Hi Wayne, On 07 Dec 2008, at 11:20, Wayne Sumner wrote:
Congratulations again!
Thanks. With something like 450,000 of them out there finding one more really doesn't amount much in the "big picture" but it's still fun to say "I discovered that.".
As the Northridge 30 cm observatory draws closer to completion, (the roll off roof is in place and covered with tar paper), I am thinking that it would be great to take a handful of students with me to visit your observatory and learn all we can about how you do what you do.
Glad to hear things are coming along with your observatory. When are you expecting first light? Not much to see at my observatory and no way the students would fit. I built it to fit the C-14 and to be used remotely so it's so tight in there that I have to "suck it in" just to get in there and open the roof.
I also wonder how critical dark skies are to the list of requirements you gave.
Well, since I've now had four reply that they're interested I'll take a moment here to go into more detail. Yes, skies are important. Virtually all of the minor planets being found these days are mag 18 or fainter. There was a time when that was pretty much out of reach to amateurs but these days with CCD cameras 18 is pretty "bright". Fortunately with the right camera, many amateur scopes can get down to 18 or 19 in 4 minutes or so which means guiding may not be necessary (just be sure the polar alignment is good). Not surprisingly, knowing where to point the scope is a big help. For that you need to know where all of the know minor planets are located and with today's software that's become simple. About once a month I download the entire catalog, either ASTORB from Lowell at ftp://ftp.lowell.edu/pub/elgb/astorb.html or MPCORB from the Minor Planet Center at http://www.cfa.harvard.edu/iau/MPCORB.html. Once I've got that displayed I find a place near the ecliptic and near the meridian with no minor planets shown. That's the spot I shoot. Wait 15 minutes and shoot again. Wait 15 minutes and shoot again and one more time. Or, to improve my chances I typically program the mount to work a mosaic of 4 adjourning fields. So I shoot field 1 then 2 then 3 then 4 and repeat that a total of 4 times. Ok, once you've got your find recorded you need to know it's there and measure its position. In the olden days (5 years ago) one could just use the computer to blink all four images in each field in succession and the movement of the target against the background stars made it stand out. But now with all the bright ones all but gone finding the faint ones in the pictures has gotten much tougher. In fact all of my finds this year have been found not by me but by the software. Only after the software flagged a particular spot on the images have I been able to see it. Ok, now as to software. I'm sure there are lots of programs out there but the ones I use are both by Software Bisque. TheSky displays the star field and all the minor planets and also points the telescope where I have scripted it to go. CCDSoft controls the camera and then searches through the images looking for things that move. Once it has found something and you confirm it was a minor planet (and not defects in the images) the program calculated the positions and puts them in the proper format to report to the Minor Planet Center. The two programs work together as one. I recommend them highly to anyone wanting to find minor planets. Oh and one other thing. Once you've found it and checked with the Minor Planet Center to be sure it's something new you have to get a second night on the object before you can report it. For me, it's that waiting (and hoping the weather will be ok) that I have the most trouble with. After all, if someone else gets two nights on it before you do (even if you saw it first) they get the credit. Now I'll finish with a word of caution. This is not something that impatient folks or those without a lot of time should consider. The software does take some time to master (though I'm willing to help with that) and, barring a stroke of luck, you're probably going to be at it for a while before (if) you find anything. To give you some idea, I just checked my observing log and saw that so far this year I've used my observatory 185 nights. Out of that I've made three finds and one of those was later taken away when the Minor Planet Center found my "find" was actually a "recovery" of a previously known but lost object. Of course those with even bigger scopes and time to run much larger search mosaics will increase their chances. But I like to spend most of my time doing light curves (thanks to to the Footes) so I only allow myself an hour or two each night to do searches. Oh, and since people are always asking: No you can not name a minor planet you find for yourself. I think I'll stop now. If there's anyone still with me and wanting to follow up please let me know. Carpe Noctem! patrick