SAO 2021, Писмен тур — Задача 18. P(C) All Sky
Singapore Astronomy Olympiad 2021 · 22 т.
Указания
- The entire Olympiad lasts for 3.5 hours and is worth a total of 200 marks.
- Fill in these details on the cover page (after the Contents page), the Summary Answer Sheet and each side of an SAO answer sheet:
- Year of competition
- Your participant code
- The page number – which should be continuous from 1 to N
- The part of the paper, and the question number
- Cross out all workings or answers you do not wish to be evaluated.
- You are allowed to leave the venue early upon submission of your answer script (see Instructions on Cover Page), but only after one hour after the start of the paper and not within 30 minutes to completion of the paper.
- Please raise your hand to seek assistance from the invigilators (e.g. to visit the restroom, request for more answer sheets, enquire about an ambiguity, etc.)
Competition Rules and Regulation
- Only the use of scientific calculators is permitted. No graphing or programmable calculators are allowed.
- Disruptive behaviour, cheating, collusion to cheat or any integrity-related offences are grounds for immediate disqualification.
- You may opt to retain the question paper and constants sheet for personal use. Return all unused answer sheets to the Organising Team.
References for Data Analysis Question
- MS Star Details are derived from: Zombeck, Martin V. (1990). Handbook of Space Astronomy and Astrophysics (2nd ed.). Cambridge University Press
- Additional MS Star Details are derived from: Vardavas, Ilias M.; et al. (2011), "Chapter 5. Incoming Solar Radiation" Radiation and Climate: Atmospheric Energy Budget from Satellite Remote Sensing.
Astronomy.SG would like to thank the organizing committee and the question setters. This document is typeset in LaTeX.
Cover Page
- Fill in all required details below, before time is up.
- Ensure that all materials (answer sheets, graphing paper, practical question paper) you intend to submit for grading have been attached. Amendments to any answer script after it has been collected will not be entertained.
- Details on each side of answer sheet:
- Your participant code.
- Question number.
- Page number – continuous from 1 to N throughout your answer script.
- DO NOT WRITE YOUR NAME ON YOUR ANSWER SCRIPT.
- Order of answer script:
- Stack 1: i. This cover page.
ii. Summary Answer Sheet iii. Answer sheets from Part 1 to 3, in continuous order from page 1 to M. - Stack 2: i. Answer sheets for Part 4, in continuous order from M to N.
ii. Graph(s) from Part 4. - Stack 3: i. Practical cover page.
ii. Practical Component from Part 5.
1 Section A [12]
Write all your responses in the summary answer sheet provided.
Section B(1): Short Questions [36]
This section contains a total of 5 short-length questions worth 9 marks each.
You are to choose 4 to do.
Section B(2): Medium Questions [18]
This section contains a total of 2 medium-length questions worth 18 marks each.
You are to choose 1 to do.
Practical Cover Page
INSTRUCTIONS TO PARTICIPANTS:
- Fill in all required details below, before time is up.
- You are to detach this page and all subsequent pages as part of your response.
- All detached pages are to be re-stapled and be part of your 3rd stack of your answer script.
- All responses to this section of the paper are to be written on the question paper itself, in the spaces provided.
- There will be a star chart provided as part of the question. Responses to the corresponding questions in that section are to be answered on the star chart itself.
- All final responses shall be written legibly and unambiguously.
- Details on each page:
- Your participant code.
- DO NOT WRITE YOUR NAME ON YOUR ANSWER SCRIPT.
Section A
Each question is worth 2 marks.
Summary of answers:
| Q1 | Q2 | Q3 | Q4 | Q5 | Q6 |
|---|---|---|---|---|---|
| D | C | A | C | B | B |
Условие
Answer ALL questions in this section.
You’re suddenly teleported to the antipode of Point Nemo (41.123° N, 56.607° E). Even though you’re at the opposite end of the “loneliest place on Earth”, you’re still stuck in the middle of a desolate desert in Kazakhstan-Uzbekistan border, and you’ve resigned to your fate. To kill time, you’ve decided to do some night sky observation.

Luckily for you, you have 2 watches! But you remember that’s because one of them is faulty… You read the watches and they read as follows:
Watch 1: 20th March 2021 07:20 a.m. (GMT+8)
Watch 2: 9h 28m 25.68s
Where both watches read the local time and local sidereal time respectively.
Thankfully, your obsession with the constellation Boötes resulted in you being able to precisely remember the equatorial coordinates of Arcturus (14h 15m 38.22s, +19° 10’ 10.0”).
1. For starters, let’s get your bearings straight. Mark on the star chart the cardinal directions (North, South, East and West) right outside the boundaries of the star chart with ‘N’ and ‘S’ respectively. The size of the letters should be similar to this font size. [1 т.]
2. Trace and label BOTH the ecliptic and meridian. [2 т.]
3. You remember a village elder from a nearby village said that today is the Vernal Equinox. Knowing this,
3.(a) Mark with an ‘X’ on the boundary of the star chart where the Sun would rise. [1 т.]
3.(b) You suddenly remember that watch 2 is the faulty watch. Provide an estimate to what a correct reading should be. [2 т.]
4. Now, for observation,
4.(a) Is the Summer Triangle visible? What are its 3 constituent stars? Clearly mark it on the star chart by connecting the 3 stars and label it. [2 т.]
4.(b) Is the Keystone in Hercules visible? Clearly mark it on the star chart by connecting the stars that comprise this asterism and label it. [1 т.]
4.(c) Clearly mark and label ANY 2 of the following constellations (They must be fully visible):
- Aquila
- Scorpius
- Sagittarius
- Ophiuchus
- Perseus
- Lupus
- Cepheus
- Orion
Note: As long as all of the lines fall within the constellation boundaries, the answer will be accepted [4 т.]
4.(d) Circle clearly and label ANY 3 of the following Deep Sky Objects (They must be visible):
- M4 Crab Globular Cluster
- M16 Eagle Nebula
- M41
- M29 Cooling Tower
- C94 Jewel Box
- M44 Praesepe
- C80 Omega Centauri Cluster
- M45 Pleiades
- C102 Southern Pleiades
- Small Magellanic Cloud [6 т.]
4.(e) A prominent star has been omitted from the star chart this whole time.
4.(e) i. Circle the approximate location of the star and identify the star. [2 т.]
4.(e) ii. Name ONE Deep Sky Object that lies within the constellation boundaries this star is in. [1 т.]
Отговори
- 3.(a) East
- 3.(b) LST = 14h 57m 19.2s ± 5m
- 4.(a) Yes; Altair, Deneb, Vega
- 4.(b) Yes
- 4.(c) Accepted: Aquila, Ophiuchus, Cepheus
- 4.(d) Accepted: M4 Crab Globular Cluster, M16 Eagle Nebula, M29 Cooling Tower, M44 Praesepe
- 4.(e) i. Regulus (in Leo)
Решение
3. (a) ‘X’ should be marked on East. A1
(b) LST = 14h 57m 19.2s ± 5m A1
Given that the RA of Arcturus is 14h 15m 38.22s, we can estimate the LST of the observer by considering the distance between Arcturus and the meridian. M1
4. (a) A1
Yes, refer to star chart.
- Labelling
- Tracing
Full credit will only be given if the asterism was correctly traced and identified; Else, 0 credit. A1
Altair, Deneb Vega
0 Credit if any of the 3 stars were misidentified.
(b) A1
Yes, refer to star chart.
- Labelling
- Tracing
Full credit will only be given if the asterism was correctly traced and identified; Else, 0 credit
(c) A2
Accepted answers: Aquila. Ophiuchus, Cepheus
If the constellation lines lack labels, deduct 0.5 points; If the constellation was misidentified, 0 credit; 0 credit if any traces lie outside of constellation boundary.
(d) A2
Accepted answers: M4 Crab Globular Cluster, M16 Eagle Nebula, M29 Cooling Tower, M44 Praesepe
If the DSO lacks labels, deduct 0.5 points; If the DSO was misidentified, 0 credit; 0 credit if most of the DSO identified does not fall within their respective circles drawn in part (c)
(e) A1 A1
Refer to star chart.
Regulus, Leo

Оригинал в Архива: SAO 2021 Question Paper.pdf · официални решения: SAO 2021 Compiled Solutions.pdf