Frequently Asked Questions

Why do I have to do this?

A variety of reasons.

What length should my MSB be?

Heterodyne: The aspect of the MSB you most want to think about is its length. Let's say you have been allocated eight hours for a single source. Now, you could submit a single 8-hour MSB if you wanted. But that would be a very silly thing to do. For one thing, if your source is not up for more than eight hours, it would never be scheduled as our software would detect that it would set before the MSB could be completed. But even if your source were observable for 8 hours solid, the observer won't chose to undertake it except near the very beginning of the night, which vastly decreases your scheduling opportunities.

In the past calibrations have been charged to your project resulting in huge overheads for short observations. This is no longer the case. However if many short observations are all scheduled one after the other they would have to be sent to the queue one by one, thus driving the telescope operator and observer insane.

If your sources are well separated across the sky a pointing may be required between them (even if they are only separated in time by ten minutes). However if they are close by each other they can be done consecutively. If you are including multiple sources in an MSB try to pair or group them so they are all are all close together. If this is not the case then include a note highlighting this to the operator.

The golden mean? A 30–to–90 minute MSB. If you have any questions about the best way to distribute your sources please consult your Friend of Project for ideas.

SCUBA-2: We have a 40 minute limit on SCUBA-2 observing blocks. See here for details. This upper limit usually concerns large pong maps while small daisies fall at the other end of the scale being potentially only a few minutes each. Having short MSBs for SCUBA-2 does not incur the same overheads as heterodyne. Like heterodyne observation consecutive sources that include a large slew will likely require a pointing between them, however SCUBA-2 has the additional factor or requiring the arrays to be set up again after a move between sources.

My MSBs only last half an hour so it is a waste to do a calibration for each one!

Don't worry about this. The person doing the observing will have the choice of not doing calibrations that are highly redundant.

My project wont load when I enter my project number?

If you have not previously stored anything to our database there will be nothing to retrieve, however space assigned for your project code is there for you when you create and first submit your MSBs. Create your project following the instructions above and store to the on-line database.

I have a lot of sources — how can I speed up creation of my MSBs?

If you have a large number of sources you may want to use the survey container; instructions on how to use this can be found here. Another option is to use the replication tool. This requires access to EAO machines and details can be found here.

How do I submit my project?

Ensure that you have filled out the title of your project correctly (Title, PI, Queue, Project ID), then go to 'Database' along the top menu and select 'Store to on-line database'. Once you have done this your friend of project will be able to access your MSBs and check them. For more details follow this link to the main OT primer page.

I want to do something that is not in the library

You certainly can. However I suggest you let us know for two reasons. First, for your benefit, we'll be able to look your MSBs over to ensure that they will actually do what you intend. Secondly, for our benefit, we would like the chance to create a library MSB that matches your observing mode in case that will be useful to other users.

What does this warning mean? "Some of the observations in the MSB contained default settings for the target information"

You probably forgot to enter your co-ordinates! If you really meant to observe 0:0:0, 0:0:0 just ignore it.

I don't agree with the time estimates shown in the OT

We are fine-tuning these, but they will always be just that — estimates. However it doesn't really matter if they are a bit off. The estimates are used for three things. First, they are used by the QT to check whether the observation can be carried out before the source sets. Second, they allow the observer / telescope operator to plan the observing. For example, if they believe that the opacity is going to change in the next hour, they can select an MSB that is estimated to last less than an hour.

Third, time estimates are used to provisionally debit remaining time during the night to keep a running tab on projects' use of their allocation. However the final time accounting is done the next day based on the actual time used by a project as derived from the data files and logs. If you find you still have time left after that you can submit an MSB to use it up.

Please notify us if you believe the time estimate to be grossly in error.