- Email: [email protected]
Organizing a professional–amateur collaboration with a Lhires III spectrograph
ARTICLE IN PRESS
Planetary and Space Science 56 (2008) 1878–1881 www.elsevier.com/locate/pss
Organizing a professional–amateur collaboration with a Lhires III spectrograph Olivier Thizya,b,c,, Christian Buila,d, Franc- ois Cocharda,b,c, Coralie Neinere a
AUDE Association, Paris, France Shelyak Instruments, Les Roussets, F-38420 Revel, France c CALA, 37 rue Paul Cazeneuve, F-69008 Lyon, France d CNES, 18 Avenue Edouard Belin, F-31000 Toulouse, France e GEPI, Observatoire de Meudon, F-92195 Meudon, France b
Accepted 5 February 2008 Available online 24 July 2008
Abstract Amateur spectroscopists are getting organized to contribute to professional astronomy work. We present here the work done within the AUDE association to design, manufacture and distribute the Lhires III high-resolution Littrow spectrograph, which fits usual amateur telescopes and CCD cameras. We also review how the communication is organized through the ARAS distribution list (Spectro-L), forums, and workshops to develop and promote spectroscopic work among amateurs. Last but not least, we introduce the Be stars spectra (BeSS) Virtual Observatory-compatible database and its use for the monitoring of Be stars in association with the COROT satellite. r 2008 Elsevier Ltd. All rights reserved. Keywords: Professional/amateur collaboration; Spectrograph
1. Introduction For more than a century, amateur astronomers have been contributing to professional work. At the end of the 19th century, Seth C. Chandler, Edwin F. Sawyer or Paul S. Yeendell, for example, made a large contribution on variable stars while remaining independent amateurs (Saladyga, 1999). The variable stars section of the British Astronomical Association (BAA) has been created in 1895; the American Association of Variable Stars Observers (AAVSO) in 1911; the ‘Association Franc- aise d’Observateurs d’Etoiles Variables’ (AFOEV) in 1921. Variable stars are thus an area where amateurs contributed significantly and still do with more than 900,000 measure-
Corresponding author at: AUDE Association, Paris, France.
E-mail address: [email protected] (O. Thizy). URL: http://astrosurf.com/aude (O. Thizy). 0032-0633/$ - see front matter r 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.pss.2008.02.027
ments from 740 observers from 43 countries in 2004–2005 for the AAVSO alone. More recently, with the development of CCD cameras, amateurs have also contributed to asteroidal work. Photometric light curves are published with an increased frequency and more than 25% of them are obtained by amateurs (Warner, 2004). Occultations, astrometrics measurements and even a few minor planet discoveries are obtained today by amateur astronomers. A recent governmental study identified, in France alone, 250 fixed observatories including 15 telescopes larger than 0.6 m, a number growing over the years (Martin, 2006). However, a quick search of published papers on ADS indicates that only 3% of the amateur contribution concerns spectroscopy, far from the professional astronomers published paper ratio. Amateur spectroscopy is evolving nowadays thanks to new high-performance equipment, organized communication and common projects with professional astronomers.
ARTICLE IN PRESS O. Thizy et al. / Planetary and Space Science 56 (2008) 1878–1881
1879
2. Lhires III: a high-resolution spectrograph for amateurs
3. Organizing communication
In 2003, at an astrophysical school organized by CNRS (Centre National de Recherche Scientifique) in Oleron about amateur–professional collaboration in spectroscopy, it became obvious that the few existing spectrographs available commercially to the amateurs (Mais and Stencel, 2004) did not have enough resolving power. We then worked within AUDE (Association des Utilisateurs de De´tecteurs Electroniques) to design a high-resolution spectrograph: the Lhires III. We used a Littrow design to allow a compact equipment, optimized for 8-in f/10 telescopes, which are the most common telescopes among amateurs. We also used a direct connection to telescope, as opposed to fiber optic link (Kannappan et al., 2002), to maximize captured flux .
Following the Oleron’s school, we structured the communication between professional and amateur astronomers through internet tools:
The resolution of the Lhires III is 17,000, its weight is 1.7 kg and a wide range of CCD cameras is supported (even a visual mode and SLR digital camera for educational purpose). With a 9 mm-pixel camera, its inverse dispersion is 0.011 nm/pixel at Ha. The 2400 grooves/mm grating can be easily changed for lower resolution work (down to a resolution of 600). It also has a reflecting slit for guiding. First distributed within AUDE, Lhires III is now manufactured and distributed by Shelyak Instruments (http://www.shelyak.com). Gamma Cas spectrum shown here is an example of result obtained with a Lhires III. Resolution, measured on Neon spectrum, is 0.36 a˚ (power of resolution R ¼ 18; 000). Signal/noise has been measured at 315 on continuum for an exposure time of 1800 s with a 0.28 m Schmidt– Cassegrain Telescope. We measured limiting magnitude on several stars and modeled it for different gratings—results are shown in Table 1. Overall system (including Schmidt–Cassegrain Telescope and atmosphere) transmission has been calculated at 10–15% without slit and 2–3% with slit. Other examples of spectra taken in high resolution also show the results. Beta Lyrae spectra has been taken near doublet Sodium and interstellar lines illustrate spectrum’s resolution (see Figs. 1 and 2).
(1) the ARAS home page (portal): http://astrosurf.com/ aras/, (2) the Spectro-L mailing list: http://groups.yahoo.com/ group/spectro-l/ and (3) the forum: http://valerie.desnoux.free.fr/forum/. Moreover, meetings between amateurs and professionals are regularly organized. Another professional–amateur CNRS school took place in 2006 at La Rochelle. AUDE organized practical spectroscopy camps at Haute Provence
Observatory (2004, 2005 and 2007) as well as multiple training sessions for amateurs. One of the issue concerning amateur spectra is the disparity in file formats and places (web pages) to access them. To solve this, the GEPI laboratory developed a database for Be stars spectra (BeSS), jointly with amateur astronomers, and defined a standard file format for BeSS spectra based on FITS (Neiner et al., 2007). Today, four widely used amateur softwares are compatible with this standard: IRIS, AudeLA, PRISM and VisualSpec. The objectives of the BeSS database are to: (1) centralize available spectra of Be stars, (2) standardize the spectra files (format, content), (3) archive these spectra with easy access (internet download), (4) make all spectra available at one unique place and (5) allow multi-criteria search (Virtual Observatory and compatible). The BeSS database is located at the Meudon Observatory. Developed jointly by professional and amateur astronomers, it will be used by both communities.
ARTICLE IN PRESS O. Thizy et al. / Planetary and Space Science 56 (2008) 1878–1881
1880 Table 1 Configuration
P Cygni (Lhires III/2400 + 0.28m f/10 / 2007-08-25 19:00:27 + 1810sec)
SNR ¼ 25 SNR ¼ 50 SNR ¼ 100 SNR ¼ 150
2400 grooves/mm ðR ¼ 17; 000Þ 7.5 1200 grooves/mm ðR ¼ 6200Þ 8.9
6.7 8.1
5.9 7.3
1 0.9
5.4 6.8
0.8
intensity
0.7 Telescope F/D = 10 Doublet F = 27mm Guiding camera CCD
Flat mirror Reflecting slit
0.6 0.5 0.4 0.3
Diffraction grating 2400 g/mm
0.2 0.1
Flat mirror
0 6540
Doublet F = 200mm
Acquisition camera CCD
0.9
0.8
0.8 intensity
1
0.9
intensity
0.7 0.6
0.6 0.5
0.4
0.4
0.3
0.3
0.2
0.2 6590
6590
0.7
0.5
6550 6560 6570 6580 wavelength (Angstroems)
6580
1.1
1
6540
6560 6570 wavelength (Angstroems)
zeta Tau (Lhires III/2400 + 0.28m f/10 / 2007-09-15 03:30:21 + 2715sec)
gamma Cas (Lhires III/2400 + 0.28m SCT (2007-08-24 21:45:34 + 1800sec)
0.1 6530
6550
6500 6520 6540 6560 6580 6600 6620 6640 6660 wavelength (Angstroems)
6600
beta Lyrae (Lhires III/2400 + 0.62m / 20-Jul-2007)
Fig. 1. Limiting magnitude obtained with 1 h exposure and 0.28 m Schmidt–Cassegrain Telescope.
2.2 2 1.8
4. Ongoing projects intensity
On top of the educational projects that can be conducted to promote spectroscopy and increase the public interest in science, our goal is to increase the number of amateur contributions to professional astronomy. The availability of the Lhires III high-resolution spectrograph, processing softwares and internet communication tools will, for example, help amateurs to record spectra of Be stars that will be monitored by the COROT satellite. The objective is to see if the pulsations observed in photometry by COROT and the Ha emission-line profile observed by amateurs are correlated. This would provide an important clue on the mechanism at the origin of the disc of Be stars. Be COROT targets are 6th–9th magnitude stars and are thus accessible to amateur (0.3–0.8 m) telescopes equipped with a Lhires III and 1200 grooves/mm grating. Several tests have been successfully performed at the Pic du Midi
1.6 1.4 1.2 1 0.8 0.6 0.4 5860 5865 5870 5875 5880 5885 5890 5895 5900 wavelength (Angstroems) Fig. 2. Examples of spectra: (a) P Cygni, (b) zeta Tau and (c) beta Lyrae.
(AT60) and Pic de Chaˆteau-Renard (AstroQueyras) observatories. While COROT will observe each Be star during 150 consecutive days, with one photometric measurement
ARTICLE IN PRESS O. Thizy et al. / Planetary and Space Science 56 (2008) 1878–1881
every 32 s, the amateur contribution to the project will consist in obtaining, for each star: (1) Ha spectra once a week during 150 days, (2) intensive Ha monitoring for two weeks and (3) continuous Ha monitoring during outbursts. Other scientific projects are conducted with such highresolution spectrographs for novae, massive hot stars activity monitoring, Herbig Ae stars, overall Be stars monitoring, etc. More programs can be proposed by professionals and chosen by amateurs through the ARAS portal: http://www.astrosurf.com/aras/.
1881
References Kannappan, S.J., Fabricant, D.G., Hughes, C.B., 2002. PASP 114, 577. Mais, D.E., Stencel, R.E., 2004. Bull. Am. Astron. Soc. 36, 705. Martin, E., 2006. Enqueˆte: les curieux du ciel de plus en plus nombreux. Ciel et Espace, January. Neiner, C., de Batz, B., Mekkas, A., Cochard, F., Martayan, C., Floquet, M., Hubert, A.M., 2007. Astron. Astrophys., submitted for publication. Saladyga, M., 1999. The ‘preembryonic’ state of the AAVSO: amateurs observers of variable stars in the united states from 1875 to 1911. J. AAVSO 27, 154–170. Warner, B., 2004. The Minor Planet Observer: working and learning together. Minor Planet Bull. 31, 98.
Planetary and Space Science 56 (2008) 1878–1881 www.elsevier.com/locate/pss
Organizing a professional–amateur collaboration with a Lhires III spectrograph Olivier Thizya,b,c,, Christian Buila,d, Franc- ois Cocharda,b,c, Coralie Neinere a
AUDE Association, Paris, France Shelyak Instruments, Les Roussets, F-38420 Revel, France c CALA, 37 rue Paul Cazeneuve, F-69008 Lyon, France d CNES, 18 Avenue Edouard Belin, F-31000 Toulouse, France e GEPI, Observatoire de Meudon, F-92195 Meudon, France b
Accepted 5 February 2008 Available online 24 July 2008
Abstract Amateur spectroscopists are getting organized to contribute to professional astronomy work. We present here the work done within the AUDE association to design, manufacture and distribute the Lhires III high-resolution Littrow spectrograph, which fits usual amateur telescopes and CCD cameras. We also review how the communication is organized through the ARAS distribution list (Spectro-L), forums, and workshops to develop and promote spectroscopic work among amateurs. Last but not least, we introduce the Be stars spectra (BeSS) Virtual Observatory-compatible database and its use for the monitoring of Be stars in association with the COROT satellite. r 2008 Elsevier Ltd. All rights reserved. Keywords: Professional/amateur collaboration; Spectrograph
1. Introduction For more than a century, amateur astronomers have been contributing to professional work. At the end of the 19th century, Seth C. Chandler, Edwin F. Sawyer or Paul S. Yeendell, for example, made a large contribution on variable stars while remaining independent amateurs (Saladyga, 1999). The variable stars section of the British Astronomical Association (BAA) has been created in 1895; the American Association of Variable Stars Observers (AAVSO) in 1911; the ‘Association Franc- aise d’Observateurs d’Etoiles Variables’ (AFOEV) in 1921. Variable stars are thus an area where amateurs contributed significantly and still do with more than 900,000 measure-
Corresponding author at: AUDE Association, Paris, France.
E-mail address: [email protected] (O. Thizy). URL: http://astrosurf.com/aude (O. Thizy). 0032-0633/$ - see front matter r 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.pss.2008.02.027
ments from 740 observers from 43 countries in 2004–2005 for the AAVSO alone. More recently, with the development of CCD cameras, amateurs have also contributed to asteroidal work. Photometric light curves are published with an increased frequency and more than 25% of them are obtained by amateurs (Warner, 2004). Occultations, astrometrics measurements and even a few minor planet discoveries are obtained today by amateur astronomers. A recent governmental study identified, in France alone, 250 fixed observatories including 15 telescopes larger than 0.6 m, a number growing over the years (Martin, 2006). However, a quick search of published papers on ADS indicates that only 3% of the amateur contribution concerns spectroscopy, far from the professional astronomers published paper ratio. Amateur spectroscopy is evolving nowadays thanks to new high-performance equipment, organized communication and common projects with professional astronomers.
ARTICLE IN PRESS O. Thizy et al. / Planetary and Space Science 56 (2008) 1878–1881
1879
2. Lhires III: a high-resolution spectrograph for amateurs
3. Organizing communication
In 2003, at an astrophysical school organized by CNRS (Centre National de Recherche Scientifique) in Oleron about amateur–professional collaboration in spectroscopy, it became obvious that the few existing spectrographs available commercially to the amateurs (Mais and Stencel, 2004) did not have enough resolving power. We then worked within AUDE (Association des Utilisateurs de De´tecteurs Electroniques) to design a high-resolution spectrograph: the Lhires III. We used a Littrow design to allow a compact equipment, optimized for 8-in f/10 telescopes, which are the most common telescopes among amateurs. We also used a direct connection to telescope, as opposed to fiber optic link (Kannappan et al., 2002), to maximize captured flux .
Following the Oleron’s school, we structured the communication between professional and amateur astronomers through internet tools:
The resolution of the Lhires III is 17,000, its weight is 1.7 kg and a wide range of CCD cameras is supported (even a visual mode and SLR digital camera for educational purpose). With a 9 mm-pixel camera, its inverse dispersion is 0.011 nm/pixel at Ha. The 2400 grooves/mm grating can be easily changed for lower resolution work (down to a resolution of 600). It also has a reflecting slit for guiding. First distributed within AUDE, Lhires III is now manufactured and distributed by Shelyak Instruments (http://www.shelyak.com). Gamma Cas spectrum shown here is an example of result obtained with a Lhires III. Resolution, measured on Neon spectrum, is 0.36 a˚ (power of resolution R ¼ 18; 000). Signal/noise has been measured at 315 on continuum for an exposure time of 1800 s with a 0.28 m Schmidt– Cassegrain Telescope. We measured limiting magnitude on several stars and modeled it for different gratings—results are shown in Table 1. Overall system (including Schmidt–Cassegrain Telescope and atmosphere) transmission has been calculated at 10–15% without slit and 2–3% with slit. Other examples of spectra taken in high resolution also show the results. Beta Lyrae spectra has been taken near doublet Sodium and interstellar lines illustrate spectrum’s resolution (see Figs. 1 and 2).
(1) the ARAS home page (portal): http://astrosurf.com/ aras/, (2) the Spectro-L mailing list: http://groups.yahoo.com/ group/spectro-l/ and (3) the forum: http://valerie.desnoux.free.fr/forum/. Moreover, meetings between amateurs and professionals are regularly organized. Another professional–amateur CNRS school took place in 2006 at La Rochelle. AUDE organized practical spectroscopy camps at Haute Provence
Observatory (2004, 2005 and 2007) as well as multiple training sessions for amateurs. One of the issue concerning amateur spectra is the disparity in file formats and places (web pages) to access them. To solve this, the GEPI laboratory developed a database for Be stars spectra (BeSS), jointly with amateur astronomers, and defined a standard file format for BeSS spectra based on FITS (Neiner et al., 2007). Today, four widely used amateur softwares are compatible with this standard: IRIS, AudeLA, PRISM and VisualSpec. The objectives of the BeSS database are to: (1) centralize available spectra of Be stars, (2) standardize the spectra files (format, content), (3) archive these spectra with easy access (internet download), (4) make all spectra available at one unique place and (5) allow multi-criteria search (Virtual Observatory and compatible). The BeSS database is located at the Meudon Observatory. Developed jointly by professional and amateur astronomers, it will be used by both communities.
ARTICLE IN PRESS O. Thizy et al. / Planetary and Space Science 56 (2008) 1878–1881
1880 Table 1 Configuration
P Cygni (Lhires III/2400 + 0.28m f/10 / 2007-08-25 19:00:27 + 1810sec)
SNR ¼ 25 SNR ¼ 50 SNR ¼ 100 SNR ¼ 150
2400 grooves/mm ðR ¼ 17; 000Þ 7.5 1200 grooves/mm ðR ¼ 6200Þ 8.9
6.7 8.1
5.9 7.3
1 0.9
5.4 6.8
0.8
intensity
0.7 Telescope F/D = 10 Doublet F = 27mm Guiding camera CCD
Flat mirror Reflecting slit
0.6 0.5 0.4 0.3
Diffraction grating 2400 g/mm
0.2 0.1
Flat mirror
0 6540
Doublet F = 200mm
Acquisition camera CCD
0.9
0.8
0.8 intensity
1
0.9
intensity
0.7 0.6
0.6 0.5
0.4
0.4
0.3
0.3
0.2
0.2 6590
6590
0.7
0.5
6550 6560 6570 6580 wavelength (Angstroems)
6580
1.1
1
6540
6560 6570 wavelength (Angstroems)
zeta Tau (Lhires III/2400 + 0.28m f/10 / 2007-09-15 03:30:21 + 2715sec)
gamma Cas (Lhires III/2400 + 0.28m SCT (2007-08-24 21:45:34 + 1800sec)
0.1 6530
6550
6500 6520 6540 6560 6580 6600 6620 6640 6660 wavelength (Angstroems)
6600
beta Lyrae (Lhires III/2400 + 0.62m / 20-Jul-2007)
Fig. 1. Limiting magnitude obtained with 1 h exposure and 0.28 m Schmidt–Cassegrain Telescope.
2.2 2 1.8
4. Ongoing projects intensity
On top of the educational projects that can be conducted to promote spectroscopy and increase the public interest in science, our goal is to increase the number of amateur contributions to professional astronomy. The availability of the Lhires III high-resolution spectrograph, processing softwares and internet communication tools will, for example, help amateurs to record spectra of Be stars that will be monitored by the COROT satellite. The objective is to see if the pulsations observed in photometry by COROT and the Ha emission-line profile observed by amateurs are correlated. This would provide an important clue on the mechanism at the origin of the disc of Be stars. Be COROT targets are 6th–9th magnitude stars and are thus accessible to amateur (0.3–0.8 m) telescopes equipped with a Lhires III and 1200 grooves/mm grating. Several tests have been successfully performed at the Pic du Midi
1.6 1.4 1.2 1 0.8 0.6 0.4 5860 5865 5870 5875 5880 5885 5890 5895 5900 wavelength (Angstroems) Fig. 2. Examples of spectra: (a) P Cygni, (b) zeta Tau and (c) beta Lyrae.
(AT60) and Pic de Chaˆteau-Renard (AstroQueyras) observatories. While COROT will observe each Be star during 150 consecutive days, with one photometric measurement
ARTICLE IN PRESS O. Thizy et al. / Planetary and Space Science 56 (2008) 1878–1881
every 32 s, the amateur contribution to the project will consist in obtaining, for each star: (1) Ha spectra once a week during 150 days, (2) intensive Ha monitoring for two weeks and (3) continuous Ha monitoring during outbursts. Other scientific projects are conducted with such highresolution spectrographs for novae, massive hot stars activity monitoring, Herbig Ae stars, overall Be stars monitoring, etc. More programs can be proposed by professionals and chosen by amateurs through the ARAS portal: http://www.astrosurf.com/aras/.
1881
References Kannappan, S.J., Fabricant, D.G., Hughes, C.B., 2002. PASP 114, 577. Mais, D.E., Stencel, R.E., 2004. Bull. Am. Astron. Soc. 36, 705. Martin, E., 2006. Enqueˆte: les curieux du ciel de plus en plus nombreux. Ciel et Espace, January. Neiner, C., de Batz, B., Mekkas, A., Cochard, F., Martayan, C., Floquet, M., Hubert, A.M., 2007. Astron. Astrophys., submitted for publication. Saladyga, M., 1999. The ‘preembryonic’ state of the AAVSO: amateurs observers of variable stars in the united states from 1875 to 1911. J. AAVSO 27, 154–170. Warner, B., 2004. The Minor Planet Observer: working and learning together. Minor Planet Bull. 31, 98.