AllSky camera

Today I installed an AllSky camera (DMK camera with a fisheye) whic allows me to check the sky before starting the observatory opening sequence for exemple. Tonight I started the cameras and opend the dome while in the city down in the valley... the camera was a way for me to check the sky was ok (well, not perfect but ok).

The AllSky is operated from a second small PC which is always ON, which also run the weather station continuously.


I first took a serie on V357 Lac and when I got back home, I started a sequence on V442 And but some clouds were still there:

My signal was below 6kADU when it is usually around 10-11kADU. But I am able to acquire spectra, almost two months after the outburst discovery of V442 And:

Everything is ready for a full, far away, remote session...

Remote observation from a smart phone

The observatory is now 100% operational with the replacement of the mount power supply. The previous one didn't power on when the 220V was applied, I had to manually switched a button. The new one is a Voltcraft NPS-125 which is set at 18V and automatically switches ON when power is applied.

I can now power ON all equipments remotely and last night, for the first time, I did it from my smartphone and was able to run the SetUp.pgm script to connect all through PRISM v10 software. Then I pointed to V404 Lac Be star and started the autoguiding and the acquisition sequence. All while sitting in Grenoble, 20km away...

V442 And still active

V442 Andromedae was found in emission on the night of august 21st. An outburst occured shortly before that date and is beeing monitored in spectroscopy by a group of astronomers. I have been very lucky with a good weather which allowed myself to acquire lot of spectra of this star:

The spectra show a nice evolution of the double peak emission line since that date:

Here is a daily selection to avoid a too much crowded graph. The emission is still active today even if it is fainter:

Hbeta emission but is now gone:

Measurement of V/R ratio shows this evolution of the Halpha double peak emission with some stable phases and more active/variable ones:

The variations match closely with the photosphere rotation of the star:

A measurement of the HeI 6678 line is by the way showing a nice stellar photosphere rotation period:

The V+R mesurement initially increased, then decreased and is now more stable:

I also measured the distnce between the two peaks. It is now showing a clear increase:

Those measurements are "quick & dirty" ones made automatically using MatLab script. I checked couple of recent measurements as the emission is faint, but it seems to work ok (an offset of 0.75 is substracted on the emission lines):

In summary, I have been very lucky with the weather and the monitoring of V442 And is fun and seems to show some intersting details on this outburst... spectroscopy rocks!

99% remote spectroscopy

I have made two additions on the observatory: one Gembird SIS-PMS USB controled power plug for the dome (mount, robofocus, dome control & light) and one EnerGenie EG-PMS-LAN network controled power plug for the PC, echelle calibration lamps, USB hub & the Atik 460 CCD camera.

This allow me to do an almost 100% remote observation. I still have to press a button for the 18V power supply for the Losmandy Titan mount Gemini controler. It is a high end laboratory power supply but it does require manual intervention to power on - what a crap! OK, a new power supply is now on my shopping list...

Otherwise, I can switch ON all the equipment, open the dome, do all the spectra acquisition & calibration and then close the dome and switch everything OFF at the end.

Next step is to observe remotely from another location and to use more PRISM scripting functions to automate more the observations.

Checking spectra quality

It is important, specially at the beginning but also from time to time, to check your spectra quality. Here is a quick checklist of how I do it for my setup:

• échelle fiber fed spectrograph with Atik 460ex CCD camera, now cooled at -10°C (winter)
• C11 telescope; diameter 0.28m and focal 1.74m (f/6)
• Robofocus motorized focuser
• Losmandy Titan mount, guided with Atik Titan CCD camera
• Pulsar 2.7m motorized dome
• PRISM v10 software to control all equipment

Note that this checklist  works for high resolution spectra. For lower resolution, more care should be taken on the overall profile and continuum.


Fist, let's look at Halpha. A good thing to do is to compare with spectra available. For variable object, look at ARAS or BeSS databases:

• http://www.astrosurf.com/aras/Aras_DataBase/DataBase.htm
• http://basebe.obspm.fr/basebe/

Find a spectrum taken at a close time and compare it, for exemple:

 You can also, for hot stars, look for telluric (our own atmosphere) lines as they are fixed and are a very good indicator of the wavelength calibration. In the exemple above, I have plenty of absorption line from the cool star in VV Cep system and comparison with Olivier Garde's echelle spectrum shows a very good match.


With echelle spectra, the overall spectrum is sometimes more difficult as each order have to be merged together and this process is not always perfect. In BeSS, each orders are stored individually.In ARAS database, I put the merged spectrum but make also available a ZIP archive wih all invidividual spectra. Anyway, I also check the overall profile - there is here some differences certainly due to uncorrected air masses differences (observers at different latitude) but I considere this within acceptable limits:

For several weeks now, I am monitoring my exposures on Be stars spectra and measure the Signal to Noise Ratio (SNR) on the continuum near Halpha spectral line. This is a good indication of the sky transparency & seeing.

I use ISIS to measure the SNR. On Be stars I just take a continuum near Halpha. I always use SNR(2) value in the FWHM measurement tool provided by ISIS:

For cooler star, I reduce two individual spectra and divide the profile near Halpha, then measure the SNR as shown here on VV Cep:

Because I am measuring two spectra, I have to divide the SNR by 1.4 (square root of 2) to get the individual exposure SNR; in this exemple SNR(one exposure)=61/1.4=44.
Then, for 7 exposures as I have taken that night, my SNR will be multipled by the square root of 7, ie: SNR(7 exposures)=44*2.6=114.

Here is my monitoring:

For each spectra, I note the individual exposure time, the number of exposures and the count in ADU (intensity levels) of the maximum reach o the spectrum. I have of course to avoid saturation (65k) and usually look for max ADU=40000. I also note the achieved SNR on spectrum after reduction.

Based on this, I first calculate te exposure I should use to reach 40k ADU level (with a maximum of 20 minutes for my setup). I round the result to the 10th. Of course, it varies depending on the night quality, mainly the transparency and seeing conditions.

Exp40k =  min [ 1200 ; Exp(s) * 40 / Max_kADU ]

For exemple on 28 Cyg: Exp40k = 600 * 40 / 36 = 670 seconds

Then I calculate the ideal exposure time (rounded to the minute) to reach SNR=100 which is the minimum goal for BeSS Be Star Spectra high resolution Halpha monitoring program.

BestExpMin = Exp(s)*NbExp * (100/SNR2)^2 / 60

For 28 Cyg: BestExpMin = 600 * 3 * (100/108)^2 /60 = 1800 * 0.96 / 60 = 26 minutes


This gives me the rounded number of exposures I should acquire:

Nb/SNR100 = BestExpMin * 60 / Exp40k

For 28 Cyg: Nb/SNR100 = 26 * 60 / 670 = 2.3 = 3 exposures


This monitoring is a good way of tracking the night quality. It is also a great tool to quickly find the individual exposure time and the number of exposures to reach the SNR>100 goal. I used to do short 10s exposure to calculate the individual exposure time and do more than required exposures before. With this tool, I have been able to skip the short exposure and be overall more efficient in my Be star spectra monitoring program.

Here is, in a graph version, the best exposure time to reach SNR=100 per star magnitude:

One can see the dispersion between the nights, specially the vertical bar which is V442 Andromedae whom I took lot of spectra recently. Expsure time varies in the range of 50 to 250 minutes depending on night quality.

I encourage you to keep track of your own spectra in order to monitor your quality over time and keep in mind, for Be stars but not only, that the SNR is an important indicator of quality of your spectra, as important for me as the wavelength calibration or instrumental response quality.

Status on V442 And outburst

Couple of days are missing from the monitoring due to weather and not enough geographical coverage. But we still have a nice follow up of the outburst with lower emission level as V+R graph shows but still some variability in the V/R ratio.

144 spectra have been collected by 8 observers for a total of 159 hours of acquisition.

Here are the updated graphs, with one showing the distance (in speed) between the two peaks.

 Fainter Halpha emission now

 Hbeta emission is now gone

 HeI 6678 photospheric line shows a clear 2.6217 days stellar rotation period

Difference between the two peaks

 V+R show a clear decline

V/R variability over time with different "sequences"

V/R seems to show two periods (quick analysis)

Several records beaten at Observatory of Belle Etoile

The past few weeks have been very busy at the Observatory of Belle Etoile, with lot of observing hours! And several records have fallen in my history of astronomical observations and spectroscopy.


I/ First,  this third quarter of 2017 (from july to september), I have observed 45 nights for a total of 250 hours. This is my all-time record - and I am recording my observing time for more than 23 years now!

II/ Second, I reached 1334 spectra (58 in Halpha) waiting for validation - well, this is not critical but I kept the BeSS administrators busy! All have been validated now.

III/ Third, I crossed the key 10k milestone for Be stars with now 11391 spectra in BeSS. Just few days after Olivier Garde ("sans rancune", Olivier!) crossed this milestone as well... I am now 3rd in the amateur top observers:

IV/ Fourth, I have acquired 564 spectra in Halpha alone, crossing the 500 milestone and making me entering in the Top 10 of Halpha observers - a first for me. Well, the 5th position is within reach:

V/ Fifth, my observing time since I have the observatory crossed the 500 hours observing time milestone (564 hours actually). 50% of that time is actually acquiring spectra (ie: "photon time"). My best efficient night was the night of september 19th with an efficiency ratio of 87% ("observatory open time" actually acquiring spectra).
Looking at the other 50% time, here is a rough breakdown:

• 21% technical downtime
• 12% non spectroscopy time (outreach, visual observation, photometry)
• 9% opening/closing time
• 8% download/waiting time (including lost exposure due to clouds or waiting time between two individual exposures)

VI/ Sixth, I reached one millions seconds of total exposure time since I have the observatory in the backyard (1.17 millions seconds actually).

VII/ Seventh, and this is a real improvement for me, I reached three night in a raw observing remotely from home. But I still have sometimes the Atik 460 frezing at the end of an exposure, usually right after the first Thorium-Argon calibration or the first acquisition after calibration is done. It freezes after download and image is not saved; I have to physically remove and reconnect the USB cable to make it work again.I suspect a USB issue but haven't found the problem yet.
Otherwise, my only operations at the observatory are to connect the Atik Titan USB, remove telescope cover & add the anti-dew cover, power ON the Atik 460 camera and the mount at the begining & just the reverse steps at the end. Everything else is done remotely through TeamViewer (including file transfer at the end) and it works great.
An important thing is that I have done a pointing model for the Losmandy Titan mount with about 7-8 stars few weeks ago. Since then, the target is always in the guiding chip for GoTo within 40° and otherwise not very far. Pointing procedure has become very easy. I always point on the same side of the pier so that helps. But still, this is a real improvement on my setup!
Anyway, while I still have some motor lags and need to re-adjust the DEC axis (I think it is too tight), the overall the setup works very well now and I have been able during several nights to successfully take long sleep while acquiring long series of V442 And spectra for exemple.

watching Star Trek documentary during remote observation session

Spectroscopy of Be stars & remote observations rock!