The much anticipated “SMSW 2” has arrived! Attendees from 20 or so US states and several countries around the world convened for the 3 day spectroscopy workshop featuring the world renowned experts in the field (scroll to bottom of program for bios on the featured speakers)
Unfortunately the one day we needed to have good weather it did not pan out. Rain and clouds blew in for the evening’s observing session so my big event was cancelled! However all the preparation I did do only made the event more useful for me since I had many questions to ask the experts! I figure I will be better than I was before and ready to do more challenging projects.
Some of the highlights from Day 1:
The second annual astronomical spectroscopy workshop has a record number of attendees, close to 80. Last year it was 21!
Dr David Whelan, a professional astronomer from Austin College in Texas gave a fascinating talk about Be stars and explained how the different emission line patterns we see have to do with our line of sight to the star
Dr Stella Kafka gave a very inspirational talk about how we all can participate in research by contributing spectra to the newly configured AAVSO spectral database. This is also a great way to see if your spectra is “on the level” as they will reject the spectrum if certain acquisition criteria are not met. Dr Kafka is the president of the American Association of Variable Star Observers (AAVSO) which until recently was focused primarily on visual and photometric observations of variable stars but now they have a newly developed “spectroscopy arm”
Other great sessions included talks by Francois Cochard, founder of Shelyak Instruments, addressing spectroscopy basics and instrumentation, processing software for spectra and other aspects of spectroscopy science and set up.
Yes it was quite disappointing the observing session didn’t happen but a great conference day #1 nonetheless! My wife also had a great time as one of the tour guides for the “spectroscopy wives”. They toured Las Cruces and saw many interesting aspects of New Mexico life.
Thanks for reading!
Success! I went back to the telescope and tried to get the guider to plate solve. (See last entry). Unfortunately the peripheral stars in the field I think are too distorted and probably not enough of them to get a consistent solution. I did get it to work sporadically but this was not going to be sufficient to get the job done. Went to plan B which was to remove the spectrograph and put the regular focuser back on, then proceeded with the mount pointing model and polar alignment with the imager, the Atik 460EX. In other words, I did the mount calibration the usual way with the main camera like we do in the case for regular imaging. After we got a decent pointing model and more accurate polar alignment, I reattached the spectrograph. Moving around the sky confirmed satisfactory pointing accuracy. The star shows up in the guider field consistently. Although not centered, it was a simple matter to center the star using the cross hair in the software program. Interestingly, the spectrograph slit in the guider field is easy to see now due to the waxing gibbous moonlight! Thank you Moon! I found it was very easy to place the star onto the slit even if it was slightly off center! Next step was to test the guiding capability . I calibrated the guider on the target star because that is typically the brightest star in the field and the software will default to that if you select a dimmer star. Great! I see the calibration is successful. I select a star in the field other than the target star and start guiding! So the target star starts on the slit and lets see if we can keep it there after 10 minutes. Looks like we can! Now the guiding accuracy is OK. Generally we are staying under a pixel error but because of the moonlight probably there is a lot of noise that perhaps fools the guider thinking those pixels are part of the star (see image below). Looks like we are ready to take our first test spectrum! I slew to a nearby medium bright star, 4th magnitude. I’m not sure about the spectral type but this is a test. The star is centered manually. Guide star is selected and we start the guiding. I start a 10 minute exposure on the imager and wait…………..Image download……….A stellar spectrum is seen on the screen!!! I have never been so excited to see a thin streak of light across a computer screen. It actually works!
So this is a star in the constellation Cygnus which has a Hipparcos catalog number HIP106481 (see below). Turns out it is a “G” type star and as you can see there are lots of absorption lines. For now we won’t worry about what it means but we celebrate a successful spectrum acquisition! Next we slewed to the star Alhena in Gemini which I know from my early spectroscopy experience with a simple grating called a “star analyser” that it is an A0 star with a strong H alpha absorption line. After a 5 minute exposure there I was able to recognize a distinct absorption line which must be what we’re looking for. Won’t know for sure until we process it but I would say we are moving along pretty well now! Looks like we are ready to do a full project including calibrating and processing. Onward and upward!
Thanks for reading!
Live spectroscopy set up! The Lhires is connected directly to the C14. No intervening focuser. We are using the knob on the primary to focus.
This is the guide field. You can see the target star is centered on the spectrograph slit (dark oblique line running from upper left to lower right through the center). Notice as you go out from the center the stars are distorted. I am thinking this is due to the lens in the guide port. Doesn’t matter though as we can find several stars near the center that are suitable for guiding!
Active guiding session! The guide star is pretty well centered. Guider exposure here is 4 sec. Guide errors probably average less than a pixel although in this image you can see it’s a little more than that (left side guide set up window) . Notice the noise in the guide star live image (right) which is likely affecting guide accuracy. The Moon is 2 days before full on this night!
Very first spectrum captured! G type star, HIP106481. You can see multiple absorption lines. The broadest line (arrow) is probably H alpha
Spectrum from a known A0 star. Very strong H alpha absorption line! (arrow)