Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

New to me (used) Celestron Nexstar 9.25 GPS question and maybe tips?

  • Please log in to reply
21 replies to this topic

#1 Traffalger1698

Traffalger1698

    Vostok 1

  • -----
  • topic starter
  • Posts: 105
  • Joined: 08 Apr 2019
  • Loc: Central Minnesota

Posted 14 September 2020 - 11:16 AM

Greetings,

 

So I recently got a used Celestron Nexstar 9.25 GPS  I have used a Zhumel Z130 tabletop dob for the last year and a half (my first scope)  I know this is an older scope, but what I have been able to find on it still seems to be a pretty good upgrade from what I had.

 

Mechanically it seems in good shape. Motors work, slewing works, GPS connects, no gear grinding Primary mirror looks good from what I can tell (clean).  Overall I see no dents, dings, scratches or cracks in the OTA or mount.  The only thing I don't care for is the corrector plate has some crud on the inside and some smudges on the outside of the glass.  Does anyone know if this is relatively easy to clean?  It did not appear to be something that affected the limited views of the horizon I have been able to see so far.  (as standard it was cloudy last night after I received it.)  Right now it is "supposed to be clear tonight but there is haze in the air from the wildfires out west.  Fingers Crossed.

 

It did not come with a dew shield and this time of year is prone to happen.  Is that something I should be looking into to get?  Is there a specific type I should be looking at?  Heated vs nonheated?  I also believe I will need to get a power tank or similar as I eventually want to take it away from the house.  Is there anything else you guys recommend that you use I should look into getting?

 

Lastly are there any specific tips or things I should know more, or read up on?  Any tips and thoughts would be very appreciated.  

 

 

I am excited to check my new scope out. 

 

 

Thank you and clear skies to all.  


  • Procyon likes this

#2 markb

markb

    Apollo

  • *****
  • Posts: 1,086
  • Joined: 16 Jun 2006
  • Loc: Long Island; in transition to Arizona

Posted 14 September 2020 - 11:51 AM

Giving your concern with the condition of the corrector, my number one tip is to not disassemble it to clean it.

 

There are factory rotational alignments of the optics including both the secondary and the corrector plate that are easily lost without proper research and preparation to maintain the original factory alignments. Newer celestrons also have the corrector placed precisely within the cell, not merely centered, another adjustment that you must be prepared to duplicate on reassembly.

 

So just clean the outside if you wish.

 

No problem with cleaning the outside surface as long as you follow accepted practices on using a fresh new loop type microfiber, which absorbs quite well, or PEC pads, available on amazon, along with an acceptable cleaner such as Zeiss fluid, also available in Amazon.

 

Do not use acetone, while it's okay for glass outside of a cell, it will wick into every tiny surface and cause issues.

 

 

You don't really need a power tank unless you get a dew heater. The Talentcell lithium battery packs frequently recommended here on CN are all you need for the GPS scope for several hours. I run my GPS 11 without any issues whatsoever, and the talent cell also has USB outlets to power my tablet if necessary. They are the size of a paperback book and very light, and fairly inexpensive.

 

You may encounter issues getting the correct time and date from the satellite, due to a quirk in the GPS standards be dating back nearly 20 years.

 

---

 

You may also have trouble getting accurate location data downloaded because the internal lithium rechargeable battery that maintains satellite information goes flat after a while, and it may take an hour, and even up to a a couple of days of being powered on and positioned next to a window with view of the satellites to download all the information needed from the GPS satellites and give an accurate location. 

 

The internal batteries have been known to go bad, however, very often they just need to be charged by having the scope powered on and left on for a while.

 

My own GPS 11s had to be left on for nearly two days to both recharge the battery and to give proper location data.

 

---

 

As if that was not enough to delay getting started, you have to go through the menus and find out the version number of your hand controller, and compare it to the information on

 

http://www.nexstarsi...GPSRollover.htm

 

Mike Swanson's wonderful website that provides lots of free information to help you out.

 

Go there, read all the tips on using the GPS scopes, and consider buying his book, worth every penny. It goes into much more detail and gives many more tips than the site.

 

You probably have the earlier of the two hand controllers, for which the version 4.22 firmware programming provides necessary fix to have the GPS 9.25 return the proper date and time information. Without it you get dates far in the past.

 

There are workarounds so you can use the scope immediately, I think the easiest is to download Sky Safari for either Android or iOS, on a phone that has GPS capability.

 

it's a wonderful program that can eventually control your telescope if you get the proper adapter, I use StarBT from astro-gadget.NET for my Android tablet.

 

But one of the handy parts is that it Sky Safari will display the satellite exact location common date and time on the screen then you can then manually enter into the telescope until you get the hand controller updated, if it needs it.

 

I really like the GPS 11, enjoy your scope.

 

Hold off on adjusting combination until you are familiar with using the scope.  when you are ready to collimate it, I highly recommend starting with daytime collimation using

 

http://www.robincasa...ro/collimation/

 

(You may not get perfectly concentric circles, due to slight variations in manufacturing tolerances in centering of the optical elements).

 

After that there are many posts on confirmation, but I am personally experimenting with the use of a Duncan mask, which you can search for here on CN. I finally got around to cutting one out for myself yesterday and I'm waiting for clear skies to try it.


  • Procyon, Bean614 and Traffalger1698 like this

#3 markb

markb

    Apollo

  • *****
  • Posts: 1,086
  • Joined: 16 Jun 2006
  • Loc: Long Island; in transition to Arizona

Posted 14 September 2020 - 11:53 AM

I forgot to mention that, as far as the internal crud on the corrector, if it is just flakes of paint, or bits of debris, as opposed to smears of oil or something similar, it's highly unlikely it would have any effect on your images.

 

The external smudges can be fairly easily cleaned as in my post.



#4 Traffalger1698

Traffalger1698

    Vostok 1

  • -----
  • topic starter
  • Posts: 105
  • Joined: 08 Apr 2019
  • Loc: Central Minnesota

Posted 14 September 2020 - 12:59 PM

I forgot to mention that, as far as the internal crud on the corrector, if it is just flakes of paint, or bits of debris, as opposed to smears of oil or something similar, it's highly unlikely it would have any effect on your images.

 

The external smudges can be fairly easily cleaned as in my post.

Thank you for the info, I’ll be going through all of this more thoroughly when I have more time.

 

I have seen a few places saying to find the firmware but I cannot figure out how to do that at the time being. I currently have the scope in the backyard to try and connect w the satellites. I have it plugged in and powered on to also try to recharge the batteries. (To see if they are still good or need replacing).

 

Here is a picture of the corrector plate showing what I am seeing. The outside is dusty and I’ll try cleaning that today. But this on the inside is what I am talking about.

 

https://imgur.com/a/RzK7WXm



#5 markb

markb

    Apollo

  • *****
  • Posts: 1,086
  • Joined: 16 Jun 2006
  • Loc: Long Island; in transition to Arizona

Posted 14 September 2020 - 01:21 PM

Anything Nexstar is made a thousand times easier by going to Mike Swanson's website nexstarsite.com

 

And the books, one for early and one for late scopes, have probably 10 times as much information for everyday use.

 

This is the page for the GPS update version status

 

https://www.nexstars...GPSRollover.htm

 

The bottom of the next page has the information how to determine your version.

 

https://nexstarsite....GPSFirmware.htm

 

Mixed throughout are links to places to get the software and determine what cables you need for the update.

 

From here on you should be able to handle it yourself, using Mike's site, as long as you have motorboard versions 3.x or higher.

 

If you run into older motor control boards versions 1 or 2, may have some update issues, hopefully you will not end up in that situation period if you do, follow the links on Mike's site.

 

 

 

As far as the pictures are concerned, I'd clean out or surface, and not be in a rush to do it, and then rephotograph your corrector to see what's on the inside.

 

Again, I would not put the cleaning highest on the priority list, and would totally forget about the interior of the corrector plate for quite some time.

 

Your images will be better than you would think. I have a Meade 8 with one of their defective silver coated mirrors from 20 years ago, bought with knowledge of the defect for a trivial price, and it gives surprisingly usable images despite a secondary covered in splotches and what looks like bubbles. given the size of the secondary, that's causing a lot more impairment to the image than your corrector, likely by a factor of 1000. I'll get a recoded after I move, finally.

 

I would only be particularly concerned if you had sizable areas with smears of oil and grease, at least for now. even with all those specs, you're not going to see noticable impairment. when you're ready to go further, PM me and I'll send you some information on alignment checking and preserving alignment if it has never been disturbed.


Edited by markb, 14 September 2020 - 01:26 PM.

  • Traffalger1698 likes this

#6 Traffalger1698

Traffalger1698

    Vostok 1

  • -----
  • topic starter
  • Posts: 105
  • Joined: 08 Apr 2019
  • Loc: Central Minnesota

Posted 14 September 2020 - 02:23 PM

Anything Nexstar is made a thousand times easier by going to Mike Swanson's website nexstarsite.com

 

And the books, one for early and one for late scopes, have probably 10 times as much information for everyday use.

 

This is the page for the GPS update version status

 

https://www.nexstars...GPSRollover.htm

 

The bottom of the next page has the information how to determine your version.

 

https://nexstarsite....GPSFirmware.htm

 

Mixed throughout are links to places to get the software and determine what cables you need for the update.

 

From here on you should be able to handle it yourself, using Mike's site, as long as you have motorboard versions 3.x or higher.

 

If you run into older motor control boards versions 1 or 2, may have some update issues, hopefully you will not end up in that situation period if you do, follow the links on Mike's site.

 

 

 

As far as the pictures are concerned, I'd clean out or surface, and not be in a rush to do it, and then rephotograph your corrector to see what's on the inside.

 

Again, I would not put the cleaning highest on the priority list, and would totally forget about the interior of the corrector plate for quite some time.

 

Your images will be better than you would think. I have a Meade 8 with one of their defective silver coated mirrors from 20 years ago, bought with knowledge of the defect for a trivial price, and it gives surprisingly usable images despite a secondary covered in splotches and what looks like bubbles. given the size of the secondary, that's causing a lot more impairment to the image than your corrector, likely by a factor of 1000. I'll get a recoded after I move, finally.

 

I would only be particularly concerned if you had sizable areas with smears of oil and grease, at least for now. even with all those specs, you're not going to see noticable impairment. when you're ready to go further, PM me and I'll send you some information on alignment checking and preserving alignment if it has never been disturbed.

Thank you I'm just excited to try it out.  I'll dig into that site you sent.  I appreciate the advice and help.  



#7 mclewis1

mclewis1

    Thread Killer

  • *****
  • Posts: 20,468
  • Joined: 25 Feb 2006
  • Loc: New Brunswick, Canada

Posted 14 September 2020 - 04:15 PM

If your scope performs a GPS link and updates the time, date, and location correctly I would not touch it at all ... leave the firmware alone.  It would however been good to know the firmware levels as that will give you and idea of age and capabilities (so the appropriate manual can be used as a reference). Run the Version command (it's under the Utilities menu) and if there's no Version command present it will tell us about the scope too (the very earliest hand controller version)

 

It's battery (singular) as the GPS battery is the only chargeable device in the NS GPS scopes. 

 

One common thing to do with any older NS GPS scope is to clean the azimuth bearing surface, it attacks dirt and gets lumpy over time. While you are inside the base it might also be helpful to visually check the split ring power distribution to see if there are any excessively worn or burned (from arcing) areas (those would cause intermittent power resets).

 

When you are using the scope be gentle with the clutch levers, especially the altitude one as they can be broken and if that happens there are no replacements. 



#8 markb

markb

    Apollo

  • *****
  • Posts: 1,086
  • Joined: 16 Jun 2006
  • Loc: Long Island; in transition to Arizona

Posted 14 September 2020 - 05:23 PM

Cleaning the azimuth bearing, if I remember correctly from when I had to disassemble one of my scopes, is not the easiest thing to reach and requires removal of circuit boards. So I consider it more of a 'do it only if you have to' item.

 

But that's from going by memory.

 

The disconnects used inside the telescope are not real disconnects made for frequent use, apparently they are adapted header plugs, so I try and leave mine alone.

 

Besides, they all look identical, so you have to carefully mark them since incorrect attachment may blow circuit boards that can no longer be replaced. They also our subject to accidental reversal, another way to blow a board.

 

The split ring is simple enough to reach, but should not require servicing unless someone was tempted to apply power through the top panel 12v output, or, used it for what was designed for, but with a higher amperage accessory than it could handle.

 

The GPS 9.25/11 should only be powered using the plug in the base for that reason. If powered from the 12-volt accessory output the amount of current required to run the motors will burn the slippering tracks.

 

I would assume that putting a particularly power hungry accessory into the top panel 12 volt output would also burn the tracks. Like a dew heater.

 

I would power any device requiring more than half an amp directly from the external battery.

 

Ah yes, the altitude lock!

 

I have no idea if they were all set up this way, but my 2006 GPS 11 is extremely rear heavy even without diagonal and eyepieces!

 

The amount of pressure that has to be put on the altitude lock can easily snap the aluminum or soft alloy used to make the thin lock arm and ring mechanism.

 

I have always assumed they set it up this way to offset the weight of the hyperstar/fastar lens assembly, which almost no one bought because it was so expensive.

 

I was going to make one of the homemade sliding weight counterweights, very similar to the one sold by scopestuff.com, but was lucky enough to get one of the 1980s originals. Actually two, one for my sandcast rear cell C8.

 

An alternative is to locate one of the half pound thread in weights that threads into the front cell, but they are very hard to find in the correct thread pitch. They are easy to locate in 1/4-20 because they are used in that format for camera rig balancing. Easy to buy on ebay. I haven't looked but I would assume that an adapter from 1/4-20 to whatever pitch is used on the front cell, possibly 8-32 should be easy enough to source.



#9 robodan

robodan

    Ranger 4

  • -----
  • Posts: 343
  • Joined: 04 Feb 2011

Posted 15 September 2020 - 05:20 AM

I remember seeing on you tube people taking the corrector plate off, but has to go back exactly. To do this you need to mark corrector plate and outer ring so you put it back in the same place.

#10 Traffalger1698

Traffalger1698

    Vostok 1

  • -----
  • topic starter
  • Posts: 105
  • Joined: 08 Apr 2019
  • Loc: Central Minnesota

Posted 15 September 2020 - 10:41 AM

Anything Nexstar is made a thousand times easier by going to Mike Swanson's website nexstarsite.com

 

And the books, one for early and one for late scopes, have probably 10 times as much information for everyday use.

 

This is the page for the GPS update version status

 

https://www.nexstars...GPSRollover.htm

 

The bottom of the next page has the information how to determine your version.

 

https://nexstarsite....GPSFirmware.htm

 

Mixed throughout are links to places to get the software and determine what cables you need for the update.

 

From here on you should be able to handle it yourself, using Mike's site, as long as you have motorboard versions 3.x or higher.

 

If you run into older motor control boards versions 1 or 2, may have some update issues, hopefully you will not end up in that situation period if you do, follow the links on Mike's site.

 

 

 

As far as the pictures are concerned, I'd clean out or surface, and not be in a rush to do it, and then rephotograph your corrector to see what's on the inside.

 

Again, I would not put the cleaning highest on the priority list, and would totally forget about the interior of the corrector plate for quite some time.

 

Your images will be better than you would think. I have a Meade 8 with one of their defective silver coated mirrors from 20 years ago, bought with knowledge of the defect for a trivial price, and it gives surprisingly usable images despite a secondary covered in splotches and what looks like bubbles. given the size of the secondary, that's causing a lot more impairment to the image than your corrector, likely by a factor of 1000. I'll get a recoded after I move, finally.

 

I would only be particularly concerned if you had sizable areas with smears of oil and grease, at least for now. even with all those specs, you're not going to see noticable impairment. when you're ready to go further, PM me and I'll send you some information on alignment checking and preserving alignment if it has never been disturbed.

 

It seems my handset is new enough to have a "version" menu on it.  I get 5 sets of numbers (2.2,4.5,4.5,2.2,2.2)  I do seem to have the bug where the onboard gps gives me a date of 2001 and an hour off of correct time.  I just turned that off and entered manual date and location.  

 

I cleaned off the outside of the corrector plate and it looks way better. I don't think I will tackle the inside fore the time being as long as I can get some good views.  I had to adjust the view finder so I could actually find things in the scope.  I seriously think I might need either  a right angle viewfinder or Telrad or something.  The straight through one kinda blows.  

 

I do not know if It was the smoke in the atmosphere or there was some clouds but I could not get anything to focus last night.  Jupiter and Mars were just were blobs and Vega while better I could not resolve to a nice sharp point.  Regarding focusing is the focuser supposed to feel almost "loose"?  Its not loose on the housing but turning it is VERY easy I guess I was expecting some more resistance.  



#11 Traffalger1698

Traffalger1698

    Vostok 1

  • -----
  • topic starter
  • Posts: 105
  • Joined: 08 Apr 2019
  • Loc: Central Minnesota

Posted 15 September 2020 - 10:43 AM

If your scope performs a GPS link and updates the time, date, and location correctly I would not touch it at all ... leave the firmware alone.  It would however been good to know the firmware levels as that will give you and idea of age and capabilities (so the appropriate manual can be used as a reference). Run the Version command (it's under the Utilities menu) and if there's no Version command present it will tell us about the scope too (the very earliest hand controller version)

 

It's battery (singular) as the GPS battery is the only chargeable device in the NS GPS scopes. 

 

One common thing to do with any older NS GPS scope is to clean the azimuth bearing surface, it attacks dirt and gets lumpy over time. While you are inside the base it might also be helpful to visually check the split ring power distribution to see if there are any excessively worn or burned (from arcing) areas (those would cause intermittent power resets).

 

When you are using the scope be gentle with the clutch levers, especially the altitude one as they can be broken and if that happens there are no replacements. 

No my scope does not show the correct date and time (shows me a 2001 date and the time is an hour in the past.  Do you know if there is any resources to show how to take off the housing to replace the battery.  I have a feeling mine is completely dead.  Left it on all day yesterday and each time i turn it on I have to reenter the info.  



#12 Procyon

Procyon

    Fly Me to the Moon

  • *****
  • Posts: 6,704
  • Joined: 23 Feb 2009
  • Loc: Eastern Canada

Posted 15 September 2020 - 06:57 PM

Some links you may find useful:

 

Manuals and Drivers:

 

https://www.celestro...anuals-software

 

Great dew shields and other accessories: (Regular Astrozaps are great)

 

https://starizona.co...sc&q=dew shield

 

Might want a simple dew heater strap at some point also.

 

I use this as a battery, works great for me... https://www.celestro...ank-lithium-pro

 

PS> Don't forget to add your location on the controller as well as switch to the appropriate daylight savings time option. 

 

Nice scope you got. 


Edited by Procyon, 15 September 2020 - 07:18 PM.

  • Traffalger1698 likes this

#13 markb

markb

    Apollo

  • *****
  • Posts: 1,086
  • Joined: 16 Jun 2006
  • Loc: Long Island; in transition to Arizona

Posted 15 September 2020 - 07:46 PM

Get a 4.x compatible HC, upgrade it to 4.22 and the GPS will work again. It looks like you have the 2.2 'north and level' firmware, and those controllers won't upgrade.

 

If you are getting a correct location and GPS lock, the hardware is okay. The battery takes a bit to recharge, and infrequent use causes slow locks anyway.

 

Don't think about a battery swap for a while, and it does require mechanical skill and care. My battery-less GPS board works okay with slow locks.

 

I would try collimation before exploring further (disassembled scopes often lose the factory 'rotational' alignment that should make the optical and mechanical axes align). A rotational alignment forum search when you get to that point will help.

 

For now, assume the scope still has the factory adjustments in place, and think about collimation.

 

Remember, atmospheric movements make many nights disappointing. Where I live, population density and geography usually give me poor atmospherics and poor images.

 

On collimation, I've tried lots of methods, but the most fool proof I've used is 

 

Start with a Robin Casady daytime collimation

 

http://www.robincasa...ro/collimation/

 

Then make and use a Duncan Mask

 

http://alpha-lyrae.c...-a-duncan-mask/

 

In daytime, using a 3/8" chrome ball bearing stuck to metal with a supermagent 150 or so feet away (closer should be okay if needed).

 

More details at 

https://www.cloudyni.../#entry10506704

 

I've wanted to try a Duncan for months, and today was my first try. 30 minute learning curve and success. Great night results, too. Despite the county-spanning smoke...


  • Traffalger1698 likes this

#14 Traffalger1698

Traffalger1698

    Vostok 1

  • -----
  • topic starter
  • Posts: 105
  • Joined: 08 Apr 2019
  • Loc: Central Minnesota

Posted 15 September 2020 - 09:04 PM

Get a 4.x compatible HC, upgrade it to 4.22 and the GPS will work again. It looks like you have the 2.2 'north and level' firmware, and those controllers won't upgrade.

 

If you are getting a correct location and GPS lock, the hardware is okay. The battery takes a bit to recharge, and infrequent use causes slow locks anyway.

 

Don't think about a battery swap for a while, and it does require mechanical skill and care. My battery-less GPS board works okay with slow locks.

 

I would try collimation before exploring further (disassembled scopes often lose the factory 'rotational' alignment that should make the optical and mechanical axes align). A rotational alignment forum search when you get to that point will help.

 

For now, assume the scope still has the factory adjustments in place, and think about collimation.

 

Remember, atmospheric movements make many nights disappointing. Where I live, population density and geography usually give me poor atmospherics and poor images.

 

On collimation, I've tried lots of methods, but the most fool proof I've used is 

 

Start with a Robin Casady daytime collimation

 

http://www.robincasa...ro/collimation/

 

Then make and use a Duncan Mask

 

http://alpha-lyrae.c...-a-duncan-mask/

 

In daytime, using a 3/8" chrome ball bearing stuck to metal with a supermagent 150 or so feet away (closer should be okay if needed).

 

More details at 

https://www.cloudyni.../#entry10506704

 

I've wanted to try a Duncan for months, and today was my first try. 30 minute learning curve and success. Great night results, too. Despite the county-spanning smoke...

Thanks for the info, Ill look into the duncan mask/colimation.  Appreciate the comments.



#15 mclewis1

mclewis1

    Thread Killer

  • *****
  • Posts: 20,468
  • Joined: 25 Feb 2006
  • Loc: New Brunswick, Canada

Posted 16 September 2020 - 11:59 AM

Personally with a 2.2/4.5 era scope (IMHO the best of the GPS series) I'd be tempted to leave it alone and continue to do the initial alignments with manually input data. It's getting quite difficult to find a v4 hand controller in good condition. Fortunately (so there are at least more choices) you can re flash any v4 hand controller from any type of scope with the correct NXS4.22 firmware. When you do this on an NS GPS scope you effectively turn it into a CPC scope (so no more Auto GPS alignment options, and instead SkyAlign is now available).

 

Markb - you seem to think that the split rings only supply power to that little 12v external connection. With a fixed position power connection on the base how do you think 12v power gets to all the boards and motors in the rest of the scope that rotate above that lower base? All the power for the scope goes through those split rings ... and because of that it's good to check them (although you can't do much other than clean up any little dirt or electrical arcing that might have occured). If in the worse case where these rings wear out the scope starts to exhibit all sorts of intermittent problems. 

 

This is one of the things they re designed (cost reduced) on the CPC series. There they got rid of the rings and put the power connection on the upper part of the base so CPC owners have to watch for cord wrap where the NS GPS owners don't/didn't.

 

You're right it isn't easy to get to all of the Azimuth bearing track but it's not a take everything apart process (more like a carefully move a few things). It's helpful for owners to take a look at this track and clean what they can. A lot of folks who complain about jumpy tracking find that removing the bits of sticky dirt on the track can really help smooth things out. And of course if a scope is already nice and smooth there's not really much point in messing with it.



#16 markb

markb

    Apollo

  • *****
  • Posts: 1,086
  • Joined: 16 Jun 2006
  • Loc: Long Island; in transition to Arizona

Posted 16 September 2020 - 01:01 PM

My point was that cleaning the azimuth bearing track is not trivial, and I have read reports of folks blowing out their scopes when they reverse the cheesy headers Celestron used instead of the proper keyed connectors they should have used. Let alone the possibility of static damage when handling the electronics, and the tools needed.

 

Great tip to share that azimuth roughness or jumping can be cured by a good cleaning.

 

No problem for you, no problem for me, but many folks should think twice and review available videos and written documentation before attempting a major scope disassembly.

 

I'm glad Celestron has been addressing many of the quirks in the design, even if many of us would have made a different choice than the ones they made, such as on the slip rings.

 

One that popped up recently was that they finally got around to making cast cutouts for the locating ovals for the base attachment pads, eliminating most of the need for a Starizona landing pad, although tactile centering cues seem to be desired by some.

 

The following is for a reader of the thread that might be interested in swapping tripods.

 

Incidentally, the pad locations with respect to the center point on the limited number of nextstar variations I've handled are identical, but Celestron uses two different locations for drilling the threaded holes for attachment, one inboard, one outboard, so my nexstar 8 cannot be bolted down to the GPS 11 tripod. Also, the center pin is a slightly different diameter.

 

To allow use of the 8 on the GPS 11 tripod, there was enough metal present to let me drill out the center hole on the 8 th to fit over the center pin on the 11 tripod, and I will come after I complete my move, drill and tap new holes on the 8 base to allow it to be bolted down onto the 11 tripod.

 

Yes , of course the slip ring supplies power power to the electronics, and are rated for an additional half amp or more for accessories. But the internal boards themselves are unlikely to cause track burning, I would think.

 

I have not read of burning of the tracks unless power hungry accessories were plugged into the 12 volt accessory port, or the scope was powered through the 12 volt accessory port, but I'm sure it is possible.

 

The problem I have read about, however, is that the tracks can wear through with heavy use. I don't think Celestron still has that part available but I'm not sure. I had assumed that I would make a replacement track or track board if it came to it, although I don't use my scopes heavily enough to worry about it.

 

On the hand controller availability issue, I haven't seen any real issues in getting good condition 4.x controllers, ended up with five or six when I was going through my early GPS11 update and second GPS 11 purchase, the former which for some reason, required physical replacement of the motor board chips instead of programming by header and programmer.

 

Unlike the Meade Autostars, the Celestron units seem much more durable electronically, with the exception of the display ribbon wire issue, itself normally curable.

 

I'd still take a 4.x or Plus controller with the GPS rollover fix over using my 2.2 hand controller (which I kept).

 

I miss the cute North and level sequence though.



#17 Orion68

Orion68

    Ranger 4

  • *****
  • Posts: 396
  • Joined: 18 Jan 2014

Posted 16 September 2020 - 05:14 PM

Wondering now if I missed cleaning part of the RA track in my NS11 GPS.

I dont recall having to move any boards or cables except the two prong cable that goes to the top of the slip ring.

After raising the base cover, I just rotated the scope enough to get at all parts of the track. It helps to have nimble fingers!

#18 markb

markb

    Apollo

  • *****
  • Posts: 1,086
  • Joined: 16 Jun 2006
  • Loc: Long Island; in transition to Arizona

Posted 16 September 2020 - 06:03 PM

Orion68, thanks for that addition.

 

I had my GPS 11 completely disassembled two years ago, and thought I recalled the track being partially accessible, but didn't mention it because I really wasn't sure. And I have no great desire to pull the covers off to check!

 

If anyone does feel the need to disconnect the blue connectors on these older GPS scopes, plan in advance to be able to clearly mark them, preferably with distinctive colors for each connector, particularly noting polarity, in other words, that the same end of the two parts of the connector will rejoin on reassembly.



#19 mclewis1

mclewis1

    Thread Killer

  • *****
  • Posts: 20,468
  • Joined: 25 Feb 2006
  • Loc: New Brunswick, Canada

Posted 16 September 2020 - 08:10 PM

Markb, I do agree with your points in your post above ... and yeah it sure is a personal thing about the preference for v2 or v4 firmware. 

 

I have seen slip rings with what appears to be arcing, no not a common problem for sure but it did seem to occur. It might have been caused or triggered by dirt or debris getting in between the tracks, I'm not sure. I've also seen slip rings that appear pristine after many many years of use ... so go figure. None of this was much of an issue for quite a long time, but now that some folks are re discovering the GPS scopes and some very old scopes are being put back into operation I think keeping an eye on the slip rings makes some sense.

 

What Orion has mentioned is certainly true, you do really need to have nimble fingers to get to the whole track, and if you don't moving the boards a bit helps. But the biggest step is to be able to move the top cover back as far as possible and that requires pulling that little power connector on the wires that go into the top of the slip rings.



#20 Traffalger1698

Traffalger1698

    Vostok 1

  • -----
  • topic starter
  • Posts: 105
  • Joined: 08 Apr 2019
  • Loc: Central Minnesota

Posted 16 September 2020 - 10:01 PM

OK you guys are speaking way over my head.  I know I'll get there sometime but I will stick with making sure it is colimated for the time being.  That and I think I will have to read over some of these comments a number of times along with research for some things to make some sense.  :)

 

 

I was able to take the scope out tonight and what a difference!  After getting things roughly aligned (work in progress I'm new at this) The air was significantly more clear and I got some decent views all around.   I mainly used the 4.7mm and 6.7mm deg eyepieces with my Z130 tonight however I favored my ES 8.8mm and 32mm meade.  Taking a break until Mars, M31 and M45 rise a little bit higher in the sky.  

 

Thanks to everyone so far who has commented its very appreciated.  


  • Procyon likes this

#21 Michael_Swanson

Michael_Swanson

    Author of The NexStar Users Guide

  • *****
  • Vendors
  • Posts: 3,191
  • Joined: 23 Apr 2003

Posted 21 September 2020 - 09:15 PM

Regarding cleaning the azimuth bearing track, on this page of my website:

https://www.nexstars...OddsEndsGPS.htm

see the article "NexStar GPS Azimuth Motion Rough - Cleaning the Roller Bearings".  It is actually a very simple process.

 

Best regards,
Mike Swanson
https://www.NexStarSite.com


  • Traffalger1698 likes this

#22 Traffalger1698

Traffalger1698

    Vostok 1

  • -----
  • topic starter
  • Posts: 105
  • Joined: 08 Apr 2019
  • Loc: Central Minnesota

Posted Yesterday, 08:38 AM

Get a 4.x compatible HC, upgrade it to 4.22 and the GPS will work again. It looks like you have the 2.2 'north and level' firmware, and those controllers won't upgrade.

 

If you are getting a correct location and GPS lock, the hardware is okay. The battery takes a bit to recharge, and infrequent use causes slow locks anyway.

 

Don't think about a battery swap for a while, and it does require mechanical skill and care. My battery-less GPS board works okay with slow locks.

 

I would try collimation before exploring further (disassembled scopes often lose the factory 'rotational' alignment that should make the optical and mechanical axes align). A rotational alignment forum search when you get to that point will help.

 

For now, assume the scope still has the factory adjustments in place, and think about collimation.

 

Remember, atmospheric movements make many nights disappointing. Where I live, population density and geography usually give me poor atmospherics and poor images.

 

On collimation, I've tried lots of methods, but the most fool proof I've used is 

 

Start with a Robin Casady daytime collimation

 

http://www.robincasa...ro/collimation/

 

Then make and use a Duncan Mask

 

http://alpha-lyrae.c...-a-duncan-mask/

 

In daytime, using a 3/8" chrome ball bearing stuck to metal with a supermagent 150 or so feet away (closer should be okay if needed).

 

More details at 

https://www.cloudyni.../#entry10506704

 

I've wanted to try a Duncan for months, and today was my first try. 30 minute learning curve and success. Great night results, too. Despite the county-spanning smoke...

I was able to get a V4 4.21 fw handset. (not sure what scope it came from) I am however having trouble figuring out what adapter to get to be able to plug it into my computer do you have any info on what to look for?  

 

Edit: Nevermind I found one on amazon.  just need the serial to usb adapter now.  


Edited by Traffalger1698, Yesterday, 08:44 AM.



CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics