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Autoguiding with the Nexstar 5SE & 6SE

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#1 PaPa Doc

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Posted 06 April 2014 - 03:55 AM

I have two Nexstar SE scopes, a 5 inch & 6 inch. I use the 6" on the wedge base. I use a digital spirit level to set the wedge to match location & polar alignment instructions.

My main question; Does anyone know much about autoguiding with the SE series. Can I compensate for the inherent gear problems? I'm using an Orion 50mm mini & have a short tube 80 available, but I think that is too big for any SE. I'm not looking for super long exposures maybe 1-3 minutes rather than the 30-45 seconds max, not guiding. Is it realistic or am I wasting time?

I have other uses for the guide-scopes, they won't go unused. I'm also using the Canon 60Da. I want to photo-hunt a few Neb's I've seen as ghostly apparitions in the night's sky.

Any & all thoughts, feelings & opinions from those in the know is greatly appreciated. Links to prior posts greatly appreciated as well.

Clear Skies & Clean Lens. :rainbow:

#2 Tel

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Posted 06 April 2014 - 06:02 AM

Hi PaPaDoc,

Welcome to CN and to this Nexstar forum ! :bow::bow::bow:

I can't help you directly with regard to autoguiding an 8SE on a wedge, but the following archived thread may go some way towards helping you in the set up to produce longer imaging exposures.

http://www.cloudynig...d=nexstar&am...

Hoping this helps a little,

Best regards,
Tel

#3 Midnight Dan

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Posted 06 April 2014 - 09:06 AM

Hi Papa Doc:

Since you already have the autoguider, I'd say go for it! I agree that the 50mm miniguider is the one to use. You really want to avoid adding too much weight.

Several years ago, there was a thread here by Lord Beowulf (I think) entitled something like, "Autoguiding, it does work!" where he added an ST80 to his 8SE and used it for autoguiding. The miniguider was not available at the time. However, he went to great lengths to mount things in such a way as to balance it well and not put too much torque on the fork arm bearings. In spite of the title of this lengthy thread, towards the end he began to conclude that it still was too much weight for the mount, and that autoguiding with the SE mount was a bit of an exercise in frustration. Bottom line, you can get it to work ... sometimes ... and to some degree. But it will never be a german equatorial mount.

Again, since you already have the guider, why not?

-Dan

#4 jeffpkamp

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Posted 08 April 2014 - 04:45 PM

I use the 6se on a wedge with the SSAG. A few things I ran into when first doing this was a problem with my auto guide port. I would use a computer with something like PHD and a serial to hand controller for guiding. Second, it's super important to get things balanced, otherwise auto guiding is difficult. I built a ron's rail out of wood because the balance point with all the AP gear was behind the end of the rail.

When it comes to dealing with the exorbitant amounts of backlash in the DEC gears (I have no problems with the RA gears) I find that you need to use big steps in the calibration mode, otherwise PHD thinks there is no DEC control and only guide in RA. Also once calabrated, I find it helpful to run out the backlash by hand once I know what direction I am correcting for (ie if the scope is drifting north, I run out the backlash using the hand controller, then start guiding).

let me know if you have any other questions.

#5 Amith

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Posted 10 April 2014 - 02:53 AM

Hi Jeffkamp,

I am having issues with my guiding.. I know its probably to do with backlash but in all honesty as much as Tel explained it to me.. I think I am as brainless as can be when it concerns backlash settings.

I am thinking that I need to go back and mount the scope in alt az then sort out the backlash (if I ever figure it out) and then put it back onto the wedge.

My problem is that I dont understand what the positive and negative backlash settings do (and I am someone that needs to know this before I can interfere) and which direction each affects. I dont think I have ever had a problem with the azimuth tracking misbehaving. If I can get this rectified then maybe I will be able to put the autoguider back onto the scope and take it from there.

This is the link to my original query regarding guiding ( http://www.cloudynig...rd=nexstar&a... )but I think that I need to learn about backlash first. Any help is welcome (bear in mind I need this explained as though I am dumb as they come). Also, I am based in the Southern Hemisphere.

Clear Skies,
Amith.

#6 Tel

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Posted 10 April 2014 - 05:54 AM

Hi Amith,

I don't want to pre-empty any question you've directed at Jeff because he obviously has a lot more experience than I when it comes to mounting SEs on a wedges; (I failed miserably when I set mine up back in '06 or '07) !

What I would suggest though, is that I'd personally carry out any backlash adjustment with the 'scope still mounted on the wedge and tracking: tracking or not, when adjusting backlash, being a moot point of late.

I just feel that all else aside, the 'scope will inevitably be mounted on the wedge and be tracking once aligned and therefore, logically, settings should be made and attuned to its practical use and circumstances.

Best regards,
Tel

#7 Tel

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Posted 10 April 2014 - 06:17 AM

By the way, Amith, have you investigated the claims that both Craig Stark's "Nebulosity" software package and the freeware "Deep Sky Stacker" claim to be able to de-rotate Alt./Az. produced images ?

I don't know how far this extends, (limiting exposure times ?), but might it be worth investigating ?

Anyone know any more ?

Best regards,
Tel

#8 jeffpkamp

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Posted 10 April 2014 - 10:14 AM

Hey Amith, I have my backlash settings at 0 and 0 when guiding. When you think about backlash, all it is is space between the gear teeth in which they turn but no movement happens because they are not engaged with each other. For guiding with the SE which has a lot in the DEC gears (like I said, I don't see any in my RA gears), you need to run out the backlash in the north direction (I believe this is down on the hand controller) before you start calibrating on PHD if you are using that software (If not let us know). This is because the calibration steps start E,W,N,S. The South calibration isn't actually needed as it just uses the size of the steps of the North calibration to calibrate with.

Once calibrated, if you shut the guiding off (Disable guide output in the brain menu of PHD) you notice a specific drift for the Declination, indicating imperfect polar alignment, as long as your close this is fine and benefical for guiding with the SE. Figure out what direction the scope is trying to guide in, it will say this at th bottom something like "north, .3 seconds". Use this to guide you in what direction to run the backlash out with on the hand controler, ie push the down button on a low rate setting until the stars start moving in the PHD window. Then turn on guiding, select your star and you should be ready to go.

Like I said, all of this is for naught if you don't' have a well balanced scope, so make sure you get things balanced.

#9 Amith

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Posted 11 April 2014 - 02:12 AM

Hey Tel/Jeffpkamp,

Sorry Tel but I didnt intend to direct the question to just one person so I must apologise for that firstly.

@Tel, I will definitely take your advise and adjust while mounted on the wedge. Regarding the software, I have only used DSS and in all honesty, I do not know 3/4 of the features in it. I still dont know how to get darks, flats and lights. I will do some research and get back to you on that.

@Jeffpkamp, As much as Tel explained to me about backlash settings I still cant figure it out (and believe me he has explained it nicely because others got it). I think that I literally need to be shown what to do in order to get it right. I have balanced the scope previously but another one is required because of the added weight from the guidescope and camera. I have a longer vixen dovetail that I need to add on. I am not using phd as the nexguide connects directly to the autoguide port on the mount.

Maybe I will add on the new dovetail first to balance the scope then take the next step with backlash settings. If either one of you could help me with that when the time comes I would greatly appreciate it, or anyone that can help for that matter (provided you have allot of patience to deal with me haha).

Clear Skies,
Amith

#10 jeffpkamp

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Posted 11 April 2014 - 10:47 AM

it's no problem. It can be a little frustrating (okay really frustrating) working with the SE mount sometimes.

Honestly, I don't think you need to worry about backlash settings. Those are really made for when you are using the hand controller for visual observing. Like I said in my earlier post, "Backlash" is just play in the gear, which means after you run it in one direction, if you try to switch directions, it will take a little bit of gear movement before the scope actually starts moving, something you won't truely notice above a slew rate of 7. All the backlash settings do is automatically run the motor in the opposite direction quickly to make it so you can switch directions without waiting for a long time. It's not terribly important, just a convenience thing. For autoguiding, it will have no true value.

I haven't worked with the nexguide, so I don't know all it's little quirks or even what it looks like when it runs, but like I said in my first post, the very first thing you should do it hook it up to your scope via the auotguide port and make sure that you can move it with its manual commands, because for somereason my autoguide port was broken, which made me very very confused when I first tried using my SSAG.

So before you do anything, plug it in, put it in preview mode, and make sure it moves the scope like it's suppose to. Then get your scope balanced, take it out, and if you run into problems let us know :) Hopefully you won't.

As for what tel said, you DSS rotates pictures to align them, but once the stars star twirling in the actual frame, there's nothing to do but put your scope on a wedge. I actually did see orion had something that rotates your camera so you could use an ALT/AZ scope, but that's probably more expensive than the wedge :).

#11 PaPa Doc

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Posted 17 April 2014 - 06:44 AM

Thank You to all who commented.

I appreciate the knowledge gained, the useful links & the useful comments. Once I have it all set up & tested, I pop back & let you know how things went.

Until then, Cheers!

#12 mudhwk

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Posted 07 June 2014 - 04:31 PM

I'm a bit late to the party, but I can vouch for the fact that it's indeed possible to autoguide with a Nexstar-5se using Nexremote, Ascom and PHD. (For a wedge, I used the tripod's "tilt" mechanism.

In my case, I used the 5-se itself as a guidescope, and was taking photos through a piggyback camera, so I don't have any experience taking pictures THROUGH the scope with this configuration, but it stayed locked on a star for several hours once I got it all set up and tracking...

I think the Nexstar-6 base has an ST-4 port, which makes it substantially easier.

It takes a bit of doing, but indeed it can be made to work.

--al

#13 frankroshi

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Posted 17 July 2015 - 09:10 AM

I'm a bit late to the party, but I can vouch for the fact that it's indeed possible to autoguide with a Nexstar-5se using Nexremote, Ascom and PHD. (For a wedge, I used the tripod's "tilt" mechanism.

In my case, I used the 5-se itself as a guidescope, and was taking photos through a piggyback camera, so I don't have any experience taking pictures THROUGH the scope with this configuration, but it stayed locked on a star for several hours once I got it all set up and tracking...

I think the Nexstar-6 base has an ST-4 port, which makes it substantially easier.

It takes a bit of doing, but indeed it can be made to work.

--al

Hi, Al,

 

Your post speaks to exactly what I'm looking for. Can you point me to the information/directions/instructions/howtos for autoguiding the NexStar 5SE?

 

Frank

 

Celestron NexStar 5SE

Celestron NexImage 5

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