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akemikat

Celestron NexStar 102 SLT Telescope - is it faulty ????

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My partner and I bought our first telescope recently, a Celestron NexStar 102 SLT. We took it out for the first time last night and spent 3-4 hours trying to star-align it unsuccessfully. We used Sky-Align, one-star, two-star and three-star align methods (there was only one solar system object visible, so we couldn't try solar-system align). Every single time it came back as failed, and each method was tried 5-6 times, if not more. There were a couple of times with the one-star alignment where it said that it was successful, but the telescope followed this by rotating on it's alt az mount continuously and aimlessly until we had to switch it off to stop it from doing so.

We have put all the information in the hand-set correct to our knowledge, including location by degrees, minutes & seconds latitude and longitude using a GPS app on our phones to enter the exact coordinates. We put the date in American style but it was 8/8/15 anyway, the time zone we put as GMT and then set controller to Universal Time and Standard, but also tried Daylight Savings time with GMT+1 (basically both ways in which it can produce the time zone that we're in, in England). When we first set the tripod up we had the bubble level of the scope centred, but I did notice when we dismantled this was a little off centre (we weren't on exactly flat ground, but we had adjusted the tripod legs to sort this out) I wondered if this could be a factor in our issues, but it was doing the same continuous rotation thing when we tried a one star-align in our living room on hard-wooden floors with the bubble level aligned correctly. The telescope was mounted correctly as per the instructions. We used the Stellarium app to locate the stars after finding Saturn, and were very accurate in using the finder-scope to align the stars, and then centring it in the eyepiece - we also tried to use stars as far apart as possible, such as Arcturus and Caph. After a while, we tried a factory reset on the NexStar hand control as some forums suggested, but that didn't work either. 

Does anybody know if it's us...or if the telescope is faulty? The continuous rotation of it after an alleged "successful" one-star align seems to suggest this. Any help would be so much appreciated - thanks in advance!  :smiley:

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Hello and welcome to SGL'

Quote:-

  "There were a couple of times with the one-star alignment where it said that it was successful, but the telescope followed this by rotating on it's alt az mount continuously and aimlessly until we had to switch it off to stop it from doing so"

This doesn't sound right. If the mount just keeps on rotating on its azimuth axis then I suspect that there is something wrong. This could be due to an electronic fault with the mount or inadequate power supply. If you bought the telescope from a reputable astro dealer they should be able to check to see if the mount is functioning correctly or exchange it. If you are using alkaline batteries make sure that they a new ones, low voltages can cause problems with the operation of the mount. Similarly, if you are using a mains power supply ensure that this has a regulated output and can supply the required amps that the mount needs.

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Unless your selecting other than the stars that the mount is expecting, or you're not getting enoughpor to your mount, it might be a mechanical fault.

Does it move in the altitude and azimuth when you press the remote buttons?

Also if your using rechargeable batteries, they are not 1.5V per battery as needed, but only 1.2V and might also be a indication of a reason for your problem.

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I agree with others, you should definitely be powering from a 12v source such as a car jumpstarter or indeed the car cigarette lighter. My 4se will not run longer than about 45 mins on new batteries, then it goes haywire.

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It does resemble a power problem, it is sort of classic that when the power drops then the scope can/will wander around.

I assume that you were using batteries, so were they new and were they NOT rechargeables ?

Rechargeables are only 1.2 volts so 8 in the scope will give 9.6 volts not the wanted 12 volts.

Equally get some reasonable ones, a friend had a similar problem with a small scope that was partially my fault. I took a set of the bulk ones from Poundland and they were not really up to the task. So it worked OK initially then soert of went a bit haywire.

The scope needs to be reasonably level so it sounds like you were OK on that.

Is there a start position on the scope - don't think there is a specific one for it - it is usually described as Level and North.

That being the tripod level and the base bit of the scope and then the scope level and the scope OTA pointing North <- not at polaris.

This may be a start position for 2 star align, as it then defines a starting reference.

Although never used it I am not a great fan of the 3 star alignment, it sounds nice and easy for the observer but determining it from the software aspect could be a problem. I sometimes wonder if to make it appear easy on the user they have compromised something else.

Cannot work out what you did concerning the timezone, too much information to unravel it. Basically Timeone = UTC and then you set the time as per a watch and say DST is Yes.

Usually planets are not the best option to align with. Stars are "fixed" (lets ignore the habit of circling the earth every 24 hours) planets are not quite so "fixed". That means that the position of the planet needs to be calculated. Not too bad except for the fact they slow down, stop and go backwards at times, then they slow down the backwards movement, stop and start going forward again.

If the scope is to be run at home look at the Maplins L06BR item, just make sure the polarity is correct if you get one - centre positive.

If all this fails then try The Baker Street Irregular Astronomers one night.

This is the London group that meet in Regents Park monthly.

http://www.bakerstreetastro.org/

Think they meet on a Wednesday every month, not sure how you get in, if clear this Wednesday they will meet to sit and hopefully observe the Perseid meteor shower peak that evening. If you go take lots of good batteries.

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Thanks so much for all your responses  :smiley:

Re the power supply - we used brand new, non-rechargeable Energizer alkaline power 1.5V batteries whilst out last night, and a 12v, 5 amp power supply at home. The power requirements listed in the manual is 750 mA (0.75 amps). It displays exactly the same behaviour using both, oddly enough. If you mean this Maplin product - http://www.maplin.co.uk/p/maplin-20w-switched-mode-acdc-multi-voltage-power-supply-l06brour supplies more than that so it should be fine there. My partner say it's almost definitely not the power that's the issue. 

It does move in the alt & az when using buttons on the hand set, in all directions.

Not sure about starting point for the 2-star align? I don't recall seeing a prompt for this. It just said to choose first star and gave a list of all in the database. We bought the telescope through Amazon, it was listed as only having a minor cosmetic fault, so we can't turn to the supplier for help here, unfortunately. We're going to give it another go in the house just now to see if we can get any joy before then probably returning it, to be honest  :embarrassed: 

I'll look into the Baker Street Astro group! Unfortunately my partner works away during the week and I'm otherwise engaged every Weds evening for the foreseeable future, though, sadly. We're getting to know the Flamsteed Astro Group as they meet on Saturdays which is more convenient for our hectic weekly schedules!  :grin:

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I know everyting looked OK but you did say you got Latitude and Longitude from GPS. You did actually enter Longitude first then Latitude ???

Most (all) GPS things give Lat then Long, we talk of Lat and Long.

So for whatever reason the scope wants Longitude then Latitude entered in that order.

Happens more then you would expect and the scope then decides it is sort of in Brazil and more or less on the equator.

The other thing is just check the Longitude, for you I would expect 000o nn"

The handset has been known to not get the leading zero's right.

I know why they have the 3 star alignment but it seems more trouble then it's worth.

When you think about it the first star is meaningless, all the scope "knows" is that it is pointed at some star somewhere.

You probably cannot try the scope out in the house owing to the absence of a start position as you cannot centre a star for the software to work with. Your scope tells you to go to the stars for alignment, Meades have this defined start position so they presume you have set the start position and if so then Arcturus is sort of over there left a bit and up a bit, so it moves itself to Arcturus. Yours does not ahve this in it - I assume Meade sort of patented it and so Synta cannot adopt it. But it is good and also useful if solar observing.

For alignment they tend to display the one they think of as a default, likely 3 star align. To get to one of the others I "think" you press Esc, but not sure, it may simply be you press the Up or Down arrow to move to the next option in the list.

As power sound OK, bit lost.

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Not sure if this helps but I'm new to Nexstar myself and it does take a bit of getting your head around.  After trying Sky Align and am now using just single star align.

I've done single star align on polaris with my Nexstar with reasonable success.  For indoor testing I used the method (but just for one star) described here:

http://www.nexstarsite.com/Book/Updates/IndoorsAlign.htm

I use a mobile phone for compass and latitude adjustment of the 'scope.

I then pick a "test" target, goto that and use a star map app (Google Sky or SkEye if you're on Android) to make sure the 'scopes pointing in roughly the right direction.

As has been said before, power is really important (more than I expected).  I tried using a couple of sufficiently rated mains power supplies.  One blew and one was intermittent.  I ended up getting a 12v golf trolley battery and rigging that up.  Works great and cheaper than a power tank!  I don't know if this or the single Polaris align is what's made the difference though!

You could also try a full factory reset on the handset and set everything up again from scratch.

One other thing and I don't know if it'll make any difference is I made sure all firmware is up to date on the mount.

The whole setup process takes a bit of getting used to and was all wrong my first few nights.  It takes practice and you will get there so stick with it.  Last night I was hitting all targets within the centre 75% of the field of view of the standard 25mm eyepiece.

Clear skies.

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Thanks so much for all your responses  :smiley:

Re the power supply - we used brand new, non-rechargeable Energizer alkaline power 1.5V batteries whilst out last night, and a 12v, 5 amp power supply at home. The power requirements listed in the manual is 750 mA (0.75 amps). It displays exactly the same behaviour using both, oddly enough. If you mean this Maplin product - http://www.maplin.co.uk/p/maplin-20w-switched-mode-acdc-multi-voltage-power-supply-l06brour supplies more than that so it should be fine there. My partner say it's almost definitely not the power that's the issue. 

It does move in the alt & az when using buttons on the hand set, in all directions.

Not sure about starting point for the 2-star align? I don't recall seeing a prompt for this. It just said to choose first star and gave a list of all in the database. We bought the telescope through Amazon, it was listed as only having a minor cosmetic fault, so we can't turn to the supplier for help here, unfortunately. We're going to give it another go in the house just now to see if we can get any joy before then probably returning it, to be honest  :embarrassed: 

I'll look into the Baker Street Astro group! Unfortunately my partner works away during the week and I'm otherwise engaged every Weds evening for the foreseeable future, though, sadly. We're getting to know the Flamsteed Astro Group as they meet on Saturdays which is more convenient for our hectic weekly schedules!  :grin:

The 750ma that they say is only during 'normal tracking' - it pulls somewhere nearer/over  2A when slewing. I've used a number of lithium batteries rated at anywhere between 1A and 2A and the SLT always screws up when slewing. Like you - I use a 5A mains supply when at home, but a 12V marine battery when away.

And that Maplins power supply only provides 1.7A @12v - so I don't think its enough.

Useful articel - http://www.nexstarsite.com/OddsNEnds/PowerSources.htm

Edited by ngwillym

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For testing in daylight the scope is easily fooled. Tell it you want to solar system align, then choose Moon, then point it anywhere you like using the direction arrows, press enter, then it will tell you to use the direction keys again (it will slow the motors right down now) to do the fine alignment. Just press enter and it will assume you are pointing at the moon without "checking". At least you will be able to leave it a while to see if it tracks.

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hi akemikat,

the problem is likely technique and 'the Learning Curve'. the first few tries are failures and then it succeeds and it becomes easy.

the alignment is best done with 'two star auto'...

see:Aligning the NexStar telescope with Auto 2 Star method - YouTube...this nice fellow explains it well

this nice man explains it well.

if the batteries are low the scope will start to slew very slowly.

I would start by using 'solar system align ' and using the Moon. it is hard to miss ! this will allow you to use 'goto' and see some stars which you know. please note that you will not find the first alignments exact.

the accuracy gets better as the evening gets darker...

the quality control with Celestron is high so it is more likely you learning than the scope.

Happy skies !

Ps.

there are other tips if you are still having problems

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First thing when I got my SLT Mount at Christmas was update the firmware for controller and motors. Even the FLO supplied scope was way out of date. Using a power pack I've never had a failed alignment.

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I had a similar problem with my SkyWatcher AZ goto mount which is similar to your mount. Turned out to be a defective mountthat was replaced by the vendor (Green Witch). The replacement mount worked great out of the box and continues to do so 6 years later.

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Hi guys!

I just thought I'd update you on this. It did turn out to be a fault with the mount, so we returned it and got a Celestron Nextar 127 SLT instead, which we star aligned in about 2 minutes!! After all that effort and thinking it was us haha!

Thanks again for all your help and advice :)

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I have b

On 9/6/2015 at 17:47, akemikat said:

Hi guys!

I just thought I'd update you on this. It did turn out to be a fault with the mount, so we returned it and got a Celestron Nextar 127 SLT instead, which we star aligned in about 2 minutes!! After all that effort and thinking it was us haha!

Thanks again for all your help and advice :)

Hi. I have a Nexstar 127 SLT that is doing exactly the same thing. I have tried firmware upgrade, power tank, power supply on mains. I align using Sky align. once alignment is done It says press enter on controller and after I do that the mount starts rotating on the Azimuth axis.

I have star aligned it before and it is only recently that this started happening. Could it be me? or is this the same problem you had?

 

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11 hours ago, RainyNight said:

I have b

Hi. I have a Nexstar 127 SLT that is doing exactly the same thing. I have tried firmware upgrade, power tank, power supply on mains. I align using Sky align. once alignment is done It says press enter on controller and after I do that the mount starts rotating on the Azimuth axis.

I have star aligned it before and it is only recently that this started happening. Could it be me? or is this the same problem you had?

 

If it still under warranty you should return it.

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7 hours ago, Cornelius Varley said:

If it still under warranty you should return it.

I bought it in October 2015 so according to EU law it is still under warranty right?

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26 minutes ago, RainyNight said:

I bought it in October 2015 so according to EU law it is still under warranty right?

Where was it from?

 

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2 hours ago, jimbo747 said:

Where was it from?

 

Baaeder Planetarium in Germany, bought via Amazon UK

Edited by RainyNight
more information.

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16 hours ago, RainyNight said:

Baaeder Planetarium in Germany, bought via Amazon UK

 

Ah right. If it was from amazon direct you'd be in luck (I only ever order from amazon if I can as they'll refund no questions asked even 2 years down the line)

You can try contacting amazon CS and see what they say, I've had them get involved successfully in a few cases where the order was direct from the seller and outside the standard 30 day window, failing that contact BP directly, and should that even fail see what your bank says.

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Hi all,

i contacted amazon and they replaced the whole thing so its all good now!

 

thanks for all the help.

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