New answers tagged

2 votes

Recommendation for green laser pointer for 6" Orion SkyQuest; one integrated with finder or a separate laser added to current configuration?

I hesitate to post this as an answer because it doesn't directly answer your question, but it does answer your overall problem. Do not rely on a laser as a finder. Any dark site will have rules ...
  • 2,942
2 votes

Are apparent magnitudes corrected for extinction at zenith?

Apparent magnitudes in standard photometric systems are defined above the atmosphere. i.e. They should have been corrected for atmospheric extinction unless otherwise specified. As the Wikipedia ...
  • 120k
3 votes

Are apparent magnitudes corrected for extinction at zenith?

The IAU has a conventional value for solar luminosity of 3.828×1026 W. (see Prša et al. 2016). This corresponds to an absolute bolometric magnitude of 4.74 (this includes all the light, including ...
  • 93.5k
1 vote

Are apparent magnitudes corrected for extinction at zenith?

Photometry is a mature subfield, and has been taken to greater and greater significant digits by now. Certainly, the pursuit of exoplanets by the transit method has spurred the subfield to mind-...
3 votes
Accepted

The Interpretation of Uncertainty Map of NEO in Minor Planet Center page

These uncertainty plots are meant to aid observers trying to confirm Near Earth Object (NEO) candidates found by the surveys. Since the NEO surveys typically take 3-4 observations of a survey field ...
  • 7,384
2 votes

Fitting isochrone on color magnitude diagram obtained from growth india telescope for M67

To put an isochrone on your colour-magnitude diagram, then you need those isochrones to be predictions in terms of colour and magnitude. There are models out there which do predict isochrones in terms ...
  • 120k
5 votes

How exactly was Giovanni Cassini able to measure the distance to Mars?

This is my first post on Stack Exchange so bear with me, I'm new to this. I've been looking into the Cassini / Richter measurement for quite some time, and I think I have something to add here. Using ...
4 votes

How often and for what reasons does Hubble use two different instruments at the same time?

I can't answer the first one but I can give a plan for figuring it out: How often does Hubble use two different instruments at the same time? Unfortunately the Hubble search tool does not have a way ...
  • 1,924
2 votes

What is an "Off Rowland-circle Telescope"? Are there "On Rowland-circle Telescope" as well?

@Roy_Smart has helpfully answered the second part of the question, so I'll answer the first :) TL;DR Basically NASA just pasted a Rowland circle on the telescope with adjustments and other equipment ...
  • 736
3 votes

What is an "Off Rowland-circle Telescope"? Are there "On Rowland-circle Telescope" as well?

The term 'off-Rowland-circle telescope' is a bit awkward, I think normally we would call the arrangement of FORTIS an off-Rowland-circle spectrograph, and they probably just used the word 'telescope' ...
3 votes
Accepted

Can we see atomic positronium lines in space? What could be learned from it and what are current challenges to doing so?

The wavelengths of the lines you found are not problematic per se to observe, with space telescopes. If there were an isolated cloud of cold positronium nearby, we would have observed the lines in ...
0 votes

How would a small TCO (temporarily captured orbiter) or other natural Earth satellite most likely be detected?

Both 2006 RH120 and 2020 CD3 are listed as being Catalina Sky Survey discoveries. CSS is not a particularly large telescope, they’re just a tight program with on-the-ball management. How would a ...
6 votes
Accepted

Have we detected spectra of exotic atoms in stars?

Yes, we look into stellar spectra searching for whatever exotics. This way new elements were discovered (helium, in solar chromosphere), exotic states of other elements not studied well in terrestrial ...
4 votes
Accepted

How did this artefact end up in the SIMBAD sky map?

The artifact comes from the DSS, the Digital Sky Survey. SIMBAD is a star catalog, and it displays sky maps from Aladin. Aladin sources the data from different sky surveys, and DSS is the one with ...
  • 1,924
18 votes

Which (if any) space telescope would have worked longer if it hadn't simply run out of helium?

The Herschel infrared telescope is another recent telescope that stopped working once it ran out of Helium for its coolant.
  • 1,569
19 votes

Which (if any) space telescope would have worked longer if it hadn't simply run out of helium?

Past infrared telescopes (IRAS, Spitzer, others I can't remember) in space have generally used expendable liquid He. They either ceased operation or lost a large part of their capability when the He ...
  • 1,077
6 votes

Would a nearby "Orphan planet" be detectable?

The infrared satellite WISE did an all sky survey at near and mid-infrared wavelengths. A nearby "rogue planet" would likely be moving quickly on the sky and if the size of Jupiter would ...
  • 120k
8 votes

Is it possible to tell the time of day by shadows on the photo

I know that it's an old post, but there is an app available online which might help in similar situations: https://shadowmap.org It calculates and visualizes sun light and shadows in a 3D sense ...
  • 81
3 votes
Accepted

Reference request (explaining) how optical correlators combine light from multiple telescopes to produce ultra-high resolution interferometric images?

Reference request (explaining) how optical correlators combine light from multiple telescopes to produce ultra-high resolution interferometric images? There's some good information to be found in the ...
  • 546
4 votes

Would a nearby "Orphan planet" be detectable?

Rogue Planets are Discovered Mainly Through Micro-Lensing We have alreqdy discovered a number of rogue exoplanets, but we don't do it by directly imaging them. Rather, we detect them by watching their ...
  • 1,026
5 votes
Accepted

Would a nearby "Orphan planet" be detectable?

All sky surveys tend to be at optical or radio wavelengths and more rarely at infra-red or x-ray wavelengths using space-based telescopes. The exposure times are short, so the chances of finding a ...
  • 1,307

Top 50 recent answers are included