What image sensors (imaging electronics) are used in telescopes? Like CCD, is that the best option?
What is the typical physical size and resolution of the photo-sensitive surface of the currently active largest ones?
Asked
Active
Viewed 217 times
7
-
2Can you add more details? – WarpPrime Jan 04 '21 at 14:10
-
@fasterthanlight Sure, what details do you think will improve this question? – Ilya Gazman Jan 04 '21 at 14:22
-
If I understand it well, the question is the size of the imaging electronics in the telescopes (ccd cam?), and also their resolution. Probably he wants to know the current record holder (which is probably Hubble). – peterh Jan 04 '21 at 14:29
-
Please elaborate your question, I f*y hate to vote border cases for closure... – peterh Jan 04 '21 at 15:04
-
tnx @peterh-ReinstateMonica I edit it based on your suggestion – Ilya Gazman Jan 04 '21 at 15:31
-
As far I know, it uses CCD optic (there is a silicon sheet, where light arrives on it, changes its conductivity, this can be read out by underlying electronics). It is monochrome - multicolor images are created by filters. Afaik Hubble has multiple CCD and maybe mirrors select the currently active one. – peterh Jan 04 '21 at 15:39
-
I edited the post, I am not sure if I used the correct terminology because also I am not very familiar with the topic - but I hope, so is it already clear. – peterh Jan 04 '21 at 15:42
-
1@peterh-ReinstateMonica Looks good to me. tnx – Ilya Gazman Jan 04 '21 at 15:52
-
Great question! At 3.2 Gigapixels The Vera C. Rubin Observatory is certainly one of the largest and most massive set of pixels being built, but I don't know if it is the absolute largest. For further reading see the links in Why was the Vera C. Rubin Observatory LSST Camera tested with a broccoli and a pinhole? While not as large, the Hyper Suprime-Cam is fun to read about as well. – uhoh Jan 04 '21 at 16:00
1 Answers
6
The current largest digital CCD camera is that of the Vera C. Rubin Observatory1 which has a whopping 3.2 gigapixels. The previous largest features on the Panoramic Survey Telescope & Rapid Response System (Pan-STARRS), and has a resolution of ~1.4 gigapixels.[1]
Based on the spec sheet provided by the Vera Rubin Observatory, the LSST camera has a resolution of roughly 0.2 arcseconds per 10 $\mu$m pixel. It is about 5 feet (1.52 meters) wide and weighs over 6000 lbs (2721 kilos, $2.6\times10^9$ dyn).[2] The actual photosensitive portion of the camera is ~64 cm ($4\times10^{34}$ Planck lengths) across.
Cameras of this size often have pointing, calibration and recording issues. These sources of error are usually extremely well understood, but it's still interesting to see. Pan-STARRS has a detailed list on their data site[3]. These issues include:
- Randomly missing data that gets filled in later
- Pointing errors related to astrometric positions of their targets
- Registration issues near the celestial pole resulting in poor photometry
1formerly known as the Large Synoptic Sky Survey or LSST. The acronym has now been repurposed: What is the LSST now? Where does LSST end and Vera C. Rubin Observatory begin?
Joseph Farah
- 286
- 1
- 4
-
-
@ProfRob I chose the primary units I did in order to be consistent with the spec sheet provided by Vera Rubin Observatory (linked in answer). However, as a possible resolution, I have updated the answer with additional unit conversions to SI. – Joseph Farah Jan 05 '21 at 21:24
-
-
1due purely to @pela 's charm, I have provided the weight estimate in dynes. – Joseph Farah Jan 06 '21 at 14:55
-
Although the camera as a whole may be this size (1.2m is closer to 4 feet than 5 incidentally), the sensor array is 64cm across. – Steve Linton Jan 06 '21 at 15:05
-
-
@SteveLinton the 1.2 meters was a typo--great catch! And thanks for the additional info on the camera, I've updated my answer to include it. The 64 cm spec is provided on the same page about the camera I cited for the statement before, so I didn't add an additional source. I've also included the unit conversion you suggested to truly make the answer a smorgasbord. – Joseph Farah Jan 06 '21 at 15:08