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Starsense Explorer Stand Alone Conversion


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Looking good there Mark and way nicer than my hacked plastic board solution. Oh for a 3d printer, not that I've space anyway 😉

As for a droid phone, John bought a relatively inexpensive one that he posted earlier in the thread and seems to work fine.

In terms of hacking the camera to flip, that's likely to need root and/or custom kernel components isn't it? So would void the Sammy Knox/warranty trip, not sure that any others have that mechanism in-built as they don't implement Sammy's secure enterprise environment facility. For sure physically having a fast lens and good sensor will be key and the lower end phones are less likely to have those (J3 etc) but the S series or note are much better equipped, same Knox issues tho. 

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Finally managed to finish off the mods to allow me fit the Starsense phone holder to my OOUK Dob mount. Was hoping to get to try it tonight. Clear skies when I finished up and put the Dob outside

Not quite sure if the mounts section is the best place for this but not sure where else to put it. 🤔   Finished adapting the Starsense Explorer untit to a standard Synta type finder shoe fit

It’s been really really frustrating having made the phone bracket but not being able to test it with the weather we’re enduring but I had first light with the new phone bracket mounted on my Fullersco

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45 minutes ago, markse68 said:

Thanks Alex, it’s not home printed- SLS isn’t really a home print solution as the machines are big expensive complicated and messy! But the quality of the final print is worth it I think- very tough and aesthetically pleasing. I did think about having the prism clip in but I figured it’d be better to have it removable for cleaning and for if it got really wet, to dry it. A production version would probably be better glued in as that would also seal from moisture ingress.

Not really 😉 Making it full length would have doubled the cost (not cheap) and this way the phone is easier to remove. The camera lens assembly protrudes from the body on this iphone (7) and that locates in the hole it sees through to the prism- that and the springy clip side rails hold it pretty securely. I just added a small pad of heli-tape which helps by gripping the back of the phone, completely eliminating any free play from the tolerances- should be good to go i hope.

Re SLS: I have figured that's an ordered print. Just teasing you with the possibilities opening when you have a fast prototypes materializer at hand 🧙‍♂️ I'm often so pleased with mine that skipping the "final" print ordering.

Re the "snubnose": Considering observed swinging forces I'm experiencing on my smartphone holder near the focuser of my z12 for like a decade already, I would hesitate trusting the friction-only holder not only for the camera position stability but for its safety 😅

For the design, I'm leveraging the "3-poins of grip" principle with great results to avoid any play or the need of fastening screws.

Edited by AlexK
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3 minutes ago, AlexK said:

I would hesitate trusting the friction-only holder not only for the camera position stability but for it safet

Ah but from the looks of it your phone is a bit of a monster!- mine’s a svelte little thing by comparison- ;) I think it should be ok. Of course the battery won’t last long and i’ll have to think about external power if I end up using it all the time. That’s not the plan though- I do enjoy finding things the old way too

Mark

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17 minutes ago, markse68 said:

Ah but from the looks of it your phone is a bit of a monster!- mine’s a svelte little thing by comparison- ;) I think it should be ok. Of course the battery won’t last long and i’ll have to think about external power if I end up using it all the time. That’s not the plan though- I do enjoy finding things the old way too

I see you've got i7? That one on my blogpost is a 10 years old phone (HTC-H2 iirc) in the OtterBox defender case. It's actually much lighter and smaller than my current telescope phones Galaxy N4, and N7 (also in the OtterBox) an I bet than the i7 as well :).

For the phone power, just reboot and enter the "Airplane mode" immediately. You will be amazed (at least on Android) how long a 3-4 AmpHours battery can go on the red on black AMOLED screen. I do have an elaborate power-bank-counterweight piece of gear on my Dob, but rarely have its magnetic cable connected to the phone.

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Yeah! Nice device for that time. I have re-flashed mine almost the next day with the Cyanogen Mod Android. Just until recently it was serving as the living room music player "head", but lately everything has been "hijacked" by the Google Home ecosystem. The OtterBox defender is also roomy enough to undercut its back and allow the HTC accepting a double-capacity battery.

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It’s been really really frustrating having made the phone bracket but not being able to test it with the weather we’re enduring but I had first light with the new phone bracket mounted on my Fullerscope last night and am pleased to report that it worked pretty fine :)

I was a bit worried that the ota rotation and non horizontal mounting of the phone would cause issues with the imu accelerometers but the app doesn’t seem to care- it works out the phone orientation from the plate solving (displayed as a rotated square around  the target bullseye) so it must apply geometry calculations to the imu sensors. Whatever it does I was able to swing the scope between Polaris and M42 repeatedly and it was always close before re-plate solving. There were times when it seemed to get a bit confused by its sensors- jumping back and forth either side of a target whilst trying to home in accurately. No idea what causes that but it can be a bit frustrating- it’ll tell you the target is a little to the right of the bullseye so you move it that way, then it plate solves again and tells you you went too far and it’s a little to the left. This can be a bit of a slow process so probably best to stick to a wider ep i guess and just accept a little innacuracy. I was using my 14mm so 0.6deg fov and most of the time the target ended up just inside but sometimes it was off a bit and needed a bit of gentle sweeping to find. 

It also got lost when close to the horizon- not sure if that was just it not being able to see stars or it being confused by street lights etc but i might look to fit a ball head or angled bracket just for that reason. I think it should be more accurate if the target is on optical axis of the camera as it won’t have to deal with lens distortion but having it look more skyward when scanning the horizon would probably be a worthwhile compromise.

I wasn’t out for long but it found me Bodes, M31, M35, Owl cluster, Uranus, Herschel’s Garnet star with ease and much quicker than i could have found them using star hopping and my finder scope given the sky condition- thin hazy cloud most of the time! There were things I wanted to look for that weren’t in its catalogue though which was frustrating- hopefully they will make an advanced standalone version if we pester them for it - full skysafari database or even RA/Dec input would be amazing

It is a really cool tool :)

Mark

Edited by markse68
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I guess you have the phone mounted level/parallel to the OTA?

The OEM mount has the phone tilted upward at the front end which I guess keeps its FoV a little above the horizon when aiming at low targets. Is the scope on an EQ mount, sounds like it is. Seemed to work fine on the TAL-1 but I rotate the OTA if needed of course so I can use the focuser comfortably, which brings the starsense rig back to a more vertical orientation when I'm closer to target.

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14 minutes ago, DaveL59 said:

 

I guess you have the phone mounted level/parallel to the OTA?

 

Yes Dave- there’s pics earlier in the thread. It’s mounted between my focuser and finder scope parallel to the ota. It’s a dob and the ota is rotatable. I usually have the focuser horizontal or for low targets tilted up a bit so the phone would be 30-45 deg from horizontal. Seems to work ok. But would probably work better or at least be less work for the app if the phone camera aligned to the horizon.

Yes the Celestron mount tilts the phone up a bit- I had assumed it was just to clear the view of the OTA but more likely it’s to keep a full sky view when tilted towards the horizon. I’ll see what I can find to mount the phone a similar way and experiment to see how much difference it makes

Mark

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Just got that first smartphone camera prism in the mail. It is erecting (correct, not mirrored image). Otherwise it's producing nice images with tolerable vignetting at short edges of the camera frame. Some masking might be crucial though, as I had a position with kinda "split screen" which might confuse the algorithm showing stars on the shot from a different direction. Also the integrated clip is overlapping the screen too much on my Galaxy s8.

(The image is rotated to show where the bottom of the frame with the mirrored ghost image is; the black stripe is the roof of the prism, not a terrestrial obstacle)

prism1_20201119_132026.jpg

Edited by AlexK
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Looking at the above, a note for the CSSE standalone software successor: Make a feature to limit the PS area to a certain manually selectable region of the camera frame. That way you can avoid dealing with the DIY enclosure issues.

The other obvious one: don't limit your ingenious creation to the mirrored image only. But I do understand Celestron limiting DIY hacking possibilities of their product, unless that's their software developer's negligence :) 

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ahh I found I got a reflected view with the regular bino prism in bright lighting but was able to damp that down with flocking and the wing baffles but on a roof I expect that'd be harder still given the light paths. Pity as it almost looked like a nice cheap way to hack a solution.

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  • 2 weeks later...

A head up  - there's a Celestron Starsense Explorer DX102 up on eBay at the moment for a Buy It Now price of £349.99 with free postage.  This model is a 102mm f/6.5.  The item no. is 154223154844.  The seller is Messier 44000, the eBay shop of Lincolnshire Optics who have a 100% positive feedback.   

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