astrophotography, believe it or not… …is not as hard as rocket science
TRANSCRIPT
Astrophotography,
believe it or not…
…is not as hard as rocket science.
It’s not rocket science.
• No Physics degree required• No Computer Science degree required• No Engineering degree required• Some computer skills can be useful• Some mechanical ability is useful• A basic understanding of electronics is useful• Some understanding of the underlying
science is a great plus• While equipment continues to improve, the
core technology itself is reasonably mature – it is highly unlikely that you will need to invent anything in order to be successful
• Patience and perseverance are absolutely mandatory!
It’s not black magic, either.
using practical and measurable considerations when making equipment choices will ultimately simplify the job
a little simple math can greatly assist in understanding how things work as well as what you might expect as a result
taking the time to develop a logical and tested workflow will improve your odds of repeatable results
It’s not black magic.
understanding the critical elements involved leads to better results
How Solar System Imaging differs from Deep Sky Imaging
• most objects are generally much brighter than DSO’s
• good results can be achieved at relatively fast shutter speeds
• highly effective cameras are generally much less expensive than purpose-built astronomical CCD cameras
• accurate tracking is not as critical to success – guiding is completely unnecessary
• good results can be had using moderately priced telescopes and mountings with uncomplicated setups
• trips to dark sky are not required in order to get good results
How Solar System Imaging differs from Deep Sky Imaging
• the details we are trying to capture are generally much smaller in apparent size than DSO’s
longer focal length instruments are useful for best results
telextenders (“powermate”, barlow and/or extension tubes) are very helpful in increasing image scale
• larger aperture instruments help overcome light loss due to the high focal ratios involved
• much more susceptible to poor seeing, focus and collimation
Cameras
Solar System Cameras
Philips ToUcam Pro 740K• No longer in production but widely available
used on the Web on eBay and AstroMart • Can be bought ready to go for astrophotos
for $50.00 or less• Uses Sony ICX098BQ CCD chip• Has 640x480 array with 5.6µm pixels• Works best at 5 to 15 frames per second
Solar System Cameras
Phillips SPC-900NC• No longer in production but still
available brand new from eBay and used from eBay and AstroMart
• Cost to make this camera ready for astrophotos is generally under $75.00
• Uses Sony ICX098BQ CCD chip• Has 640x480 array with 5.6µm pixels• Works best at 5 to 15 frames per
second
Solar System Cameras
Celestron NexImage • Commercially produced imager based
on the Phillips ToUcam design• Available at major astronomy and
photographic shops as well as on Amazon.com for under $100.00
• Uses Sony ICX098BQ CCD chip• Has 640x480 array with 5.6µm pixels• Works best at 5 to 15 frames per
second
Solar System Cameras
StarShoot Solar System Imager III• Commercially produced imager using 1.3
megapixel CMOS chip• Priced at $189.95 at Orion Telescopes• Comes bundled with MaximDL Essentials
software• Uses Micron MT9M001 CMOS chip• Has 1280x1024 array with 5.2µm pixels• Maximum frame rate of 15 frames per
second
Solar System Cameras
SAC Systems Model 7b Imager• Commercially produced modified webcam
with Peltier cooling and long exposure capability
• No longer in production, but available used on websites like AstroMart for generally less than $200.00
• Specs vary per production run but all imagers have 640x480 CCD chips
Solar System Cameras
DV Camcorder (aka – the camera that you already have)
• Lower TCO by using a camera you already have
• Conversion for astro use is not permanent and can cost as little as $30.00
• Fixed lens requires that images be taken using afocal photography rather than prime focus photography
Tips for Afocal Photography
• Use an eyepiece with long eye relief• Couple the end of the camera lens as close as
possible to the eye lens of the telescope eyepiece
• If possible, set the digital camera at macro mode rather than infinity
• Use full optical zoom, but do not use digital zoom
• If possible, use a camera lens with a focal length longer than the eyepiece focal length
Solar System Cameras
Imaging Source DMK 21AU04.AS• Commercial camera originally designed for
industrial applications• monochrome but available in a color model• Suggested retail price $390.00 but can be
had for less at certain retailers• Uses Sony ICX098BL CCD chip• Has 640x480 array with 5.6µm pixels• Has a maximum frame rate of 60 frames
per second using firewire port, but this USB model performs better at 30 fps on my laptop
Solar System Cameras
Luminera SkyNyx 2.0• Commercially produced camera specifically
for astrophotography, this is the entry level model for this line
• Monochome and color versions available• Retail price $995.00• Uses Sony ICX424 chip• Has 640x480 array with 7.4µm pixels• Maximum frame rate is > 100 frames per
second
Solar System Cameras
Dragonfly ExpressBy Point Grey Research
• Industrial firewire camera – Point Grey is just beginning to cater to the astronomy market
• Monochrome and color versions available• Suggested Retail price is $1195.00• Uses Kodak KAI-0340DM/C CCD chip• Has 640x480 array with 7.4µm pixels• Has maximum frame rate of 350 frames
per second
Software
Image Scale
3777mm efl @ f/18
5846mm efl @ f/25
6342mm efl @ f/23
8416mm efl @ f/24
13,149mm efl @f/40
So – how does this work in practice?
Image Scale – Prime Focus
Image Scale – Prime Focus
Image Scale – 2X Barlow
Image Scale – 2X Barlow
Hey, wait a minute…
Hey, wait a minute…
• If the line is 72 pixels long at prime focus, shouldn’t the line be 144 pixels long with the 2X Barlow?
Hey, wait a minute…
• If the line is 72 pixels long at prime focus, shouldn’t the line be 144 pixels long with the 2X Barlow?
• No. The actual magnification of a barlow is determined by how far the imaging chip is from the last lens in the barlow.
Hey, wait a minute…
• If the line is 72 pixels long at prime focus, shouldn’t the line be 144 pixels long with the 2X Barlow?
• No. The actual magnification of a barlow is determined by how far the imaging chip is from the last lens in the barlow.
• This behavior gives us some interesting options for increasing the image scale in our Solar system images!
Televue Barlow Magnification
Image Scale – Barlow w/extension
Image Scale – Barlow w/extension
So – what did we get?
• 72 Pixels represents “1X” – baseline• With the “2X” barlow in place, the line went
to 176 pixels – in actuality, my “2X” barlow is really a “2.44…X” barlow – an over achiever to be sure
• Adding 36.76mm of extension to the optical train took the line to 228 pixels, giving us a total increase in scale of 3.2X over the native scale – increase this extension and you increase the scale!
What’s Next?
How some easy math provides answers to questions you need to know:
• How big will Jupiter be on *my* telescope?• How long *was* my effective focal length?• What *was* the focal ratio of the system?• How long can I expose Jupiter before the
planet’s rotation causes smearing?• Yes, I will talk about capture and
processing too!