Preparing an Observation Request on LCO

Summary

If you're new to observing using LCO, this is a good place to start.

Planning

Materials

To schedule observations on the LCO network you will need a user account. To register as an education user, speak to one of our Education Partners.
Computer w/ internet connection,
Stellarium,
Observation Planning Worksheet (.docx)

Background

Las Cumbres Observatory

Las Cumbres Observatory (LCO) is a global telescope network consisting of two 2-meter telescopes, thirteen 1-meter telescopes, and ten 0.4m telescopes.

Requests on the LCO network do not identify specific sites or telescopes, however the telescope aperture class (e.g. 0.4m telescope) may be defined. The telescopes of each aperture class are identical. LCO’s scheduling software (or simply “the Scheduler”) assigns each observation request to the best telescope available, and reassigns it to the next available telescope if the initial attempt fails (due to weather or technical problems).

For education projects users will be offered observing time on the 0.4m telescopes only. The 0.4-meter network includes two telescopes at Siding Spring Observatory in Australia, one at Sutherland Observatory in South Africa, two at Teide Observatory on Tenerife, two at Cerro Tololo Observatory in Chile, one at McDonald Observatory in Texas, and two at Haleakala Observatory in Hawaii.

Atmospheric effects on observations

As light from cosmic objects makes its way through the Earth's atmosphere, photons may collide with atoms and molecules. The photons may be absorbed by these particles or scattered in different directions. Either way, they no longer reach the telescope on the ground. As a result, the observer detects fewer photons from the star than would have been seen on a planet without an atmosphere. We call this “extinction”. The amount of extinction is directly dependant on how much of the atmosphere photons must pass through. Astronomers use the term “airmass” to describe this: one airmass is the amount of air directly above an observer. So, if you are looking at a star at the zenith, you are looking through one airmass.

Instructions

Students will carry out an observing session on the LCO robotic telescope network, using astronomical catalogues and planetarium software to determine target objects suitable for observation with the instruments available, within the allotted time window. Students will select appropriate observation parameters including filters and exposure times.

The LCO network is used by thousands of astronomers, communicators, educators and students around the world. To ensure telescope time is used efficiently, it’s essential that users take the time to adequately prepare before scheduling observations. Select a date to submit your observations and begin preparation at least two weeks in advance. Before submitting your observation request, you must complete the planning checklist below:

Define your Time Window
Select a visible target object
Check target dimensions
Select a suitable exposure time
Check for previous archive observations

1. Define your Time Window

Select the time period within which you'd like your observations taken, we recommend a minimum length of one week. Enter the time window on your Observation Planning Worksheet.

2. Select a visible Target Object

While star maps can be useful for locating naked eye objects, they often only show the brightest stars in the sky. However, many resources are available to help you select a suitable deep-sky target, we recommend using the free planetarium software, Stellarium, which can be downloaded from: http://www.stellarium.org

Las Cumbres Observatory have created a guide on how to plan an observing session using Stellarium: https://lco.global/education/article/how-plan-observing-session-stellarium/

When you open Stellarium, it will adopt the date and time from your computer clock. Set the date and time on which you will be submitting your observation request. Be aware that you will be entering the time at one of the telescopes, be careful to take note of the time zone of the telescope by referring to the table below. Next, set the location to match one of your chosen 0.4-meter telescope by entering the coordinates and altitude from the table below.

Observatory	Latitude	Longitude	Altitude (m)	Time Zone	Telescopes
Siding Spring	31° 16′ 23″S	149° 4′ 15.6″E	1,116	UTC+10	0.4m
Teide	28º 18′ 00″N	16° 30′ 35″W	2,330	UTC	0.4m
Cerro Tololo	30° 10′ 2.64″S	70° 48′ 17″W	2,198	UTC-3	0.4m
McDonald	30° 40′ 12″N	104° 1′ 12″W	2,070	UTC-6	0.4m
Haleakala	20° 42′ 27″N	156° 15′ 21.6″W	3,055	UTC-10	0.4m

Stellarium will now be displaying the sky that will be visible from your chosen observatory during your time window. Search for a selection of potential deep sky objects that are located at least 10 degrees above the horizon, although 30 degrees is recommended. Remember that your target object must contain several visible stars, recommended object types are open clusters or globular clusters. Click on an object in Stellarium to see the “Type”. Enter the name of each target on your Observation Planning worksheet.

Visibility Plot: When scheduling your observations, after you have defined your time window a plot will appear showing the visibility of your target object at the 0.4-metre observatories during this period. Each site is coded with a different color and visibility is shown as the change in airmass (essentially, the amount of atmosphere through which light from the target object must travel) of the target over time.

4. Check target dimensions

The amount of sky visible through a telescope at any one time is called its Field of View. When choosing your target keep in mind the field of view of the SBIG camera aboard the LCO 0.4m telescopes. Information about the instrument can be found in the table below.

The dimensions of your target object(s) can be found in astronomical catalogues and online databases. SIMBAD is an astronomical database that contains information on most of the known cosmic objects, including the angular size, distance and morphological type.

Go to the SIMBAD website at http://simbad.u-strasbg.fr/simbad/.
Select “Basic Search” and enter the name of each target object.
Check the object’s angular size to ensure it will fit into the field of view of the telescope. Details of the instrumentation on board the 0.4m telescopes can be found in the table below.
Enter the dimensions for each object on your Observation Planning worksheet.

Telescope Class	Instrument	Field of View	Appropriate magnitude range
0.4-meter	SBIG STX-6303 (optical imager)	20 arcmin x 30 arcmin	6-18

5. Select a suitable Exposure Time

The exposure time is how long the telescope shutters stay open and light is collected from your target object. A suitable exposure time must be selected: if the exposure time selected is not long enough, the target object will appear too faint, while over-exposure leads to saturation and loss of detail.

The table below provides a very rough guide to exposure times by object time. Exposure times can be found by looking at the previous observations in the LCO archive (learn how to navigate the archive below).

Go to https://archive.lco.global/
Enter the name of your target in the Point field.
Set the date range to “All time“ using the calendar at the top of the left menu.
Set the Telescope field to “0M4A”, which is one of the 0.4m telescopes.
You will see the exposure times (Exp. Time) for any listed observations.

Object Type	Usual exposure range (seconds)
Galaxy	50-300s
Nebula	60-120s
Star Cluster	10-60s

6. Schedule your observations

Ensure that you have completed each section of the planning checklist before going further. At this point you should have selected at least one target object to observe and know the exposure time needed. Note that even If you have more than one object, due to the LCO scheduling system, you do not need to worry about the observing order.

To schedule your observations, refer to the the LCO observing webpage, there you will find an instructional video, a quick guide to observing, and an FAQ.

7. Download your data

Once you’ve submitted your observations, if successful they will be returned within your defined time window. All submitted requests are listed on your LCO Observing home page.

To download data, select the row that contains the data you wish do download using the checkbox (multiple rows can be selected at once), then click the download button. You will be prompted to download a .zip file containing your data.

Activity