Our first assignment was to GTFOutside and find something in the night sky. I had big plans to use my larger camera and long exposures over the weekend but alas I was struck with a terrible fever and going outside became a very bad idea.
So I resorted to ‘taking a quick snap’ with my phone on the only clear night that was left to me. The first trouble was of course finding something in the sky. With NYC’s light pollution and tall buildings everywhere it was tough to see more than one or two faint spots. The second trouble was when my phone told me to move back to improve focus, which was dumb; how can I move back from the sky?
With the help of an app called “Sky Map” I an relatively confident the object I found is Vega. This is an overlay of what SKy Map showed me at the same angle:
It’s not a far stretch to imagine that Sky Map was off by a little and the spot we’re looking at is Lyrae and Vega.
A quick google search revealed Vega to be the second brightest star in the northern hemisphere. Since it was one of the few that I could actually see, this fact helps corroborate my assumption.
Vega has been extensively studied and we know a lot about it:
| Right ascension | 18h 36m 56.33635s[4] | |
|---|---|---|
| Declination | +38° 47′ 01.2802″[4] | |
| Apparent magnitude (V) | +0.026[5] (−0.02…+0.07[6]) | |
| Characteristics | ||
| Evolutionary stage | Main sequence | |
| Spectral type | A0 Va[7] | |
| U−B color index | 0.00[8] | |
| B−V color index | 0.00[8] | |
| Variable type | Delta Scuti[6] | |
| Astrometry | ||
| Radial velocity (Rv) | −13.9 ± 0.9[9] km/s | |
| Proper motion (μ) | RA: 200.94[4] mas/yr Dec.: 286.23[4] mas/yr | |
| Parallax (π) | 130.23 ± 0.36[4] mas | |
| Distance | 25.04 ± 0.07 ly (7.68 ± 0.02 pc) | |
| Absolute magnitude (MV) | +0.582[10] | |
| Details | ||
| Mass | 2.135 ± 0.074[11] M☉ | |
| Radius | 2.362 × 2.818[11] R☉ | |
| Luminosity | 40.12 ± 0.45[11] L☉ | |
| Surface gravity (log g) | 4.1 ± 0.1[12] cgs | |
| Temperature | 9,602 ± 180 (8,152–10,060 K)K | |
| Metallicity [Fe/H] | −0.5[13] dex | |
| Rotational velocity (v sin i) | 20.48 ± 0.11[11] km/s | |
| Age | 455 ± 13[11] Myr |
Table from Wikipedia