Is It Possible to Do Photometry Without Using a CCD?

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    Ccd Photometry
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SUMMARY

This discussion explores alternatives to CCDs for differential photometry on stars of magnitude 5 and under, specifically using a 6" Newtonian telescope. Participants consider photomultiplier tubes like the 1P21, which are affordable but require costly 1000V power supplies. The conversation also highlights the potential use of single photodiodes and photoresistors, although concerns are raised regarding their sensitivity to faint starlight. Ultimately, the consensus leans towards using area detectors, such as DSLRs, for more effective differential photometry.

PREREQUISITES
  • Understanding of differential photometry techniques
  • Familiarity with CCD and photomultiplier tube technology
  • Basic knowledge of photodiodes and photoresistors
  • Experience with long exposure photography using DSLRs
NEXT STEPS
  • Research the specifications and sensitivity of photodiodes for astrophotography
  • Investigate the use of DSLRs for differential photometry
  • Explore the operational principles of photomultiplier tubes
  • Learn about the limitations and applications of photoresistors in astronomy
USEFUL FOR

Astronomy enthusiasts, amateur astrophotographers, and researchers interested in low-cost alternatives for differential photometry techniques.

mishima
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CCDs are very cheap, but I was wondering if there was an even cheaper alternative to CCDs if the goal is differential photometry on magnitude 5 and under stars. The data only needs enough precision to prove/demonstrate the concept, and to develop a good sense of the workflow in doing photometry from observational data. Assume I have a 6" Newtonian.

Photomultiplier tubes such as the 1p21 can be found for less than 40$, but require expensive 1000V power supplies.

I am more curious about single photodiodes, or even more crude ways of collecting starlight such as photoresistors. Just wondering if anyone has experimented with some off the beaten path electronic detectors.
 
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mishima said:
I am more curious about single photodiodes, or even more crude ways of collecting starlight such as photoresistors. Just wondering if anyone has experimented with some off the beaten path electronic detectors.

I would suggest that their sensitivities would be way too low for the faintness of starlight
 
A photoresistor could not even detect something like Vega? Just curious, not sure how to calculate something like that using a datasheet.

I was thinking photodiodes at least had been in use a few decades ago.
 
It is much simpler to do differential photometry with an area detector where the target and comparison star can be on the same image. You can use a DSLR or even a point and shoot camea if it can do long exposures.
Regards Andrew