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There is no greater pleasure than to build your own astronomical instruments!

No hay un placer más grande que construir y observar con tus propios instrumentos

F/3.4 astrograph on the Tacande bench test

                              Testing a triplet 150 mm. f/3.4 objective

      Resolution test pattern of a 150 mm. f/3.4 triplet using a home made collimator

                       Parts of the collimator build at the Tacande workshop

                                   Testing the collimator lamp

                                       The completed 50mm collimator   

                           Homemade waterproof meteor camera 

     Inside the box we can see the camera, battery, voltage regulator and an interval                                                               timer box

             Image taken using the waterproof meteor camera (Moon rising)

                     Robotic observatory working in Tacande for a French institution

                                Tacande workshop, showing the optical test bench

                                             Homemade Shack interferometer

                                         Only for electronic mind people :-)

                                            Making metal parts on lathe

            Main telescope in use at Tacande Observatory, 400 mm. diameter, f/6.5

                       T400 CAD layout of the optical components 

Spot diagram of T400 telescope, please note that from 400-700 nm. wavelength, 
                             95% of the light beams are inside Airy disk

   The 500 mm. Newton/Cassegrain telescope designed and built by the author for the           observatory  headquarters Agrupacion Astronomica de Sabadell (AAS), Spain

                            Foucault testing of AAS 500 mm. primary mirror

                                    Wire test of AAS 500 mm. primary mirror

                             500 mm. primary mirror cell for AAS primary mirror

                             Centering AAS mirror in cell at +- 0.01mm on cell

                             Assembled cell + mirror ready to be installed in the tub

    A  4 m. robotic observatory dome from Scopedome installed in Tacande campus

For more details on the equipment and techniques used, see the page: Astronomical Observatory Handbook on this blog

Para más información de las técnicas y el equipo empleado, ver la página:  Manual del Observatorio Astronómico en este blog


  1. ---> A new possibility for an object of unknown type, resembling a nebula, within our solar system near the ecliptic at 65 degrees longitude.

    Method. I surveyed the ecliptic from 0 to 180 deg longitude using the automated search features of the VizieR online USNO-B catalog. In circles of radius 5deg, I compared the number of stars in Set 1 to the number in Set 2:

    Set 1: R1 magnitude >14, R2<14
    Set 2: R2>14, R1<14

    That is, Set 1 gives a large number of stars which appear dimmer on the older, Palomar sky survey plates. Set 2 gives stars which appear dimmer on the newer, Chilean survey plates. The difference in R1 and R2 can be due to calibration error or to true variable stars.

    I found one location at which Set 1 is extraordinarily small relative to Set 2. That is, here the R2 magnitude tends to be anomalously dim relative to R1.

    This location is the disk of 5deg radius centered on the ecliptic at longitude 67.5deg. Probing with an array of smaller disks of radius 2deg, I found that the most extreme anomaly is within the disks centered at ecliptic coordinates (66,0), (66,3) and (63,-3). If this were an edge effect on plate calibration, I would expect to see a NS and EW periodicity of 6 degrees (the plate size) which I do not see; so, I think this is a real change in apparent brightness involving thousands of stars in this region.

    A change in brightness could be caused by a nebula WITHIN OUR SOLAR SYSTEM which moves significantly between c. 1950 (Palomar plates) and c. 1990 (Chile plates). Where was the nebula at the time the Palomar survey plates were made? In the half of the ecliptic I have had time to check, the greatest anomalous dimness of the R1 magnitudes, is at 150deg longitude. So perhaps something has moved retrograde 150-65=85deg in c. 40 years.

    Be that as it may, I did find confirmation of the longitude 65deg position, in the 1851-star interstellar absorption catalog of Welsh (2010, relying on data typically 20 years older). The star HD 26571, visual magnitude 6.16 and spectral type B8 in the online Henry Draper catalog, lies within the region of interest and has the second highest NaI interstellar absorption in the entire catalog! (Though its CaII absorption is unremarkable for a star at its distance.)

    Crawford (MNRAS, 1990) published a spectroscopic study of this star. I don't know whether Crawford's explanation of its interstellar absorption is valid or not.

  2. There is opportunity for someone to repeat Crawford's old spectroscopic study of HD 26571, a rather bright star at Vmag 6.16. If the interstellar NaI (i.e. first sodium line) absorption has returned to normal, this is evidence for a moving cloud: a nebula within our solar system.

    Today I finished the coarse survey (disks centered on the ecliptic at whole and half clock hours ecliptic longitude, radius 5deg). I found Set 1 anomalously small at 18h, 18:30, 22h, and 22:30, but not as extremely so, as at 4:30 discussed previously. I also found Set 2 anomalously small, similar to 10h discussed previously, at 15h, 16h, 19:30, 20h, and 20:30.

    Future work should include doing the same with the B1 & B2 magnitudes. These plates are from different years than the R1 & R2 (red filter) plates. Especially for dimmer stars, these blue magnitudes often are missing. The blue (no red filter) plates are of poorer quality, with more skylight. Yet they might help.

  3. Indeed an interesting research but Crawford used a spectrograph of 100,000 resolution (R) for his work and my spectrograph only attain R=5,500

    If I understand well you want to measure the NaI lines of HD 26571 and eventually compare it with another star of same spectra out from ecliptic and/or galactic plane?

    Anyhow, tell me exactly what shall I do for you?