Astrophotography, believe it or not… …is not as hard as rocket science

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


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


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


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


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


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


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


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


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…


• 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.



• 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!

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Astrophotography, believe it or not… …is not as hard as rocket science