28 March 2016 at 5:47 pm #573549
I’m preparing to invest in my first spectrograph and I was wondering if you’d have a recommendation on software?
I last used MaximDL to produce spectra (a few years ago now) but that was very a very manual process in conjunction with Excel. And also very expensive of course. I’ve played with VSpec (using my old spectra frames and also with a Star Analyser) and replicated decent results. VSpec seems very usable but I’ve also noticed ISIS.
The spectra David, Andy, et al have posted in the previous thread are an inspiration so I’m also wondering about APLY vs LISA vs LHires (although the latter seems a step too far at present).
And finally, this forum is much appreciated. How about a rough ‘How to’ guide from capture, through VSpec/ISIS processing to data submission (or has it already been written/planned?).
So many questions so little time…
Tony28 March 2016 at 7:37 pm #577295Andy WilsonKeymaster
I started out using a combination of MaximDL and BASS for my spectral processing. Though BASS could do it all I was used to Maxim and so it was easier to use that for dark frames and flat fields to begin with. I find BASS fairly easy to use and intuitive, at least for the basic stuff. Instrument response gets a bit more involved. BASS can be downloaded for free from the astrobodger Yahoo group (don’t be put off by the name!):
Though I still use BASS for my final ‘displaying’ of spectra, I’ve switched to ISIS for all of my processing including dark frams and flat fields. Though it is a lot harder to use, once you’ve got to grips with it, then spectral processing is quick and easy. It automates much of the processing, and so is a lot quicker than the more manual processing in BASS. It is also used by many of the top amateurs which I consider a good indication that it does things right. It can be downloaded for free from Christian Buil’s website:
There are also some tutorials on the site. Though they are quite long I was able to get to grips with ISIS by going through the Lhires III tutorial in detail a couple of times.
I’ll just mention guiding as well, as this is very important for obtaining good spectra. I think there are several good packages out there. I use PHD2, which is free and has built in functionality that is good for spectroscopy. You can setup and adjust a spectrograph slit rectangular guide reticle. You can also nudge the guide location to move the target star exactly over the slit.
On the spectrograph front I think there is going to be something in the next BAA Journal, so I’d suggest holding back until this is published.
Andy29 March 2016 at 10:29 am #577296
Much appreciated. Thank you. I know I could simply have emailed you but since this is a new forum I guess others will have the same queries.
I’ve played with ISIS and it looks like it’ll repay the investment in time/effort. I’ll get BASS asap.
I already use PHD for long photometry runs.
I’m looking forward to that article next month. David alluded to it but it sounds much more substantial than I first thought.
I’ll hold off ’till then.
Tony.31 March 2016 at 10:06 am #577299David BoydParticipant
Like Andy, I now use ISIS for processing my spectra including calibration and producing spectral profiles to send to the ARAS database. It does have a fairly steep learning curve but the effort is repaid many times when you discover the range of functions for working with spectra which Christian Buil has built into it. There are lots of “how to” pages on Christian’s website about use of ISIS although I have never found a simple index to where they all are. It’s a bit of a treasure hunt to find everything but he has written up most of its functionality somewhere. The originals are in French but quite a lot has been translated by either Christian or Robin Leadbeater and Google translate makes a passable job of the rest.
I still use VSPEC http://www.astrosurf.com/vdesnoux/ which is free and useful for quickly looking at and comparing spectra and for most of the basic processing functions. I do find it a bit prone to crashing but I used it a lot in my early days.
I have used Astroart http://www.msb-astroart.com/ for many years for controlling my cameras and this also has a very good slit guiding facility which will happily keep the target in the slit for long exposures.
I’ve just posted details on the Forum about the BAA scheme to help members acquire an Alpy spectroscope if you decide to go in that direction. All the Shelyak spectrographs will deliver good results, you really need to decide whether you are more interested in seeing the whole spectrum which you get with an Alpy or LISA (higher resolution but more expensive) or in studying specific lines at much higher resolution with the LHIRES.
Don’t worry about asking questions, that’s the way to find out!
David31 March 2016 at 12:34 pm #577300Robin LeadbeaterParticipant
I have a LHIRES III and an ALPY 600. I would not say the LHIRES is more advanced as such, they just complement each other and fulfill different roles. The ALPY 600 is more “fit and forget” and although the LHIRES is an excellent high resolution instrument, the ALPY is easier to use and performs much better than the LHIRES when used at low resolution. In many ways I find that producing good quality spectra can be more challenging at low resolution than at high resolution. (eg the targets are fainter, the sky background higher and atmospheric extinction correction more important)
Regarding rough guides from acquisition to final spectrum, I gave some very general walk thoughs for Star Analyser, ALPY600 and LHIRES using Vspec and ISIS at the recent BAA workshop at NLO Sidmouth, which can be downloaded here
They may not be totally self explanatory though so I am in the process of writing some words to accompany the slides which hopefully should make them more useful
For ISIS, Christain Buil has some tutorials which take you through the steps, though because ISIS is continuously evolving, the current version of the program does not always match the tutorials
Robin2 April 2016 at 9:19 pm #577302Steve CuthbertParticipant
I echo what Andy, David and Robin say about Isis especially when using an Alpy spectroscope because you can use a Relco starter bulb (easily available from Amazon!) for calibrating spectra and is practically automatic!. Bit of a learning curve to start with but well worth sticking with it.
Steve12 April 2016 at 3:56 pm #577313
Many thanks gents.
That just about nails it.
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