This interface allows you to search the LT data archive. It effectively generates observing logs for any set of observational (e.g., instrument configuration) or administrative (e.g., project P.I.) criteria. You can then preview JPEG versions of your data or download individual reduced images.
With the exception of certain calibration data (e.g., photometric standards), LT data are generally proprietry until one year after the completion of the programme for which they were obtained and are held online in password protected web space. The PI of each programme should have been notified of their password.
Full details on formatting queries are given below, but here are the few main points you need to know:
Text in the criterion box is matched as an exact sub-string. No wild cards are available. Multiple words in the box are combined with an implicit AND operator. The character "|" is available as an OR operator. For example, "fred | jim", will match anything that contains "fred" or "jim" as a sub-string. Entering "fred jim" will find anything that contains both "fred" and "jim" as substrings. Either of the above searches would match a field in the database containing "freddy is jim's friend". Search are case insensitive.
Any of the following comparators are allowed: = < > ~ ±.
The ~ symbol is an alternive for ±, since the latter is not always easy to enter, depending on
OS, keyboard etc. For example, to select values in the range 10 to 20, you can type
any of ">10 <20" , "15±5", "15 ~5" or "=15 ~ 5" into the criterion box.
If you use a mutually inconsistent set of comparators (for example < and ~), an error message is written out, but the process is not aborted. The search continues using any valid limits which were specified. The only valid pairings of comparators are (=,~), (=,±) and (<,>).
A simple number in the box is assumed to have an implicit "=". Take care of this. For exmaple, entering "0.8" in the "Seeing" field will return only those images of precisely seeing=0.8 with no tolerance, which in most case will be none or very few.
Highlighting more than one item, will find observings which match any of the selections. I.e., multiple selections are combined with an OR operator. The exception is 'Filters' where you have a choice of AND or OR.
Deselecting a selected item is browser specific, but most commonly it is "<Control> click" or "<Apple> click" with the mouse.
Name:
Name of object for which you wish to search. This is of very little general use, since you need
to know exactly what object name was entered into the phase II database. It is only likely to be of use to the PI for whom the data were originally obtained.
See the definition of 'text fields' above.
Equatorial Coordinates:
RA may be entered as 'hh mm ss.ss', 'hh:mm:ss.ss' or 'dd.dd'
dec may be entered as 'dd mm ss.ss', 'dd:mm:ss.ss' or 'dd.dd'
You may use range criteria (<,>,~,± ) but only if you select 'Radial search mode: None'. Otherwise it would be unclear what you meant
by specifying both a box size and a range on the target position.
Galactic Coordinates:
Galactic l,b may only be entered in decimal degress ('ddd.dddd')
You may use range criteria (<,>,~,± ) but only if you select 'Radial search mode: None'. Otherwise it would be unclear what you meant
by specifying both a box size and a range on the target position.
Search radius:
Find pointings within this distance of the requested target position.
Format may be either 'dd mm ss.ss' or 'dd.dd'.
Resolver:
You can use one of these internet-based name resolvers (NED, SIMBAD) to get the RA,dec for a named
object. The co-ordinatesa (RA,dec or l,b) of the resolver's best guess at the object you wanted are
automatically entered into the form, overwriting any that you had typed in.
Names are not automatically resolved when
the search submit button is pressed. You must press the Resolve name now button yourself.
Date of observation:
Time of observation specified as the civil date or modified Julian day.
If the check box is set, the output table will contain the date in the format selected in the drop-down list.
Integration:
Standard 'numeric' criterion, so comparators and ranges are allowed.
Seeing:
Standard 'numeric' criterion, so comparators and ranges are allowed.
To find data with seeing values in the range 0.9 < seeing < 1.1, use either '1~0.1' or '>0.9 <1.1'.
Airmass:
Standard 'numeric' criterion, so comparators and ranges are allowed.
Instrument:
Standard 'selection list' criterion. Selections combined with implicit OR.
Frame Type:
All frames are flagged as to whether they are a science target observation or a calibration file. By
default the archive returns all frames, but you may constrain the search to contain only a certain
kind of exposure. Far the commonest use for this will be to select "Expose" which will reject all arc
frames etc.
Instrument Mode:
Standard 'selection list' criterion. Multiple selections are combined with implicit OR.
A small subset of the most commonly used configurations are described. Others can be added if a
specific use case arises. For example, you can currently search for SPRAT spectra taken in the
red or blue optimised modes, but the web form does not offer a preset to find SPRAT slit images.
Please contact us if you see other common instrument which you believe would be worth adding
here.
Imaging Filters:
Multiple selections may be combined with either AND or OR operators using the drop-down list on the form.
All the currently installed imagers have two filter wheels. A filter of "Clear" therefore refers to an empty
slot in one of the filter wheels. It is not a "clear" piece of physical glass. Conceptually, every exposure is
taken through two different filters, though in almost all cases, one of those is "Clear".
Binning:
Legal values are 1, 2, 3 or 4. This is a standard 'numeric' criterion, so comparators and ranges
are legal.
Wavelength:
This is not a central wavelength. The archive
will provide any spectra which cover the requested wavelength at any point.
Standard 'numeric' criterion, so comparators and ranges are allowed.
Resolution:
Standard 'numeric' criterion, so comparators and ranges are allowed.
Care: Note the lingustic subtlety here that greater resolution means a smaller number.
Units are Angstrom (Å). For example to find
data with a resolution better than 2Å, use '<2'.
Dispersion:
Units are Angstrom per pixel (Å / pix).
For example to find
data observed with a dispersion better than 5Å/pix, use '<5'.
Care: Note the lingustic subtlety here that greater dispersion means a smaller number.
Standard 'numeric' criterion, so comparators and ranges are allowed.
Processing Level:
For certain instruments the archive may contain simple reductions which have removed the basic
instrumental signatures such as bias, dark and flat field and also derived products
where the automated pipeline has generated 'value added' products. For example, with IO:I
the basic 'level 1' option provides fully reduced versions of each individual dither position and
the 'level 2' derived product is an aligned, co-added stack of the dithers to give a final
full integration image.
For the spectrometers, the 'level 2' data product will include an
extracted, wavelength calibrated spectrum whereas the 'level 1' product, when present in the
archive, is simply a reduced CCD frame.
By default all available data are returned. Select an option to constrain the search to a limited range of data products.
Adheres to the conventions for Selection Lists as defined above.
Group ID:
Arbitrary ID string selected by the PI when group was entered into the phase 2 database. Follows the standard matching rules for 'text fields'
defined above.
Observation ID:
The concept of ''observation ID'' does not exist from semester 09B onwards; i.e., after 2009-08-01. The finest granularity to which an observation is defined is now
the ''Group ID''.
Arbitrary ID string selected by the PI when group was entered into the phase 2 database. Follows the standard matching rules for 'text fields'
defined above.
Display thumbnail images:
Select this check box to include a small thumbnail of the data in the search results. The image is not displayed
for data still in their proprietary period. Obviously this can significantly slow down the loading of your
search results.
Return plain text search results:
By default the search returns a formatted HTML table to your browser and also a plain text file of the results
which is avilable from a link at the foot of the search results page. Selecting this option disables the
HTML table and returns just a link to the plain text file. This option may be useful if your search
returns many (>10000) results, since the results page can render a lot more quickly.
Maximum records to return:
Some search criteria will return many thousands of matching observations. In order to protect you from your
web browser trying to load them all, this parameter can be set. The search results page will inform you if the
reply table has been truncated. You may set this parameter arbitrarily large if you really want to return all matching
observations.