Starsense Explorer Stand Alone Conversion

[AdeKing]

I had mine out again last night and am still impressed with the performance of the system when fitted to my Skywatcher 200 dob which is on an OOUK Dob Mount.

Last night I slowed down a bit and the system worked exactly as the marketing material said it should and put the vast majority of targets very near the centre of an ES24 68 degree FOV, and placed all of them within the FOV.

The system showed me several Messier objects that I've previously struggled to find or have failed to find and the only target that took a bit of effort to locate was Neptune as its a very small disc and it took me a while to work out which point of light was actually Neptune.  Consequently, I had to move away and re-centre a couple of times and refer to SkySafari on my other phone which could have the FOV of the OTA & EP combination displayed on screen.

Whilst I was using it last night, the end of the mirror furthest from the phone lens started to get condensation on it.  Fortunately, this didn't seem to affect the accuracy of the system, though I can see that heavy condensation on the mirror is probably the achilles heel of the system as the mirror isn't particularly well shielded, but I'm not sure what could be done about it short of attaching a dew heater as the mirror obviously need to be open to the sky to provide a view of to the camera.

35 minutes ago, DaveL59 said:

Yep, alignment is done via the app so no adjusters required on the mounting. A quick test I did the other night on the TAL-1 seemed to work fine with my phone and that included the usual flip from pointing NW to get location and then the flip & rotate around to Mars in the E. That said mine is a note-10+ so may have more sensors but it did seem to work just fine. The app seems happy to scan and locate even when at a tilt so having the phone level is more aesthetic it seems. It also didn't seem phased by me rotating the OTA to get the focuser where I could use it 🙂 

Thats really good news Dave, sounds like it'll still prove to be useful on my manual Vixen GP then.

[StevieDvd]

6 minutes ago, markse68 said:

I can see why you thought it Steve- the complex phone holder Celestron made with its rack and pinion sliders could suggest just that but I think they’re just to make the holder universal for any phone- by tayloring it to one phone (mine  ) it all gets much simpler

Mark

I'd seen the cradle had adjustments for the phone camera position but I guess the addition of ball-head adjuster by others and cloud fever led me down the wrong thought path.

[markse68]

26 minutes ago, StevieDvd said:

I'd seen the cradle had adjustments for the phone camera position but I guess the addition of ball-head adjuster by others and cloud fever led me down the wrong thought path.

🤔 you’ve got me thinking now Steve. One possible and really huge advantage of a more flexible mount is that if i understand correctly, it doesn’t matter which part of the sky you point the camera at to do the tracking. Taking Ades example of neptune, neptune is quite low to the horizon and there’s a lot of light pollution  there from my observing site. In theory i think you could point the camera vertically where the stars are much clearer but still use it to aim at Neptune. Likewise you could point your camera away from any local light sources that might obstruct the imaging with their glare, avoiding the need for a light/dew shield. At least that’s how i think it works but accuracy might suffer from targeting too far from the plate solve i guess.

Mark

edit- ah no that wouldn’t work as you need to be pointing at least in the general direction as the scope to do the alignment  

Edited October 26, 2020 by markse68

[DaveL59]

The way this works is to plate solve the section of sky the camera/mirror sees and then give a direction to move to for your chosen target. It will try to plate solve again if you stop motion and as you near the target so it can fine-tune the directions it gives. Phone motion sensors aren't accurate enough to do the job alone in most cases. If a bright moon is out it will advise to aim elsewhere so it can locate and suggest you choose targets away from the moon to make location easier, so strong light pollution may not help in getting a star fix. Likewise cloudy areas where it can't see stars will result in it asking to try another area to get a fix. A bit of loss of FoV via mirror/prism doesn't seem to affect it so long as there's a good bit of sky captured centrally for it to solve against.

Makes me wonder tho about the LT mounted scopes that have a fair degree of wobble, as it'll sense that and complain about moving the telescope while its trying to get a fix 😉 

 

Edited October 26, 2020 by DaveL59

[StevieDvd]

As I understood this is a phone is just like a platesolving finderscope that gives arrows to the chosen target.  So I am at a loss to see how it would help if not at least roughly aligned (but preferbaly properly aligned).

[DaveL59]

Just now, StevieDvd said:

As I understood this is a phone is just like a platesolving finderscope that gives arrows to the chosen target.  So I am at a loss to see how it would help if not at least roughly aligned (but preferbaly properly aligned).

there's an alignment feature that you should go thru when you fist set it up where you get it and the scope pointing at the same target, much like aligning a regular finder, only you use the touchscreen to indicate the offset.

[markse68]

8 minutes ago, StevieDvd said:

As I understood this is a phone is just like a platesolving finderscope that gives arrows to the chosen target.  So I am at a loss to see how it would help if not at least roughly aligned (but preferbaly properly aligned).

it gets a fix on the sky then calculates the offset you created doing the alignment to give you your pointing direction in the software starchart. Unfortunately (but obviously) you need to be able to see the thing you align on with the scope in the camera fov but it could be right in a far corner i guess. If you could then add a 90deg offset and subsequently use a right angle bracket for the phone i think at least in theory you could point up at the zenith and target near the horizon. Though accuracy might be another matter...

Mark

[DaveL59]

Here's a vid showing alignment, from around 11:10m into it

 

[Second Time Around]

Here are some more detailed instructions for my easy conversion of the Starsense Explorer I outlined in my previous post on this thread.

1) The dock mount comes attached to the telescope tube and is in 2 pieces that need to be separated.  This can be done only by taking it off the tube.  The lower part can then be reattached to the tube.

2) On the underside of the top part of the disassembled dock mount you'll see 3 screws as in the left hand picture below.   The slotted dovetail is then screwed into the large lower hole.  This is deeply countersunk so you'll need a long bolt. plus a nut and washer.

3) The mini ball head is then attached to the middle threaded hole on the dovetail.  These have the same thread.

4) The second slotted dovetail is then attached to the mini ball head as seen in the middle lower part of the photo.

I've read conflicting comments on whether the phone has to be level for the Starsense Explorer to work.  If it doesn't the ball head may not be needed.  However, it does make it easier to use in practice and so mine is staying.

 

Edited October 26, 2020 by Second Time Around

[StevieDvd]

28 minutes ago, markse68 said:

it gets a fix on the sky then calculates the offset you created doing the alignment to give you your pointing direction in the software starchart. Unfortunately (but obviously) you need to be able to see the thing you align on with the scope in the camera fov but it could be right in a far corner i guess. If you could then add a 90deg offset and subsequently use a right angle bracket for the phone i think at least in theory you could point up at the zenith and target near the horizon. Though accuracy might be another matter...

Mark

I'll let others confirm or not whether that would work, I can't quite get my head around it. But I do understand the normal use and now how it's aligned.

[DaveL59]

not sure you'd want to aim the unit too high Mark, but on the OEM mount the phone isn't parallel to the OTA but at an inclination back to front of the phone of around 20-30 degrees. I guess the idea being that it is aiming above the horizon when the scope is level to improve the chance of a plate solve. Or maybe just to not catch the end of the scope in frame 😉 

 

Edited October 26, 2020 by DaveL59

[AlexK]

9 hours ago, markse68 said:

it gets a fix on the sky then calculates the offset you created doing the alignment to give you your pointing direction in the software starchart. Unfortunately (but obviously) you need to be able to see the thing you align on with the scope in the camera fov but it could be right in a far corner i guess. If you could then add a 90deg offset and subsequently use a right angle bracket for the phone i think at least in theory you could point up at the zenith and target near the horizon. Though accuracy might be another matter...

Mark

Correct. The CSSE alignment routine is asking you to point the scope manually to some distant target, and then move the cross on the phone screen, showing the view from the camera, with your finger to accurately mark that target on the image. No Plate Solving (PS) happening yet. Just marking of the camera image spot corresponding to the center of view of your telescope. So it can be done daytime if you sure that until the night the camera alignment wouldn't shift accidentally.

At night, when you point your scope into the sky and command to help finding your observing target, the image is taken, and the PS algorithm figure where the camera is pointing in the sky. Based on that initial alignment session the app will know where the telescope is actually pointing on that image too. So it can calculate the needed angles set (dA, dZ) to make that point coincident with your observing target and provide you with the directions how to move the OTA in order to get closer to your target (will show the arrow on the screen). Smartphone accelerometers sensors are used to track your progress and display it on the screen for the simple visual feedback loop (it's not the real image anymore, just the simulation on the star chart app screen driven by accelerometers sensors). When accelerometers are confirming to the algorithm that your telescope is close enough to that (dA dZ) shift (accelerometers are quite good at taking the angles change, contrary to absolute angles measurements involving the magnetometer), then the second PS is performed to confirm the scope is perfectly on target. If not, the sequence repeats. That sequential approximation of needed adjustments is the key to the CSSE success on otherwise imperfect and non-uniform (on different phones) sensors, the camera included.

The alignment with the target in the very corner of the screen might work, however, the additional factor of the camera optics distortions at play there might reduce the accuracy or reliability/timing of pointing. Ideally it should be in the center of the camera frame to minimize any optical issue a particular smartphone might have.

Edited October 26, 2020 by AlexK

[AlexK]

12 hours ago, DaveL59 said:

hi Mark

I'd be worried about the phone sliding out as you elevate the scope, unless there's another means to secure it or the pic is a cutaway of a repurposed phone case.

Yep, alignment is done via the app so no adjusters required on the mounting. A quick test I did the other night on the TAL-1 seemed to work fine with my phone and that included the usual flip from pointing NW to get location and then the flip & rotate around to Mars in the E. That said mine is a note-10+ so may have more sensors but it did seem to work just fine. The app seems happy to scan and locate even when at a tilt so having the phone level is more aesthetic it seems. It also didn't seem phased by me rotating the OTA to get the focuser where I could use it 🙂 

Very interesting. I'm indeed surprised it worked on the GEM. As I have already mentioned above, it was consistently failing on the Ballscope when the phone was at some significant slant to the horizon sideways. If you are sure it was not just a smallish slant (e.g. the target is close to the meridian where the GEM motions are equal to an Alt/Az mount in general), that could mean the success might depend on the phone model, as indeed the Samsung Galaxy Note 10 is frankly the second best smartphone on this planet (after Note 20) with top accelerometer and gyros sensors used for the seamless 3DVR HMD applications experience (virtual reality head mount display called Samsung Gear VR). Please, experiment more with that, like try it completely upside down. As that would mean a lot for the venerable ball scope owners (the inventor of the ball scope mount Pierre Lemay, for example, has abandoned this idea as CSSE doesn't work with his iPhone at any significant slant).

Edited October 26, 2020 by AlexK

[DaveL59]

2 minutes ago, AlexK said:

Very interesting. I'm indeed surprised it worked on the GEM. As I have already mentioned above, it was consistently failing on the Ballscope when the phone was at some significant slant to the horizon sideways. If you are sure it was not just a smallish slant (e.g. the target is close to the meridian where the GEM motions are equal to an Alt/Az mount in general). Which could mean that might depend on the phone model, as indeed the Samsung Galaxy Note 10 is frankly the second best smartphone on this planet (after Note 20) with top accelerometer and gyros sensors used for the seamless 3DVR HMD applications experience (virtual reality head mount display called Samsung Gear VR). Please, experiment more with that, like try it completely it upside down. As that would mean a lot for venerable ball scope owners (the inventor of the ball scope mount Pierre Lemay, for example, has abandoned this idea as CSSE doesn't work with his iPhone at any significant slant).

Will gladly report further but the testing that night the phone was edge vertical and a bit further as I flipped to then get the next target in view. Can't see that I'd end up with it upside down tho as you'd not be able to see if to direct the scope without contorting which is kinda the point to avoid lol. Also on the GEM you can pause and rotate the OTA which helps get the screen back to a more visible orientation, not sure if the ball mount you'd do that? I didn't tho till I was back on/near target so as to get the focuser back to a useful position.

Of course with GEM getting the direction arrow on screen is one thing, down to the user tho to figure the mechanics of getting the OTA headed in the right RA/DEC directions, meridian flips etc which is ok if familiar but a little more involved than the simpler Alt/Az the OEM scopes are mounted on.

[markse68]

Just picked this up- so it’s all systems go  Seller has lost the card with the code but retrieved it from his app for me so i’ll have to contact Celestron to transfer it to my email address anyway- hope they’ll do that!

Mark

[AlexK]

Congrats, Mark!

[DaveL59]

Congrats Mark, at least he was able to give you the code so you can use the app, oh and a new brolly holder came free with it 😉

 

[markse68]

3 minutes ago, DaveL59 said:

Congrats Mark, at least he was able to give you the code so you can use the app, oh and a new brolly holder came free with it 😉

 

Are they really that bad? 😂

[DaveL59]

the 114 is a bird-jones I believe, so not the best I expect. The LT's are quite wobbly too, am thinking about getting some wood to insert in the leg tubes to see if that'll stiffen things up a little. But the Alt adjuster on mine seems very slack on the threads, not worked out a non-destructive way to open that up to see if it can be improved. All in all tho, they are bottom-end rigs so can't exactly expect them to compare to my EQ5's or even the EQ2 🙂

Oh I thought I'd go register mine, been a bit slack with doing that so far. So as per the card in the box I went off to the website and got this:

oh dear 😮 LOL

[JamesF]

33 minutes ago, DaveL59 said:

Oh I thought I'd go register mine, been a bit slack with doing that so far. So as per the card in the box I went off to the website and got this:

It seems celestron.com was due to expire exactly four weeks ago.  I wonder if it did expire because someone had forgotten to renew the domain, and today it reached the end of the "grace period" for renewals.  It appears to be working for me now, but "last update" time for the domain appears to be only a couple of hours back, so they may only just have sorted it.

James

[DaveL59]

3 minutes ago, JamesF said:

It seems celestron.com was due to expire exactly four weeks ago.  I wonder if it did expire because someone had forgotten to renew the domain, and today it reached the end of the "grace period" for renewals.  It appears to be working for me now, but "last update" time for the domain appears to be only a couple of hours back, so they may only just have sorted it.

James

yeah was thinking the same as it worked about 20 mins after that post. Won't be the first time someone "forgot", same re digital certs running out and sites going untrusted. I used to have diary reminders well ahead of renewal so you could kick the procurement process off early in case the bean counters & co dragged their heels dealing with such trivia...

[markse68]

Had a look at this LT114 and it’s perplexing- celestron seem to have invested more in the locking knobs (cast metal items) than the important bits like eyepieces (christmas cracker grade plastic monstrosities!) and the phone holder seems the best engineered part of it! It is a BJ and it looks out of collimation but if it’s clear tonight i’ll have a look through it...

But back to the subject: i just tried entering the passcode i was given and it worked which is good, but it didn’t require me to enter my email. So my question would be, how can they limit it to 5 devices if there’s no feedback to them of where the code has been used?!? (and could i have saved some money by just using the code from that ebay listing 😉😂)!!

Mark

[DaveL59]

24 minutes ago, markse68 said:

Had a look at this LT114 and it’s perplexing- celestron seem to have invested more in the locking knobs (cast metal items) than the important bits like eyepieces (christmas cracker grade plastic monstrosities!) and the phone holder seems the best engineered part of it! It is a BJ and it looks out of collimation but if it’s clear tonight i’ll have a look through it...

But back to the subject: i just tried entering the passcode i was given and it worked which is good, but it didn’t require me to enter my email. So my question would be, how can they limit it to 5 devices if there’s no feedback to them of where the code has been used?!? (and could i have saved some money by just using the code from that ebay listing 😉😂)!!

Mark

that's odd as I had to enter my email on both phones. Yet to contact them to remove the old note-3 registered since it didn't like something about it. It is an older phone that I've thrown a droid-10 port onto but I note the camera is now very dark which certainly won't help it.

As for the bits thrown in the box (literally I expect) yep they ain't great. The frac came with a spherical plastic diagonal which is erecting, works ok but a proper mirror is a big improvement, not bothered to look at the EP's or Barlow as I'll never use them so they remain "fresh in box". At least the RDF is reasonable. The phone holder is probably an adaptation of their Nex-YZ eyepiece holder and is pretty good if somewhat large and clunky 🙂 

I may keep my eye out for an Alt adjuster rod from a vintage scope as that seems a weak area on these LT mounts, very sloppy tho usable.

[AlexK]

6 hours ago, markse68 said:

i just tried entering the passcode i was given and it worked which is good, but it didn’t require me to enter my email. So my question would be, how can they limit it to 5 devices if there’s no feedback to them of where the code has been used?!?

That's simple. On activation, the app establishing a link to their server,  confirm the code is legit and uses counter on it is not maxed out yet, increment the use counter on the server, enable the app. That's the cheapest way for Celestron (instead of paying Google for their Playstore full-fledged auth service AND to have the app enabled without the Internet connection needed any time in the future). The primary drawback is in the fact that this is a single use code. So if you will ever have to reset/reflash that smart you will have to enter the code again and trip the counter. That's why you have 5 attempts for that code. Use them wisely.

[markse68]

yes and i guess if you do register with them then if worst came to worst i’m sure they’d give you a new code if you contacted them

Mark