Part VI

Keele Observatory project

63

Chapter 12

Keele Observatory project

Goal-of-the- Write an observing proposal and evaluate other observing proposals.

12.1 Keele Observatory

Today’s project takes place at Keele’s Observatory, situated at the highest elevation on the Keele campus. It is host to a 31 cm refractor dating from the 1870s, and a computer- controlled CCD-equipped 60 cm reflector that is also used for scientific measurements.

12.2 Telescope time application process

Most world-class observatories are run by consortia of institutes or national research councils, and many astronomers would wish to use their telescopes. The decision to allow a certain astronomer to use the telescope is made via an application process, in which the astronomer (or more often a team of astronomers) submits an observing proposal to a Time Allocation Committee (TAC). On the basis of the quality of the scientific justification and feasibility of the proposed observations, the TAC decides to allocate (or not) a certain amount of observing time to the applicant(s). The observing proposals need to be in by a strict deadline (late submissions are usually ignored), which usually happens twice a for observations to be proposed for a half-year period (“observing season”). Today you are going to write your own observing proposal, and you will join a TAC to evaluate the proposals.

12.3 Writing an observing proposal

The deadline is for Tuesday 5th May 2020, 16:30 UK time. You are applying for observing time either at Keele Observatory (geographical latitude +53◦) or at the Southern African Large Telescope ( 32◦), the largest optical telescope of the world which was taken into − operation in 2005 and in which Keele University has a (small) share. The observing season you are applying for runs from October until March inclusive. In the middle of this season, objects with RA 5h will cross the meridian around midnight, making them visible for most of the night≃ — depending on their though.

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In Table 12.1 you find a list of targets, from which you will have to choose one. In Table 12.2 you find some information about the two observatories, with a list of available instruments from which you also have to choose one. Application forms are available at the observatory. You may use a bit of imagination to make up the scientific aim of the observations, but try to be as realistic as possible, relying on your current general knowledge of astronomy. Introduce the topic and target, and be specific about what you are after and how the proposed observations are going to achieve this. Table 12.1: Objects to consider for your observing proposal. Object RA(hms) Dec(◦ m s) Description d Betelgeuse 05 55 10.3 07 24 25 Red supergiant, mV =0.6, variable: P = 2000 ◦ M 33 01 33 51.0 30 39 37 Spiral , mV 6, diameter 1 ∼ ∼ 51Pegasi 225728.0 204608 Solar-typestar, mV =5.5, harbours planets 47Tucanae 00 24 05.2 72 04 58 , brightest stars mV 12 − ∼ M 87 12 30 49.4 12 23 28 Elliptical galaxy with nuclear jet, mV,total =8.7 3C273 122906.7 020309 Quasar,redshift z =0.158, mV = 13 TWHydrae 11 01 51.9 34 42 17 (mV 11) in a young M42 053517.3 −05 23 28 Star forming region∼ (Orion ) − Wasp-17b 15 59 51.0 28 03 42 Exoplanet with detected atmosphere − Table 12.2: Observatories and instruments. Observatory Instrument Description Keele ST7 CCD Imaging camera, blue and red filters, pixels 1′′, field 10′ SALT SALTICAM Imaging camera, blue and red filters, pixels 0.2′′, field 5′ SALT RSS Spectrograph, resolution 30 km s−1, 30 objects at once SALT HRS Spectrograph, resolution ∼ 5 km s−1 ∼ Exercise 12.3 (a) Write and submit your own observing proposal along the guidelines given above.

12.4 Time allocation procedures

The TAC will have to decide which proposals are feasible and whether they are worth spending valuable observing time on. Usually proposals that are technically feasible are then ranked according to their scientific merit. Depending on how much observing time is available, this time will then be distributed amongst the proposals with the highest ranked proposals being served first, and proposals below a certain threshold not being allocated (even if enough observing time were available). The amount of time allocated to a certain observing programme may also differ from what the proposal asked for.

Exercise 12.4 (a) Make a TAC with about 5 members and select a TAC chair; (b) Plan on how to assess the observing proposals; divide tasks amongst the TAC members as appropriate; (c) Rank the proposals; (d) Report and justify your proposal ranking.