Thursday, March 7, 2024

SeeStar S50 trick: No leveling nor compass ever?

Being working on the Plate Solving project myself in the past, I've figured that SeeStar firmware implementation might follow a similar math for its functionality.


That led to a few simple experiments confirming that initially. After a few software updates from ZWO  rendering my initial findings obsolete I now have reworked my quick guide below.

The SeeStar S50 is the most effortless all-in-one starry sky imaging system capable of producing professional results which available on the market at the moment (2024). It's targeting an absolute newbie in Astro Photo and could be considered an essential sky documenting tool in the arsenal of an avid amateur astronomer (visual or imager) as well.

The only problem with it hitting the market is the lack of proper documentation dividing users to those with some AP (Astro-Photography) experience trying to apply it to this innovative rig in various ways and overcomplicating things drastically and those without any AP experience, who often failing to follow these instructions just blindly.

But there is a good news! The SeeStar S50 is accidentally so good, that it in fact needs nearly zero learning curve to start getting mind-blowing results right out of the box. Just make sure that:
  1. All what SeeStar needs for making great images (given the sky is not totally cloudy) is its setup location ground stability in time on a micro level, matching its high "effective magnification". The supplied tripod is absolutely adequate for the setup on any not shaky surface, unless it's severely obstructed by tall grass or furniture, for example.
  2. You have enough open sky in front of it, a 180 deg. wide "window" (contiguous opening) in any direction at altitudes above 30 deg high would be ideal. Smaller windows are workable too, but would require some additional effort to make it work as described later.
  3. Remember that the sky is moving for approximately 15 degrees per hour from East to West, thus select your shooting targets so they are still visible in that open sky window after the expected exposure time.
Let me stress it out once again: I have never ever leveed my SeeStar, nor calibrated it's compass since January 2024, when I got it in the mail. It just works. I believe that's how it supposed to be used for the best results, despite the user manual and the common sense of avid Astro-Photographers (I quit that "job" 20 years back) stating the opposite.

My setup flow

Since January I'm imaging with SeeStar following the same technique but with a bit different flow as the SeeStar app user interface is gradually progressing. I have nearly zero dropped frames and always decent end-result (around 200 imaging sessions in different conditions) following the initial telescope setup sequence below:
  1. Screw in the closed mini tripod into S50 (that's easier and safer than mounting it on that tripod as typically done with regular telescopes). Until I feel the Azimuth clutch in the scope base slowly giving up to the tripod rotation (rotate it slowly at the end).
  2. Spread the tripod out, put it down somewhere convenient (I do it on a coffee table inside the home), turn it on, and wait for the connection prompt.
  3. Connect the ZWO SeeStar app, raise the scope to about 45 degrees altitude with the screen button, remove the cap (a cap is highly recommended against the dust and insects; the stock solar filter will work just fine as a dustcap).
  4. Bring it out and put down under the stars on the most sturdy ground you could find. No need to have it perfectly leveled, but it should be away from any high traffic route, safe from any falling down debris, and running kids/pets. A house deck or a table would NOT work well unless designed for an AP rig specifically (e.g. a granite slab table with the deep foundation), or there is no traffic, no wind, no thermal gradient passing which might flex that ground surface randomly while imaging.
    I plop it right on the solid ground, far away from my visual setup, when in the field, and on the concrete slab of my 10 story high balcony at home.
  5. No leveling or compass calibration needed AT ALL if you are imaging the night sky (you should be able to see at lease several bright stars in the sky to be sure it would work). But it helps to orient the telescope approximately in the North direction initially, as it was opened on the step #3 above and keep it as a habit for reproducibility of the initial orientation (that would render the internal digital compass calibration absolutely not needed).
  6. Now, in the SeeStar app, knowing the direction your "sky window" is open towards (or if you see the familiar constellation, like Cassiopeia, in the sky), select on the app's Sky Chart any starry region around 45 deg. high in that direction. E.g. mine is centered on NNE, so today I would select a region in Cassiopeia, e.g. near the Gamma Cas for example. No need to have any specific object centered, a rich "pile of stars" would be ideal for PS.
    Tap the GoTo button, and stay with the telescope as it moves to that Calibration target.
  7. Monitor the S50 moving to that direction on the tripod and in the app on the Chart screen. If you see that the app is mostly settled on the target region (red and blue rectangles coincide), but the telescope itself is clearly pointing well away from that target region in the sky (often into the obscured direction, e.g. the house wall), stop the GoTo process in the app (button), pick up the tripod, manually rotate it so the telescope is pointing more like into the right direction, put it down and repeat from #6 (the same object would work just fine, so just tap GoTo again).
  8. As soon as you notice that the S50 is done following the final "3-points alignment" sequence using it's Plate Solving algorithm without a failure message, and starts shooting subs you can assume it is 100% calibrated, stop the calibration target shooting and move on to the actual target you plan to image for the night.
And that's all!
 
No need to fiddle with the leveling or any other calibration settings ever again. No additional leveling attachments or "better" mounting options ever needed. Just avoid touching the telescope or even come close to it (to avoid shaking/rocking the ground it stands on) after #8 is done or invest in a truly sturdy fundament for your shooting spot at home (e.g. an imaging pier). The SeeStar software will take care of the rest way better than you ever could manually.

Other Tips

  1. Don't search for buttons and controls literally as described above, the user interface is still changing from version to version, so use some common sense identifying the needed feature control in your present app version interface.
  2. Don't extend legs of the stock tripod unless the sky is obscured by tall grass or something low getting into the way. The lower the center of gravity of the system the less any shaking ground effect amplification. The mount sturdiness is the single point of failure you are able to control yourself.
  3. The final automatic 3-point-alignment with Plate Solving can fail if there is not enough space in the sky around your (initial) target (approx. +- 30 degrees around the target need to be open for Plate Solving of the stars visible. Watch for the failure message on the screen while the progress % is "ticking". Use a different target instead for the initial GoTo if the one you have selected first fails. Also you can rotate the tripod a bit, if one of the obscured calibrating directions (left or right) is obscured (e.g. a tree, house corner).
  4. Watch for passing clouds/fog. They can disrupt the 3-point-alignment.
  5. When selecting the initial "calibrating" target, consider selecting it in the same region you planning to shoot for hours. That would improve the tracking of the actual target.
  6. Don't calibrate at anything lower than 30 deg. altitude, atmospheric refraction can distort stars making the initial calibration less accurate. Shooting most anything below 30 deg is sketchy at any rate, unless your night sky there is SUPER clear (rare).
  7. If your "Sky Window" is very small, you can try shooting without the 3-point-alignment success displayed, just ignore the error and try shooting. But if it clearly fails (drops, trails, wrong stars), then start it over with a different calibration target wel away from the previous one.
  8. Remember the angle you need to adjust from the North direction for on the step #7 of the flow. Use it next time shooting from the same location AFTER you have "parked" the scope using the button in the app ("Shut Down" sliding button). That will save time repeating the #6 if failed to point initially (the note for ZWO devs: it can be 100% avoided by your software tweak which worked before with the now removed Sync button).
  9. Don't use any heavy attachments to the scope/mount body. They are shifting the center of gravity of the system and could affect the tracking in certain orientations, especially if the mount is not leveled.
Please, don't overcomplicate this little rig. Enjoy it's integrated perfection as is!

Feel free to post any questions or your own experience with this modern marvel in the comments below.

2 comments:

  1. With the latest update ZWO took away the sync button.

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    1. Correct. I believe they have finally figured that it's rather redundant too. Now (with the latest update), all you need is to point it roughly North, select object on the chart near North (bar Polaris) and tap "shoot". But there is a caveat: if you don't have a well open segment of the sky for it to accustom for about 90 deg error of the initial pointing possible, and it fails to point right, then you will have to reiterate on another object manualy. I'm yet to figure if there is a way to circumvent that by the setup flow changes. The former observation, that it remembers the calibration after parking North seem to be not the case anymore.

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