Hello, I am thinking of buying the CCD47-10 camera, but my observatory gets very hot in the summer. How hot can the CCD47-10 get without harming (lowering the life of, reducing the sensitivity of, etc.) the CCD chip, the CCD chamber or the CCD47-10 camera? Please tell me what empirical evidence you base this recommendation on. Thanks.
This is not a concern. The components are rated to 125C, though some do run about 40C above ambient. We recommend keeping the components below 90C for long-term reliability, which means a maximum ambient of about 50C. We have tested the cameras in an environmental chamber to ensure reliable operation over the expected outdoor temperature ranges. The only long-term reliability threat is moisture in the chamber, which can damage the sensor. As a general rule, I recommend switching off the cooler when the camera is not in use. This reduces the gradient between inside and outside the chamber, which helps prevent moisture from migrating into the chamber. For most cameras, if you are in a humid environment, I recommend purging the desiccant annually; otherwise, every two years is fine. That said, for windowless sensors I tend to be more conservative, because you do not want any risk of frost forming on the sensor. Therefore I recommend purging the desiccant annually for the 47-10.
Thanks Doug. I am not sure I understand this sentence: "We recommend keeping the components below 90C for long-term reliability, which means a maximum ambient of about 50C." If the ambient is 50C, then the camera will be 50C.
Ed, there are components inside the camera and power supply such as voltage regulators, power transistors, the FPGA/CPU, resistors, motor drivers, and other electronic components that generate heat when they are powered up. So what Doug is saying is that if the camera is powered up, some of the components would be hotter than ambient. Generally speaking, I try to keep all my electronics below 40C during operation. (That's 104F). So if you're being hit by the current heat wave, consider powering down during the daytime.
Thanks. I know that CCD chips and their chambers are delicate, so I was concerned about 100 degree + ambient temperatures, but apparently theses systems are more robust than I imagined. Did I understand correctly that you recommend getting the chamber recharged once a year?
The maintenance needed is to remove the Desiccant Plug, heat it to drive out the moisture from the desiccant, and replace it in the chamber. This removes moisture that gets past the seals into the chamber. For these unprotected CCD sensors, many people purchase a second desiccant plug, bake it, and swap them immediately. https://diffractionlimited.com/product/replacement-desiccant-plugs/ You're not "recharging" the chamber - you're drying out the molecular desiccant after it's holder is removed from the chamber. You cover the hole where the plug was removed, or stick in another one. Other cameras have a vacuum or hold dry argon, and have to be pumped down or purged and re-filled. That's not the case with our SBIG Aluma CCD series.
Many manufacturers just hide a large amount of desiccant in the chamber, and when it saturates out you have to send the camera in for maintenance, which means downtime and cost. The SBIG desiccant plugs eliminate this by making it a simple maintenance step that any user can do.
Colin, That is an EXCELLENT solution!!! This problem is the bane of CCD camera ownership. I learned this the hard way. Apogee sold me a very expensive camera years ago, but the salesman said NOTHING to me about the necessity of this maintenance (even though I am sure he knew about it). The camera predictably went bad, and it was too late to do anything about it. Once those chips have frost on them, they are not recoverable. You
Sorry, my previous post was not complete. This is what I wanted to say: Colin, That is an EXCELLENT solution!!! This problem is the bane of CCD camera ownership. I learned this the hard way. Apogee sold me a very expensive camera years ago, but the salesman said NOTHING to me about the necessity of this maintenance (even though I am sure he knew about it). The camera predictably went bad, and it was too late to do anything about it. Once those chips have frost on them, they are not recoverable. Your solution to this will greatly improve the lives of all SBIG camera owners.
Doug, you are right. But that is, by far, not the worst that can happen. What if the manufacturer of your camera is out of business (and uses a proprietary method to recharge the chamber) and has not sold the business to someone else. Then you are completely, 100% screwed!
Doug, that is excellent news! I always assumed that the chip and the chamber were so delicate that they would be susceptible to damage at relatively high temperatures. I use two 10 BTU air conditioners in my observatory (total of 20BTUs) and they help keep the inside dome temperature down to a level that is below ambient, but still higher than I would like. But after your input, I can see that the camera would do just fine in that environment.
Yes, you are right. I meant to write 10K BTUs and 20K BTUs. The two AC units help, but not as much as I would like considering that the dome is as hot as a frying pan in the Arizona sun.
