does not look like any significant orientation change from the shadows in the the pre and post hop images.
but why are the ramp deployed images(pre and post hop) looking so different ?
does not look like any significant orientation change from the shadows in the the pre and post hop images.
The picture on the left has Pragyaan still on the ramp before it rolled down- no tracks.
There doesn't seem to be much rotation, the view remains very similar (and moved back along the camera axis). But even a couple of degrees of elevation might make a difference and not be very perceptible to the human eyeChandrayaan-3 project director P Veeramuthuvel told to TOI in an exclusive interaction.
“A full lunar day is from 0° Sun elevation angle to 0° angle. But the mission is not designed like that. For landing, the angle requirement was 6-9° elevation and we managed to land when elevation was 8.75°. For operations, we need a minimum of 6° elevation angle because our cameras and other systems are characterised for that. It's also for solar panels to remain optimal. Once it goes below 6° elevation, there’s a long shadow,” he said.
RHU, which are of the size of a c- cell, developed and available to ISRO, are much simpler solutions... For background see my post a few posts above.RajaRudra wrote: ↑04 Sep 2023 19:55
1) What if we fire this for 10 seconds every day(not the propulsion) but sending power internally.
2) May be in next mission - Invent an adapter for Rover to get energy from lander during winter days.
Infact, whatever we are doing is a new avenue from here on. Possibilities, possibilities everywhere.
Image is a beautiful depiction of Chandrayaan-3 and pragyan on the South Pole of the moon. Tis my desktop background.beautiful illustration from CanberraDSN
Amber G. wrote: ↑03 Sep 2023 00:25 I knew Carl Sagan very well (over 25 years) but I have not heard of it before. He did not talk about it and in none of the books/articles I have seen, he mentioned it . Yet the items presented in the video are basically correct, and main-stream newspapers did have articles. So the video is quite well and well produced.
Carl Sagan who was student of Kuiper (also worked with Urey, Gamow, Chandrasekhar) has written *several* books and articles -- both for scientists and popular. (We both are physicists and have a great interest in astronomy/astrophysics). I highly recommend his books and extremely popular COSMOS series. (If you have not seen it, it is as good as it gets for any student for astronomy). Voyager record, which has greetings in many languages , Greetings in all Indian languages (including Rajasthani were recorded by a few of Indian grad students in Cornell. )..
(In younger days he did have top/secret clearance but later he never worked for military etc .. he was quite against using science for anything other than peace ... and had great relationship with international scientists)
Glad you met Dr Sudan. He was a beloved uncle of mine.Amber G. wrote: ↑05 Sep 2023 05:15 OT but Short answer Yes, Sagan and Ravi Sudan both were in Cornell .Cornell/Ithaca (and Up State NY) already had quite a few Indian's in late 60's (when I came ) ( I did not chose Cornell for grad school but it was one of my top choices - and have attended seminars etc there ).Prof Ravi Sudan was already a big-shot/well-known in Plasma Physics -- He came to Cornell when he was already well known.
Cornell is a beautiful place.. Lived in that area for many years and have lot of family still in that area. (My niece went for UG, My son as a post-doc and many of my friends went to school or taught there) -- I have visited the place many times and keep visiting it even after all these years..) ..
It would be great if the rover could have clicked the lander's pic with Earth in its back ground. It has 11 cameras onboard, some of the cameras definitely have some pics of the earth. Need to wait for ISRO to share them publically someday. Can the angle of the earth at the South Pole be a hindrance in getting good pictures?
The orbits shown are extremely accurate -- they are based on *actual* ISRO/JPL data. (that's why some times we have to wait till the data is available and update the orbits after the events which required burns, have taken place)SriKumar wrote: ↑05 Sep 2023 07:22 So is the orbit shown in sankaranet accurate i.e. did CY3 essentially traverse the same path as represented here.
https://sankara.net/chandrayaan3.html
I am talking specifically about the lunar orbit insertion portion of it (and not the other parts) i.e. after the end of TLI and before CY3 settles in a lunar orbit. The change from essentially an equatorial plane to a polar plane is seen. TIA.
Amber G. wrote: ↑04 Sep 2023 06:50 There has been some discussion about remaining day light near Vikram:. Sun is quite low at present..so power generation is low too... ityadi.. ityadi...
While we all wait for the dawn in September at Shivshakti point ..“ A full lunar day is from 0° Sun elevation angle to 0° angle. But the mission is not designed like that. For landing, the angle requirement was 6-9° elevation and we managed to land when elevation was 8.75°. For operations, we need a minimum of 6° elevation angle because our cameras and other systems are characterised for that. It's also for solar panels to remain optimal. Once it goes below 6° elevation, there’s a long shadow,..”
Currently, the battery is fully charged and the solar panel is oriented to receive the light at the next sunrise
Just for fun, and knowledge here are few questions for those who are not annoyed by math:
---Assuming it is now: September 4, 2023 6:30 AM (IST) (= 2023/09/04 01:00 UTC)
Q1 - What is the elevation of Sun at Vikram Now?
Q2 - When will sun set ? ( Date, Time in Hours, Minutes)
Q3 - When will be the first rays of sun will hit Vikram ?
Q4 - When will the elevation reach 6 degree?
Q5 - When will be the next 'noon' (Highest elevation of the Sun in the vicinity)?
Q6 - When will be the next dawn (or noon) in October?
Q7 - What is the length of the "day" (Noon in September to Noon in October.
And a 3 more (or less) challenging questions:
Q8 Where and when can one see Brightest star Sirius and second brightest star Canopus (There position on a given date or time of their rise or setting)
Q9 - How long does it take for these stars to make a full cycle (time it takes that it repeats it's position in the sky.
Q10 - What planets are visible in the night sky ?
Give your values here in this thread. Curious to see the values posted here -- Discussing the math can be done in the math dhaga..
Code: Select all
import math
from datetime import datetime, date, timedelta
# Latitude and longitude of ISRO bangalore location (in degrees)
earth_latitude = 12.8984834
earth_longitude = 77.55906449999998
# Latitude and longitude of Moon's location (in degrees)
moon_latitude = 69.367621 # °S Example latitude on the Moon
moon_longitude = 32.348126 # °E Example longitude on the Moon
# Date (in days from the start of the year)
day_of_year = 247 # Example: September 4th
year = 2023 # Initialize year
# ------------
# Approximate number of days in a lunar month
lunar_month_days = 29.53
# Calculate the lunar day (phase of the Moon)
lunar_day = (day_of_year % lunar_month_days) + 1
# Approximate lunar day length (in hours)
lunar_day_length = 24.0 / lunar_month_days
# Calculate the lunar time (in hours) since sunrise
lunar_time_since_sunrise = (lunar_day - 1) * lunar_day_length
# Convert lunar time to degrees of longitude
lunar_longitude = moon_longitude + (lunar_time_since_sunrise / 24.0) * 360.0
# Calculate the angular distance between Earth and the Sun
earth_sun_angle = (day_of_year - 1) / lunar_month_days * 360.0
# Calculate the difference in longitude between Earth and the Sun
sun_longitude_diff = earth_longitude - lunar_longitude + earth_sun_angle
# Calculate the sunrise and sunset times
sunrise_time = 12.0 - (sun_longitude_diff / 15.0)
sunset_time = 12.0 + (sun_longitude_diff / 15.0)
print(f"Sunrise on the Moon: {sunrise_time:.2f} hours")
print(f"Sunset on the Moon: {sunset_time:.2f} hours")
Anaglyph is a simple visualization of the object or terrain in three dimensions from stereo or multi-view images.
The Anaglyph presented here is created using NavCam Stereo Images, which consist of both a left and right image captured onboard the Pragyan Rover.
In this 3-channel image, the left image is positioned in the red channel, while the right image is placed in the blue and green channels (creating cyan). The difference in perspective between these two images results in the stereo effect, which gives the visual impression of three dimensions.
Red & Cyan glasses are recommended for viewing in 3D
NavCam was developed by LEOS / ISRO. Data Processing is carried out by SAC / ISRO
Thanks for bringing up Giordano Bruno. Yes, Bruno was burnt at the stake for his very radical theories of helio-centric system(s) and for some reason the only name I could recollect was "Bruno Mars"Vayutuvan wrote: ↑02 Sep 2023 02:25 Atcually Giordano Bruno was burnt at the stake for proposing SOlar centered universe and stars being distant suns.
https://en.wikipedia.org/wiki/Giordano_Bruno
Yes, the above is true. US has hidden away those discussions as "top secret". Just shows how much US was interested in actual science then. BTW, the physics behind the plan was calculated among others by one Carl Sagan. It was assigned to him by Uncle Sam, that is to check if it is feasible to set off a nuke on Moon, which he could not talk, but his biographer found it out since he mentioned it in his resume while he applied for a position in UC Berkeley.
First of all, I hope you are correct on the bolded part. We all wait with baited breath. And no, there is no RTU in the lander. ISRO has been very forthcoming with data, and is transparently putting the data out there (it is a different issue with a different team on how that data is put out there), so ISRO would have declared that it carries RTU or not. And if the lander wakes up, it will be a remarkable feat of ISRO's engineering.Piyal.g wrote: ↑05 Sep 2023 06:43 ... Last week, I was discussing about a hypothesis if the lander could hop to another location where sunlight is available. Isro proved me partially correct, however, it will need a lot of fuel which will increase its weight. As the moon's gravity is 1.62 m/s² and with no atmosphere available on the moon it can coast with little thrust and drop at desired location.
I still believe the Lander will wake up on the 22nd Sep, though the rover's chances are 50:50. Is it possible we have installed an RTU unit inside the lander but not declared it? Maybe Isro will surprise us the next lunar morning once the design is tested and successful.
Thanks for confirming.Amber G. wrote: ↑05 Sep 2023 07:48The orbits shown are extremely accurate -- they are based on *actual* ISRO/JPL data. (that's why some times we have to wait till the data is available and update the orbits after the events which required burns, have taken place)SriKumar wrote: ↑05 Sep 2023 07:22 So is the orbit shown in sankaranet accurate i.e. did CY3 essentially traverse the same path as represented here.
https://sankara.net/chandrayaan3.html
This includes the part you are talking about.
I can clarify more, if you describe what part is not accurate..(though a screen shot or which time you are looking at)
)
Meanwhile this may help - The axis this animation is using:
z - axis points toward ecliptic pole.
xy is ecliptic plane. x - axis towards vernal equinox.
(No axis points towards sun or earth - which are moving)
There are three other planes: Earth's equatorial plane , Moon's equatorial plane, and plane of moon's orbit around earth. (One has to be careful, exactly what you mean by 'polar' plane or 'equatorial' plane... as xy plane is neither (exactly) earth's equatorial plane or moon's.).
(Change in inclination is easier to see - (at least from mathematical point of view) - if you see it in xy-yz-zx projections)
Also - you may want to see S^3 (and my ) post(s) about orbit inclinations -- about ISRO performing 'magic'.. that is carefully selecting orbit inclination(s) right almost from start so that after TLI, LOI itself was quite efficient and LBN#2 got it to almost polar orbit around Moon.
Amber G. wrote: ↑06 Sep 2023 00:51 Meanwhile: Japan's rescheduled moon mission to kick off on Sept 7
The live coverage of the launch of the X-Ray Imaging and Spectroscopy Mission (#XRISM) and the Smart Lander for Investigating Moon (#SLIM) onboard the H-IIA Launch Vehicle will start around 8:10 am (JST)on September 7/23:10 pm (UTC) on September 6.
Yes, the Hop test is one thing that proves many technical features for the future:disha wrote: ↑06 Sep 2023 02:36First of all, I hope you are correct on the bolded part. We all wait with baited breath. And no, there is no RTU in the lander. ISRO has been very forthcoming with data, and is transparently putting the data out there (it is a different issue with a different team on how that data is put out there), so ISRO would have declared that it carries RTU or not. And if the lander wakes up, it will be a remarkable feat of ISRO's engineering.Piyal.g wrote: ↑05 Sep 2023 06:43 ... Last week, I was discussing about a hypothesis if the lander could hop to another location where sunlight is available. Isro proved me partially correct, however, it will need a lot of fuel which will increase its weight. As the moon's gravity is 1.62 m/s² and with no atmosphere available on the moon it can coast with little thrust and drop at desired location.
I still believe the Lander will wake up on the 22nd Sep, though the rover's chances are 50:50. Is it possible we have installed an RTU unit inside the lander but not declared it? Maybe Isro will surprise us the next lunar morning once the design is tested and successful.
Coming to hop test, yes, that was a very good bonus. Nanjumar'ji in one of his post pointed out that the lander has some ~140 Kg of fuel and surmised on can it be returned to Earth. At that point, I was of the opinion that ISRO should do a hop test (I might have mentioned it in post, but not finding it now).
The reason for the hop test, as Sanman'ji surmised correctly, is to pave way (or gather data) on what it takes to return a sample back to Earth. Maybe C4 can be a sample return mission. And C5 can be a "hopper". Yes, it will take additional fuel, but there are some inherent advantage with an "hopper"compared to Rover.
The advantage will be the ability to reach centers of certain craters which a rover may not be able to reach. C5 can be either a "hovering hopper" where it actually launches itself, rises up and hovers over the right spot and lands down gently or a "parabolic drop hopper", where it launches itself into a parabolic trajectory and drops to a point. Also can the parabolic hopper use springs instead of rocket fuel? It may take multiple hops, but the point is to reach a particular spot, either a single hoppity-hop or multiple hops.
Israelis are designing a hopper-lander for the moon south pole. So the idea is not new.
Also in C5, if ISRO can put an RTB or RTU, that will be great! ISRO will definitely need RTB's if it needs to go beyond Mars.
I read your post carefully but sorry, but this 'equatorial plane to 'polar' plane which scientifically makes little sense to me in the context .. perhaps some some confusion on mine (or your) part .. ... Let me explain --SriKumar wrote: ↑06 Sep 2023 04:49Thanks for confirming.
Yes I did see all the posts you mention above. I only wanted to confirm this was still true after the actual orbit is known. Indeed I was a little loose with my term 'equatorial' plane. i meant it for the moon (while knowing its axis is inclined by 1.5 degrees to the ecliptic). I looked at sankara.net's orbital paths and the LOI trajectory in the XY plane and one sees that:
1. The lander was placed 'ahead' of the moon i.e. it 'intersected' lunar orbit around earth and got there before the moon did, and 2. appears to come to a stop (almost) because the approaching moon pulls it towards itself, and 3. then retraces its path towards the approaching moon a bit before going into orbit, but is now in a polar plane.
Quite interesting....I was wondering how it went from an essentially an 'equatorial' plane to a polar plane without significant thrusters. The LOI trajectory shows it clearly.
Of course, ISRO achieved this in 2008 (as I understand it, it orbited the poles .....inferring from the fact that it detected water at the poles), so I guess no surprise that they did it a third time in 2023.
Galileo Galilei and Giordano Bruno were both prominent figures in the history of science and astronomy, ..Both Italian Scientists lived around the same time..
जिन्हें सपने देखना अच्छा लगता है, उन्हें रात छोटी लगती है और जिन्हें सपने पूरे करना अच्छा लगता है, उन्हें दिन छोटा लगता है।
Those who like to dream, the night seems short to them and those who like to fulfill their dreams, the day seems short to them.
#Chandrayaan3 #PragyanRover
It is an excellent short book and doesn't shy away from getting into Mathematics as well. I found it to be a great read.A History of Pi Hardcover – January 1, 1993
by Petr Beckmann (Author)
“Do not touch my circles!” said the thinker to the thug. Thereupon the thug became enraged, drew his sword and slew the thinker.
The name of the thug is forgotten.
The name of the thinker was Archimedes.
Looking at this picture which was released/taken on 8/30 -- This is "noon" there at the Shakti point.sanman wrote: ↑30 Aug 2023 13:49 Here we go! A picture of the lander taken by the rover -- at last!
https://twitter.com/isro/status/1696792992718442558