Search found 6 matches
- Fri Dec 31, 2021 6:21 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: JWST on the Road to L2 (2021 Dec 31)
- Replies: 27
- Views: 7464
Re: APOD: JWST on the Road to L2 (2021 Dec 31)
I see a lot of brightness variation in the sequence. I would expect JWST to be constant brightness because it is stabilized to keep the same orientation relative to the Sun. The second stage booster that it was released from is in nearly the same orbit, and is not stabilized so it will get brighter ...
- Mon Mar 01, 2021 4:33 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: A Venus Flyby (2021 Feb 25)
- Replies: 25
- Views: 37612
Re: APOD: A Venus Flyby (2021 Feb 25)
I grabbed some images from the website and found some long exposures* with the spacecraft in motion, rotating to streak the stars. The rotation also causes the dust streaks to curve (linear motion of dust combined with rotational motion of spacecraft and camera) and demonstrates that those streaks a...
- Sat Feb 27, 2021 4:50 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: A Venus Flyby (2021 Feb 25)
- Replies: 25
- Views: 37612
Re: APOD: A Venus Flyby (2021 Feb 25)
If that’s the night side, what is the source of light? ... infrared light from the hot surface making it past the optics filters; bioluminescence from aerial plankton. ... Answering myself: probably infrared light, in WISPR's nominal band. WISPR specs: 0.42 cm^2 aperture, 490-740 nm bandpass (for c...
- Sat Feb 27, 2021 3:36 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: A Venus Flyby (2021 Feb 25)
- Replies: 25
- Views: 37612
Re: APOD: A Venus Flyby (2021 Feb 25)
If that’s the night side, what is the source of light? Is this the ‘ashen glow’ that some observers have seen on the night side of Venus from Earth? Possibilities: airglow or other chemical reactions in the atmosphere; sunlight scattered through the atmosphere from the dayside; infrared light from t...
- Tue Aug 02, 2011 3:17 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Asteroid Vesta Full Frame (2011 Aug 02)
- Replies: 31
- Views: 8600
Re: APOD: Asteroid Vesta Full Frame (2011 Aug 02)
The upper left area is not the northern hemisphere, it is the equator. If you look at the rotation movie, you will see that Vesta has grooves all around its equator. These look to me like impact grooves rather than, e.g. rift valleys. Vesta is so oblate that most objects in low orbit around it (e.g....
- Wed Feb 23, 2011 10:20 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Star Size Comparisons (2011 Feb 22)
- Replies: 131
- Views: 39277
Re: APOD: Star Size Comparisons (2011 Feb 22)
In order to expand the FOV enough to go from The Moon to the largest stars, you really have to pull back the camera (since zoom lenses with that much range are beyond the budget of an educational film.) In fact, you have to pull back faster than the speed of light, so at any given time you are actua...