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Many thanks Jeremy,
I see Richard Lee has a tutorial on AstroImageJ which also details how to submit to BAA via output from this package
Hi Robin
Thanks for sharing…
It looks a really good object for the ALPY (and apparently SA too..)
Cheers
Kevin
I have used the Method outlined by David in his slides and spectro-aras posting…
See attached for results.
Kevin
Thanks Robin,
Yes, I see there is an ‘Auto atmosphere’ button in the general tab in Isis but sparse documentation…
So, I think I’ll recycle IR data with care… I think if you separate the instrument components (camera and Alpy) and are working at quite different temperatures, you might want to be sure to use new IR data, but otherwise it looks OK. In addition I have discovered the comment field in FITs editing in BASS! (Homer Simpson moment here…). Suitable use therein should make it clear.
Cheers
Kevin
Sorry about recent absence from forum as we are in France and have just got reliable wifi.
Hagh! so maybe an original item…
Robin is right, I tend to put any reference stars in the filename… Sorry about confusion.
Kevin
Apologies for double image upload – I thought it had missed it and I repeated – can’t seem to delete one.
Kevin
Hi Andrew
“I just use the standard The Sky X autoguider.” I use Prism… (I used to use PhD2 for guiding). But, in any case, I think main difference is that, if you are using a slit, then the star is double lobed, which can cause problems with normal (unimodal spread function) guiding; hence use of slit guiding. You use a fibre which presents a hole so you can use regular guiding.
” have to take very short exposures….so as not to chase the seeing.” Surely other way round? (longer exposures stabilise against seeing)? I use between 4 and 9 secs…
Kevin
Hi Robin
Great tip! I get it now….
I had measured the line positions by just positioning the cursor and noting the value….
Nevertheless, I was quite pleased with the result. In the final spectrum, the water lines were as expected, and I measured Halpha shifts associated with radial velocities given in Simbad.
Kevin
Hi Robin
Worth looking at systemic difference between water and main lines…
I didnt get the part about switching between emission and absorption… All I do is enter the pixel-wise location of water and calib image lines into the table, having determined them from the combo image with no calibration. Then press ‘calculate polynomial’ and obtain the dispersion. I am not using Isis to actively seek the lines in the image. In this way I get a function that is fixed at both ends (and the centre). I do, however, then specify one of teh calib image lines as a reference point, but apparently this is optional with the ‘predefined dispersion’ option – you can put zero as the wavelength and it doesnt try and pick up any reference (at least that’s how I read it)
Kevin
Just watched Andrew’s video (joint BAA/AAVSO)… Incredible rig, and I think I can see the differences with mine..
(i) Use of on axis guiding (ONAG) to help locate star
(ii) accurate pointing model
(iii) A guiding algorithm that ‘pulls in’ the star onto a *hole* – not a slit
I don’t bother with a pointing model – I sync to one star and then ‘star-hop’ using a guidescope with ZWO camera. I take my scope down periodically (if we are going to be away for more than a few days), so I figured getting a good pointing model would be a waste of time…
I dont have ONAG.
I use slit guiding with the target star (23mu or 34mu slit). I haven’t tested this to the limit to see how good it is as ‘pulling’ something in that isnt actually on the slit, but it does lose DEC sometimes and can oscillate in RA if not parameterised well, so I am not confident it would do this.
On the other hand I have written a script for attempting to position the star, once its in the guide cam image. It gets pretty close, but relies on human interaction to position cross hairs on the star in the first place. I am happy with remote control just now without the full robotic thing but – one day, one day 🙂
Kevin
Hi Andrew
Sounds a few steps beyond mine! I just use TeamViewer to see my obsy-based laptop indoors, and the bit of hardware I descibed here to control the scope. How do you position a star on the slit? I would have though this is hard without manual fine control? I’ll look for the video..
Kevin
Hi Jack
Everything is controlled at the business end by relays which mimic switches. Note, you can turn the lamps on and off with switches using the lamp control port on the Lhires. There is a wiring diagram in the ‘add on kit’ documentation I believe (back in teh day when it was an add on…). You just have to switch in 12V for the required lamp.
I think Shelyak’s gadget does the same thing.
I have used Prism’s automated method for imaging (as its handy to do filter changes, refocus etc on the fly) but I just use the camera sequnce panel for spectroscopy.
cheers
Kevin
Hi Nick
I have a dedicated outdoor wifi point which gives a pretty strong signal… but in general, I agree, I like wires too. I am currently running a session – I’ll let you know if it goes pear shaped!
Kevin
Hi Robin
Yes – I saw a vertical extension beyond the normal line spectrum too… and was wondering about nebulosity. I think R Mon maybe even ‘worse’ in this respect as it is associated with NGC 2261 (Hubbles variable neb.)? I havent taken this one yet.
My binning could have been slightly tighter (but not much). And if the nebulosity is part of the system, then its fair game perhaps..
Kevin
David – thanks for the astrophysics backdrop. It does look like one might see interesting variation…
Robin – following the direct link you gave (forum topic), I can see comparable spectra from Paulo Berardi and Tim Lester… similar features to mine (reassuring I guess…).
But on the ARAS databse…
http://www.astrosurf.com/aras/Aras_DataBase/DataBase.htm
…the link for T Tauri is greyed out, and the direct link from the home page goes to a broken link..?
Guenther was also behind the recent appeal for HAeBe spectra related to a Chandra campaign. (I took V1410 Ori and sent on…). I suppose the T tau and HAeBe are similar objects so that makes sense. (Guenther looks very young on his web site, but maybe thats also the contrast effect with me getting older 🙂
Kevin
Thanks Robin!
I have contacted him (both addresses for belt and braces…). I have suggested they take down the web pro-forma if its redundant
Kevin
I use Hyperion Prism for framing, focus and guiding. This is an Anglicised relauch of ‘Prism’ which was developed by the French imaging and spectroscopy community. It has slit guiding which I try and use. I used to use PhD2 and I’m sure its fine ( I seem to recall a slit guiding option there too?). Slit guiding needs careful choice of parameters to work properly (it can cause oscillations as it hunts the sidelobes) but when setup properly it seems to work well.
Kevin
