Requesting Observing Time and Delivered Data

As a user of a Tenagra telescope you are assigned a place on our FTP server. Each user uploads an ASCII file in a defined format so that the scheduler can read all requests and place them in optimal order. You just need to specify the night(s) in which you wish to observe each target; the scheduler will choose suitable observation times for each of your targets.

Please follow these guidelines when uploading observation requests to our FTP server: Files containing observation requests must contain only observation requests in the format to be described below. Each observation request consists of a single line. Do not use tabs to format the columns.  The name of files that contain observation requests cannot have blank characters. Files containing observation requests must have extension '.txt' Files containing observation requests must be uploaded to the root directory of your FTP area, not to any of your subdirectories. Observation requests meant to be carried out on the next night at Tenagra must be uploaded to our server before 22:00 UT. For example, if you wish to observe some target on 2009 Sept. 20 UT, the deadline for uploading your observation request is 2009 Sept. 19, 22:00 UT.

After each uploaded file containing observing requests is processed by our software, a receipt will be sent to you by e-mail and also placed in subdirectory /receipts of your FTP area. You should check this receipt to see if your observing requests were accepted; if some requests were not accepted, the reasons for the rejections will be given. The receipt also lists the serial numbers assigned to each of your accepted requests. These are unique numbers which identify each of your observing requests in our internal bookkeeping system.

If you decide to cancel some of your observation requests, please contact us as soon as possible, specifying the serial number(s) of the request(s) you wish to cancel. The above 22:00 UT deadline also applies to the cancellation of user requests.

This section describes the five types of observation requests which we can accept at this time. Click on the links below for a detailed description of the format of each type of request.

1. Non-solar system objects.
This category includes every object that is not in the solar system (therefore not moving with respect to the stars), from the closest stars to the most distant galaxies.
2. Solar system objects with a published ephemeris
. Targets in this category must have ephemeris available at the Minor Planet Center's web site (at either the Minor Planet & Comet Ephemeris Service or at the NEO Confirmation Page). Our system does not require you to submit the ephemeris data, it automatically gets this data from the MPC web site.
3. Solar system objects without a published ephemeris.
These objects will usually be new, relatively slowly moving objects discovered by you or some other observer, which haven't yet received an official designation from the MPC, and therefore need to be confirmed on a second night. This option makes the assumption that the target moves slowly enough that a Väisälä ephemeris generated with the New Object Ephemeris Generator is accurate enough to get the object in the telescope field-of-view over a period of a few days after discovery. If you discover a fast moving object or a comet, you should report it to the MPC immediately, without waiting to get images on a second night.
4. Mosaic searches for new solar system objects.
This mode allows you to do a mosaic search for comets or minor planets. The Tenagra telescopes allows you to easily discover minor planets whose magnitude is fainter than the limiting magnitude reached by the Catalina, LINEAR and NEAT surveys. You can confirm your (slowly moving) discoveries on a second night using observation requests of type (3). If you discover a fast moving object or a comet, you should report it to the MPC immediately, without waiting to get images on a second night.

You will be notified by e-mail when some of your observing requests are carried out. These notifications will also be placed in subdirectory /notifications of your FTP area.

Your images will be placed in your FTP area as they are taken, in a separate directory for each night and telescope. For example, your images taken with the 32-inch telescope on 2006 Sept. 25 UT will be stored in directory /060925_32in. The directory corresponding to a given night will contain the following subdirectories:

Subdirectory /images contains your raw science images, which will appear in the subdirectory as soon as they are taken by the telescope. If you wish to download your images in near real time, you may use a FTP client (such as the Windows program Bullet Proof FTP) which can be configured to continuously monitor the subdirectory /images and automatically download new images as they appear. In this way, you can usually have all your night's data on your computer soon after the images have been taken.

Your science images will be named AAAnnnnn.fit, where AAA is your 3-character user ID and nnnnn is a 5 digit number. These numbers are not significant from the user's point of view. All the information you need is in the FITS headers of the files.  Automated e-mail notifications are sent to you when observation requests are carried out.  They list (among other things) which image files correspond to each of your observational requests.

You may choose between three options for compression of your science images: zip, FITS compression, and no compression. Compressed images will lead to a reduction of roughly 50% in download time. Zipped images may be unzipped with standard programs such as pkZip, WinZip, etc. Opening FITS-compressed images requires the Windows program MaxIm DL. If you use MaxIm DL for your image calibrations, FITS compression is probably the most convenient compression method.

At the end of the night at Tenagra, a file named calibrate.zip is created in subdirectory /images. This zip archive contains all the master calibration files (bias frames, dark frames, flat fields) which are necessary for the calibration of your science images. The master bias and dark frames are obtained by median combining three individual bias and dark frames, respectively. The dark frames have an exposure time of 150 seconds; you are supposed to scale the master dark frames when using them to calibrate exposures whose exposure times are not equal to 150 seconds. The master flat fields are obtained from 3-15 individual sky flats, which are bias- and dark-subtracted and then median-combined.

We automatically take flat fields in the morning and evening. Flats for R, V-band and unfiltered are taken in the evening twilight and stored in subdirectory /EveningFlats. Flats for B and I-bands are taken in the morning twilight, following the run, and stored in subdirectory /MorningFlats. If your observations do not include images taken in the B and I bands, all your flat fields will already be available at the end of astronomical evening twilight at Tenagra.  You may of course use flats from a previous night if you wish.

Bias and dark frames are always taken in the evening before observations, and stored in directories /Bias and /Dark, respectively.

If you do not wish to wait until the calibrate.zip file appears in subdirectory /images, you may retrieve your calibration files from subdirectories /Dark, /Bias, /EveningFlat, and /MorningFlat. We store both the individual calibration files taken with the telescope and master calibration files which are produced by median combining the individual calibration files. You will probably wish to use these master files for your calibrations; the individual calibration files are provided in case you wish to prepare your own master calibration files by combining the individual calibration files.  NOTE:  Master images created by median combination of images have a PEDESTAL value of -100.  If you wish to create masters (bias, dark, flats) with PEDESTAL value 0, then perform your own median combination of the raw images.

Our naming convention for master flat fields is MasterFlat_binN_BAND_OPT.fit.

This looks a bit complicated but it isn't. All master flat frames have the prefix MasterFlat. Following this is the binning of your image. This is bin1 or bin2 for unbinned or 2X2 binning. BAND is the filter used: clear (unfiltered), U, B, V, R, I,. OPT is an optional part of the name that will contain Center or not be present. Center means that the central 7.4 x 7.4 arcminute field of the CCD detector has been used. Some examples:

The names of dark and bias frames are quite similar except there is no BAND: MasterNAME_binN_OPT.fit, where NAME is either Dark or Bias. Some examples:

The names of individual calibration files follow these conventions:

where binN, BAND, and OPT are as explained above and nnnn is a 4-digit number.

On rare occasions, bad weather or other problems prevent us from obtaining a full set of calibration files. If this happens on a night when we have obtained science images for you, you will notice that the calibrate.zip file either will not be created (if none of your calibration files has been obtained) or will not contain all the calibration files you need. In these cases, you should search the directories which store the images from the past few nights, where you will normally find the calibration files you need. Unless there has been a change in optical or camera configuration, calibration images from a previous night will be virtually identical to those taken on the current night..

The directory corresponding to any given night is kept on the FTP server for 10 days, and is then moved to another computer for back-up storage. If you need to download data which is more than 10 days old, please contact us, so we can temporarily restore it to the FTP Server.

If some of your images are seriously affected by clouds, please send us an e-mail mentioning the UT date when the images were taken and the file names of the affected images, so we may provide a refund.

If you have questions about the the observation request format or about the above processes please e-mail them to mbs@tenagraobservatories.

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