Astro rom

http://www.rollanet.org/~eksi/Contact.htm

I've got a copy of their book (150+pages),' Practical Surveying Guide to Celestial Observations' from the 80's that should answer any question about using that program. It even has the?ÿ program code for various programs in the appendix.

You can have it for the cost of postage if you like.

Bob

Larry: I had never used the astro*rom, I keyed in a program on my HP41 that you had to put in the GHA and declination at oh and 24h. So the comps were as accurate as the values that were input, interpolation not extrapolation. Put I can definitely see the utility of having a standalone program in the field. I always carried a pocket ephemeris for the year out in the field in the old days. I had a small bag in my truck that had a time cube, ephemeris, solar filter, and stopwatch. And of course an HP41. That was before PC's and cell phones.?ÿ

First time I ever did a solar I was working on a crew in a swampy overgrown area running a sedimentation profile between monuments (with SPC) on either side of a lake. We found one mon, but could not find any others. So I told the party chief that I had been studying how to do solars and I could do one there. He laughed at me and said go ahead, waste my time. Took me about 30 minutes, we cut line and hit right on the monument. He was a believer then.?ÿ

@john-hamilton

Astro rom has an internal eph. And as nearly as I can tell it returns az 3.3” out. The site says good to 2” thru 2010. So it’s just old. 

I have it loaded in my iPhone i41CX. Works great. Don’t really need to reduce as in the field, but 3” is pretty useful. 

Definitely useful, didn't know you could run it on a smart phone. Once I get my windows program working the way I want I hope to create an android version

@john-hamilton

i41CX is fantastic. And iPhone 15C. Definitely keeps 41CX relevant. 

I have a favorite cogo program in both as well. 

The HP41 had the best clock and the more times you corrected it the better time it keep as it would keep adjusting the time it kept.

That did not pass on to the HP48, that clock had to be corrected just before any solar sightings.

@a-harris

I have several 41s. And the clock accuracy factors have been very carefully determined. The time standard that I use is the PPS output from a dedicated GPS receiver. 

The only appeal if ASTROROM is the internal ephemeris. 

@larry-scott

I have the HP48GX SMI v7 and it was great for solar shots until the ephemeris ran out and the updates ended.

Today there is an app called Clock Sync

@a-harris

Astro rom accuracy was stated as 2” error thru 2010. Today its output is off about 3”, maybe 3.5”. Not too bad. 

I have plenty of calculation means. I’m looking for current internal ephemeris for 41CX. 

Astro rom works ok. But I’d like to know more about it and its ephemeris  

@larry-scott

I should check the SMI against my Static shots and see where it stands today.

I used it a few times after GPS was a tool in my truck and have only used my solar lens for looking at an eclipse in the last 10+ years.

@a-harris

For the past 8 or 10 years Iƒ??ve taken hundreds. Mostly for sport.?ÿ

I have an older Astech, and use opus a lot. So Iƒ??ve positioned several radio antenna by intersection using only solar azimuth at 6-12 miles. Stsrnet trlls me 2-3 seconds on azimuth with many dozens of obs.

Data Reduction isnƒ??t done in the field. I wrote an Excel with an ephemeris for that. The i41CX is my new best calculator, and Astro rom works well in iPhone, much to my surprise and delight?ÿ

?ÿ

@a-harris

Yes, as long as the HP41(CV-CX) remained in a stable temperature environment.  The driver crystal was not temperature corrected so a radical change in temperature caused unaccounted for drift.  I've had an HP41 (actually several) stored in a desk drawer which after a few months of the HP41 "CORRECT" procedure against WWV time ticks would be subsecond accurate after another month or two.  But, throw it in to a truck glove box and it was no better than a Timex watch, +- 2-5 seconds per month.  The reason is it's hard (impossible) to manufacture cheap quartz crystals with absolute accuracy so from the factory the manufacturers compensated for crystal error rates by establishing a base "CORRECT" +-add/subtract counts" into the watch to make it seriously accurate, but unable to account for temperature.  The cool thing about the HP setup is you can change the base correction as the crystal ages to account for ageing and changing environmental conditions.

An HP41 cannot be  made with absolute precision because of temperature problems.  The solution  is an oven which runs the crystal above all environmental possibilities, like 160°, not gonna happen in a handheld.

@mike-marks

i have timing. Dedicated GPS receiver pps led blinker and using a stop watch. (Actually, iPhone NTP apps receiving LTE signal do quite well. Provide its true NTP protocol, there are a few good ones; time.gov isnƒ??t!)

the hard part is in the details. Like two point interpolation of declination, astronomic lat long conversion, DUT, Laplace, all of which are Excel sheet and DEFLEC12b,?ÿUSNO AA for ephemeris ?ÿ

then there are field techniques.?ÿ

i41CX calculation would be just for immediate QC. But, it could be as good as can be with a current ephemeris ?ÿ

http://astro.ukho.gov.uk/nao/publicat/sals.html