Instrument created

John Peterson

There isn’t a document (as this is one of the few capabilities we haven’t yet document). However, we can certainly help. First, you will need to create a new directory in the data directory. Then copy over all the files in the data/generic directory to get started. Then, you will first want to edit the optics files. Send me (John Peterson) an email when you start doing that if you get stuck, and I can help you further. Its not that hard, but we are still trying to streamline these files, yet make the detailed fidelity as deep as you want to make it.

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2019-09-26T13:03:02+00:00

Timmy reporter

Ok, so in the data/generic directory, star is a instance catalog and others are the necessary files for a instrument? So if I want to create my own instrument, just start from this file, right?

2019-09-26T13:25:15+00:00

John Peterson

yes

2019-09-26T14:43:03+00:00

Timmy reporter

ok, thanks for your help. I will send you email if I have any questions.

2019-09-27T00:25:23+00:00

John Peterson

closing. reopen or email if you have any more questions.

2019-10-01T13:29:07+00:00

John Peterson

changed status to resolved

2019-10-01T13:29:12+00:00

Timmy reporter

changed status to open

I have some questions on some items when I create a instrument. I don't understand the meaning of the followings items:

central_wavelengths.txt:

what is the meaning of column “approximate plate scale” and how to calculate it.

2. focalplanelayout.txt:

(13-18) 3 euler rotations, 3 translations;

(19-) deformation type, deformation coefficients, QE variation; what is the meaning of deformation and what is its object, chip?

3. segmentation.txt

(6-7) serialread, parallelread; in the data/lsst fold, these two items have 1 or -1, but I cannot understand what is the meaning of 1 and -1;

(8-15) there are 4 items: %variation, what is the meaning of "%variation"

(16-19, 21) also cannot understand. I noticed that in the lsst fold, 16-19 are set as 1 6 4 0, why? and is the values of hot column rate always equals to hot pixel rate?

4. star (instance catalog)

there two right ascension and two declination, first is in the header and another is in each object. if the second is star's parameter, what about the first one?

2019-10-03T08:05:08+00:00

John Peterson

Timmy,

start with getting the optics design in first. but to answer your questions:

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the approximate plate scale would be how the angle on the sky relates to the position on the detector. with complicated optical designs its easiest to ignore this value and then simulate two sources and determine there separation.
yes, focal plane layout is for all the chips.
the parallel and serial read correspond to whether the direction is positive or negative in x or y.

‌ % variation is how much it may vary from the nominal value.

‌ the “1 6 4 0” is how many pre or overscans that the readout system makes in x and y. this would depend on the configuration of the readout system. hot column rate doesn’t have to be the same, its just crudely estimate to be similar in that telescope.

4. the first ra/dec is the pointing of the telescope. and the others would be for the individual objects.

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by the way, we are working on documenting the items in the instrument directory. see the user page for more information later.

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