ING Instrumentation Poll

The new multi-object spectrograph WEAVE will see first light at WHT prime focus in 2017. Large spectroscopic surveys with WEAVE will likely take up ~ 70% of WHT nights from then onwards.

Currently, a broad range of instrumentation is available to observers at the WHT and INT, and ING needs to plan how this evolves during both 2015-17, when ING's resources are increasingly focused on preparations for WEAVE, and from 2017 onwards, when there will be less time available on the WHT for observing with the current suite of instruments.

We therefore solicited community opinion about instrumentation requirements at ING during these two periods, via an on-line poll, announced through the INGNEWS mailing list. By the closing date of 31 March 2014, we had received 119 responses (and comments accompanying 28 of these).

The table below summarises, for each instrument/mode, the responses received to the question:
'Please give us a rough idea of the probabilities that you will submit observing proposals during 2015-2017, and from 2018 onwards (era of WEAVE surveys).'
The number in each box (probability '< 25%', '25 - 75%' or '> 75%') gives the fraction of the 119 respondents who ticked that box.

(1) The poll elicited a high level of interest, with a total of 119 individuals replying: 58 from the UK (21 institutions), 37 from Spain (10 institutions), 12 Netherlands (6 institutions), 5 Germany, and 1 each from Australia, Chile, Czech Republic, France, Poland, Sweden and the USA.

(2) The differences between the numbers in the above table for '2015-17' and '2018 onwards' are for the most part statistically insignificant, suggesting that respondents do not see their observational requirements at ING evolving dramatically on this timescale. There's also a strong correlation between the numbers in the '25% - 75%' and '> 75%' columns. In what follows, we've therefore assumed that most of the information in the responses is captured in the mean, for each row, of the '> 75%' values in the '2015-17' and '2018 onwards' columns. These 'scores', shown in the rightmost column of the table, represent relative community interest in our different instruments.

(3) Summing these scores over instrument modes, we have: ISIS 0.43 (with significant interest in the polarisation and QUCAM modes); LIRIS 0.47 (with significant interest in the MOS and polarisation modes); ACAM 0.24; AF2 0.12 (years 2015-17 only); WEAVE 0.27 (years >= 2018); WHT/PF 0.04; AO 0.11; INT WFC 0.26; IDS 0.17. These numbers suggest a strong interest in maintaining diversity of instrumentation at ING.

(4) The scores for AF2, WHT/PF and the adaptive-optics suite (NAOMI etc) are substantially lower than for ISIS, LIRIS and ACAM, as might be expected on the basis of past use. Short-term interest in AF2 might also be affected by the recent (now resolved) problems with target acquisition, and by the fact that AF2 will be superceded by WEAVE.

(5) The country-to-country (NL, Spain, UK) differences in the responses are relatively small, apart from a particularly strong Spanish interest in using LIRIS.

(6) Individual comments by 28 of the respondents flesh out the above statistics, and highlight a few common themes:

Respondents felt that diversity of instrumentation (including visiting instruments) is one of the main strengths of the WHT. They were concerned about the long-term impact of reserving most of the time on the WHT after 2017 for WEAVE surveys.
There were many favourable comments about ISIS and ACAM, highlighting their productivity and versatility. Respondents noted that the polarimetric modes of ISIS and LIRIS are increasingly unique.
Comments about the INT highlighted its scientific productivity and its value for student training, and noted the possibility of new instruments e.g. a combined imager/spectograph for the Cassegrain focus.

The results of this poll will help ING, in consultation with the ING board, decide how to focus its instrument-support resources over the next few years.