How to Automatically Repeat Exposures (transit) or Exposure Sequences?

Repeat a Template (TLP)

During a follow-up, typically for transit measurements, it is necessary to repeat the same exposure for a period of up to several hours.

The application of this method is done in the EDP by assigning the variable repeatTpl to the total duration (in seconds) of the follow-up and by assigning one and only one Template to this OB (Observation Block). Once the OB is started, the template is automatically repeated until the end of the duration specified in repeatTpl. The repeatTpl field is updated at each duplication.

As long as the value of repeatTpl is greater than zero, the TPL is duplicated.

Once the exposure has started, it is possible to change the value of repeatTpl. As this value is modified by EDP each time it is duplicated (in order to indicate the remaining time), it is preferable to change it at the appropriate time.

A value of zero will stop the OB.

The exposure time value can also be changed on the last Template. This value will be taken into account for the next duplications.

You have to be careful with this:

Do not duplicate a template manually
Do not close the OB. This will stop the sequence.
Do not write a number in the field repeatOb
During a follow-up: Do not modify repeatTpl of an other OB than the current

However, it is possible to suspend the sequence (EDP: STEP-BY-STEP MODE) and restart it by means of the UIF.

Duplication of Sequence (one or more OBs)

It is possible repeat a full OB or a sequence of OB, also with different intruments

The application of this method is done in the EDP by assigning the variable repeatOb to the total duration (in seconds) taken by the full sequence.

If more than one Ob is part of the sequence, this is indicated by the plus "+" symbol in the repeatOb field.

For example:

As long as the value of repeatOb is greater than zero, the full sequence is duplicated.

The Ob is duplicated when you get to the first line. At this moment it is possible to make all the modifications on the duplicated OB.

You have to be careful with this:

Do not create 2 successives sequences, insert (for example) a Bias between sequences
Do not close the OB. This will stop the sequence.
Do not write a number in the field repeatTpl

LW 12/05/2020