Astrophotography targets
see also:
Wide angle astrophotography:
allows unguided photos on a tripod up to ~30sec (depending on focal length used) without significant star trails being evident.
star trails:
you will need:
camera that can take long exposures
preferably a wide aperture lens so you can see enough to compose and focus, although you will probably be using apertures of f/2.8-5.6 to take the photo.
sturdy tripod
a dark sky away from Light Pollution, airplane paths, with preferably no moon (eg. new moon)
no clouds
may need a dew heater on the lens to stop dew forming
don't forget to use a flash or torch to light an interesting foreground subject briefly during the exposure.
alarm clock to wake you up if taking very long exposures, otherwise dawn will ruin your photo.
if going to sleep, check forecast to make sure it will not be raining on your equipment.
most prefer a film camera (batteries and digital noise issues are eradicated),
eg. 2-6hrs at f/5.6 or 8hrs at f/8 using 100ASA film
if you have a digital camera that has enough power for a long exposure and can do automatic dark frame shots to remove camera noise, then try exposing at ISO 100 at f/2.8-4 with length of each exposure determined by sky brightness
assuming you are away from cities (eg. 150km away) and light pollution:
half moon will limit exposures to about 15-25min
quarter moon will limit exposures to about 30-40min
new moon will limit exposures to about 60-120min
a fully charged battery on a Canon 1DMII will allow two 45min exposures with dark frame shots
consumer digital cameras may struggle to get to a single 8min exposure.
remember, you could take multiple 8min exposures and combine them as this will reduce the problems with excessive sky brightness and battery issues as well as camera noise, but you will get gaps in star trails
on the net:
guided stellar scenes:
http://www.ne.jp/asahi/stellar/scenes/leonids2001/review_e.htm - uses film
can do a composite of many short exposures to capture as many meteors as possible in a shower
zodiacal light / aurorae
Milky Way (just need a dark sky away from Light Pollution):
can even create a foreground mosaic such as http://www.abmedia.com/astro/misc/stars-seashore.html
100mm effective focal length at f/2.0-2.8:
eg. 85mm lens on a Canon 1D 1.3x crop dSLR (111mm in 35mm terms) or 60mm on a APS-C dSLR with 1.6x crop (96mm in 35mm terms)
eg. 50mm lens on an Olympus dSLR (see my comet McNaught P1 photos).
this will give an angle of view of about 20.6deg x 13.8deg (thus the moon would occupy only 3.5% of image height)
unguided exposures need to be less than 8secs to avoid significant star trails which would limit one to the brighter stars and planets only with magnitudes greater than about 5 using ISO 400-800
on a cheap HEQ5 equatorial mount you should be able to get good 60-90sec sub-exposures which should be good for a range of star clusters and nebulae (the latter if H-alpha emitters image best if you have the IR blocking filter removed).
targets 10-20deg in size:
comets when they have long, bright tails
parts of the Milky Way
Prancing Horse region: Pentax67 with 165mm f/2.8, Ektachrome 200 +0.5stops, 1x40min;
parts of zodiacal light
Hyades
Barnard's Loop in Orion (H-alpha)
200mm effective focal length at f/2.8-3.2:
eg. 135mm lens on a Canon 1D 1.3x crop dSLR (176mm in 35mm terms) or on a APS-C dSLR with 1.6x crop (216mm in 35mm terms)
eg. Olympus 50mm f/2.0 macro with 2x TC = 200mm f/4 - perhaps better to settle for the 1.4x TC and 140mm f/2.8
this will give an angle of view of about 10.3deg x 6.9deg (thus the moon would occupy only 7% of image height)
unguided exposures need to be less than 4secs to avoid significant star trails which would limit one to the brightest stars and planets only
on a cheap HEQ5 equatorial mount you should be able to get good 30-60sec sub-exposures which should be good for a range of star clusters and nebulae (the latter if you have the IR blocking filter removed).
targets 5-10deg in size:
comets when they have short tails
star clusters
Lambda Orionis nebulosity (~7deg but faint)
300mm effective focal length at f/2.8-3.2:
eg. 200mm lens on a Canon 1D 1.3x crop dSLR (260mm in 35mm terms) or on a APS-C dSLR with 1.6x crop (320mm in 35mm terms)
eg. 150mm f/2.0 Olympus ZD lens on a Olympus dSLR = 300mm f/2.0
eg. Olympus OM 135mm f/2.8 or better, a Leica R, Carl Zeiss or maybe Nikkor on Olympus = 270mm f/2.8
this will give an angle of view of about 6.9deg x 4.6deg (thus the moon would occupy only 11% of image height)
unguided exposures need to be less than 2.5secs to avoid significant star trails which would limit one to the brightest stars and planets only
on a cheap HEQ5 equatorial mount you should be able to get good 30-60sec sub-exposures which should be good for a range of star clusters and nebulae (the latter if you have the IR blocking filter removed).
targets 2-5deg in size:
comets when they have short tails
northern hemisphere:
Andromeda Galaxy
Alpha Persei star cluster
Gamma Cygni nebulosity (H-alpha)
California nebula (H-alpha)
Veil nebula
Northwest Monoceros nebulosity
equatorial:
Pleiades (~1.5deg) - 9x90sec at f/3.5, 1600ISO
Zeta Orionis complex - Flame nebula & Horsehead nebula
Orion nebula
southern hemisphere:
450-600mm effective focal length at f/2.8-4:
eg. Canon 300mm f/2.8 EF on an APS-C = 480mm f/2.8
eg. Canon 400mm f/2.8 IS, f/4 DO or f/5.6 EF on an APS-H = 520mm
eg. Olympus 300mm f/2.8 ZD on an Olympus = 600mm f/2.8
eg. Olympus 150mm f/2.0 ZD with 1.4xTC = 420mm f/2.8
eg. Olympus 150mm f/2.0 ZD with 2xTC = 600mm f/4.0
eg. Olympus OM 300mm f/4.5 on Olympus dSLR = 600mm f/4.5 - but may need to stop down to f/5.6
targets 1-5 deg in size:
comets when they have short tails
northern hemisphere:
Andromeda Galaxy
Alpha Persei star cluster
Gamma Cygni nebulosity (H-alpha)
California nebula (H-alpha)
Veil nebula
Northwest Monoceros nebulosity
equatorial:
M8 & M20 Triffid nebula: 4x4min @ f/2.8 ISO800;
Pleiades (~1.5deg)
Zeta Orionis complex - Flame nebula & Horsehead nebula
Orion nebula
southern hemisphere:
omega Centaurus globular cluster: 21x60sec 400mmL f/2.8 EF ;
750mm effective focal length at f/5.6:
eg. Megrez 80mm f/6.0 APO refractor (480mm) on a 1.6x APS-C = 768mm f/6.0
eg. Takahashi 180ED 500mm f/2.8 astrograph with APS-C = 800mm
eg. Canon EF 500mm f/4.0L IS with APS-C = 800mm f/4.0
eg. Canon EF 300mm f/2.8L IS with 2x tele-extender on 1.3x APS-H = 780mm f/5.6
eg. Olympus ZD 300mm f/2.8 with 1.4x TC = 840mm f/4
eg. Nikkor 200mm f/2.8 with 2x TC on Olympus dSLR = 800mm f/5.6
this will give an angle of view of about 2.75deg x 1.8deg (thus the moon would occupy only 28% of image height)
unguided exposures need to be less than 1sec to avoid significant star trails which would limit one to the moon and perhaps Jupiter
for most deep sky objects at this magnification and f/ratio you will need auto-guiding for best results.
targets 0.5-2deg in size (see under 1000mm)
equatorial:
Orion nebula -
M45 Pleiades - 20x5min @ f/5.6, 400ISO
M27 Dumbbell nebula (0.1deg) - 13x180sec
southern hemisphere:
Omega Centaurus globular cluster (mag. 3.7) -
Eta Carina:
1000mm effective focal length at f/5.6:
eg. 800mm lens on a Canon 1D 1.3x crop dSLR (1040mm in 35mm terms) or 600mm on a APS-C dSLR with 1.6x crop (960mm in 35mm terms)
500mm f/4 IS EF lens with TC1.4x gives 1120mm on APS-C dSLR and 910mm on APS-H
eg. Nikkor 500mm f/4.0 lens on a Olympus dSLR = 1000mm f/4.0
eg. Olympus 300mm f/2.8 ZD with 2x TC = 1200mm f/5.6
this will give an angle of view of about 2deg x 1.4deg (thus the moon would occupy only 37% of image height)
unguided exposures need to be less than 0.8secs to avoid significant star trails which would limit one to the moon and perhaps Jupiter
on a cheap HEQ5 equatorial mount you should be able to get good 10sec sub-exposures which may be pushing it for a star clusters and nebulae (the latter if you have the IR blocking filter removed).
you really need a high quality mount for this such as a Losmandy
a Tak 180ED astrograph which is a 500mm f/2.8 could be used without autoguiding on a Losmandy mount for 1min exposures, slower apertures will require longer exposures and the hastles of autoguiding.
for example, the Andromeda galaxy imaged with a total 50min at f/8 at 1600ISO, could be imaged at 12min total at f/4, and 12x1min is MUCH easier than 10x5min, and if you use the Canon 1D mark III, its improved noise would allow 3200ISO and thus maybe 9X45sec at f/4 using a 1.4x tele-extender with the Tak 180ED to give 1120mm effective focal length at f/4.
targets 0.5-2deg in size:
the moon - 0.5deg
comets heads
northern hemisphere:
Andromeda Galaxy - 10x5min @ f/8, 1600ISO; 23x75sec @ f/5.6, ISO 800;
Spiral Galaxy in Andromeda - 22x5min @ f/8, 1600ISO
Ring nebula in Lyra -
equatorial:
Horsehead nebula in Orion - 5x5min @ f/8, 1600ISO,
Orion nebula - 30x2min @ f/8, 800ISO with 1050mm; 44x1min @ f/5.6, 400ISO;
southern hemisphere:
Omega Centaurus - SBIG ST8XME LRGB 60:30:30:30min @f/7; 2x100sec 10" f/5.6 ISO1600;
2000-3000mm effective focal length at f/5.6:
prime focus telescopes
eg. 1850mm f/5.6 (eg. 10" f/5.6 Newtonian on APS-H dSLR)
eg. 2276mm f/5.6 (eg. 10" f/5.6 Newtonian on APS-C dSLR)
eg. 2560mm f/6.3 (eg. 10" Meade LX200 on APS-C dSLR)
eg. 2800mm f/5.6 (eg. 10" f/5.6 Newtonian) on a Olympus dSLR
at 2000mm, this will give an angle of view of about 1deg x 0.7deg (thus the moon would occupy only 74% of image height, while Jupiter & Saturn would occupy ~1.8% or about 50 pixels on a 10mp dSLR - must verify this when I get my 1D)
unguided exposures need to be less than 0.4secs to avoid significant star trails which would limit one to the moon and perhaps Jupiter, Mars and Saturn
Saturn (mag. 0.4)
webcam users often use 4000mm eff. f/l at f/40, 1/25th sec and resolution is only 640x480px
Canon 1DMIII with OM 2xTC + 10" f/5.6 Newtonian gives 3700mm f/11 so perhaps 1/50th sec at ISO 3200 - I need to try this (cannot use EOS TC's on telescopes as get error message)
Olympus E510 with two 2x TC's gives effective 11,400mm f/22 and need at least 1/15th sec 1600ISO but at this magnification you will be severely limited by poor seeing &/or poor focus
on a cheap HEQ5 equatorial mount you should be able to get good 10sec sub-exposures which is pushing it for star clusters and nebulae (the latter if you have the IR blocking filter removed).
Omega Centaurus (mag. 3.7 ie. ~4EV less bright than Saturn but a lot bigger) needs about 30sec f/2.8, 800ISO => 30sec, F/5.6, 3200ISO =>
a Canon 1D Mark III could do 15sec, f/5.6, 6400ISO which may be good enough
you really need a high quality mount for this such as a Losmandy
targets 0.1-1deg in size:
the moon (Jupiter and Saturn at opposition are about 0.01deg in size including rings)
comets heads
northern hemisphere:
M104 Sombrero Galaxy - 23x1min, f/10, 1600ISO
equatorial:
M20 Triffid Nebula - 13x2.5min, f/6.3, ISO800
M51 Whirlpool galaxy - 9x5min, f/6.3, ISO800
Orion nebula - 15x3min, f/4.8, ISO400;
M45 Pleiades - 40x4min, f/4.8, ISO400;
southern hemisphere:
NGC 5128 in Centaurus - remarkable extra-galactic object ~0.1deg, needs at least 75mm aperture