1 Purpose - sparky.rice.edu

1 ASTR 230 ASTRONOMICAL LABORATORY - SPRING 2016 LAB#1 INTRODUCTION TO TELESCOPES AND OBSERVING TECHNIQUESDue: Tuesday, February 23, 2016 in class1 PurposeThe Purpose of this project is to introduce you to the basic characteristics of telescopes andfamiliarize you with observing techniques that you will need for your projects. In the processof doing this lab you will learn to identify constellations and enjoy observing several celestialobjects. Initially the lab assistant or instructor will be present to assist you, explain things,fix things that do not seem to work right, etc., but in the end you must do the actualobserving and writing of the lab report.

2 Students will observe together in small groups(typically two people), but each person should make and report their own others is not the way to learn how to observe (thoughthere are some benefits inworking with an experienced observer).This laboratory will take several outside observing periods to complete. An observing periodis about 3 hours or more under good (less than 50% cloudy) weather conditions. You areencouraged to observe as long as you can if you have a clear skyand low humidity (rarein Houston!). While all of the observing for the first lab can be done on campus, some ofthe exercises such as identifying constellations are much easier to do at a dark site suchas George Observatory in Brazos Bend State Park.

3 You are encouraged to make a trip toGeorge for one of their public viewing nights held on the weekends. Alternatively, we willhave at least one night where the class may come to the prof s house in Manvel to observewith the Meade 10 . These sessions where someone finds the objects for you do not countfor the Deep Sky part of the lab, but they are a fun way to see a lot of different objects inone observing you begin, you will need to read the material assignedin class, and work with thecomputer program Stellarium (get a copy on-line, current vesion seems to be ).2 PreparationGood preparation is essential for success in this and any observing project.

4 An observationalastronomer usually has to spend much more time preparing foran observing run than actualobserving. Before you touch a telescope, you should: Carefully read this entire writeupbeforeyou go out. Do the portions of the lab that don t require a telescope working with Stellarium, andconstellation Study the star charts in your reference book of choice to find out which stars and planetsare visible by going outside your home or college if weather permits to check out what isup there before observing with the telescopes. Buy yourself a flashlight and lab record book and be sure someone in your group has awatch/phone with a working timer (or analog equivalent).

5 Your time at the telescope will be spent more efficiently if youknow the basics of telescopes(types, magnification, f-ratio, resolution, etc.), the equatorial coordinate system (right ascen-sion (RA), declination (DEC), sidereal time (ST), universal time (UT), meridian, celestialequator, zenith, etc.), the astronomical stellar magnitude system (apparent magnitude, colorindex, etc.), and the nature of the object (the Moon, planets, star clusters, nebulae, galaxies,etc.). Most of this will be explained in our weekly lectures,but you may have to do someoutside reading on your Lab AssignmentThe assignment consists of several activities that don t require a telescope which are meantto introduce you to how celestial objects move in the sky and what types of objects arecurrently visible.

6 The observing program consists of exercises that first familiarize you withthe performance of the C8, and then develop your observing skills by identifying variousobjects. Section can be done without a telescope, and youshould do this first. & introduce you to the operation of the telescope and can be completed your firstnight. The remaining portions of the lab can be done on the second or third nights ofobserving, while observing that requires dark skies may be done at George Observatory orin Manvel south of will need to write up the answers to the questions in each section in a lab report, sotake good notes about what you are Stellarium (telescope not required)Stellarium is a very useful program for studying the sky and identifying objects for telescopicstudy.

7 It saves hours of work in preparing finder charts and obtaining current coordinatesfor both amateur and professional observing. It s also fun to play with, so feel free to explorethe night sky via computer simulation beyond what you are directly instructed to do. Youcan get plots of the night sky at any place and at any time of theyear (including thousandsof years in the past or the future). It can be used to find many objects by name, show wherethey are in the sky, make finding charts of the fields where theyare located, show picturesof numerous objects, animate the motions of the sun-moon-planets, mustdo this part before you observe.

8 You can work with the computer software at yourconvenience, but do this before beginning your first outdoorsession. You will need severalhours to do this, so don t wait until the last minute and thinkyou are going to do this while2observing. Using the programs is good cloudy night astronomy program is generally self-explanatory, and you simply need to spend some time with itso you know where to look for the feature you want. When you first open the program itwill launch a full-screen window that depicts what it thinksthe sky should look like at thetime and location it inferred from your computer. You may need to set these as describedbelow.

9 First though, familiarize yourself with the two menubars. Thebottom menucan befound by sliding your cursor to the bottom-left of the window. A horizontal bar will appearthere detailing about a dozen options. Hover your cursor over the icons. Briefly, these arefrom left to right: Constellation Lines: Toggles lines on-and-off between stars to help you see constellationpatterns. I usually turn this on. Constellation Labels: Toggles the names of the constellations. There are 88 of them in leave this on as well usually. Constellation art: This is rather amusing, but allows you tosee, for example, what Herculesis supposed to look like. Hmmm.

10 Somebody 3000 years ago had a good imagination. I findthis distracting and leave it off, but it is a fun thing to toggle. Equatorial grid: This is the key coordinate system used to identify objects in the sky. Itis what we will spend time learning, and it essential to know when at the telescope in orderto determine what is up in the sky at any given time. The visibility of any object dependson the time, date, year, and location on the Earth. It looks a lot like longitude and always leave this on. Azimuthal grid: Another spherical coordinate system. Thisone determines how far abovethe horizon an object is situated, and its azimuth ( , north, south, northeast).