MIRC/VEGA

Cophasing of VEGA and MIRC on UT 2010-10-12: (SK)

MIRC ealing mount position after cophasing:

IR1=58350, IR2=65449, IR3=66000, IR4=71600

(Configuration: E1-E2-W2-W1; B1-B2-B3-B4)

Cophasing of VEGA and MIRC on UT 2010-10-13/14: (SK)

For the E1-E2-W2-W1 configuration, the MIRC ealing mount positions were still suitable.

However, when we changed to the S1-S2-W2-W1 configuration and tracked with MIRC, the fringes were somewhat off-centered at VEGA, possibly due to differences in the LDCs of the individual telescopes.

Cophasing of VEGA and MIRC on UT 2011-09-26: (SK)

configuration: W1-W2-S2-E2-E1-S1, VEGA used the first four telescopes, and MIRC used all 6. W2 is the reference.

Here is the detailed procedure:

start with some bright cal, Hmag < 4, and size ~0.4mas. VEGA needs to do some alignment first, then MIRC can do fiber explorer. Then MIRC take over the control of delat carts to find all fringes just as what we usually do alone. Write down the offsets. Then VEGA will take over the control of delay carts, and find fringes alone, write down the VEGA offsets. Then MIRC take over the control again, find the fringes.

Now mirc will try to move the delay carts and ealing mounts at the same time to keep the fringes. My experience is that the amount that delay carts move is about the same as the ealing moves, e.g. moving delay cart 1mm will require moving ealing mount ~1mm to keep the fringes.

In this run, here are the ealing position of beam1, 3, 4 after cophased with VEGA.

beam 1: 60000 beam 3: 56550 beam 4: 78800