & a number of others on here for their advice, tips & patience.

Tonight's viewing was sublime, the weather here in Cairns is wonderful with cool (well, cool for up here) crisp nights.

After taking the time to carefully setup & align my scope tonight I managed about a dozen DSS objects including Ring Nebula, Swan Nebula, Eagle Nebula and a bunch of globular clusters as well as Saturn & Mars.

When carefully setup & aligned, together with use of the High Precision setting for goto's every object was well within the FOV of my 40mm Plossl & often, within the FOV of my 12.7mm Plossl.

This is a truly remarkable instrument & I am one very happy observer this evening... Even in my somewhat light polluted backyard, the views were stunning. Can't wait to get this scope out to a dark site.
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Old 06-09-2018, 12:24 PM
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iborg (Philip)
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Hi



I also have the LX90 8", and goto is usually OK, but, not good.


So thank you for posting this link and for saying that it has helped. I'll make sure I work my way through it in the near future.


As you have been communicating with the doc, is there anything you feel you can add to what is in the link?


Have fun


Philip
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Old 06-09-2018, 04:38 PM
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Outcast (Carlton)
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Hi Philip,

Basically you need to be very precise in how you conduct your alignment star centring.

Follow his process in the article with respect to doing a reset on your handset, conducting motor calibration & then drive training. He recommends Polaris, which of course is not much good to us here in the South but, the alternative for us is to find a easily identifiable landmark at a least 1 mile distance & then using the highest magnification you can to conduct the drive training & being absolutely precise in the centring of this object. If you miss for whatever reason, do it again & do it at very slow speed.

Then when setting up for viewing, be very careful about leveling the tripod (use a small spirit level, not a bubble level) then after you have attached the fork & ota, make sure the mount is in the home position & then check that the ota is level. North pointing only needs to be within a couple of degrees.

Once you have done this, initialise the unit & check time, date, daylight savings & site entries & make sure they are correct.

Choose two star alignment & when you are centring the stars, do so at the highest magnification possible; at least 12mm eyepiece.

He then recommends slewing to a 3rd star & using the synchronise function. He strongly recommends never using the synchronise function on planets or moon.

When looking for DSS objects, select High Precision mode (this is found under the setup menu). It adds an extra step in the goto process, namely it takes you to a nearby bright star first, you centre that, again very precisely then, it slews to the DSS object.

After last nights session, I can highly recommend the High Precision mode for DSS hunting; every single nebula, cluster, etc.. was very close to centre view in a 40mm plossl & I was able to change out to a higher powered eyepiece without having to re-centre the object.

Mechanically, there is also a process referred to as 'Grease Redistribution'. I used this method as I wasn't keen to delve into the innards of the drives. It's not in the article but, it is available on Weasners site. I can copy it & PM it to you if you like.

Essentially though, it came down to making sure that one was a bit anally retentive in the setup process & ensuring high accuracy when centring alignment stars.

Happy to chat back & forth via PM about what I learnt if you would like

Cheers

Quote:
Originally Posted by iborg View Post
Hi



I also have the LX90 8", and goto is usually OK, but, not good.


So thank you for posting this link and for saying that it has helped. I'll make sure I work my way through it in the near future.


As you have been communicating with the doc, is there anything you feel you can add to what is in the link?


Have fun


Philip
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  #4  
Old 06-09-2018, 06:52 PM
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iborg (Philip)
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Location: Lynbrook, Australia
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Hi



Thanks for the additional info. I will have to look up "the synchronise function" as I had not noticed, or I ignored, that looking through the manual.


Most of the things listed, I normally do, but, not necessarily all of them all the time. I do align and train with a 12mm illuminated reticule, but, possibly not slowly enough with the training.



I have used the high precision, but, I don't always remember to turn it. Powering off the handset turns it off.


I really need to get it connected to the computer and update it.


I do have a hint for you that may be useful. If you move your tripod by putting your hand underneath and holding the long bolt to lift and move, I found that the metal ribs dug into my hand. I happened to have a disk of aluminium the right diameter, drilled a hole in the middle - and now - everything is much more comfortable. Plywood or MDF would do the job just as well.


Once I have worked through the 'fixes' I may some queries, so thank you for the offer of further discussion.


Philip
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