diveboss@xmission.com wrote: Dallan E wrote: Canopus56 wrote: Thanks for the input Guy, Dallan and Kurt, As it turns out I just got back from some field work and finding that I can do what I had hoped. The transit predictions I get tell me various points to stand to see ISS cross the Sun, Moon and planets. They look like this: 11 Feb 13514 40.3668 -112.5347 11 Feb 13515 40.4081 -112.4595 11 Feb 13516 40.4485 -112.3875 But I've yet to receive a report where any of the points corresponded with a convenient location to set up a scope. Up to now I've used a spread sheet to interpolate between the points and then used a site on the web to plot the data on a map. It worked but it's time consuming. So I figured I might be able to plot the way points on a GPS receiver and just drive until I'm between those two points. Turns out you can. And, to make it even better the receiver even draws the line. So now it looks like all I need to do is plot two points from the predictions and then drive until I reach the line. Seemed to work in this evening's test run. Now I'm looking forward to trying it for real. Patrick
--- Patrick Wiggins <paw@trilobyte.net> wrote:
But I've yet to receive a [an ISS transit] report where any of the points corresponded with a convenient location to set up a scope. Up to now I've used a spread sheet to interpolate between the points and then used a site on the web to plot the data on a map.
Patrick, If I'm reading your post correctly, I just wanted to say that's absolutely brillant and is an original tool for making photographs of ISS transits of the Sun and Moon. One of the limitations of IIS tracking on heavens-above and CalSky with respect to ISS transits of the Sun and Moon is that you have to put your geographic position in and then search for those times when the ISS and the Moon and/or Sun will be aligned with your OP. At most you might get two or three occurrences per year. Like a reverse version of the parable about Mohammed and the mountain, I usually plug in my geographical position into CalSky and try to pull out the one or two times a year that the ISS (the mountain) will align with the Moon and/or Sun at my OP. One of the painfully obvious parts of the Stardust reentry was just how sensitive satellite observing is to geographic position. When you were at the Wendover Airport during the reentry, you saw Stardust from the side. I was 30 miles south and saw it travel on an East-West line straight-overhead. The same principal applies to ISS overpasses, althought the ISS is at a higher altitude. CalSky gives for visible ISS overpasses, a separate geographic latitude and longitude ground track. In theory, you can take the predicted ground track of a near overpass, the satellite's altitude, and the altitude and azimuth of the Sun or Moon during the transit, and then solve a spherical right triangle to find an ~approx. 1/2 degree wide swath at a nearby geographical location that you can drive to see a transit. So, like Mohammed, you can go to the mountain, that is drive 30-60 miles north or south, and watch an ISS transit of the Sun or Moon that will not be revealed by CalSky or heavens-above. This technique would greatly increase the number of opportunities to photo ISS Sun/Moon transits during a year. I'm guessing that you have built some variant of the Stardust reentry track calculation spreadsheet (prepared by a professional astronomer) that you sent me in January. Anyway, if so, what you have done is pretty original and amazing. That observing technique would greatly increase the number of opportunities per year one could photograph an ISS transit of the Sun and/or Moon. I know of no other amateur who has developed anything similar. To wrap up - 1) You have strong astro kung-fu. -:) 2) Your astro kung-fu is much stronger than my asto kung-fu. -:) 3) I bow before your superior astro kung-fu. -:) 4) After you get bored milking your spreadsheet for as many ISS transits photos as you can make, you should send your observing-reduction technique off to S&T in an article. (Really). - Canopus56 P.S. - If I have misinterpreted what you are up to, I apologize. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
Canopus56 wrote:
If I'm reading your post correctly, I just wanted to say that's absolutely brillant and is an original tool for making photographs of ISS transits of the Sun and Moon.
Thanks but (blush) your praise is misdirected (my head size is too big as it is). The spreadsheet I mentioned only interpolates between points. It does not generate the points. I get those via a service I've subscribed to on the web. I supply them with my long/lat/ele and they send me a report once or twice a week with upcoming ISS transits of the Moon, Sun and the brighter planets visible from with 40 km of my house. There are a surprising (to me at least) number of ISS transits. Several per month, in fact. But most of them occur when the transit is low in the sky which makes ISS so far away that it's hard to see even in a telescope. Patrick
Patrick, did you get a photo or see it? Thanks, Joe
--- Patrick Wiggins <paw@trilobyte.net> wrote:
Thanks but (blush) your praise is misdirected . . . I get those [ground track points] via a service I've subscribed to on the web.
So, where do I send my subscription money? - C __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
Canopus56 wrote:
--- Patrick Wiggins <paw@trilobyte.net> wrote:
Thanks but (blush) your praise is misdirected . . . I get those [ground track points] via a service I've subscribed to on the web.
So, where do I send my subscription money? - C
Happily the service is free. Unhappily the signup page has been down for weeks. Here's a page that describes ISS transits: http://www.perseus.gr/Astro-Tips-ISS-Transits.htm BTW, the guy that generates the reports is looking for someone to help him out. Here's part of a copy of his most recent report, including his request for help: ********************************************************************************* Who wants to generate ISS Transit reports for a while? I have limited free time these days, and I could better use my time to do some related things like getting the signup page back online. Based upon a 2.8 GHz Pentium 4 with 1 GB of memory, generating (currently 400) reports takes about 5 minutes, while emailing them can take 7 minutes to an hour (typically, about 10 minutes), depending on how reponsive the net is (once started, emailing requires no operator attention). Minimum hardware requirements are a 1 GHz Pentium 3, with about 500 MB of memory. Reply to tfly@alumni.caltech.edu ********************************************************************************* Reference notes: http://iss-transit.sourceforge.net/alert-notes.html TLEs used for orbit computation follow this report. A - travel distance (kilometers) and direction B - date C - time (hhmmss) D - elevation angle of the ISS E - azimuth angle of the ISS ( + is East from North; - is W from N) F - range (kilometers) G - latitude for observing the transit H - longitude I - elevation above Mean Sea Level (meters) J - how far (kilometers) can I be from the centerline? (i.e., angular error = 0.25°) For other than solar transits: K - lunar transits: is space station sunlit? planetary encounters: 1=Mercury; 2=Venus; 4=Mars; 5=Jupiter; 6=Saturn L - sun elevation angle M - sun/moon or sun/planet separation angle A------- B----- C----- D--- E----- F--- G------- H-------- I--- J---- K L---- M---- 36.1 SW 11 Feb 13514 58.4 -111.5 412 40.3668 -112.5347 2073 1.9 n -61.6 159.5 28.8 SW 11 Feb 13515 58.3 -111.5 412 40.4081 -112.4595 1568 1.9 n -61.5 159.5 22.4 S 11 Feb 13516 58.2 -111.5 412 40.4485 -112.3875 1543 1.9 n -61.4 159.5 16.7 S 11 Feb 13517 58.2 -111.5 414 40.4881 -112.3174 1830 1.9 n -61.4 159.5 13.0 S 11 Feb 13518 58.1 -111.5 414 40.5280 -112.2467 2005 1.9 n -61.3 159.5 12.6 SE 18.50 40.5479 -112.2111 1.9 13.0 SE 11 Feb 13519 58.0 -111.4 414 40.5678 -112.1755 2149 1.9 n -61.3 159.5 17.2 E 11 Feb 13520 58.0 -111.4 414 40.6089 -112.0999 1659 1.9 n -61.2 159.5 23.2 E 11 Feb 13521 57.9 -111.4 414 40.6494 -112.0260 1446 1.9 n -61.1 159.5 29.9 E 11 Feb 13522 57.8 -111.4 414 40.6897 -111.9526 1304 1.9 n -61.1 159.5 37.0 E 11 Feb 13523 57.8 -111.3 415 40.7297 -111.8800 1307 1.9 n -61.0 159.5 46.2 NW 21 Feb 40818 14.7 146.4 1077 40.9317 -112.6867 1278 6.1 n -36.0 88.1 34.6 NW 21 Feb 40819 14.8 146.5 1072 40.8569 -112.5919 1265 6.1 n -36.0 88.1 22.4 NW 21 Feb 40820 14.9 146.6 1067 40.7759 -112.4920 1479 6.0 n -35.9 88.1 11.6 NW 21 Feb 40821 15.0 146.6 1064 40.7069 -112.4029 1280 6.0 n -35.9 88.1 1.0 SW 21 Feb 40822 15.1 146.7 1059 40.6319 -112.3088 1302 6.0 n -35.9 88.1 13.2 SE 21 Feb 40823 15.2 146.8 1054 40.5447 -112.2045 1779 6.0 n -35.8 88.1 24.9 SE 21 Feb 40824 15.3 146.8 1049 40.4668 -112.1087 1930 6.0 n -35.8 88.1 35.2 SE 21 Feb 40825 15.4 146.9 1046 40.4017 -112.0239 1628 6.0 n -35.7 88.1 46.0 SE 21 Feb 40826 15.5 147.0 1041 40.3315 -111.9351 1513 5.8 n -35.7 88.1
participants (3)
-
Canopus56 -
Joe Bauman -
Patrick Wiggins