bkloppenborg

From a comparable project, Georgia State University's Center for High Angular Resolution Astronomy ([CHARA](https://en.wikipedia.org/wiki/CHARA_array)) interferometric array was constructed for about $15m in 1985. That facility has six one-meter telescopes. That would be about $45M in 2024 dollars.

While I cannot attest for the accuracy of the cost estimate, I can note that the BFT takes several approaches which I think will help control costs. In particular, they are leveraging a multitude of proven technologies, COTS components, and smaller telescopes.

In case anyone is interested in learning more about this star, Dr. Brad Schaefer wrote a nice article about it in the March 2024 issue of Sky and Telescope (subscription required):

https://skyandtelescope.org/sky-and-telescope-magazine/insid...

There is also an open-access journal article from March 2023 that summarizes his research on the system:

https://academic.oup.com/mnras/article/524/2/3146/7077557.

And a blog post announcing the latest estimate for the eruption (2024.4 +/- 0.4):

https://www.aavso.org/news/t-crb-pre-eruption-dip

My organization, the AAVSO, has material that can help you learn how to observe variable stars and make scientifically useful measurements. You can do this by eye, with binoculars, with a telescope, or with various digital sensors. In the case of T CrB, visual observations will yield very useful information. Please see https://www.aavso.org/tutorials and https://www.aavso.org/observing-manuals for more information.

Suburbs aren't as bad as you might imagine. I observe from my patio under Bortle 6 skies (you can looks yours up at https://flexspec1.readthedocs.io/en/latest/) with a 5" telescope. We use to have a robotic telescope located in Cambridge, MA and it produced useful science.

As you mentioned, astronomy is a field where contributions by amateurs / citizen scientists are extremely valuable. A few organizations that exemplify this are: (1) the American Association of Variable Star Astronomers (disclaimer, I'm their Executive Director) which collects photometric (brightness) data as well as spectroscopic data on variable stars and kindred objects including exoplanets (2) the Society for Astronomical Sciences which is more broad than AAVSO, but with a moderate focus on instrumentation (3) the Center for Backyard Astrophsyics (hyper specialized on one type of variable star, a good collaborator of the AAVSO) (4) the International Occultation and Timing Association that observe asteroids occulting (blocking) stars to infer their shapes

Most countries have organizations similar to these too.

Edit: There is a group within the SAS working on an automated optical spectrograph for astronomy called the FlexSpec 1 (https://flexspec1.readthedocs.io/en/latest/). It is about $500 in parts. Similar devices sell for about $3,000.

American Association of Variable Star Observers | Remote (US), Full-Time | Jr. Full-Stack | https://www.aavso.org/software-developer-job

The American Association of Variable Star Observers (AAVSO) is a small, science-focused 501c3 non-profit that wroks with the professional astronomical community to unlock the secrets of the cosmos through observations of variable stars and kindrid objects.

We are looking for a junior full-stack web developer to add features and maintain our external and internal Python (Django) websites. This individual will develop, maintain, and operate the software and cloud services used in our web infrastructure. This is a full time (35 hour per week) position that can be fulfilled as in-person, hybrid, or remote work depending on the employee’s location.

To apply, send your résumé / CV to Kathy Spirer at kspirer@aavso.org with the subject line “AAVSO Software Developer Opportunity.”

More information can be found here: https://www.aavso.org/software-developer-job

Betelgeuse is ~47 milliarcseconds in diameter, making it one of the largest stars (in angular diameter terms) observable from Earth. It was first resolved using the Michelson Stellar Interferometer (which had a diameter of 20 meters) in the 1880s.

I don't know the observational wavelength for the images in the article (VLT-SPHERE has filters that go from ~1-2 microns), but if the image were in H-band (1.6 micron wavelength) the resolution of the 8.2 meter telescope is ~49 milliarcsecond, putting this image just at the formal resolution limit. Still, quite impressive stuff.

A while back I found a copy of my 1998-era and early 2000s websites on an old hard disk. The data were incomplete, so I went through a pretty fun process of recovering much of the missing information from Archive.org. Then I fixed the HTML to comply with more modern standards. I wrote up a blog post about it here: https://www.kloppenborg.net/blog/2019/07/04/restoring-maxis-.... I put the website (pure HTML) up here: https://maxis-ville.kloppenborg.net/

We've been doing optical interferometry for quite some time. Homodyne techniques (see facilities, CHARA, VLTI, COAST, NPOI, SUSI) in which the light is interfered with itself are quite common. Heterodyne methods (one facility, ISI) in which the incoming light is mixed with a stable laser and downconverted to longer wavelengths are uncommon though.

You might try JPL's HEALPIX library.

Are there any reasonable, self-hosted alternatives that can provide me with information on how visitors use my website without submitting them to cross-site tracking?

Most importantly, the Government receives "Government Purpose Rights" to Data and Computer Software (including source code). The "SBIR/STTR Protection Period" gives the government a copy of the product for evaluation during which the government has limited distribution and use rights. After four years, the Government has Unlimited Rights (see the SBIR Policy Directive [1]which means they have a royalty-free license to use, authorize others to use, distribute, and disclose said data and software for Government purposes. All of this is defined in the model contract [2] for Phase I and Phase II awards. There are some restrictions, but you'll need to read the documents carefully to determine when these items apply and/or can be excluded.

With that said, I've found SBIRs to be exceptionally useful for my business (I've won $750k in Phase I funding and administered $1M in Phase II funding). The proposal forced me to hone my idea and I received feedback fairly quickly (6 months) with a week or so of invested time. The product is built with minimal risk to my business and the Government can set up meetings with potential users (something that is exceptionally difficult if you aren't on contract). Lastly, with most SBIRs you can request up to $10-15k of additional funding for Commercialization Assistance which permits you to sit down with an adviser who can guide you on bringing your product to market. SBIRs are really an ideal method for Small Businesses to grow.

[1] https://www.sbir.gov/sites/default/files/SBIR-STTR_Policy_Di...

[2] https://www.acq.osd.mil/osbp/sbir/sb/resources/model-contrac...

Edit: fixed links, added statement about my involvement with SBIRs.

That's why radio VLBI is a thing, but not optical VLBI.

Hi, long baseline optical interferometrist here who specializes in modeling and image reconstruction.

To set the record straight, long baseline optical interferometry really is a thing. At present there are two optical interferometers operating in the USA and one under construction: Georgia State University's Center for High Angular Resolution Astronomy (CHARA), and the Navy Precision Optical Interferometer (NPOI), and New Mexico Tech's Magdalena Ridge Optical Interferometer (MROI, under construction). Europe operates the Very Large Telescope Interferometer (VLTI) in Chile. Australia has the Sydney University Stellar Interferometer (SUSI). Optical interferometers have been around for a really long time. Michelson famously measured the diameter of Betelgeuse in December 1920. The first image from an optical interferometer was of Capella produced by the University of Cambridge's COAST telescope in September 1995.

The key difference between VLBI and optical interferometry is that we must combine the light from each telescope in real time, rather than recording the RF data to disk and forming the interference patterns later using correlation. Our interference patterns are recorded on high speed cameras, extracted, calibrated, and then stored as OIFITS files. These files are then later reconstructed using a variety of methods, including Markov chain processes and regularized maximum entropy.

Except for the CLEAN deconvolution process, the methods used to reconstruct images from the EHT data are identical to what optical interferometry has been doing for decades (see https://iopscience.iop.org/article/10.3847/2041-8213/ab0e85, Section 2.2.2 for references to literature). The maximum entropy process used for optical interferometric image reconstruction was, in turn, developed for MRI image reconstruction.

Don't get me wrong, I am not attempting to trivialize the result of the EHT team. The effort involved is monumental and the result is astonishing. In fact, I suspect my facial expression was very similar to Katie Bouman's now famous photo when I first saw the image. Then my jaw hit the floor when I found that some of my work (Baron, Monnier, Kloppenborg 2010) was cited in their imaging paper! However, my first inspection of the "eht-imaging" and "SMILI" repositories has yet to reveal anything new or novel that is not regularly employed by optical interferometrists.