Star Analyser Grizma spectrometar

[Mount Pleasant Observatory (Bojan)]

Proslu Srijedu nije bilo ni dima ni oblaka iznad Melbourne-a, pa sam se malko igrao sa spekrtrometrom (SA100 + 3° prizma = grizma).
Kamera je bila modani Canon 450D, sve skupa montirano na C11.
Rezultati su dosta dobri, nije tesko dobiti spektar sjajnijih zvijezda (Betelgeuse i Sirius.... treba jos kalibrirati graf u BASS Project software-u).
To radim sad jer ce eta Carinae biti u periastronu krajem Feb ove godine... pa treba uvjezbati proceduru.

[Mount Pleasant Observatory (Bojan)]

A ovo je moy SA100 Grizma spektrograf..
To je zapravo SCT foto adapter (sa ebay), nasarafljuje se na C11.
Kamera je modani 450D (kupio ga na ebay za AU$50, trebalo ga je popraviti (slana voda usla u memory slot pa je trebalo staviti par vodova koje je elektroliza pojela).

[Mount Pleasant Observatory (Bojan)]

A ovo je rezultat... Spektri su kalibrirani po valnoj duzini ali jos ne i po amplitudi - to bu slijedeci projekt
(gore je Beltegeuse, dole je Sirius... kursor je postavljen na Halfa).

[Mount Pleasant Observatory (Bojan)]

Naucio sam kako kombinirati spektre u jedan graf...

[Danijel]

Ovo je zanimljivo. Sad samo treba naučiti kako to sve protumačiti, da ne ispadne, radim spektre, a ne znam što prikazuju.

[Acheron]

Naucio sam kako kombinirati spektre u jedan graf...

intenziteti su apsolutne mjere ili relativne?

[Mount Pleasant Observatory (Bojan)]

Ovo je zanimljivo. Sad samo treba naučiti kako to sve protumačiti, da ne ispadne, radim spektre, a ne znam što prikazuju.

He he lijepe slikice, lijepi grafovi  .. ali imas pravo.
Kalibracione vertikalne linije oznacuju Balmerovu seriju, dakle u spektru Sirius-a to je vodikova absorpcija...
Takodjer, vidi se koliko vise Betelgeuse svijetli u IR spektru...

intenziteti su apsolutne mjere ili relativne?

Intenziteti na ovom grafu su relativni..  zasad. I nisu kalibrirani, pa se vidi manjak u zelenom dijelu - "takozvani Canon - dip".

[Beorn]

 
Interesantno bi bilo promatrati i promjene u Spektru Betelgeusea, ne samo u sjaju

[Mount Pleasant Observatory (Bojan)]

Interesantno bi bilo promatrati i promjene u Spektru Betelgeusea, ne samo u sjaju

AAVSO je zatrazio takva promatranja, vidi dolje:


AAVSO Alert Notice 690
Rare very faint minimum of Betelgeuse (alpha Ori)

January 6, 2020

AAVSO Forum threads
(scroll to the bottom of a thread for latest posts):
- Campaigns and Observation Reports: https://www.aavso.org/alpha-ori-campaign-2020
- General AAVSO Discussion: https://www.aavso.org/alpha-ori-0
- Long Period Variables: https://www.aavso.org/question-about-betelgeuse-article-re-comparison-stars
- Spectroscopy: https://www.aavso.org/betelgeuse

The semiregular variable alpha Ori (alf Ori, Betelgeuse) is undergoing a very rare, very faint minimim. On behalf of numerous astronomers, the AAVSO is requesting that AAVSO observers monitor alf Ori in multiple wavelengths and obtain spectroscopy.

Of particular interest are observations in V, R, H, J, and B, along with spectroscopy. Time-resolved observations (at least 2-3 observations per night) are requested. Visual observations (not more than one per night) are also welcome.

PEP observers should contact AAVSO PEP Section Leader Tom Calderwood; his email address is "tjc at cantordust dot net".

Alf Ori typically has a minimum magnitude that may be 0.7 - 1.0 V, with occasional cycles brighter or slightly fainter. The previous minimum (Dec 2018-Jan 2019) was ~ 0.9 V (PEP, T. Calderwood, Bend, OR; DSLR, W. Vollmann, Vienna, Austria). Recent observations submitted to the AAVSO International Database show the current minimum at 1.407 V +/- 0.014 on 2020 Jan. 1 8462 UT (DSLR, Vollmann), 1.4 visual on Jan. 6.8374 UT (V. della Vecchia, Italy).

The extreme brightness of alf Ori presents a problem for choosing suitable comparison stars for DSLR and visual observing. Nearby bright stars and their V magnitudes include:

Rigel (bet Ori) - 0.12 V mean mag - note that color is blue; use with caution
Procyon (alf CMi) - 0.36 V
Aldebaran (alf Tau) - 0.87 V
Pollux (bet Gem) - 1.14 V
Castor (alf Gem) - 1.58 V - not recommended due to color of star
Bellatrix (gam Ori) - 1.64 V - not recommended due to color of star
Alnitak (zet Ori) - 1.79 V
Alhena (gam Gem) - 1.92 V
Saiph (kap Ori) - 2.06 V

Finder charts for alf Ori may be created using the AAVSO Variable Star Plotter (VSP). However, the most practical finder chart for alf Ori (showing Orion, comp stars, and nearby constellations) is the one given in the AAVSO's 10-Star Tutorial (https://www.aavso.org/sites/default/files/10startutorial-2013.pdf). Comp stars included on it (V magnitudes rounded for visual observing) are: Rigel at 0.1, Procyon at 0.4, Aldebaran at 0.9, Pollux at 1.2, Alhena at 1.9, and Saiph at 2.1, as well as others more relevant to other targets on the chart.

Visual observers need to be aware of the Purkinje effect and use the quick-glance method to make their observations; do not stare at alf Ori or the comparison stars, as doing so may make them become artificially bright.

Coordinates (J2000): R.A. 05 55 10.30  Dec. +07 24 25.4

Please report all photometry observations to the AAVSO International Database using the name ALF ORI.

Spectroscopy reports should be submitted to the AAVSO Spectroscopy Database (https://www.aavso.org/apps/avspec/).

This Alert Notice was compiled by Elizabeth O. Waagen.

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[Mount Pleasant Observatory (Bojan)]

U medjuvremenu sam napravio nekoliko verzija spektrometra..
Uglavnom, pokusavao sam povecati disperziju koliko je moguce, uzimajuci u obzir dimenzije sklopa.

Zasad koristim sklop kao na prvoj prilozenoj slici.
Udaljenost izmedju SA100 i senzora je ~144mm (moze se dodatno produljiti na ~200mm, vise od toga nije prakticno).
Na trecoj slici je spektar Altair-a, dobiven tim sklopom.

Radim i na slijedecoj verziji (v4, 5) - taj sklop ce koristiti Zenit 2x tele extender i tilter. Spektar se fokusira objektivom iz ruskog dalekozora ( ø30mm, FL=120mm), alternativno namjeravam za to upotrijebiti Tair-11A sa montiranim SA100, kojeg bi inace koristio za spektrografiju (pa necu morat mijenjat kalibraciju.. treba samo jedan  adapter (M42x1 -> M55x0.75) da bi se to montiralo na 2" adapter)

[Mount Pleasant Observatory (Bojan)]

Ova kombinacija sa modificiranim Rubinar 8/500 (izvadjen stop tako da mogu fokusirati na sensor udaljen ~120 mm) plus Grizma + 60DD(a) daje bolje rezutate.. bolji je S/N, a i LP smeta znatno manje (taj Rubinar kad se fokusira preko tih dodataka ima FL= ~700mm FL, ~f/10).
Dolje je spektar Siriusa napravljen u Svibnju ove godine (da, sa 60D(a), na slici dolje je 450D(fsm).

Inace, razmisljam i o vecoj udaljenosti Resetka-sensor za C11.. moglo bi se dobiti oko 200m kad bi se Grizma ugurala u C11 baffle, kao na crtezu.
Imam skoro sve sto mi treba za to sastaviti, moram samo istokariti nosac za prizmu (morat cu je zalijepiti na cijev, koja se onda natakne na SA-100)