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Basic Photometry Setup

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Basic Photometry Setup

I am a relative newcomer to astronomy and astrophotography, and have a very basic setup- an Explore Scientific AR102 scope, Orion Atlas EQG mount, a ZWO ASI290MM camera, along with a guide scope and camera.  If I were to try my hand at photometry and measuring light curves, what equipment would I need to change?  In looking at the CHOICE training, it seems that CMOS cameras are undesirable, CCD cameras being their focus.  What are some examples of lower-end cameras that will get the job done?  Seems like I would need to purchase a different set of filters for photometry, different from AP filters, correct?  Also, does CA and SA in a simple achromatic telescope matter, or does photometry require an ED or apo telescope? 

Just trying to ascertain the impact on my budget if I try my hand in a new area.  Thanks for your inputs.


Bikeman's picture
ASI 290mm should be fine

CMOS vs. CCD is a hot and active discussion. However, you will be more than fine making your first steps with a ZWO ASI 290mm. It's a bit smaller in chip size than you would ideally want, but still ok. I think you don't have to be a prophet to predict that in the not too distant future, CCD astro-cameras will anyway completely vanish from the low- to mid-price segment, and maybe even from most of the high-end market as some manufacturers are ramping down or even terminating their CCD sensor production in favor of CMOS.

 See this here for how one of the AAVSOnet telecopes was upgraded to use a CMOS sensor. There can be no doubt that CMOS and photometry go together just fine.

As for filters: You could even use RGB filters to do meaningful photometry (like DSLR people do), but as you are actually thinking about spending money, my recommendation would be to put that money into photometric filters ("B" and "V" filters  for a start), they are already quite expensive, unfortunately.   

Don't worry about color or geometric imperfections of your scope. Photometry is not about making super sharp images, it's more about throwing photons in the general direction of a sensor :-), Indeed we sometimes defocus intentionally to spread light over more than one pixel (you might have seen that part already in the CHOICE material).

So you are basically ready to go! Good luck and if you run into problems, don't hesitate to ask the good people at for help :-)

Clear Skies



spp's picture
Camera for CHOICE CCD courses

There is a forum topic for exactly this kind of question:

Thank you for your comments

Thank you for your comments and advice. 

The CCD1 class, is that with scheduled times/dates, or is that a "work at your own pace/self taught" style class?

Clear skys,


spp's picture
CCD1 class questions

Please post this question to the forum topic which I just posted above.  We can discuss all your questions there.


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