Using the ZWO Seestar S50 for photometry

There was a lot of discussion going on in the “old” forum and it would be a shame if the forum-software switch would kill the discussion. So here is a new home for comments.

I’ve submitted a few data points done with Phoranso on the R , G , B channels of images stacked by the Seestar itself for the Nova in Vulpecula (observer code EHEA) and especially the TR filter results look ok-ish. TG scatters a lot also for other observers, I guess the object is too red and has too much emission in a relatively narrow (H_alpha, right?) band right at the edge of the filter, so that doesn’t make much sense. TB is consistent with others observers but very much off wrt. the corresponding Johnson B filter.

Thoughts? Other experiments?

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I’m making light curves for eclipsing binaries I observed the past few weeks. Is it Ok to use V magnitudes for aperture photometry in the TG band/channel? I mean, do we just assume G is the same as V but then report it as TG? I know there’s a transformation process also but I’m still trying to figure out how to work that out. Anyways, light curves for eclipsing binaries with ~1 mag variation look pretty good after averaging ~4-6 images at a time. I’ll eventually quantify precision but it’s certainly not ~0.01 mag level from the city. I did a few nights under dark skies so maybe those will give us a better idea of the maximum precision possible. Stay tuned!

IF your camera image has a TG bayer filter channel, report your magnitude as TG but use the known V comparison star magnitudes for untransformed photometry.

Ken

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I bought a Seestar S50 at the end of June.

I use it in particular from time to time for magnitude estimates on LPV. I have good feedback using the ASTAP software. It automatically recognizes variable stars in the field. The FITS files are calibrated and it allows me to make reliable estimates without having to resort to differential photometry. ASTAP photometrically calibrates the entire image ; just note the magnitude of the variable star. This only works with the green layer (TG) but for me it is sufficient. I regularly obtain values ​​between 0.05 and 0.1 magnitude compared to other observers in CCD Green or visually.

I don’t own a smart telescope but watching these products closely as they become better and better for photometry.

There is an Astronomical League Live webinar by Dr. Barbara Harris “Doing Science with Seestar”. It’s coming on October 25, 2024 at 7pm EDT. @BHarrisHBB

Worthwhile for beginners in smart telescopes like me who are also interested in photometry.

Andrew

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I’ve produced a Youtube video along similar lines of doing science with the Seestar. It covers photometry and astrometry of variable stars, comets and asteroids.

Doing Science with the Seestar S50

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Well done and thank you very much Andrew for sharing your experience with the Seestar. Until now, I was pointing stars and running my program from the original ZWO application for smartphone and tablet. Thanks to you, I discover the possibility of automating my observations on LPV lists with the python language from Windows. You probably used “seestar_run”. Have you tried “seestar_alp” ? It seems to offer an even wider field of automation for the Seestar.

Hi Arnaud

Thank you. I have had trouble getting seestar_alp to work, so have only used seestar_run at this time. I find it’s all I need anyway.

Andrew

Andrew:

Thanks for the “Heads.Up” on the Webinar that Dr, Barbara Harris is offering on the Astronomical League: “Doing Science with Seestar”. I have a Seestar and I use it for Outreach, so I think this is one talk not to miss.

Patrick

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