Andy Wilson

Forum Replies Created

Viewing 20 posts - 381 through 400 (of 466 total)
  • Author
    Posts
  • in reply to: EXOPLANETS #577652
    Andy Wilson
    Keymaster

    Very interesting. There is also the SPHERE instrument which is mounted on the VLT.

    http://www.eso.org/public/unitedkingdom/teles-instr/vlt/vlt-instr/sphere/

    in reply to: Not sure about this flat! #577617
    Andy Wilson
    Keymaster

    Hi Steve,

    I’m not really an Alpy expert but I do agree that looks a bit odd. Was it taken in darkness or daylight? Just in case stray light might have been getting in. Also, do you know if that bright “line” is oversaturated and do you have an approximate idea of its wavelength from your wavelength calibration.

    Best wishes,

    Andy

    in reply to: Finding/Guiding with a Lodestar #577591
    Andy Wilson
    Keymaster

    Hi Tony,

    The new BAA Spectroscopy Database could well be the ideal place to share and compare results, assuming people have reached the stage of producing 1D fits files from ISIS.

    I’m just looking at making a final tweak before go-live. This would be to add a “flat field” flag. Though in theory all spectra should be flat fielded before submission, there may be cases where this is not possible, hence why we might want to record that information.

    I’ve been busy since the workshop, so I’ve not had a chance to work on this change. If I can’t find the time to do it within the next few days then we’ll probably go-live without it to avoid further delay.

    Best wishes,

    Andy

    in reply to: Focal reducers for Alpy! #577580
    Andy Wilson
    Keymaster

    I think I suffered from the chromatic aberrations for a time. It looked as though I had a problem with the slit drifting across the star image, so sampling different parts of the image that had been colour dispersed by the Earth’s atmosphere.

    Here is a plot that shows the result as the continuum varies, just looking at 2 points in a series taken 20 minutes apart. I’m glad to say I’ve not suffered from this problem recently.

    Andy

    in reply to: Finding/Guiding with a Lodestar #577579
    Andy Wilson
    Keymaster

    That is a decent guide image Tony. I find that for good results the target star has to be bang on the slit. This is not just to get the maximum number of photons through the slit, but also to avoid sampling parts of the star’s image which may have been colour dispersed by the atmosphere.

    Cheers,

    Andy

    in reply to: Imaging camera temperature ? #577571
    Andy Wilson
    Keymaster

    Hi David,

    I have a Starlight Xpress SXVR-H694 and I usually run it at -20C. During the Winter months I sometimes run it at -25C. Of course I have to make sure I have a full set of darks and flats to match whichever temperature I use.

    I agree with what Francois said, it is important to run your camera at a temperature that it can easily maintain, so that you do not get too much temperature drift. I find the temperature drifts by a few 10ths of a degree, but no more during my exposures.

    Best wishes,

    Andy

    in reply to: Alpy workshop 2016! #577566
    Andy Wilson
    Keymaster

    Hi Steve,

    I’d also like to thank David and Ann for organising such a great weekend, and to Francois Cochard for all the work he put into the presentations and demonstrations. Thanks for your kind words on the database. Watch out for an announcement sometime soon..

    I would also like to re-emphasize to everyone who attended the weekend, and to all BAA members, the forum is a great place to ask questions and share results, even if your results don’t look right. Starting out in spectroscopy is hard. One of the tools that makes this possible today is the internet. It is quick and easy to share results and ask questions. Remember there is no such thing as a stupid question. There are probably others out there struggling with the same problem as you.

    If anyone from the weekend has trouble accessing the forum then drop me an email.

    Best wishes,

    Andy

    in reply to: Database format #577538
    Andy Wilson
    Keymaster

    Hi Tony,

    Thanks for the file. I’ll be at the spectroscopy workshop, so hopefully there will be a chance to discuss photometry file formats.

    I’m unlikely to have the time to work on this until next year. I’m studying at weekends and have several meetings to attend in the run up to Christmas. Once my schedule has calmed down, then that will be the ideal time to look at the format in more detail and make the changes. Having sample files to work with will be a big help, as I’m not currently setup to do my own photometry.

    Cheers,

    Andy

    in reply to: Database format #577532
    Andy Wilson
    Keymaster

    Hi Graham,

    You could also try emailing William-Bell to see if you can get hold of the book and software, or maybe just the software if they have run out of the books.

    http://willbell.com/contact.htm

    The other thing to watch out for is if you find a copy to make sure it is version 2. William-Bell used to offer an upgrade from v1 to v2, but I’m not sure if that is still available.

    Andy

    in reply to: Database format #577528
    Andy Wilson
    Keymaster

    Hi Tony,

    AIP4Win MMT does not produce files in the BAA VSS format. It is on my list of things to do to amend the VSS Photometry spreadsheet to read the MMT files, but that is likely to be at least a few months away. (Anyone could create a spreadsheet or other application to do the conversion but I suspect it will wait be me to produce something.)

    Another one of the items on my to do list is to investigate building compatibility in to the VSS Database website for loading the AAVSO data format. The main issue here is the last time I reviewed the AAVSO format it did not provide all of the data we store in the BAA VSS database. However, we may just accept that we do not get all of the data.

    I’ve not had a chance to look at the MMT format recently, so perhaps you could email me a copy? That will give me an idea of how much work the development will be.

    Thanks,

    Andy Wilson (BAA VSS Database Secretary)

    in reply to: spectrum of sn2016fnr discovered by Ron Arbour #577487
    Andy Wilson
    Keymaster

    Congratulations Robin. A great achievement to take the confirmation spectrum for a mag 16 supernova!

    Cheers

    Andy

    in reply to: spectrum of sn2016fnr discovered by Ron Arbour #577481
    Andy Wilson
    Keymaster

    That is a fabulous spectrum for such a faint target Robin. A shame you were clouded out but this is another demonstration of what you can achieve with your setup.

    Andy

    in reply to: PDF versions of the publications #577478
    Andy Wilson
    Keymaster

    I very much hope that a digital subscription will be rolled out as an option to all members in the near future. I would like to take advantage of this cost efficient way of being a member, with the ability to access to the journal and handbook online. I subscribe to a number of astronomical organisations and magazines and the annual total is not insignificant. So I applaud initiatives like this.

    Andy

    in reply to: 34 Cygni #577473
    Andy Wilson
    Keymaster

    Hi Alun,

    Nice spectra! I’m interested to hear about your setup as that is something I had contemplated. A low res spectrograph on a small telescope, piggy backed on a larger telescope with a high res spectrograph. I thought getting the slits aligned would be just about impossible, so I’m very interested and impressed to see that you have achieved it.

    Well done!

    Andy

    in reply to: More meteor spectroscopy #577467
    Andy Wilson
    Keymaster

    Hi Bill,

    That is a very interesting comparison between your Perseid spectrum and the VLT meteor. Encouraging that they show a similar continuum and line profiles.

    Cheers,

    Andy

    in reply to: Sky & Telescope Spectroscopy Webinar #577466
    Andy Wilson
    Keymaster

    Thanks for posting this Calum. Very interesting that spectroscopy is gradually getting more coverage.

    I’m tempted to watch, but as there is a cost and it is more targetted at those starting out in spectroscopy I’ll probably give it a miss. Still very pleasing that S&T are showing an interest in spectroscopy.

    Cheers,

    Andy

    in reply to: Vega profile #577411
    Andy Wilson
    Keymaster

    Great spectrum Alun! That is a good demostration of the effects of the instrument and atmosphere.

    Andy

    in reply to: Thank You #577398
    Andy Wilson
    Keymaster

    Hi Wayne,

    It was good to meet you before the meeting. I used to live in the South East and was a regular visitor to meetings and the pub afterwards. A really enjoyable way to meet new people and chat about astronomy. Unfortunately now I’m in the South West I had to leave before the end of the meeting to get home by midnight!

    I hope to meet you for a longer chat at a future meeting.

    Andy

    in reply to: The Sun (Narrow band UV imaging) #577386
    Andy Wilson
    Keymaster

    Hi Bill,

    Great idea to try out a narrow band filter with a full aperture white light filter. Your results look pretty good.

    Andy

    in reply to: Outburst of the symbiotic star AG Draconis #577345
    Andy Wilson
    Keymaster

    A fascinating post David. It encourages me to take the next step and learn flux calibration.

    Below is an H-alpha spectrum I obtained on 27th April. It is interesting to contrast that though I see detail in the profile, I miss even the nearby little blueward absorption line and redward emission line that you pick up. A good example of how low resolution and high resolution spectroscopy can complement each other.

    Best wishes,

    Andy

Viewing 20 posts - 381 through 400 (of 466 total)