Finding Charts

Finding charts should be submitted through the Phase II system in your program tab (created once the TAC awards time to the PI) as pdf files. For multiple targets it is best to name the PDF files exactly like the target names, ie. one PDF file per target. This will allow us to bring up the finding chart automatically for every target and thus save setup time and possible confusion.

A tar or zip archive of pdf files is allowed.

Each finding chart must have a field of view of approximately 4 x 4 arcminutes (HRS targets can be 2 x 2 arcminutes), with North at the top and East to the left, and must be clearly labeled with the following:

  • PI name
  • Program number
  • Object name
  • Object right ascension
  • Object declination
  • Coordinate equinox
  • North indicator (at top)
  • East indicator (at left)
  • Size of charts (in arcmin, preferably 4x4 for LRS or 2x2 for HRS)
  • Target should be clearly labeled and preferably centered, never near chart periphery
  • Offset stars should be marked and labeled
  • The name of the .xy offset file or .cfg mos file should be cited
  • It is very helpful to cite "high proper motion" if appropriate
  • If more than one object is expected to be on the slit, mark each and cite the PA
  • Stars should appear dark on light background,also for the mos array cfg layout picture. Lots of large blacked-in finders is bad for our printer cartridges.
  • All faint targets must have finding charts
  • If a target is faint and of distinctive color please make that information clear to us. We can perhaps set up using a B or I filter better, at the margins of feasibility (e.g. a faint blue nova in a crowded but reddish extragalactic starfield).
  • When a faint target will fade into crowded surrounds, the chart must have sufficient depth and scale to prevent confusion
  • Please use an identical identifier on the finding chart name as on the submitted TSL target name. We would rather not have to use simbad to research matches between SDSS, IRAS, BD, NLTT, TYC, [C93], etc. identifiers

For MOS setups

  • Follow the above for the initial imaging of the MOS fields if you are not using astrometric setups.
  • You can create the MOS field slitlet setup picture using the makemos package. We have found that such a picture, while useful once the field is identified and centered, is generally unsatisfactory as a "finder." Please send a finder for the field also, centered on the approximate center of the MOS array. IMPORTANT: Please use consistent naming for the target, finder, makemos slitlet setup picture, and cfg file that belong together. If you revise the target name for example, please send us an email showing the explicit name changes you want, so we can keep each foursome from diverging in names. This is especially critical for a large list of MOS targets with revisions and renamings during Phase III.

One way to prepare good finding charts is with the utilities at
this link.

For targets that are very bright the PI need not supply a finding chart IF they are absolutely sure that no confusion will occur with targets within 2 arcminutes and 2 magnitudes. If a PI chooses to not provide a finding chart and some confusion occurs at the telescope the PI will be charged for the wasted time. Occasionally even for a bright star (thus no finder), it is a good idea to put a comment early in the target comment line like "the N one of pair", "SE of brighter star", etc. to guarantee that the ID is unmistakeable (potentially saving the PI some overhead).

Carrying Forward Finding Charts

To spare wasted effort and resources, long term active programs often carry over finder charts from one trimester to the next. This can get rather ad hoc , with RAs rummaging through old file boxes in the AM hours in a hurried search. What we mainly need at the start of each trimester is the explicit following information as a kind of prompt for us to do the correct preparation: (a) Please propagate all of last trimester's finders to the new trimester folder. (b) Please propagate only the following old object finders to the new trimester folder. (c) No past trimester finders will be needed. This prompting will make sure we avoid last minute scrambling for a finder, or on the other hand stuffing folders with irrelevant passé finders.

Guide Stars

At the present time the PI is not required to mark the guide star on the finding chart BUT not finding guide stars for LRS fields has been found to add significantly to the overhead charged to the PI! Thus we recommend trying to mark the guide stars:


If you feel the need to mail or delivered charts or ancillary material to the HET please use:

HET Astronomer
82 Mount Locke Rd.
McDonald Observatory TX 79734

or if a street address is required (FedEx, UPS)

HET Astronomer
32 Mount Fowlkes Rd.
McDonald Observatory TX 79734

Last updated: Wed, 08 Aug 2012 15:40:05 -0500 shetrone

Phase II


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Keyword Table

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TSL Control of Calibrations

Program Notes

Finding Charts

(old format: Description)

(old format: Examples)

(old format: Checker Utility)

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