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Does Starsense help with tracking

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#1 Joey44

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Posted 22 January 2020 - 09:49 AM

I an a relatively new user of a Nexstar 6SE  in alt/az mode and have spent some time practicing with 2 star alignments visually for planets, clusters, and am just getting into some of the easier DSOs. I have used Michael Swanson’s advice from his excellent User’s Guide and calibrated my go-to, adjusted backlash settings, and understand which buttons to use for final movement settings to facilitate best tracking. Basically, as far as I can determine, I have done everything that I know to do to maximize this scope’s alignment and tracking.

In spite of this, I find that with medium to higher power eyepieces after alignment I usually will find that a new go-to object is not centered, requiring some fine-tuning of position with the hand controller. Also, some drift from the field of view will occur after tracking for a few minutes. Maybe this is normal; I know that this scope does not have the most accurate gearing that more expensive models use.

I have considered getting a Starsense, but would not want to spend the extra $ unless it not only made alignment easier, but also helped some with tracking accuracy. I understand from reading Michael’s description that Starsense allows adding up to 10 alignment points, as opposed to only 2 alignment points with my hand controller. What is not clear to me is whether this would make tracking more accurate. I would appreciate any advice from those with Starsense experience, and especially an opinion about whether in my situation tracking would be expected to improve.



#2 Noah4x4

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Posted 22 January 2020 - 10:49 AM

Starsense makes alignment easier and if properly calibrated will place an object dead centre in an eyepiece or camera.  However, it will not necessarily improve tracking thereafter. That depends on the quality of your mount and its motors etc. Starsense has no function other than alignment. 

 

What I discovered though was what I thought was the centre of my eyepiece during an alignment wasn't. You might benefit from an illuminated cross hair reticle eyepiece, or simply defocus until you see a big donut rather than a star. It is easier to centre that compared to a tiny star. 


Edited by Noah4x4, 22 January 2020 - 10:52 AM.

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#3 aa6ww

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Posted 22 January 2020 - 11:24 AM

Leveling your tripod and Polar alignment seems to be what makes a mount track efficiently provide the tracking speed is set to whatever objects you are observing.
Starsense will help tracking if you cant do a manual polar alignment and instead, rely on Starsense to put in an offset from true polar alignment by performing the All Star Polar Alignment.

I have starsense and can not believe how accurate and easy it is to use. I would highly recommend getting the GPS unit also. This would then become a fully automatic system where you wont have to input any info about your locations, time etc. Basically turn it on and perform the Auto align. After about 4 minutes, its done.
If you have to calibrate StarSense to the OTA, then that's a one star calibration you would have to do.
After a bright known stars is selected, you are asked to center the star in the eyepiece using the hand controller, then the offset to OTA is calculated and your scope becomes deadly accurate.

There's a small learning curve but its well worth is.

Good luck.

Ralph in Sac.

Edited by aa6ww, 22 January 2020 - 11:25 AM.

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#4 Joey44

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Posted 22 January 2020 - 01:04 PM

Leveling your tripod and Polar alignment seems to be what makes a mount track efficiently provide the tracking speed is set to whatever objects you are observing.
Starsense will help tracking if you cant do a manual polar alignment and instead, rely on Starsense to put in an offset from true polar alignment by performing the All Star Polar Alignment.

I have starsense and can not believe how accurate and easy it is to use. I would highly recommend getting the GPS unit also. This would then become a fully automatic system where you wont have to input any info about your locations, time etc. Basically turn it on and perform the Auto align. After about 4 minutes, its done.
If you have to calibrate StarSense to the OTA, then that's a one star calibration you would have to do.
After a bright known stars is selected, you are asked to center the star in the eyepiece using the hand controller, then the offset to OTA is calculated and your scope becomes deadly accurate.

There's a small learning curve but its well worth is.

Good luck.

Ralph in Sac.

Thanks for the feedback, but I don't have a wedge or a view of Polaris so I am stuck with alt/az.  I gather from these comments that Starsense would not be a benefit for me as far as tracking. But how about just alignment? Would I get a better view in the eyepiece with initial go-to, in other words be less likely to have to fine-tune with the direction arrows on the hand controller.



#5 Freighter109

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Posted 22 January 2020 - 01:59 PM

Thanks for the feedback, but I don't have a wedge or a view of Polaris so I am stuck with alt/az.  I gather from these comments that Starsense would not be a benefit for me as far as tracking. But how about just alignment? Would I get a better view in the eyepiece with initial go-to, in other words be less likely to have to fine-tune with the direction arrows on the hand controller.

Just my two pennies about StarSense. I got it not to long ago for my 6se. I didn't need it, but got it just because fancy tech and a little liquid encouragement. I was using SkyAlign and usually could align on 3 objects in less than two minutes with my Telrad. StarSense on my 6se has me aligned in about 70 seconds. I don't use the hand control, but rather an old iPhone and SkyPortal. So time/date/GPS comes from the phone and I have to input no data. I connect and tell it to align. I don't have any issues tracking, but I can't say that's due to StarSense, as I never had tracking issues before.


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#6 outofsight

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Posted 22 January 2020 - 04:01 PM

"I have considered getting a Starsense, but would not want to spend the extra $ unless it not only made alignment easier, but also helped some with tracking accuracy.

 

I would appreciate any advice from those with Starsense experience, and especially an opinion about whether in my situation tracking would be expected to improve."

 

StarSense (SS), essentially, has nothing to do with tracking, but I suppose it could be perceived to help if it was aligning more exactly than you are. All SS does is align your scope, after the alignment is complete, it doesn't provide information to tracking or aid in tracking. Though it is possible to keep adding stars for better alignment, I'm pretty sure that's possible with your current setup.

 

If your mount was tracking properly, once you went to an object and centered it, that object, in general, should stay centered for a long time. Some objects will stay centered longer than others, for whatever reason, so you should have, by now, run across an object that would stay centered for a fairly long time.

 

The only thing I can add is that you might try a reticle eyepiece to help with exact alignment, and possibly undo your backlash settings, essentially start from scratch, and very carefully read your manual for alignment tips. Like page 16 for Improving Pointing Accuracy. SS is not the answer to tracking.

 

https://celestron-si...3 languages.pdf

 

Keep messing with it and try to narrow it down. For alignment start with a lower power eyepiece and increase to a higher power EP. Read those pages of the manual carefully and try to practice them. You have a fairly narrow field of view scope so tracking problems will quickly get out of control with greater magnification. Try to work with it, and if you can't get it solved and it's still under warranty then contact Celestron.

 

One more thing. What's your power supply, these things are notorious for performing poorly with less than adequate power supplies?



#7 outofsight

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Posted 22 January 2020 - 04:16 PM

"In spite of this, I find that with medium to higher power eyepieces after alignment I usually will find that a new go-to object is not centered, requiring some fine-tuning of position with the hand controller."

 

A couple of alignment tips I just thought of. You say that medium to higher power EPs are more troublesome after alignment, that would be expected, if your initial alignment was with a lower power EP and the alignment wasn't spot on to start with, remember, your scope has a narrow field of view. 

 

So end your alignment with as powerful EP as you will probably use for viewing. Things may drift too fast for you to center a powerful EP, do the best you can. And when you begin your alignment, use a lower power EP and defocus the star, make the star like a round shaped donut and that should aid in your initial centering.

 

Keep at it, it actually sounds like it is working (since it is tracking at all) and that possibly your alignment technique needs refining. Easier said than done. Take as much time as you need to center that star, also easier said than done. Good luck with it.



#8 mikenoname

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Posted 22 January 2020 - 04:43 PM

StarSense not only automates your alignment, but also makes it much more precise, especially if you add two or three additional alignment points to the initial three that it will automatically get. The easiest way to do that is to do a manual StarSense alignment choosing five or six points around your sky and save it as a user auto alignment and then use that user auto alignment every time you align in the future.

 

Generally speaking, the more alignment points you add to your alignment procedure, the more accurate the resulting alignment map is that your scope operates from, and therefore, the more accurate your GOTO's should be. With the regular hand controller you can never have more than two stars as part of your alignment. StarSense allows you to have as many as 10.

 

While it is true that StarSense is not concerned with tracking accuracy, it is true that your tracking accuracy is directly

proportional to the accuracy of your alignment. So it will help at least a little.

 

However, with that said, if your primary purpose for acquiring StarSense is not making your set up a lot easier, it probably isn't worth the expense.



#9 Michael Harris

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Posted 22 January 2020 - 10:13 PM

With the StarSense, be sure you are thinking about the correct terms. The “alignment” that StarSense performs with it’s plate solving capabilities is the mathematical corrections that allow the mount computer to calculate the positions of celestial bodies at your specific date and time, and convert them to motor pulses to point the scope where you want it to go. The SS does this by assuming a level starting position or “home” position, then builds the model by taking three brief images of your sky and solving the star pattern, therefore determining the center point of each image. As you pointed out, the SS then allows you to refine the model by adding more points.

 

All this math will get you improved pointing accuracy for the rest of the evening, so most of the targets you are hunting are within at least a low power field and sometimes better. But once this process is complete, the SS is done for the evening. It does not involve itself in the tracking process and does not find objects for you by active plate solving. After you are happy with your alignment you might as well turn it off. And if you move your scope from place to place the process has to be repeated. To get you going, the SS is great.



#10 Joey44

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Posted 24 January 2020 - 07:57 AM

Thanks to all who have weighed in; I understand the very good points about better alignment related to more alignment points and the theoretical improvement in tracking that might occur This has been very helpful. My problem now is deciding whether Starsense would be useful because I don't have a good view of the entire sky due to some trees and other obstructions. I am not sure that I would be able to get enough sky views to 5 or 6 more alignment points. Especially if an alignment point needs to be more than just a star-for example if a 20 or 30 degree sky view were needed for each alignment that would be more like a plate solving map and these needed to be spaced wide apart then this might be an issue for me.  If anybody has a good feel for how this works I would appreciate some feedback.



#11 dcollier

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Posted 24 January 2020 - 09:41 AM

SS is specially good in situation like yours.  To add extra points  just point it to open areas in the sky to take an image select Add Align Ref.   It does not have to be pointing at a star or anything in particular.  Adding 1 or 2 more on each side of meridian will greatly improve the pointing model.  If later you completely miss a target, then select Add Align Ref and add another point  and perform a goto again.  Your target should be in view at this point. 

 

                 -Dave 



#12 deansjc

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Posted 24 January 2020 - 10:06 AM

I agree with Dave.  SS is very capable of solving for an accurate alignment even if much - in my case most - of the sky is obscured by a house and a large tree.  Imaging both sides of the meridian seems to be key.  If you set up in the same place frequently, use the ability of SS to recall where you pointed to achieve the alignment.  This is a major time saver.

 

I use SS to do an equatorial alignment for my 8SE and Skywatcher 72ED including an ASPA.  Rather than an eyepiece, I often have my DSLR mounted (Nikon D5300).  Being able to see the star being used for ASPA in the camera's viewfinder (it swivels) is very useful.

 

Just be sure to have as precise of an alignment start position, doing either an EQ or Alt-Az alignment.  I have yet to not see my ASPA alignment star in the DSLR field of view.



#13 mclewis1

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Posted 24 January 2020 - 02:54 PM

Joey,

 

Good, so now you understand the general relationship between the quality of your initial alignments and the ongoing tracking accuracy of your alt az mount. You should also notice that your tracking accuracy will change in different areas of the sky.

 

As Noah mentioned early on there is also the question of how mechanically accurate your particular mount actually is. 

 

So the answer to your question will depend on how well you did your initial alignments before SS (or how much of an improvement in just the pointing accuracy SS will provide) and how good an example of an SE mount you have. 

 

I believe you'll see an obvious improvement with SS, but how effective an improvement that is vs. the price of the SS is still going to be an open question that only you will be able to answer.


Edited by mclewis1, 24 January 2020 - 02:55 PM.


#14 mikenoname

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Posted 24 January 2020 - 10:40 PM

Thanks to all who have weighed in; I understand the very good points about better alignment related to more alignment points and the theoretical improvement in tracking that might occur This has been very helpful. My problem now is deciding whether Starsense would be useful because I don't have a good view of the entire sky due to some trees and other obstructions. I am not sure that I would be able to get enough sky views to 5 or 6 more alignment points. Especially if an alignment point needs to be more than just a star-for example if a 20 or 30 degree sky view were needed for each alignment that would be more like a plate solving map and these needed to be spaced wide apart then this might be an issue for me.  If anybody has a good feel for how this works I would appreciate some feedback.

It looks like a couple of the guys above have answered your question in terms of StarSense being very good in the obstructed situation that you are in, but didn't really go into how it is accomplished.

 

StarSense has a few different alignment modes. The first one is a fully automated alignment that basically points itself to three or four different locations in the sky, takes an image and creates alignment map from it. Another alignment protocol is a manual StarSense alignment where you actually point the scope, using the arrow keys on the hand controller, to points in the sky and then tell it to take the image. A third protocol is called a user auto align which is something you set up yourself using the manual alignment method. It goes like this:

 

The first time you set it up and use it in your yard, you will select a manual StarSense alignment, pointing your scope at three or more points in your obstructed sky where you can see through the obstacles, which will have StarSense taking pictures in each of those locations. Then you will save that alignment session as a user auto align protocol.

 

Then, every time you come out with your scope, you just point it in the same direction that you started in when you did the manual alignment, select the user auto align protocol, hit go, and the scope will automatically move to those same points and take the pictures, bypassing all of your obstacles.

 

It's easier done than said, but hopefully that came out clear.


Edited by mikenoname, 24 January 2020 - 10:41 PM.


#15 dcollier

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Posted 26 January 2020 - 01:49 PM

How it is accomplished:  1. Do a manual Starsense align.  2. Select your points to be 50/50 on either side of the meridian if at all possiable.  3. You do not have to point at anything in particular.  4.  Save Your manual alignment using the following sequence:  STARSENSE  Scroll to select USER AUTO ALIGN and press ENTER and Press ENTER again to save.  5. Add a couple of more points 50/50 on either side of the meridian. Try not to make them repeats of your initial points. Hope this helps. Works like a champ for me.

 

                    -Dave




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