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Old 28-08-2010, 02:23 PM
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higginsdj
A Lazy Astronomer

higginsdj is offline
 
Join Date: Mar 2006
Location: Canberra
Posts: 614
Keep the ideas coming.

There is a lot of 'misinformation' and 'opinions' out there. Because the bulk of what we do is differential photometry, ANY (and I do mean ANY) CCD/CMOS camera can be used.

There are limitations of course, but from a differential photometric perspective the ONLY limitation is the extent of linearity in your camera. A lot has been said about ABG cameras not being suitable - more misinformation. ABG cameras can have quite extensive linearity and some have wider linearity bands than NABG cameras. As the photometrist/observer, it is your responsibility to know the full characteristics of your camera and work to them.

Re discoveries - on the whole they are a team effort. In the team, the rule is whoever first images an eclipsing event gets the discovery credit - but everyone who participates in the observing of that target gets on the discovery notice. We hunt the asteroid binaries but we also get serendipitous discoveries as well. A side effect is that we have to chose many comparison stars in our differential photometry. Sometimes one of the comp stars turns out to be variable, showing rapid changes. I've nabbed as many eclipsing binaries as I have asteroid moons.

The AAVSO mob still call asteroids the 'vermin of the skies' but the Eclipsing Binaries are the vermin for me - because I have to remeasure my images at least twice

You can do MP photometry with as small as an 8" scope. Less targets since your limiting magnitude is a great deal lower - but for the resourceful there are ways around that - stacking images for example. 14" and larger are ideal to get all the types of targets I am working but there is a member of our group who uses a 10". Again, it comes down to experience and working within the limits of your setup and that comes down to proper planning.

Sure, some of you with small aperture scopes may not hit the 'big' time with new binary discoveries, but the asteroid photometry field is vast - there are H-G curves, Spin Axis Determination, Shape modeling etc and new avenues are constantly opening up. Do what I did - start small and build up and your experience increases. I started with an 8" LX-90, then moved to a 10" LX200GPS then to a 14" LX200GPS. I started with a tiny Starlight Xpress MX516 ABG camera (95% linearity) then moved up to a ST7 sized SX MX716 (now used as my guider) then onto a second hand parallel SBIG ST-8 (a very old camera). I had a second hand SBIG ST-9 as well - it also did a fine job (actually better than the ST-8 but its field was a little small for 100 percent reliability in robotic scope pointing).

If I had the money I would be putting up a second/third/fourth scope with cameras (a couple of my counterparts in the states have just done this) there are just so many targets out there - we (the few of us doing this work - pros included) just can't cover everything. Targets that are Prime Binary Suspects are often skipped/missed because we just don't have enough scopes to observe them all.

Last edited by higginsdj; 28-08-2010 at 02:34 PM.
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