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Starsense Explorer

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#1 davidparks

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Posted 07 January 2020 - 12:57 PM

Looks like a nicely integrated product for visual observers:  Live plate-solving via your smartphone.

 

https://www.youtube....h?v=3Hb0x-IdeDs

 

https://www.youtube....h?v=aD2_F89Qjkw

 

It appears to be a Starsense camera and technology connected directly to smartphone for a user interface.  Celestron has it mounted to several telescope models.  I wonder if they will offer the device as a stand alone product in the future, for your existing equipment and mounting imaginations...


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#2 cmooney91

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Posted 07 January 2020 - 01:36 PM

Is it just a right angle mirror using the phones camera?

If so it might not work with every phone's camera depending on low light performance.

 

It is still pretty neat if it works. 

 

It would be cool to put the phone in an enlarged telrad body with a collimating lens and plate glass beam spliter to have a  real time HUD overlay on the sky. 


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#3 eros312

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Posted 07 January 2020 - 01:37 PM

It looks like it uses your phone camera to plate solve. I wonder how well that's going to work?



#4 outofsight

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Posted 07 January 2020 - 04:42 PM

It looks like it uses your phone camera to plate solve. I wonder how well that's going to work?

Yeah, it took me a while to figure it out, because the phone's camera isn't pointing at the sky. It looks like it just sits in its cradle and the phone's camera uses a mirror to see the sky, and then it plate solves, as you said. It's all in the app, and how well the phone holder lines up with the scope.

 

Thanks for the post davidparks. It will be very interesting to see how well this works with a bunch of real world users. This could make a big difference for people who want to get into this and have some fun.

 

If it works as well as the videos show, it might be the lowest cost fun anyone's ever had with a scope and a phone. Very cool, I hope.


Edited by outofsight, 07 January 2020 - 04:46 PM.


#5 Michael_Swanson

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Posted 07 January 2020 - 08:32 PM

It does look pretty cool and hopefully works as well as the demo.  Should be much easier for beginners than the typical alignment process.  StarSense (the hand control and camera) are of course pretty much automatic but pretty expensive. 

 

When you download the app, it checks if your phone is currently compatible.  Then it asks for an unlock code that gets tied to your email address.  The code is included in the package with the Celestron StarSense Explorer telescope.  

 

The main drawbacks seems to be phone compatibility (fairly limited) and no tracking.

 

It seems to be built on Simulation Curriculum's base SkySafari product.  It would be cool if they release a generic system that can be bolted onto pretty much any scope.  Celestron is monetizing it via purchase of the scopes; Simulation Curriculum could monetize with the sale of the app and the smartphone mount/mirror.

 

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


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#6 Don W

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Posted 07 January 2020 - 08:57 PM

I can see it near the eyepiece of a dob!!


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#7 Michael_Swanson

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Posted 07 January 2020 - 09:28 PM

I can see it near the eyepiece of a dob!!

Exactly - smooth replacement for star-hopping.  We might even see Celestron get into the sale of Dobs.


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#8 halx

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Posted 08 January 2020 - 12:19 PM

Yep, recent phone cameras and processing power advancements makes such a thing finally possible. I can confirm that with just 10 sec exposure I can stack my 4 years old Galaxy N7's images to reliably resolve even 9.5m stars.

 

Don't be fooled with the cheap price though, a capable smartphone, which is the most essential part of the system, would cost you quite a bit (all the way to over a grand).

 

The performance is also quite questionable given the diversity of smartphone cameras' focal rates and sensors density. But I think it should be on par with manual settings circles. From the video I can catch that they are using plate solving only on the initial and final stages, while in between they are using gyros/accelerometers.

 

Finally, the alignment procedure should exist as you need to figure how the phone camera is aligned with the optical axis. Most likely that's a 2 stars alignment procedure as the phone cradle looks quite generic and sorta flymsy, so it cannot reproduce or hold the alignment between phone re-insertions. But that could be within tolerances the app is aware off (but still that would affect the accuracy without the alignment).

 

The better but more expensive approach would bo to make individual/modular cradles for various phone models. That's also not ideal, as many folks using their phones in the field in protective sleeves already.

 

Fortunately, the Celestron construction is super cheap and overly trivial. So the potential for DIY improvements to the system is enormous (you can replace everything to your own design, including changing the mounting location). I have no doubt that the open source software (free of charge) doing the same solving is on the way as well (as luckily there is nothing to patent here except maybe that flymsy cradle grin.gif).

 

So, folks, it's time to upgrade your smartphones. I would highly recommend Android smartphones as they are the easiest for DIY modding. Stay away from tablets, it will be hard to mount them on smaller OTAs.

 

Regarding mating with the Telrad: not necessary, just get cheap +3.0 reading glasses with widest rimless lenses and remove one of them. I'm using that with my smartphone sometimes for like 5 years already. One eye looks into the EP, another to the star chart on the phone screen (that's not for pointing, but for ID/starhopping).


Edited by halx, 08 January 2020 - 01:14 PM.


#9 Dave Bush

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Posted 08 January 2020 - 12:49 PM

I'm wondering if this thing, the whole bracket/mirror assembly could be mounted on scopes other than the ones they're selling it with.  I would love to put this on my 10" Dob.

 

To that end, I've got a question out with their tech support folks.  I'll report back with with they tell me.


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#10 halx

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Posted 08 January 2020 - 01:06 PM

Even if their corp ethics would require answering "No", you can definitely do that. I'm 100% sure it will work just fine.
I feel there will be many donated 80mm refractors and 110mm reflectors soon smile.gif (don't forget to cover starsense mounting holes with a sticker).


Edited by halx, 08 January 2020 - 01:11 PM.


#11 Dave Bush

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Posted 08 January 2020 - 01:43 PM

Even if their corp ethics would require answering "No", you can definitely do that. I'm 100% sure it will work just fine.
I feel there will be many donated 80mm refractors and 110mm reflectors soon smile.gif (don't forget to cover starsense mounting holes with a sticker).

You're probably right.  The trick will be figuring out how to properly mount it to my Dob.  I don't think there's anything specific about the mount that requires it to be mounted only on the scopes that they sell it with.

 

And yeah, I'll end up with a largely unused cheap scope but hey, might make a good grab-n-go unit.



#12 Dave Bush

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Posted 08 January 2020 - 01:54 PM

I installed the app on my iPhone.  There is an alignment procedure that you have to do to get the phone/mount aligned with the OTA.  So that would work with any scope.

 

What I did find interesting is that the app has a small database, only Messier and Caldwell deep sky objects. Planets of course.

 

So to track down NGC or other objects you can use this to get you close and then star hop.  


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#13 Euclid's Brother

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Posted 08 January 2020 - 02:15 PM

I'm wondering if this thing, the whole bracket/mirror assembly could be mounted on scopes other than the ones they're selling it with.  I would love to put this on my 10" Dob.

 

To that end, I've got a question out with their tech support folks.  I'll report back with with they tell me.

That's exactly what I'm thinking of doing.  Mounting it to my homemade 12" dob.   I have a Pixel 3a XL which is listed as compatible.

 

I was going to play with just the app first to see how well the camera aimed at a diagonal mirror would work, but it requires an unlock code that comes with the telescope.

 

Edit: Actually, instead of mounting that cradle, I may try to build a custom cradle onto the side my dob mirror box that custom fits my phone and camera position. Should make it easier to align each time?


Edited by Euclid's Brother, 08 January 2020 - 02:22 PM.


#14 halx

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Posted 08 January 2020 - 02:34 PM

Exactly! Also, you can get a prism instead of the mirror and have a more compact mount near the EP, so you don't have to go somewhere far from the EP for pointing. The small prism is also easier to protect from dew and dirt. However you need to make sure the view is not obstructed, so the mounting spot should be at the very end of the OTA, maybe even over the rim. To save on the alignment time you need a perfect fit cradle. I would find a 3d model of a tight fit protective case for your phone and modify it in a CAD app adding a fixture holding the mirror or a prism in front of the camera opening (plus any mounting hardware suitable to your mounting location).


Edited by halx, 08 January 2020 - 02:35 PM.


#15 redbaron12

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Posted 08 January 2020 - 02:36 PM

Just thinking out loud here but since this appears to be targeting new amateurs as an alternative to what has been out there before, I doubt most would be driving to dark sites to try/use this technology.  So, assuming they will use these scopes in their driveways, balconies, back yards etc., how will this be affected by a significant amount of light polution both in the sky and from surrounding home, street, and car lights in urban and suburban areas?  Will that phone be able to actually "see" enough stars to figure out where it is?

 

I guess it might be similar to the starsense cameras but they at at least appear to have a decent shield on the front.  This looks to be wide open between the mirror and phone.  Dewing up might also be an issue to consider.

 

Mike



#16 Michael_Swanson

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Posted 08 January 2020 - 07:08 PM

Finally, the alignment procedure should exist as you need to figure how the phone camera is aligned with the optical axis. Most likely that's a 2 stars alignment procedure as the phone cradle looks quite generic and sorta flymsy, so it cannot reproduce or hold the alignment between phone re-insertions. But that could be within tolerances the app is aware off (but still that would affect the accuracy without the alignment).

 

There is an alignment process but it is simply centering a single object in the eyepiece and telling the app it is centered.  The app then knows the offset from its optical center.

 

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


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#17 halx

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Posted 08 January 2020 - 07:44 PM

I see, Thank you, Mike. I guess, they are relying on the accelerometer working perfectly in the phone (which is often not the case for some phone models). Two stars would allow to find out if that's the case. But maybe the first object correction would help with that automatically. In practice, I would monitor all of the phone movements constantly between pointing sessions and guess what the user is doing. E.g. it's easy to detect that the user is manually guiding the target object after several jerks needed to center it, which would tell the AI that the object is in fact more-or less centered already and adjust the model fusing the plate solver and gyros :)



#18 Michael_Swanson

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Posted 08 January 2020 - 08:15 PM

Haven't used it myself, but I understand it this way.  The accelerometer and compass are used for getting the pointing "in the neighborhood" and then plate solving takes over.  The app deals with rotation internally (required to deal with mis-leveled tripod) so all it needs to know for the final centering of objects is the difference between the center of the scope's field of view and the center of the smartphone's camera sensor.

 

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



#19 descott12

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Posted 08 January 2020 - 08:31 PM

Very clever. The operator still has to drive the scope and star hop the old fashioned way (which I think is a good thing) but it will make it so much easier to find stuff.  A great combination of old and new. I don't do much visual but I would love to have this if I did.



#20 Dave Bush

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Posted 09 January 2020 - 10:05 PM

First response from Celestron...

 

"Celestron is not planning on selling the StarSense Explorer bracket and App separately at this time and since there is currently no way to mount a Starsense explorer bracket to your DOB, it would not work."

 

Needless to say, I don't quite believe that 2nd part so I've asked them to clarify that.  

 

Stay tuned...


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#21 Michael_Swanson

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Posted 10 January 2020 - 07:22 AM

I just think this isn't the business model they had in mind. 

 

Obviously they could create a more generic bracket mount.  The brackets on the 114mm and 80mm models are pretty much there and could easily be adapter (by an owner) to a dob or pretty much any other alt-az scope.  If the price of the 114/80 models turn out to be prohibitive for this endeavor, just watch Craig's List after the next holiday season :-)

 

Referencing the pictures of these mounts, I would note that it is almost certain the camera mount needs to be aligned with the rotation of the alt axis (see how the smartphone is level left to right).  In other words, if you mounted it in the typical location of a finderscope, the smartphone would be tilted in respect to the alt axis and I doubt that would work.

 

For that reason, a self-mounted option would only perform well if the owner took extreme care when mounting.  Big headaches for Celestron Support for a system that is marketed as the model of simplicity.

 

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


Edited by Michael_Swanson, 10 January 2020 - 07:23 AM.

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#22 Jim4321

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Posted 10 January 2020 - 10:06 AM

Has anyone heard anything FIRM about delivery / availability dates for any of these telescopes?

 

Jim H.



#23 Dave Bush

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Posted 10 January 2020 - 11:05 AM

OK, so after my first question to Celestron I followed up by asking...

 

"What is it about the specific telescopes that you equip this with that makes it usable only with them?"

 

Their reply was...

 

"The hardware. Only the Starsense explorer models have the hardware to mount the Starsense explorer smartphone bracket

None of our other models are compatible with that bracket nor do we carry the bracket separately to sell."

 

To which I replied...

 

"Ah, OK.  But if a similar bracket could be fashioned then that would work.  The key seems to be that on a dobsonian tube I would want to mount it just as it is on the 114AZ correct?"

 

Which elicited this reply from them...

 

"I would not be able to comment on that."

 

So I read that as a "yes" only they can't say it.

 

So now I've got to do some thinking about how I'd mount this on my 10" Dob.


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#24 Dave Bush

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Posted 10 January 2020 - 11:11 AM

Referencing the pictures of these mounts, I would note that it is almost certain the camera mount needs to be aligned with the rotation of the alt axis (see how the smartphone is level left to right).  In other words, if you mounted it in the typical location of a finderscope, the smartphone would be tilted in respect to the alt axis and I doubt that would work.

 

Yes, Mike I see what you mean.  For my 10" Dob I would need to determine that level, left/right point on the top of the tube and mount it there.  Not impossible.  A challenge actually.

 

The price of the 114AZ is not bad at all.  I'd get the technology and a very grab-n-go scope.  

 

I've got some studying on this to do.  :-)


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#25 halx

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Posted 10 January 2020 - 12:11 PM

Thank you for the update, Dave. So, I've been right from the very beginning grin.gif (corp. ethics only).

 

Regarding the mounting orientation, I'm 80% confident it will work with any arbitrary orientation of the phone as soon as the camera is more or less centered on the scope FOV. Otherwise they will be losing sales in the Southern hemisphere. The fusing math behind the thing is nothing special and that must be generalized for any initial angles to simplify software development and maintenance. The remaining 20% are to accustom for software bugs coming from wrong initial assumptions (like no users on the North Pole). However, the level of the math involved requires quite a clever programmers team, at such a level we don't make stupid mistakes smile.gif

In a worst case, that DIY cradle might need a more sophisticated optics design (an adjustable mirror mount).


Edited by halx, 10 January 2020 - 12:14 PM.



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