21 October 2018 at 11:36 am #574148Andy WilsonKeymaster
There have been some posts to the BAA forum and members have contacted me directly to express a desire for the BAA holding a spectroscopy workshop. I’ve discussed this with a few people, but before going very far with any planning I thought it would be a good idea to ask interested members what they would like to get out of a workshop.
Please note these workshops would be about helping members with the practical aspects of spectroscopy rather than presenting results.
Here are some ideas on what could be covered:
- Processing spectra with ISIS, BASS, and possibly other software if experienced users could be found to run those sessions. While we covered ISIS at the recent Spectroscopy and Photometry Workshop, there could be some benefit from a longer follow up session. Members could bring their laptops to these sessions, and we then work through a practical example using sample files. Each session would cover a single software package and might last half a day. So we could spend half a day on ISIS and half a day on BASS. Though maybe people would prefer a whole day on a single package?
- Advanced processing techniques such as flux calibration, line measurement techniques, correcting for interstellar extinction.
- Setup and use of spectrographs. Initial setup of spectrographs is best done indoors rather than at a telescope, so it may be possible for members to bring their spectrographs to a session if we have an appropriate venue where spectrographs can be setup on tables. More detailed problems may be harder to address without visiting individual observatories, but a discussion session with experienced observers could help to address specific points. Also there are a range of spectrographs in use by BAA members, so it may be necessary to limit sessions to specific spectrographs such as the ALPY, LISA, Lhires III, L200, or other designs where expertise is on hand.
My initial thought is to have 2 or 3 one-day workshops dedicated to different topics. One day workshops are easier to organise and cheaper, noting the workshop(s) would be organised and run by volunteers. For example we could have one workshop on spectroscopy software, and another on setting up and optimising spectrographs.
To make it easy for attendees from a wide range of locations to attend, probably hold the workshops in London or a central location with good transport connections.
These are just some ideas, so please feel free to make different suggestions. Also if anyone has any good suggestions for easy to reach venues or would like to volunteer to help out with expertise or in the organisation then please let me know.
Andy22 October 2018 at 3:10 pm #580080
Thank you for suggesting a workshop on processing spectra using ISIS. Everybody will have different issues and I agree that your ideas of how to proceed are in line with my own thoughts. I do not think that setting up a session on tuning the instrument is necessarily the most difficult part but maybe it would be welcome to those just starting out. Isis is a very quirky piece of software and do have on my PC samples produced by Francois Cochard.
Working from first principles consider the following: –
1 Setting up the working directory
2 Data reduction using the master tab
3 Wavelength calibration
4 Instrument response curves
5 use of GNPLOT22 October 2018 at 9:03 pm #580081
I was thinking perhaps the workshop could be based around some standard targets that participants would record beforehand. By processing these and comparing the results between each other and to the published spectra, any potential issues with spectrograph setup, data acquisition or processing would then be highlighted. (Something that I know helped me during an OHP workshop when I started out trying to get good quality data.)
Robin25 October 2018 at 5:21 pm #580087
Would someone kindly point me im the right direction for a catalogue of Class A & B stars.
Nick25 October 2018 at 8:50 pm #580088
I would especially welcome your 2nd and 3rd suggestions… (advanced processing and setup). I also think Robin’s idea is a good one, as we then have something concrete to nail down the problems with, by cross comparison.
I believe I might have been foolsih enough to volunteer to help at some stage 🙂 so I will honor that one if needed.
Kevin26 October 2018 at 4:08 pm #580095
Are you looking for A or B stars in general or specifically ones suitable for use as reference stars?
If the latter, then for low resolution spectra the MILES stars (included in the ISIS database) have actual spectra associated with them or alternatively Francois Teyssier has generated a list of hot main sequence stars with low interstellar extinction which can be used (with caution) with generic spectra from the Pickles library. You can find his spreadsheet which also includes the MILES stars and has tools to help with selecting stars close to the target here
with more information in this post on the ARAS forum
Robin27 October 2018 at 2:38 pm #580097
Thank you Robin. I will use these as referance stars next time. Would you kindly help me with another problem I have been experiancing viz data reduction in ISIS I get the bias frame loaded OK but cannot set the dark and flat frames.
Nick27 October 2018 at 3:13 pm #580098
Are you saying that ISIS is not finding the dark and flat files you entered in the general page when you run the data reduction?
I have developed my way of working with ISIS over several years so I probably don’t do things the standard way. I collect all the files ISIS needs to do a data reduction in one folder titled with the target name and date, copying the masters, instrument response and wavelength calibration files etc in from other folders if necessary, rather than have ISIS search for them in different folders. (See attached example from a run last night) That way, although there is some duplication of files, I can archive the folder and always rerun the reduction again using the same set of files in the future. When I run the reduction I point ISIS to that folder in the settings page and point to the individual files in that folder the general page.
Robin27 October 2018 at 4:20 pm #580100John CoffinParticipant
I would be interested in tackling some test targets. More help with ISIS would be useful and also the advanced processing too. I can get ISIS to work but I nearly always hit a problem that takes a lot of effort to overcome.27 October 2018 at 6:40 pm #580101Tony RoddaParticipant
Rather perversely I’ve gone from ISIS and Demetra to BASS in order to process spectra from my home made stuff. Refreshers, practice and ‘advanced’ techniques (such as Spectrophotometry?) are always welcome.
The BAA workshop for the ALPY600 was excellent simply from the position of talking with fellow users.
One plea though… Can we do the midlands area?
Regards T28 October 2018 at 5:45 pm #580116
“One plea though… Can we do the midlands area?”
If you stick a pin the ‘centre of mass of England’, its in Leicestershire 🙂
Kevin28 October 2018 at 9:55 pm #580117Tony RoddaParticipant
If you stick a pin in the centre of the UK?29 October 2018 at 7:31 am #580119Dr Paul LeylandParticipant
“If you stick a pin in the centre of the UK?”
https://en.wikipedia.org/wiki/Centre_points_of_the_United_Kingdom gives a point in Lancashire.29 October 2018 at 10:55 am #580120
Kevin does have a valid claim to the centre of population though.29 October 2018 at 11:06 am #580121
In this case though what we need is the geometric median which minimises the distance travelled. My first student vacation job was with the GPO, writing a computer program to decide where the international exchange should be sited to minimise cabling costs (distance from exchanges, weighted by the traffic). I think it came out near Reading (This was in the 60’s and the computer CPU time was charged by the second)29 October 2018 at 6:51 pm #580128Dr Paul LeylandParticipant
I was thinking about this problem overnight. There are several metrics which could be considered (and the considerer not to be considered to be too silly).
One is that which minimizes the person-kilometres traveled. A few people who have to travel a long distance balance a larger number who need only travel a short distance.
Another is that which minimizes the person-expenditure outlay. A few people who must take expensive routes, for example on a ferry or over a toll bridge, balance a larger number who do not need to pay for the infrastructure such as public highways over which they travel.
I have very little idea about the locations which minimize the above metrics. If forced to guess I suspect that the location would be somewhere fairly near Nottingham.29 October 2018 at 7:35 pm #580129
I seem I have a set a hare running here!… but it is interesting.
If the computer scientists can get worked up about ‘travelling salesmen’
then why cant we solve the ‘travelling astronomer’ variant? 🙂
But Tony has a serious point so we should give it some thought….
Kevin29 October 2018 at 7:51 pm #580130Andy WilsonKeymaster
If anyone knows of cheap or even free venues we could use then please let me know via the forum or by emailing me. They ideally need to be in easy reach of public transport as otherwise we’ll need to setup a taxi service 😉
I had wondered about somewhere in central Birmingham? There is also the Northamptonshire Natural History Society venue that has been used for BAA meetings in the past. Though I’d struggle to get there before 11am and might have to leave before 5pm.
Andy30 October 2018 at 12:49 pm #580140
There would be a charge but I am a member of the Civil Service Club in Whitehall there are meeting rooms, a licenced bar, restaurant and accomodation if booked in advance.
Nick31 October 2018 at 11:09 am #580148David SalmonParticipant
I’d definitiely be interested in the workshop.
Regarding Birmingham as a potential location, does anyone have contacts at either of the Universities (Aston, Birmingham) who might sponsor use of a venue and avoid the commercial conference rates ? Both are easily accesible from the centre (Aston is a short walk and Birmingham a couple of hops away by local train with a very frequent service) and I’ve been to both a few times in the last year or two in work contexts. Birmingham also has a new conference Hotel with accomodation on the edge of the campus for those who might need it.
Failing that, would there be a local Astronomy society that might help ? Birmingham Astro seems to meet at Aston if I interpret their web site correctly (and if it’s still current.)
I have contacts at Birmingham in the Research IT/HPC area, but not in Physics/Astronomy..
I’m aiming to be at the AGM later today and happy to discuss further.
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