Affiliation
American Association of Variable Star Observers (AAVSO)
Fri, 04/14/2023 - 14:33
ZWO has just begun to offer this tiny thingy:
https://astronomy-imaging-camera.com/product/zwo-seestar-2/
I guess technically it best compares to the "Vespera observation station" by Vaonis, but at a much, much more aggressive price point. (Same sensor, same 50mm aperture, also under 5kg weight, alt-az tripod mount, smart phone user interface ...)
Opinions?
CS
HBE
Fascinating.
Would this scope be capable of doing SNEWS observations?
Quick to deploy. The question is if you can do bright star photometry with it.
George
I think it would not be crazy to try. It would play in the same league as DSLRs with small telephoto lenses, but the rototic mount is an interesting feature that would make it ideal as an extra eye in the sky while you work the sky with a bigger scope(s).
I must admit that I used to shrug off this type of scope, but then a member in our astronomy club got a Vespera in the Kickstarter campaign and I was impressed how much he was using it ever since. Even if the forecast gives you only one or two hours of clear skies, it still makes sense to quickly deploy this little critter on your lawn even tho you would hesitate to set up the "big" rig where it takes half an hour to just get it going...
CS
HB
P,S,: So I ordered an S50, shipping will begin in July 2023, first come, first served. We'll see.
I will try and talk with them today at NEAF.
Looking at the specs, I don't see any non-compressed image formats. That may be an issue...
Peter
BPEC
I must admit I ordered it almost blindly, not knowing much about the detailed specs. I think I read somewhere it offered TIFF which could mean lossless compression, tho. Anyway, these things have a tendency to evolve their software after the initial realease, I can remember that one of these "intelligent scopes" (was it the Stellina??) didn't even allow the user to go-to arbitrary coordinates, it just offered a fixed catalog of objects! (like: "seriously???? This is a joke, right???"). That was changed later after feedback from the users. Unlike the start-up companies that offered earlier "intelligent telescopes" like the Stellina, Vespera & eVscopes, ZWO is an experienced player in the astronomy field and I kind of trust them to come up with something useful.
CS
HB
I'm wondering if this device will be ascom compliant as it is filled with devices that zwo designed with ascom interfaces.
Thanks,g
George
I've been using the original eVscope for several years, and it's been fun and useful. I've managed to some useful experiments in making light curves, and determined the magnitude limit and noise levels. I should write it up (when I have a bit of time).
Like the eVscope, the new ZWO device probably operates by stacking short exposures. Because the mount is alt-az, images will have field rotation and small tracking errors. The eVscope's images cadence is 3.972 seconds. As a result, if you grab the raw data feed, you end with many images and need to calibrate, derotate, align, and stack them for photometry. I did those steps using AIP4Win the eVscope, but the joker was that after uploading the images to Unistellar, you had to request a download to get your images back. No immediate access to the data. While not difficult, the upload/download step was an unnecessary obstacle to the efficient use of the images.
If the ZWO device allows the user to capture raw images, that would make it useful for many types of variable star monitoring. For example, you could schedule it to observe as many as a few hundred stars brighter than mag 15 looking for large or sudden changes in brightness. (The eVscope's effective limit is V=17.) With the right software, you could accumulate a few dozen images, calibrate, derotate, align, and stack into a single image, automatically extract photometry of the target (or for than matter, from every object in the image), and move on to the next target. It would take no more computing power than found in a RPi to accomplish this.
It really depends on whether the ZWO device is an open system or a closed system. If it's open, it will be useful for variable stars.
--Richard
I visited the ZWO booth at NEAF. Staff there didn't know much. Its not shipping until June.
I did note that tech support stated they can output in FITS. It was unclear whether cal files other than darks are available.
I ordered one this morning ($400 until June, then $500). The Sony sensor has massive IR leaks for both B and V channels, and UV leak for red filter. Oy.
But with only 2" aperture we could potentially just put a passband filter b4 the objective??? I submitted a "feature request" to thread the objective to accept 50mm threaded filters.
At this price point it may be an interesting entry level scope! I'm hopeful.
Peter
The specs mention a built-in filter changer, which I think includes exactly 2 filters (possibly also a "clear position") : a "dark" filter so it can make darks automatically without manual capping of the aperture, and an UV-IR cut filter. That filter makes sense because the device is also advertized for daylight photography ( I guess birdwatchers might like this) and there it would be important to get realistic colors. Because of the massive leaks, you just cannot use the sensor for daylight photography without an IR & UV blocking filter. So in theory, just from the hardware point of view, it should be possible to get "clean" tricolor RGB photometrywith this thing if the software allows to have that filter on in the DSO mode.
The missing 2" thread on the aperture is a real bummer, also for solar photography! E.g. the Vespera can do solar photography with an aperture filter made for it, combined with a very clever alignment method that uses the shadow pattern created by the small slit between the moving and static parts of the enclosure for alignment in daylight (obviously no star field platesolving possible :-) ).
I'm quite excited about this little gadget. I can imagine schools and astronomy clubs buying these and students could then perhaps take them home to do their own observations. Maybe the price point helps to interest a whole new group of people in astrophotography, and eventually, citizen science astronomy.
CS
HB