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HP Forum Archive 17

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Alt-Az coordinates Part 2 for35s
Message #1 Posted by Howard Lazerson on 20 Aug 2007, 10:46 p.m.

Thanks Gerson for making pgm readable! This pgm is designed to convert right ascenion & declination of any celestial body into simple altitude and azimuth. You therefor need to make/copy /draw a 360degree az circle on the mount base and a 0 to 90 degree scale for alt, 0 being level, 90 pointing straight up. Marking every 10 degrees is sufficient since its easy to interpolate. The # 6.619 is a constant and changes yearly, for2008 = 6.603, for 2009 =6.654. U is GMT for Calif, 10PM this August =5.0 , when daylight sav ends it is 6.0, use decimal minutes, 9:30 PM= 4.50 GMT. Latitude & longitude of your site are decimal degrees. Day number - add date to this # so for August 20= 212 + 20 = 232. Jan=0,Feb=31, March = 59, April=90, 120, 151,181, 212, 243, 273, 304, and 334 for Dec. Right & declination are also input in decimal degrees. To get accurate results, the scope must be LEVEL- I mounted a bullseye level on my portable scope which works well. Sight Polaris [north star] and set Az to read 0 degrees, use a red light preserves nite vision ], look up RA & Dec of object, run pgm to get alt/az and slew scope to these coordinates. Use a widefield-low power eyepiece initially since there is a 1 to 3 degree offset in position-slowly slewing from the calculated position will locate object quickly. One really appreciates this pgm with objects 0ver 50 degrees high-no more on your knees squinting up while your back complains. Howard

Re: Alt-Az coordinates Part 2 for35s-addendum
Message #2 Posted by Howard Lazerson on 21 Aug 2007, 12:44 p.m.,
in response to message #1 by Howard Lazerson

Part 2 addendum ; For leap years, add 1 day to D starting with March thru December. Howard

Re: Alt-Az coordinates Part 2 for35s-addendum
Message #3 Posted by Gerson W. Barbosa on 21 Aug 2007, 6:40 p.m.,
in response to message #2 by Howard Lazerson

Perhaps these time and date routines might be useful somehow. They should be adapted to your needs and converted to the HP-35s, in order to save labels. They are based on a program that came in the Master Library Module, for the TI-58/59.




G0001 LBL G G0002 x<>y G0003 STO A G0004 x<>y G0005 ENTER G0006 IP G0007 STO C G0008 Rv G0009 RLC C G0010 - G0011 100 G0012 * G0013 ENTER G0014 IP G0015 STO B G0016 Rv G0017 FP G0018 4 G0019 10^x G0020 * G0021 STO D G0022 2 G0023 ENTER G0024 RCL C G0025 x>y? G0026 GTO H G0027 RCL D G0028 1 G0029 - G0030 100 G0031 / G0032 1 G0033 + G0034 IP G0035 0.75 G0036 * G0037 IP G0038 +/- G0039 RCL D G0040 1 G0041 - G0042 4 G0043 / G0044 IP G0045 + G0046 RCL C G0047 1 G0048 - G0049 31 G0050 * G0051 + G0052 RCL B G0053 + G0054 RCL D G0055 365 G0056 * G0057 + G0058 RTN

H0001 LBL H H0002 RCL D H0003 365 H0004 * H0005 RCL B H0006 + H0007 RCL C H0008 1 H0009 - H0010 31 H0011 * H0012 + H0013 RCL C H0014 0.4 H0015 * H0016 2.3 H0017 + H0018 IP H0019 - H0020 RCL D H0021 4 H0022 / H0023 IP H0024 + H0025 RCL D H0026 100 H0027 / H0028 1 H0029 + H0030 0.75 H0031 * H0032 IP H0033 - H0034 RTN

N0001 LBL N N0002 XEQ G N0003 RCL A N0004 XEQ G N0005 RCL A N0006 - N0007 +/- N0008 RTN

W0001 LBL W W0002 XEQ G W0003 ENTER W0004 +/- W0005 7 W0006 / W0007 IP W0008 7 W0009 * W0010 + W0011 RTN

Length & Checksum Table:

LBL CK LN G 7A9E 318 H 75E1 210 N E3B8 24 W 3A2B 57


date 1 (MM.DDYYYY) ENTER date 2 (MM.DDYYYY) XEQ N => number of days between dates

date (MM.DDYYYY) XEQ W => weekday (0=Sat, 1=Sun, ... , 6=Fri)

Re: Alt-Az coordinates Part 2 for35s-addendum
Message #4 Posted by Howard Lazerson on 23 Aug 2007, 12:53 a.m.,
in response to message #3 by Gerson W. Barbosa

yes, you could use this for the day # however the best help would be an internal clock for the time input which means you only have to input Right Ascenion & Declination and dont have to check your watch before input of each object. Howard

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