equipment

20
May

QHY9 vs Astro40D

Any addicted astrophotographer is always considering new equipment, and also debating the merits of several options. One of the most common questions for beginners is about the difference between digital SLRs and astronomical CCD cameras. I love a good experiment so below is my answer.

Both these images were taken with a Takahashi Epsilon 160 astrograph (530mm f3.3). Total exposure time for both images is 115 minutes (almost two hours). The comparison is between a CentralDS cooling modified and spectrum enhanced Canon 40D and a QHY9 astronomical CCD camera.

Through a combination of luck and good fortune, Kaz and I have three different Canon cameras - a venerable 20D DSLR, an ultra compact IXUS 70 and most recently the G9. Phil wants to know how much he sacrifices when he takes the G9 cross country skiing instead of the 20D and Kaz wants to prove that the G9 she chose to keep (after Phil won it) is really better than the IXUS 70.

Having 'upgraded' to a Hutech modified Canon 40D Digital SLR, I was keen to see how it compared to my existing Hutech 20D and what the optimum settings were for ISO and sub-exposure length. The images and results here for the 20D and 40D should be comparable with a 350D and 450D respectively since they use the same sensor.

Astro Tips

If you've ever wondered whether it's possible to use a Meade CCD or SBIG ST4 autoguider with a Celestron mount...it is: here is a document that describes my experience at working out how, seeing as no one at Meade or Celestron or on the newsgroups could tell me at the time, although that was in 1998.

Canon 200mm f2.8L Lens Test

Star tests with the Canon 200mm f2.8L II lens and 1.4x and 2x teleconverters.

Canon 200mm f2.8L II lens


10D Centre 100% 10D Corner 100% 35mm Film Corner

f2.8

Canon 28-135mm Lens Test

Star tests with the Canon 28-125mm lens.

Canon 28-135mm f3.5 - 5.6 IS USM @28mm


Centre 100% Corner 100%

f3.5

20mm Wide Angle Lens Test

20mm Wide Angle Test

These photos were taken on a fixed tripod using autofocus on the centre of the image. These images are 100% crops from near the corner of the original.



Sigma 20mm
f1.8 EX DG

Canon EF-S 10-22mm
f3.5-4.5

Film Tips

This info is many years old, but perhaps still useful for some! It's a long time since I used any of these..

Finding good astrophotography films is tedious, especially when you have only a limited number of nights and don't want to risk them trying new films. Below are some of my thoughts on films I have used.

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