1. Northern Prairie Star Party
Black Nugget Lake
September 15, 2012
Brian Martin
The King’s University College

2. Three Fundamental “Sciences”
Measuring “Distance”, Position & “Scale”  Astrometry
Measuring Brightness and Intensity  Photometry
Measuring “Colour”  Spectroscopy
Exciting science that you can do from the back yard!

3. Astrometry How big are the lunar features in this image?
August 29, 2012
H-alpha filter
0.001 s exposure
ED80
Atik 314L+ camera
TKUCO
How big are the lunar features in this image?

4. Some Math … S R The Small Angle Formula Rq* = S where:
R = distance from object
q = angle that the object subtends in the sky
S = distance across the object
* Angle in radians

5. The Scale of Your Telescope
Scale in (seconds of arc)/mm found by:
In the previous image a ED80 telescope was used so the scale is (206265)/(600 mm) = “/mm
The Atik 314L+ has 6.45 mm pixels, so each pixel has a scale of ”/mm × mm/px = 2.22 “/px when used with the ED80
By measuring the number of pixels you can measure the angle that an object or feature subtends

6. Distance = AU
304 px = 1236 km
850 px = 3457 km
(0.5% error)

7. Some other images… Capuanus Crater: December 26,2009 C14, f/11
Imaging source DMK2104
2000 frames
Distance = AU
Scale = 0.20”/px = 0.37 km/px

8. Apennines (Eratsothenes, Archimedes)
March 1, 2012
C14, f/7
Atik 314L+
20 frames (0.005 s)
Scale = 0.52”/px
Distance = AU

10. Jupiter November 5, 2011 Distance = 3.98101 AU C14, f/11
Imaging Source DMK2104
LRGB (~2000 frames each)
Scale = 0.29”/px = 837 km/px
159 px = km
170 px = km
Oblateness = ( )/142 = 6.3%

11. M57 August 26, 2011 C14 f/7 ST7E LRGB Distance = 2300 ly
Scale 1.49”/px = ly/px
160 px = 2.7 ly

12. M15 August 21, 2011 C14 f/7 ST7E LRGB Distance = 33 Kly
Scale 1.49”/px = ly/px
534 px = 127 ly

13. Photometry – Measuring Changes in Brightness
Intrinsic Variables
d Scuti
SX Phe
Novae and Supernovae
Cataclysmic Variables

14. Consumer grade CCD cameras…
Capable of doing excellent science!
Modest cost (< $2000)
Excellent software support
Monochrome with no anti-blooming is preferred
Pixel size should be carefully matched to image scale – need to oversample
Capable of milli-magnitude precision photometry
Atik 314L+
SBIG ST7E

15. SX Phoenicis Variables
BL Camelopardalis
Average mag 13.1
Period
0.0389d
56 minutes – this is an exciting system to watch!!
40 s integration, C14 f/7
ST7E camera – KAF400 detector

16. The Light-Curve… November 9, 2009
BL Cam
Teff 7730 K
Age ~4Ga
Metal poor
Period shows a
Small change over time!
November 9, 2009, s (C2-C1) = mag

17. DY Pegasi … A Nice Intro to SX Phe
A great star!
Bright (m = 10.3)
Excellent Check and Comparison stars
Well placed for fall observations
Data collected with 8” Newtonian and SpectraSource Lynxx (TC211)

18. Cataclysmic Variable Stars
Binary stars that are exchanging mass
One of the stars is compact
Hot spot forms on accetion disk
Accretion disk around compact star produces variability
A rewarding study for amateurs!

19. Two exemplar CVs… DW Uma Period (d) 0.136606 Mag 14 - 18
TKUCO 120 s image 0.32 f/4.8
DW Uma
Period (d)
Mag

20. GK Persei Period (d) 1.996803 d Mag 11.5 - ?
TKUCO 60 s image 0.32 f/4.8
GK Persei
Period (d) d
Mag ?

21. Other Photometric Delights!
Novae and Supernovae
Algol systems
Asteroids
NGC 6946
30s exposure
September 29, 2004
SN 2004ET
0.32 f/4.8 Newtonian
ST7E camera

22. Spectroscopy Broad and Narrow band filter imaging
Low Resolution Spectroscopy
Medium – High Resolution Spectroscopy

23. Broadband Colour Imaging
M27 LRGB, August 2011, C14 f/7
ST7E G B

24. Narrow Band Imaging Ha Hb
SII
OIII

25. Ha
S II
O III
C14 f/7 Atik 314L+
March 1, 2012

26. LRGB image of central region of M51 C14 f/7 ST7E
L filter with Ha overlay showing star forming regions along spiral arms
C14 f/7 Atik 314L+

27. Stellar Spectra (Low R)
Remarkably easy to do – even with modest equipment!
Small telescope w/wo tracking
CCD or DSLR
Rainbow Optics or Star Analyzer grating
Introduces a fascinating new direction for amateurs

28. Some samples…
(trailed images with Atik 314L+, Orion 80 mm ED)

29. Vega, Teff = 9600 K Altair, Teff = 6900 K – 8500 K Ca II line
Note Deneb’s narrow lines!
Vega, Teff = 9600 K
Altair, Teff = 6900 K – 8500 K
Altair is a very fast rotator and is squished like a football! Hotter at the poles by about 20%
Ca II line

30. Other Interesting Stars…
Which is these is the hottest star?
T = K F2
T = K
B0.5e
T = K A5
Be Star with disk

31. Planetary Nebulae The “Eskimo” – NGC 2392 C14 f/7 10 minutes
April 21, 2011
The reason nebula filters work!

32. Measuring the Expansion of the Universe!
3C273 C14 f/7 60 minutes
ST7E April 5, 2011
Rest Frame (A)
Measured (A)
Dl (A) z Hb
4860
5666
806
0.166 Ha
6563
7562
990
0.151
Zaverage = 0.159

33. Universal Expansion What does z = 0.159 mean?
Apparent recessional velocity is 0.159C = km/s!
Hubble expansion law:
Hubble’s constant H = 70 km/s/Mpc
R = 681 Mpc = 2.2 billion light years!

34. Medium/High Resolution Spectroscopy
For more advanced work
Requires robust mount and tracking
Need as much aperture as possible
BUT – still well within the reach of advanced amateurs and astronomy clubs!

35. The L200 Littrow Configuration
Can resolve to about 1 A (R = 3000)
Built from a kit, cost ~$1000
Capable of useful research on Be, WR and Algol type stars (and much more!)

36. The Solar Spectrum
ST7E on C14

37. Altair

38. Homebrew for under $200!
And it Works!

39. The Magnesium Triplet…

40. Some References… Christian Buil - http://www.astrosurf.com/buil/
Tom Field - RealTimeSpectroscopy (RSPEC)
Rainbow Optics Spectroscopes
Center for Backyard Astrophysics (CBA)

41. Thank you – Questions?