Re: [Utah-astronomy] Another one
Hi Patrick, Congratulations again! 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. I'm thinking of a May or June time frame. I have already purchased the Orion Deep Sky Pro camera, but wonder if I will also need a guide camera. I also wonder how critical dark skies are to the list of requirements you gave. Thanks, Wayne A. Sumner Math/Physics/Astronomy/Engineering Boy's Tennis Coach Northridge High School Davis School District (801) 402-8610
Patrick Wiggins <PAW@wirelessbeehive.com> 12/06/08 5:29 PM >>> Now that I've had another minor planet discovery confirmed (confirmed this morning and bearing the temporary designation K08X02R) I'm thinking I've got the system for finding these things refined enough that maybe I can offer tutoring to others here that might like to get involved in the discovery game.
Requirements are a 30cm or larger clock driven scope, CCD camera and a goodly bit of time and patience. Anyone here interested? patrick _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://gallery.utahastronomy.com Visit the Wiki: http://www.utahastronomy.com
Congrats, Patrick. What effective focal length do you image at for the search fields?
Patrick Wiggins <PAW@wirelessbeehive.com> 12/06/08 5:29 PM >>>
Requirements are a 30cm or larger clock driven scope, CCD camera and a goodly bit of time and patience.
On 08 Dec 2008, at 11:34, Chuck Hards wrote:
Congrats, Patrick.
Thanks Chuck.
What effective focal length do you image at for the search fields?
That has varied over the years but all my finds this year have been at the C-14's full 3,900mm f/11. With my camera that yields a field about 9' x 13'. patrick
That's good information. What size pixels are you imaging with at that focal length? On Mon, Dec 8, 2008 at 9:55 PM, Patrick Wiggins <paw@wirelessbeehive.com>wrote:
On 08 Dec 2008, at 11:34, Chuck Hards wrote:
What effective focal length do you image at for the search fields?
That has varied over the years but all my finds this year have been at the C-14's full 3,900mm f/11. With my camera that yields a field about 9' x 13'.
Patrick, here's a dumb question: How does binning help? Thanks, Joe --- On Mon, 12/8/08, Patrick Wiggins <paw@wirelessbeehive.com> wrote: From: Patrick Wiggins <paw@wirelessbeehive.com> Subject: Re: [Utah-astronomy] Another one To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Monday, December 8, 2008, 10:17 PM On 08 Dec 2008, at 22:05, Chuck Hards wrote:
That's good information. What size pixels are you imaging with at that focal length?
6.8 x 6.8 µ. Since I'm binning 3x3 that gives me image scale of 1.1. patrick _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://gallery.utahastronomy.com Visit the Wiki: http://www.utahastronomy.com
I'm sure Patrick can answer more specifically, but binning is primarily a noise-reduction technique. I think that his "finds" are almost indistinguishable from image artifacts, being merely tiny blips- thus the multiple images of the same field for comparison. Patrick is probably imaging on the edge of detectability, thus more noise in the raw images. Am I near the mark, Patrick? On Tue, Dec 9, 2008 at 10:22 AM, Joe Bauman <josephmbauman@yahoo.com> wrote:
Patrick, here's a dumb question: How does binning help? Thanks, Joe
I seem to remember that binning is also a tool to match the effective pixel size to the resolution of the telesope. Patrick?
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
Patrick, would a focal reducer help by enlarging your field of view? -- I intend to try this the next time I'm out with the telescope. -- Joe --- On Mon, 12/8/08, Patrick Wiggins <paw@wirelessbeehive.com> wrote: From: Patrick Wiggins <paw@wirelessbeehive.com> Subject: [Utah-astronomy] How to (pretty long) To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Monday, December 8, 2008, 11:11 PM 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 _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://gallery.utahastronomy.com Visit the Wiki: http://www.utahastronomy.com
Hi Joe and Chuck, This thread is getting pretty long so I'll try to address all of your posts at once. On 09 Dec 2008, at 10:34 , Joe Bauman wrote:
Patrick, would a focal reducer help by enlarging your field of view? -- I intend to try this the next time I'm out with the telescope. -- Joe
Good point. I should have mentioned that. Before I got into lightcurve work I used a focal reducer. That does yield a wider field and could increase your chances of discovery. Just be sure and make really good master flats to remove the vignetting focal reducers tend to cause. The reason I no longer use one is because for minor planet light curves the targets have an irritating habit of passing very close to a background star. Longer focal lengths tend to minimize the bad effects of such encounters. I could switch back and forth depending on what I'm shooting but that would mean shooting new flats (and possibly darks) every time and that's not worth the effort. That's also the main reason I almost never remove or even move the camera. On 09 Dec 2008, at 10:22 , Joe Bauman wrote:
How does binning help? Thanks, Joe
In one way binning is like film grain. As you probably remember the faster the film the coarser the grain. Same with CCDs. If I bin 1x1 I get very fine grain but much slower speed. 3x3 is coarser but also records the really faint targets more quickly. So for "pretty pictures" I might use 1x1, for lightcurve work 2x2 and anything requiring maximum useable sensitivity (like trying to find new minor planets) 3x3. On 09 Dec 2008, at 12:16 , Chuck Hards wrote:
I'm sure Patrick can answer more specifically, but binning is primarily a noise-reduction technique.
I'll need to defer to Jerry or Tyler on that. I'd don't _think_ binning changes noise but I don't know for sure.
I think that his "finds" are almost indistinguishable from image artifacts, being merely tiny blips- thus the multiple images of the same field for comparison.
You've got that right on. If I remember, when I get home I'll post a shot of my most recent find. It's so hard to see I never would have known it was there had CCDSoft not pointed it out to me.
Patrick is probably imaging on the edge of detectability, thus more noise in the raw images. Am I near the mark, Patrick?
VERY near. Of course one could go with longer exposures (I use 4 minutes) but then I'd have to start guiding and guiding on multiple fields would be a real pain. Plus one has to remember the minor planets are moving so if the exposure is too long all one will have is a very faint streak that's even harder to see and harder still to measure. It's very different for the MPs I do lightcurve work on. They are typically very bright and practically jump off the screen. On 09 Dec 2008, at 12:27 , Chuck Hards wrote:
I seem to remember that binning is also a tool to match the effective pixel size to the resolution of the telesope. Patrick?
Yes. And thanks to Jerry for educating me on this one. patrick
participants (4)
-
Chuck Hards -
Joe Bauman -
Patrick Wiggins -
Wayne Sumner