eisstrom

There is usually no real schedule of targets for ground-based telescopes. There are two ways chosen at the telescope: either the astronomer who wrote the application is sitting there and decides what to do, or the staff goes through a list of approved programs and looks for objects that can be observed. This depends on the constraints described in the program (usually atmospheric conditions and height of object above horizon). Which target is chosen next is usually decided during the observation of the last target, there is no real schedule.

This is of course different for robotic telescopes (which is absolutely not the standard), like the Hubble Space Telescope but also ground-based robotic telescopes. But I'm not aware of a live feed of the pointing coordinates for them.

What one could do is regularly query the ESO archive[1] as finished observations appear there immediately (I think) and contain coordinates (just enter night: "2020 01 01" and maybe chose type: object).

In case of the Hubble Space Telescope and also ESO's telescopes, you write a proposal containing the science case, the requested time and instruments, and related previous experience, submit it before a deadline (twice each year for ESO) and hope for the best. The acceptance rate for the HST is currently ~20% [2]. It's a bit better for ESO telescopes. If you are successful you do not have to pay anything. ESO even pays your flight and hotel next to the telescopes in the middle of a desert [3].

The situation is totally different for American telescopes (as far as I know), where you either belong to an institution that has telescope time or not.

[1] http://archive.eso.org/eso/eso_archive_main.html [2] https://www.stsci.edu/contents/newsletters/2019-volume-36-is... [3] https://en.wikipedia.org/wiki/ESO_Hotel

Comment · 6 years ago

In short: No, we cannot do that at the moment.

We have photometric all-sky surveys that can map the entire sky (visible from the telescope location) during a night up to a certain brightness. But those only take images of the sky, not spectra (Zwicky Transient Facility and the planned Vera C. Rubin Observatory).

What we also have are integral-field spectrographs which can take 2D images with a twist: there is one image for every ~0.1nm from 480nm to 950nm. You take one exposure with the instrument and you get a stack of thousands of images. If you go through the stack at a fixed spatial position you get the spectrum. The problem is that the integral-field spectrograph with the largest field-of-view is already huge (it is called MUSE at is located at the Very Large Telescope). And its field-of-view is "only" 1 arcmin^2 (1 deg = 60 arcmin), which is by far too small for large surveys. If you wanted to image the whole sky each night with MUSE clones, you would need several millions of them. A single MUSE exposure is about ~5 GB in the end but there are intermediate data products which are about 10 GB, if I remember correctly.

Comment · 8 years ago

I like NGC 3201 because we found a stellar mass black hole in it (https://www.eso.org/public/news/eso1802/). There should be many more of them in all clusters, but they are hard to find. Theorists can use this to check their N-body simulations of globular clusters.

Some clusters (omega Cen, 47 Tuc) are really weird and different from all others. We think that they might be the remnant cores of dwarf galaxies.

What images do you mean?

Comment · 8 years ago

Not sure if you meant it like this but redshift estimation comes to my mind. The farther away a galaxy is, the redder it becomes. You can measure the distance (redshift) from galaxy spectra (with MUSE for example) but not from directly HST images. This mapping color -> redshift is called photo-z and was tested with MUSE data in an very famous area observed with HST, the Hubble Ultra Deep field. https://arxiv.org/abs/1710.05062

Comment · 8 years ago

Absolutely! When the lasers are used, MUSE uses a filter at the correct wavelength (Natrium D) to get rid of the laser photons.

Only one telescope is currently equipped with lasers. The other ones can't observe the same region of the sky when the lasers are activated.

Comment · 8 years ago

I was comparing it to HST WFC3 with a field of view of 160 x 160 arcsec^2 (https://www.spacetelescope.org/about/general/instruments/wfc...). Thats about 450 times larger than the MUSE narrow-field mode FOV.

I think you mean the high-resolution mode of the ACS instrument (https://www.spacetelescope.org/about/general/instruments/acs...) but that is broken and it was not repaired during the last HST service mission.

Comment · 8 years ago

This is very much unexplored territory, but ESO thinks so. The ELT (https://www.eso.org/public/teles-instr/elt/) will use more lasers but the exact configuration is still work in progress, as far as I know.

Comment · 8 years ago

Exactly! One datacube that comes out from the instrument contains 300 x 300 spectra. This is actually the main capability of the instrument which has 24 individual spectrographs. Here's a nice animation of the path the light takes inside MUSE: https://www.youtube.com/watch?v=-fh2Y6Zyhwc&feature=youtu.be...

Comment · 8 years ago

Yes, the diffraction limit is meant here. The VLT has four 8 m mirrors, for each of them the angular resolution limit is = wavelength/diameter = 8 * 10^(-8) rad. The practical resolution of the new narrow-field mode is about 4*10^(-7) rad, and it was one order of magnitude larger before.

Adaptive optics is the key invention here. As far as I know, it works better in the near-infrared than in the red part of the optical range, and it gets worse toward the blue part. Due to this, our resolution changes as a function of the wavenlength, since MUSE captures the flux from all wavelengths at the same time.

ESO wants to achieve an even higher resolution at the 40m Extremely Large Telescope (another order of magnitude better): https://www.eso.org/public/teles-instr/elt/

It's funny that your mention super-resolution microscopy because Stefan Hell, one of the Nobel Prize winners for advances in that field, works in the same city as we do. So far, I don't think we have any overlap with what he does.

Comment · 8 years ago

The advantage of MUSE is that you get all color information, i. e. the flux at any wavelength from blue to red. In principle, one can use this together with the sensitivity curve for our eyes to construct a natural image. In this case, I think, they tried to imitate the color scheme from the Hubble image which is more limited.

In short: Not sure how realistic this is, but one could make a realistic image from the new data.