63 replies to this topic

[Nightskyman]

I recently purchased my first telescope, a Celestron StarSense Explorer 8” dob. I have only used it a few times as the conditions have not been the best. I basically view from my backyard in the suburbs. The city near by is not large by any means when compared to Philadelphia or Baltimore but never the less it isn’t dark in my yard either. I am estimating around Bortle class 6.5 to 7. With that out of the way, I am hoping to engage in a robust discussion about the StarSense technology itself and not the telescope. Having nothing else to compare it to, the scope seems to be of decent build and quality and gets good reviews such as that from Ed Ting. The StarSense technology though, I am not yet sure how much I like its effectiveness in reality as compared to its promise. I guess the amount of light pollution plays a part in the process but in many reviews it seems that my rating should not cause any difficulties. The two main issues I have with it is first, it is very touchy with where it can find the position or orientation. Second, unless you are pointed rather close to the object, you have to move the scope VERY VERY slow or it will lose its position. Maybe over several months rather than several weeks will offer a better evaluation but not sure why. With the saddle for the phone being placed on the top and center of the tube, it takes up some prime real estate. The location of the red dot finderscope, by necessity due to available space, Is horrible. I am thinking of replacing it with a RACI finderscope. Well there, that should be enough to get.the ball rolling, what are anyone else’s experiences or thoughts?

[Anony]

What eyepiece are you using?

 

Ideally use a 32mm plossl, or something wide, when closing in on the target.

 

I have starsense with my SCT and I like it. And it's slower than your dob. Although I do have slow motion controls too... not sure if that makes it easier.

 

I'd think with starsense, the red dot would be less needed? Although yeah, red dots and dobs aren't always the greatest -- it's not simply due to lack of real estate, it's just how it is with all dobs... it can be very twisty on your neck. I suppose a quikfinder or telrad is an option too, if it can fit up there.

[Ice Cube]

the dob version of star sense depends on the sensors in your phone.

 

how well it points is directly tied to how good the IMU (accelometers and tilt sensors) and camera on your phone are. i would expect different phones would have different relative response.

 

totally different technology used on the star sense for SCT (external celestron camera and celestron GO-TO mount)

Edited by Ice Cube, 07 January 2023 - 10:55 PM.

[Neanderthal]

The StarSense option is there, but that does not mean you have to use it to enjoy your scope. Your scope, in of itself, is still a great tool to observe with! You can still put a traditional finder scope on it and star-hop, or a Telrad or a Az/Alt setting circle. Or a combo of all of the above!   I'm wondering if you have enough visible stars in your sky for the plate-solving to work properly?

 

I think most 8" Dob users favor something in the 30mm-40mm range for their lower mag EP. Also, a large FOV will help keep things in your sight before having to nudge. I'm not familiar with the EP's that might have come with your scope, but if you do not wear eyeglasses, consider the Astro-Tech 28 UWA or Stellarvue 28mm UWA. These are 82° FOV and give excellent views. If you do need to wear eyeglasses, then the APM 30mm UFF is an excellent choice, it's about 70° FOV. All three of these work fantastic in an 8" Dob.

[Anony]

the dob version of star sense depends on the sensors in your phone.

 

how well it points is directly tied to how good the IMU (accelometers and tilt sensors) and camera on your phone are. i would expect different phones would have different relative response.

 

totally different technology used on the star sense for SCT (external celestron camera and celestron GO-TO mount)

I should have clarified, I don't have the typical SCT flavor of starsense.

 

I have a DX5, starsense explorer, and use an old iphone... works the same way as the OP's scope does.

 

Not sure if the experience differs by phone though. I assumed if the thing worked, it sort of worked the same regardless of phone.

[Nightskyman]

Neanderthal, it is not a problem to keep it in view with the scope, purely the StarSense locating itself. Number of visible stars may make sense, but if shifted to where it does locate itself, even with very slow movement, it often looses its place along the way? I dont think my backyard is all that untypical of most suburban backyards and that is probably a place often used by amateurs who I would think the technology would most appeal or apply to.

[Nightskyman]

By the way, my phone is a Samsung galaxy 8, should be more than adequate,

[Nightskyman]

Ice Cube, I get what your saying but it shouldn’t effect just finding it’s initial location or if once located, it shouldn’t lose when turning very slowly? I really like the celestron scope but I also have not been impressed with the knowledge, responsi, or manor of their technical support either.

[Nightskyman]

Again, the scope itself, I would recommend.

[BrentKnight]

I would imagine the nearly full moon is bushwhacking the plate solving.  A darker night would likely give better performance.

[Ice Cube]

Ice Cube, I get what your saying but it shouldn’t effect just finding it’s initial location or if once located, it shouldn’t lose when turning very slowly? I really like the celestron scope but I also have not been impressed with the knowledge, responsi, or manor of their technical support either.

 

the technology for the IMU and gyro has definitely changed over the years.

for example, the latest iPhone 14 has a much more sensitive IMU and HDR-gyro than the previous models.  and there was a big shift when the BOSCH sensors where introduced in the iPhone X generation

 

 

https://www.phoneare...ection_id142433

 

having been involved with MEMS style IMU's, the low rate changes near DC are actually harder to 

deal with than high rate changes.

 

short answer:  turning slower is more challenging to do right.

Edited by Ice Cube, 07 January 2023 - 11:40 PM.

[Nightskyman]

I am 3 hours north of Washington and my phone is 34 years old. Also, there was a new moon and and two ther times within that week that were also no better than the others. Not trying to be difficult, just searching for answers.

[Nightskyman]

3 to 4 years old, not 34!

[Second Time Around]

I agree that it may be the model of phone. Despite being listed as compatible, my Google Pixel 6 doesn't work at all with SSE. (Having said that I haven't tried it with the latest update to Android 13.)

However, my wife's older Pixel 4A5G works perfectly. The object I'm looking for is always visible in an eyepiece with a field of view of a little under one degree.

I do consider SSE to be game changing.

[kwyjibo]

When moving the scope you're relying on the tilt and accelerometer sensors in the phone that are not 100% accurate. When you stop moving it will plate solve and get a more accurate position. Imo you're better off quickly moving it to where it's close to position then stop moving for a couple seconds to let it plate solve then fine tune your position. Shouldn't take more than 10-15 seconds to find what you're looking for that way.

[Corbetto]

I've had the 10" StarSense Explorer dob since early November and have had nothing but a great experience with the StarSense app. I'm in an equally, if not more so, light polluted area, in the DC suburbs. I use an iPhone 11 with StarSense, which puts my phone about 3 or 4 years old as well.

 

The first few weeks, my biggest issue was having to realign the app, that is having to center a bright star - I use the planets, Jupiter or Mars, since they are the brightest things in the sky right now - in the eyepiece and in the app. This was primarily because I fumbled with putting the phone in the dock, knocking it out of alignment. Once I figured out how to more gently and correctly place the phone in the dock, I now only realign the app with the eyepiece every handful of sessions. The first targeting of a star or planet during a session will tell me whether I need to realign or not.

 

In my bright skies, the plate solving has worked flawlessly. Each slew to a new target, with proper alignment, has been perfect. Moving the scope too fast from one location to the next will cause a warning to slow down, but once stopped and allowing the app to plate solve, it's been completely accurate for me. When selecting a target and initially slewing to the location, once you've stopped, the app will plate solve and give you the fine tuned location. It takes a few seconds, but unless the target is hidden by an object (in my case, trees or my house), it's worked as intended. Naturally, using a smaller focal length eyepiece when acquiring targets will mean it will likely be at the edge of, or outside, the FOV unless your alignment is absolutely perfect. I typically use a 24mm or larger eyepiece when acquiring targets, and if I want a higher magnification, I'll center the target and quickly swap eyepieces. Using a decent zoom is even better, negating having to swap eyepieces. (I also typically use my zoom for the app alignment to really get things synched well.)

 

I went with the StarSense dob because my skies are bright and because my pattern recognition just isn't that great, so learning the sky with charts wasn't working well for me before I bought the scope. StarSense has helped me understand the sky more in the last two months than charts, books, a planisphere did in a year using binoculars. (Of course, I could also just be a slow learner.) 

[aeajr]

Neanderthal, it is not a problem to keep it in view with the scope, purely the StarSense locating itself. Number of visible stars may make sense, but if shifted to where it does locate itself, even with very slow movement, it often looses its place along the way? I dont think my backyard is all that untypical of most suburban backyards and that is probably a place often used by amateurs who I would think the technology would most appeal or apply to.

The Starsense Explorer technology is based on plate solving using the camera on the phone.  That means it takes an image of the sky and then matches it to an internal database.   As you move from target to target it will take intermediate images to track where it is and will often take a final adjustment after you reach the target.  While it may use sensors in the phone for reference it does not use them to do the final location of the target.  This is not a traditional GoTo/PushTo system.  It uses plate solving, a process well known to astrophotographers.  

 

In my opinion, this is a game changer.  The others will try to match this eventually.   

 

StarSense Explorer series are now my #1 recommendation for newbies.   We have several in the club and they love them.  One guy has 3 of them. Another, who has some high end scopes just loves his.  A friend with an APO refractor on a Twilight 1 mount took the Starsense off the 80 mm version and put it on his high end scope and uses it all the time.  I am considering doing something similar on my 12" Dob and 4"  Refractor.  

[NeroStar]

My daughter has gotten the hang of StarSense, but it has taken her about two years of occasional use to get there.  Start with a lower power EP, then work your way up in magnification once you've become accustomed to it. 

 

She claims it's worked better for her since she moved from an iPhone to Android, and I concur. Truth be told, it probably has more to do with the accelometers, tilt sensors and camera within the individual phone vice a better implementation within the OS.  I say that because the accuracy seemed to go south after her phone took a couple of back-to-back hard spills, including a slinky bounce down the the stairs at college. That's just a general feeling after a few uses with the application on each phone.  

Edited by NeroStar, 09 January 2023 - 10:06 AM.

[RiderRoy]

I'm one of those who put the Starsense module on a non starsense telescope, an Orion XT10. Most of my observing is in my bortle 8/9 backyard. What I've noticed is that no matter how fast or slow I push the telescope around the phone still does a final plate solve when the scope stops moving. Sometimes this takes two or three seconds and then a final minor push/pull gets the target centered. As for location on the telescope, the Starsense cradle is on the far side of my Telrad from the focuser so I have to move from one side of the scope to the other. Not a big deal as far as I'm concerned.

 

Later this month will be the first time to take it to a dark site.  Looking forward to seeing how Starsense does when there's an overload of stars in the sky. 

[WillR]

I am 3 hours north of Washington and my phone is 34 years old. Also, there was a new moon and and two ther times within that week that were also no better than the others. Not trying to be difficult, just searching for answers.

You could try mounting this, but I'm not sure it would work.  ( I know you meant 3-4 years) Isn't it amazing, though that now a 3 year old phone is "old"?

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[Second Time Around]

Just after they came on the market I bought a Starsense Explorer 70mm f/10 refractor for 2 of my grandkids. This is an additional size not available on the US market I believe.

I was so impressed I immediately bought another one for myself just to get the Starsense Explorer technology. I did a very simple mod so that it fits into any standard Synta finder shoe, and now use it all my scopes.

I don't use the red dot finder, but align anytime from twilight onwards on a bright object such as Jupiter etc.

Nor do I need any other finder such as a RACI, so this saves money too. I've therefore sold off all my finders bar one.

The 70mm refractor version has now gone up to £170 from £140, but for that you still get a useable grab and go scope.

The SSE Dobsonian packages are certainly convenient and uncomplicated for beginners. However, you pay quite a premium for the technology.

I'd prefer to buy the Bresser (Explore Scientific in the US) Dobsonian with it's better mount, and for about the same total cost add a 70/80mm Starsense Explorer refractor and use the SSE unit on both.

Or, do what I did do, buy a secondhand Dob and save even more.

Edited by Second Time Around, 09 January 2023 - 03:06 PM.

[Philip Jodry]

Red dot finder? If I outgrow mine, I'm keeping it. I'm not the only eyes and hands that will touch my telescope. There's always newbies, and they get to try everything. If I had a Starsense system, I'd give it a chance. I'm sure you can find a way to take over, when you want. Learn it before you knock it. If every telescope was the same, things would get boring. 

[RobertMaples]

... I assumed if the thing worked, it sort of worked the same regardless of phone.

As mentioned, StarSense uses the camera and IMU sensors of the phone, additionally, it has to use the processing power of the phone, so I would certainly expect it's performance to vary from phone to phone.

 

By the way, my phone is a Samsung galaxy 8, should be more than adequate,

Well, the S8 is 5 generations and over 5 1/2 years old (your phone may not be, but the design is), so while it may be adequate, I wouldn't expect the same performance as a newer phone.

[Anony]

As mentioned, StarSense uses the camera and IMU sensors of the phone, additionally, it has to use the processing power of the phone, so I would certainly expect it's performance to vary from phone to phone.

 

Not sure if newer is even better. I'm using an iPhone SE (1st gen, the tiny one), and it works fine.  I think it came out like 6 years ago? That's why I assumed if the thing worked, it worked the same on all phones, even elderly ones.

 

Maybe the OP just sort of needs to get used to it a bit more. And use a wide eyepiece when starsensing. It's not uncommon for it to lose its position, but just give it a moment, and it'll find where it is again. You can't treat it like a regular scope and just zip-zap around all over the place... then starsense may get confused.

Edited by Anony, 09 January 2023 - 03:41 PM.

[Philip Jodry]

As long as you have your cradle and Starsense CD, there will always be another "phone" android or iPhone.