Filter Complement

Pupil stops needed for both AO and FEU modes are now installed in both filter wheels giving access to all filters below

SPEC Filter Wheel No. 1

L-Prime 3.420-4.120

M-Prime 4.570-4.810

KL 2.134-4.228

HeI 1.078-1.088

H2 2.110-2.129

FeII 1.639-1.654

M-Wide 4.420-5.530

Diagram of Filter Wheel 1 Layout

SPEC Filter Wheel No. 2

Nirspec-1 (Y) 0.947-1.121

Nirspec-2 1.089-1.293

Nirspec-3 (J) 1.143-1.375

Nirspec-4 1.241-1.593

Nirspec-5 (H) 1.413-1.808

Nirspec-6 1.558-2.315

Nirspec-7 (K) 1.839-2.630

K 1.996-2.382

K-Prime 1.950-2.295

Diagram of Filter Wheel 2 Layout

Filter Transmission Profiles

Download spreadsheet of SPEC filter transmissions

Filter Notes

Following the NIRSPEC Upgrade in Dec. 2018, filters are moved in four ways:

(1) Using the NIRSPEC Format Simulator (EFS) by selecting the desired filter and clicking "go" in setup mode.

(2) Using the NIRSPEC Mechanism GUI, by clicking on the Filter pull down and selecting a filter and stop.

(3) Using the command line to call a filter by name that gets paired to a 2nd default filter automatically. E.g. "filt m-wide", (sets m-wide and open, when not in AO), or "filt kl" (sets kl and ao-stop, if NIRSPAO)

(4) Using the command line to call a specific filter combination from each of the 2 science filter wheels. E.g "modify -s nsmotor scifilt1nam=open" & "scifilt2nam=nirspec-1"

As part of the Fiber Extraction Unit capability, new pupil stops were added to each of the two science filters which now accompany the smaller apperture AO-stops: named feu-stop.

Position Motor Steps Filter 1 Motor Steps Filter 2
0 9200 Open 200 NIRSPEC-1¹
1 18200 Thin 9200 NIRSPEC-2
2 27325 AO-stop 18200 NIRSPEC-3
3 36200 L-prime 27200 NIRSPEC-4
4 45200 M-prime 36200 NIRSPEC-5
5 54200 KL² 45200 NIRSPEC-6
6 63200 HeI 54200 NIRSPEC-7²
7 72200 FEU-stop³ 63250 AO-stop
8 81200 FeII 72200 FEU-stop³
9 90200 H2 81200 K
10 99200 M-wide 90200 K-prime
11 200 Blank¹ 99200 Open

Footnotes

  1. Primary initialization position
  2. Secondary initialization position
  3. FEU-stops replaced Pa-beta and CO in February 2019

Other Notes