Updated software for Guide 8.0
(23 Feb 2005) Supergalactic coordinate input and readout: Yet another coordinate system supported by Guide, along with alt/az, galactic, and ecliptic coordinates. Go into the Legend dialog, and you'll see a new "Supergalactic" check-box, which will cause Guide to show a cursor readout in that system. You can also set up a hotkey and/or toolbar button to access an "Enter supergalactic coordinates" dialog box. Clicking on the supergalactic coordinate readout in the Legend will get you that dialog box, too, as will the "Go To... Coordinates... Supergalactic" menu option.
(23 Feb 2005) Downloading of UCAC-2 data: This is a continuation of the options for downloading B1.0, A2.0, 2MASS, and GSC-2.2 data. As with those options, you can zoom in on a desired area, click on Extras... Get Star Catalogue Data, and then on "UCAC-2 from Internet." Guide will then extract star data for the desired area, and you can click on the stars to get information about them and to control their display.
Remember that in one respect, UCAC-2 differs from the other downloadable datasets: it doesn't cover the entire sky. Most areas north of about declination +40 lack UCAC-2 data.
Incidentally, the "Get Star Catalogue Data" menu item replaces the "Get A1.0/A2.0 Star Data" option. The latter was increasingly inaccurate, given that one can now access four other star catalogues through the same sub-menu.
(23 Feb 2005) UCAC-2 stars shown adjusted for proper motion: Tiziano Magni suggested that it would be nice if UCAC-2 stars were shown adjusted for proper motion. This is now true for both downloaded stars using the above feature, and for those displayed from the data as distributed on the USNO CD-ROMs.
(23 Feb 2005) Moon's age/elongation in legend: Masaki Kouda requested that Guide should be able to show the Moon's age in the legend. It can now show the age, or the moon's elongation from the sun, or both. I've not given them separate check-boxes in the Legend dialog. But if you use the Add Caption button within that dialog, and add the caption text "MoonE", then Guide will replace this with text such as "MoonE = 141.59" to indicate the moon's elongation. Positive numbers are during the waxing phase, negative during the waning phase. (That is, 0 = new moon, 90 = first quarter, +/-180 = full, -90 = third quarter.)
Similarly, "MoonA" will be replaced with "MoonA = (number)" to indicate the moon's age in days. I did provide one slight change here, because the different lengths of lunations can make this datum not very helpful. For example, an age of 29 days may mean that the moon is almost new again, or still has a day or so to go. So I arranged matters so that an age of 0 or 30 days means a new moon, one of 7.5 days indicates a first quarter moon, 15 a full moon, and 22.5 a last-quarter moon.
(23 Feb 2005) Better name and magnitude data for artificial satellites: Some sources of artificial satellite elements ("two-line elements", or "TLEs") don't provide actual names or magnitude data. Such a dataset would list (for example) the International Space Station as "25544" (the NORAD designation) or "1998-067A" (the international designation), but not as "ISS". It would also leave you with no way of determining how bright the ISS might be at a given time.
Currently, most sources of TLEs do provide name information, but most lack magnitude data. So I've revised Guide to be able to extract name and magnitude data from other sources.
When you click on Settings... TLE=(filename), Guide will inform you (about halfway down in the text) that:
If the TLE file you're using lacks magnitude and name information, you can remedy this with auxiliary files. Click here for name data (about 380 KBytes), and/or click here for magnitude data (about 50 KBytes).
Click on the indicated locations, and Guide will fetch the necessary data from files provided on Mike McCants's Web site, or tle.info, or other sites. Guide will then be able to show satellites labelled by name, find them when you enter their names, filter them by magnitude, and show their magnitudes when you click on them or generate ephemerides.
(23 Feb 2005) Display of images with WCS data: Josch Hambsch requested that Guide should be able to show images with WCS (World Coordinate System) data. Guide can already show DSS and RealSky images; these images have some information in their headers describing the RA/dec of a point in the image, the image scale (arcseconds per pixel) in each axis, and orientation. Images with WCS header data provide the same information, but in a somewhat different format.
Guide will now handle either sort of header data. Go to Extras... DSS/RealSky Images, and select "Add DSS Image". Guide will ask you to indicate the image file to be added. It will then display that image file in the background of its charts, much as if it were a DSS or RealSky image.
Josch wanted to use this feature to get Guide to display images that had been processed using Bob Denny's PinPoint astrometric software. That program will add WCS keywords to an image header. Some other images also have such headers; for example, Guide will now display FITS images downloaded from the NASA SkyView site.
(02 Oct 2004) New "centering" button: It was suggested that when you click on an object, Guide should offer a "center" button, in addition to the existing "OK", "More Info", "Next", and (usually) "Display" options. I've added this. When you click on Center, Guide will simply shift over and recenter exactly at the clicked-on object.
(02 Oct 2004) Omission of small images: Lawrence Harris pointed out that if you turn DSS images On and zoom out a bit, the program can drag to a halt as hundreds of tiny images are displayed. Guide will now omit images that would appear less than 40 pixels on a side on-screen.
You can adjust this limit to, say, 30 by hitting Alt-J and entering
(02 Oct 2004) Automated updating of artificial satellite (TLE) data: If you go to Settings... TLE=(filename), you will get a "help"-like screen with four options for getting updated artificial satellite elements. The first resembles the way Guide has worked until now: select it, and Guide will prompt you to choose a file of TLEs.
The remaining three provide one-click updating of satellite elements. You can tell Guide to access one of the three most widely used element datasets; it will download it, unZIP it, and switch to use of elements from that file.
(02 Oct 2004) Method of changing the 'horizon' display: The 'Display... Backgrounds' dialog has an "Horizon Objects" check-box. When set, this causes assorted objects (houses, cars, trees, a mountain, etc.) to appear around the horizon. By default, the shapes for the horizon as seen from Earth are defined in the text files horizon.dat and objects.dat. If Guide's "home planet" is, say, Mars, then Guide would attempt to use horizo04.dat and object04.dat, and similarly for other planets. Only if these failed would it fall back on using the "default" Earth horizon.
Quite a few people have put together their own horizon files. However, there was no way to switch from one horizon to another. This has now changed. You can hit Alt-J and enter text such as
This will cause Guide to switch the horizon shown for Earth from the default to the one you have created and defined in myhoriz.dat. If you've also defined your own objects in the file myobject.dat, you would need to hit Alt-J again and enter the text
Similarly, you might enter HORIZON_1= to reset the horizon file used for Mercury, and so on.
To return to the default, you would hit Alt-J and enter
(21 May 2004) Revised "Add MPC Comets/Asteroids" function: Previously, one could go to the Minor Planet Center site and download orbital elements in Guide format, then use the Extras... Add MPC Comets/Asteroids function to import those elements into Guide. Lawrence Harris suggested that it would help if Guide could do some of this downloading automatically, and the current version allows for this.
Now, when you go to Extras... Add MPC Comets/Asteroids, you get a list of the possible files that can be downloaded, such as comets, NEOs, "distant objects", and "unusual objects". You can click on one of these, and Guide will fetch the relevant data from MPC and add it to the database. There are also a few comments on each dataset.
For those who would prefer to do it "the old-fashioned way", or have non-MPC-supplied datasets, there's still an option provided for you to specify the file to be added.
(21 May 2004) Revised overlay line drawing mode: As before, one can go to Overlays... Edit Overlay, and select an existing overlay or a "(new overlay)". For the latter, one is prompted for the name of the new overlay. In either case, you get a small floating dialog with radio buttons for assorted overlay editing capabilities: adding lines, text, or circles, or "normal mode". The latter is handy when you want to switch back to using the mouse for "normal" purposes such as panning, clicking on objects, measuring distances, and zooming.
The only change I've made is in the line drawing mode. Here, one can (as before) add a line to the overlay by clicking with the right mouse button on the first point of the line, then dragging a line to the second point and letting go. But after this, one can now simply move on to a third point and right-click on it, then to a fourth and click on that, and so on, to generate a polyline.
When one wants to create a new polyline, one again right-clicks on the first point and drags a line to the second.
Previously, a single right-click served the usual "pick" function. To get that now, you hold down a Shift key and right-click, or you switch to the "normal" radio button. This is handy when you want to delete a segment or two; you can right-click (or Shift-right-click) on that segment and select Delete, then pick up from the previous point.
(21 May 2004) "Undo" toolbar button/hotkey: If you look in the Settings... Toolbar dialog, you'll see a "Previous Chart" option at the bottom of the list of toolbar options. Turn this on, and a button for this function will be added to the toolbar. (It currently shows a "4". As with many new functions in Guide, the toolbar art has lagged! Perhaps a button showing a clock with arrows indicating that the hands are moving backward?) And as with other toolbar functions, you can select a hotkey for it.
Be warned that the "undoing" is imperfect in nature; some actions don't get "undone" with this function. For example, if you add a DSS/RealSky image, it doesn't get "undone" when you use this toolbar button or hotkey. The same is true for toggling of user-added datasets. But the vast majority of actions are already "undoable" with this function, and I will put some effort into extending the list of "undoable" acts.
Note that right after the Toolbar dialog entry for "Previous Chart" is a "Forward" option. That is, after going to a previous chart, you can "undo the undo" with the "Forward" option. One nice use for this is to enable one to toggle briskly between two charts.
(21 May 2004) New Uranometria available in legend: It has long been possible to go into the Display... Legend dialog and check a box to add a Uranometria 2000 page number to the legend. This has followed the layout of the original U2000. Similar checkboxes have been provided for Sky Atlas 2000 and the Millennium atlas. There is now a checkbox for the "New Uranometria" as well.
(18 Sep 2003) Progress indicator for catalog downloads: Four catalogs are currently available in Extras... Get A1.0/A2.0 Data: GSC-2.2, A2.0, B1.0, and 2MASS. When one of these is selected, Guide now does what it really ought to have done all along: namely, provide a progress dialog telling you how much data has been downloaded and at what rate it's been downloaded. Unfortunately, it has no real idea in advance how much data is going to be received, so it can't give you a "percent completed" indicator.
In the next update, I expect this to be extended to include downloads of images. For these, Guide will have at least a vague idea of how much data is to be received, and will show a progress bar and approximate percent of completion.
(18 Sep 2003) Delta-T in the legend: Laren Dart asked about this possibility on the Guide user list. My first inclination was to say that this ought not to go there (it's already in the 'Quick Info' section), but it occurred to me that I could easily add it in the same manner used for showing the airmass (sec(z)) value in the Legend. So now, if you go into the Legend dialog, and click on "Add Caption", and enter "Delta-T", Guide won't treat this simply as another caption entry. Instead, it will show "Delta-T=" followed by the value for that quantity, in seconds.
(18 Sep 2003) Phobos, Deimos shown with actual shapes and images: If you download this file (about 86 KBytes) and unZIP it in your Guide directory, and zoom in very far (to the arcsecond level) on Phobos or Deimos, you will see these objects displayed in their correct, lumpy shapes at the proper orientations. By default, they will appear as simple shaded objects. Right-click on them, then on "Display... Options", and select bitmap #1, and you'll get proper images stretched over them. In the same dialog, turning on "Show/Label Features" for Phobos will cause the seven named features on that object to be labelled.
Even at the last very favorable opposition, Phobos spanned less than .1 arcsecond, and Deimos is even smaller. By default, Guide's smallest level (level 20) is an arcsecond across. You can evade this by going to level 20, then going to Settings.. Level 20: 1 arcsecond. Click on this, and enter .1", and the field of view for that level will be adjusted accordingly. (You can actually go as small as .001", and I have my level 20 set for that value. With "Fixed levels" in the Extras menu turned off, I can drag open a box with the mouse to zoom in to any desired field of view, running from 2" at level 19 down to .001" at level 20.)
Shape models for Amalthea, Prometheus, and Proteus (but no images) are available, but I'll have to revise Guide's knowledge of rotation models before I can get these to appear accurately. (At present, they would appear to rotate relative to the planet. You'll notice that Phobos and Deimos are stabilized to have their long axes pointing toward Mars at all times, much as the Earth's moon always keeps one face toward us.)
(18 Sep 2003) UCAC-2 and 2MASS in color: Guide can already show UCAC-2 from CD-ROMs and 2MASS downloaded from the Internet. Previously, these were shown as uncolored stars, despite the fact that both datasets provide photometry in three infrared bands (J, H, Ks). This has been fixed; check the "Color Stars" check-box in the Star Display dialog, and Guide will show 2MASS and UCAC-2 stars in color.
Be warned that colors estimated from 2MASS may not match "visual" colors exactly. But so far, doing things this way appears to work pretty well.
(18 Sep 2003) More DSS downloading options: Previously, the "Extras... DSS/RealSky Images" dialog offered the ability to get DSS-1, DSS-2 R, or DSS-2 B images. The last could be downloaded as a "blue overlay" to get a sort-of-color image.
Owen Brazell pointed out to me that the DSS server at STScI had been modified to offer some more options. You can now get infrared images, two different flavors of V-like images ("Quick-V" in much of the northern hemisphere, "HST-Phase-2" for the whole sky), and DSS-1 and 2 in both R and B. Guide now supports all of these options.
Furthermore, an image can now be added as a "red", "green", or "blue" overlay. Thus, one could download an R image "normally", then a B image as a blue overlay; the result would be identical to what Guide could do before. Then a Quick-V or HST Phase 2 image could be downloaded as a green overlay. At that point, one would have a "true color" image.
Alternatively, one could download an IR image normally, then one of the V images as a blue overlay, and an R image as a green overlay. The general rule with false-color imagery of this sort is that one can combine images from any three bands, as long as one makes sure that the longest-wavelength band is red; the medium-wavelength one is green; and the shortest-wavelength is blue.
(18 Sep 2003) Use of JPL DE ephemerides: When you click for "more info" on a planet or the Moon, you will now see a line mentioning the "position source". For years between 1960 to 2020, that source will be the JPL DE-406 ephemeris. (If you've got "JPL Ephemerides" installed from the second Guide CD, the range will increase to 1800 to 2200.) Outside the covered range, a variety of analytic formulae are used to compute planetary/lunar ephemerides; specifics will be given in "More Info".
Most people can safely ignore all this. Use of DE results in a modest speedup and improvement in accuracy, but it's not something most of us will notice.
Some, however, will wish to do things such as examine more distant dates/times, or make use of the older DE-200 ephemeris. Should you have a JPL ephemeris file (click here for information on getting the files; they are available via ftp or on a CD-ROM supplied by Willmann-Bell), you can tell Guide to use it.
To get Guide to use, say, the ephemeris file d:\unix.200, you would hit Alt-J and enter the text
When you clicked for "more info" on a planet or the moon, you would see that the position source had changed to DE-200. To turn it off, you would hit Alt-J again and enter
(18 Sep 2003) Ability to change time/date format and calendar: The time-setting dialog (accessed via the Settings menu, or by right-clicking on the time shown in the legend area, or by hitting Alt-T) has, since Guide 1.0, had a button for toggling between the Julian and Gregorian calendars. Clicking on that button now leads to a "Time Format" dialog, with several new options. One can rearrange the default day/month/year order to alternatives such as year/month/day. Instead of time being expressed in HH:MM:SS format, one can have it expressed in HH:MM.MMM, or HH.HHHH, or .DDDDD format, or in decimal years, or JD, or MJD. You can choose the number of decimal places to which any of these are displayed. And one can choose several calendars instead of the usual Julian and Gregorian (click here for information on other calendars.) Data for these calendars were previously given only in Quick Info.
Be warned that while this option now lets you display dates and times in assorted unusual calendars, you can't enter them in those calendars (yet).
The same "Time Format" button is available from the RA/Dec Format dialog (which is increasingly misnamed; it controls formats for lat/lon and for English vs. metric units as well), and there is a toolbar button for this function as well (which in turn means one can assign a hotkey to it, if desired.)
The format selected here will be used almost everywhere else in Guide. One exception is in the "second time" in the Legend. But you can reset the format of that "second time" by right-clicking on it. I wanted this to be controlled separately, because I am pretty sure most people will leave the "normal" time format as given in the Gregorian calendar, in seconds, and will only play around with DD/MM/YYYY versus YYYY/MM/DD. But with the "second time" separately controlled, one can set it to show the Julian Day or Modified Julian Day; persons doing astrometry may want to have decimal days shown; and some may like having the time shown in, say, the French Republican date format. (Incidentally, there is also a toolbar button for this "second time format" function.)
(18 Sep 2003) New "UTC" option in Time Zone selection: Almost everyone not interested in extremely high precision can ignore this new feature. Perhaps only 1% of Guide users will find it to be of even mild interest.
There are several different varieties of "Universal Time", each reflecting a different approach to the same problem: the earth's rotation isn't entirely regular. One can stretch the length of a "second", fitting 86400 of them into one rotation of the earth, accepting that this means the length of a second will vary over time. Or you can keep the second as an exactly fixed unit of time, accepting that every few years or so, you'll have to fit 86401 of them into a single day. The extra second is called a "leap second."
Guide, like most astronomy programs, has used the first system, called UT1. However, you can now select UTC ("Coordinated Universal Time") in the Time Zone menu. The two are kept synchronized to within a second. (This is why I said the difference matters only in high precision applications. It's rare that a fraction of a second makes a significant difference for most of us.)
The variations in the earth's rotation can't be predicted in advance very accurately, so the IERS (International Earth Rotation Service) keeps track of the actual, observed rotation and decides when it's necessary to insert leap seconds. The last one was inserted at midnight on 31 December 1998.
If you have Guide set to UT, and then add a "second time" in the legend in UTC, and also make use of the time format control to have both times shown to .01 second precision, you'll see that they differ, at present, by about .35 seconds. Set the date back to just before midnight of 31 December 1998, and animate forward a second at a time, and you'll see that at the beginning of 1 January 1999, UTC appears to "pause" for one second as the leap second is inserted. (A purist would insist that this second be labelled as 31 Dec 1999 23:59:60.xx. Guide simply has 31 Dec 1999 23:59:59.xx repeat itself... a small oddity affecting only the displayed time, and a slight annoyance to pedants such as myself.)
I added this feature because I have hopes of getting Guide to replicate exactly the output of the JPL Horizons system. Use of the DE ephemerides was a big step in that direction; handling of UTC is a small extra step.
(24 Aug 2003) Ability to display UCAC-2 data: As you may know, UCAC-2 is now available (you can look here for information as to how to get the CDs.) It's distributed on three CD-ROMs.
The data can be shown in Guide as a user-added dataset. To do so, download this file (about 1 KByte) to your Guide directory, and unZIP it.
After this, you will see a new "UCAC-2" entry in the Extras... Toggle User Datasets dialog. By default, UCAC-2 data will be shown only at fields smaller than one degree. If there happens to be a UCAC-2 disk in the CD-ROM drive, Guide will read it. Be warned that disk #1 contains data for declinations south of declination -37; disk #3 contains data for declinations north of declination +1; and disk #2 contains data for the intermediate zone.
Alternatively, if you have copied some or all of the UCAC-2 data to the hard drive, you can add a line such as this to guide.dat:
with the path indicating where the assorted UCAC-2 data files can be found. Guide will then look both at this path and the actual CD-ROM path.
(24 Aug 2003) Ability to control arrow-key panning: Several people on the Guide user mailing list have asked about providing some different ways of panning. The default is that each "pan" moves one by half a screen width or height. Some would like to move by a certain angular amount with each pan. Others would like to move by a certain percentage of the CCD frame width and height (a handy thing for CCD mosaicking.)
To accomplish this, one can now run Guide, hit Alt-J, and enter such text as:
PAN=3.4,2.7 PAN=3.4',2.7' PAN=3.4",2.7" PAN=90%,90%
(Equivalently, one can edit guide.dat with a text editor and add one of these lines.)
The first example would cause each pan to move left/right in 3.4 degree steps, and up/down in 2.7 degree steps. As you might expect, a diagonal pan would move by those amounts in each axis. The second and third examples would behave similarly, except the motions would be by arcminutes and arcseconds instead of degrees.
The fourth example is the one of particular interest to CCD imagers. If you've set up Guide's CCD Frame dialog to reflect your camera and focal length, the above would cause each horizontal step to be 90% of the width of the camera frame, and each vertical one to be 90% of its height. Thus, you can pan around and take images with a 10% overlap.
Be warned that, because the sky is a "curved" surface, going up/left/down/right, or most similar combinations, will not return you exactly to your starting point (though the difference will be unnoticeable for small panning amounts.)
Should you decide to return to "normal" panning, you would use:
(24 Aug 2003) Ability to show a second "alternative" time in the Legend: Wolfgang Rothe suggested that it would be helpful to have the legend be able to display the time in two different manners, such as local time and UT, or local time and Greenwich Sidereal Time, or UT and local mean time. If you go into the Legend dialog, you'll see a new "second time" checkbox. Turn it on, and Guide will ask you to select a time zone for the "second time". (Guide treats Greenwich and local sidereal time, and Dynamical Time, and Local Mean Time, as simply being somewhat unusual time zones. International Atomic Time (TAI) and GPS time and UTC may eventually be added to the list.)
The zone you select for the "second time" will be used only for the display of that quantity in the Legend. You'll still enter times, and see them displayed elsewhere, in the default time zone.
(24 Aug 2003) Ability to show the airmass ("sec(z)") in the Legend: This was suggested by Dennis Means on the Guide user list. If you go into the Legend dialog, and click on "Add Caption", and enter "sec(z)", then Guide won't treat this simply as another caption entry. Instead, whenever the cursor is above the horizon, Guide will compute the number of air masses in that direction, a quantity often of interest to those doing photometry.
At present, the number of air masses is indeed computed simply as sec(z) = 1 / sin( alt). There are several formulae for doing at least a slightly more accurate computation, including one given in the Explanatory Supplement to the Astronomical Almanac that does a painstaking numerical integration from observer through the atmosphere, including effects due to humidity, pressure, altitude, and temperature in an effort to determine refraction. I may make use of this method (I've already written source code to make use of this method.)
(24 Aug 2003) Ability to reset line widths: Doug Snyder suggested that the ability to make wider lines (for assorted markings) would be helpful, and I've modified Guide to do this. Click on the "Styles..." button for a given object, and in addition to the usual choices of solid, dotted, dashed, dash-dot, and dash-dot-dot lines, you will see "Wider" and "Narrower" buttons. (The latter will be grayed out if the line is already at minimum width.) Click on these, and you will see that the example lines do indeed get wider and narrower. Then select the style you want, and Guide will draw that object in that style.
(24 Aug 2003) Several smaller changes: A bunch of items of extremely limited interest to most Guide users (but of great interest to at least one or two): a new hour angle convention used in the legend, a way to reset the altitude of the horizon, some more photometric data for Tycho-2 stars, a way to switch to an alternative method of computing Johnson photometry from Tycho-2 photometry, support for five new SBIG CCD cameras in the CCD Frame dialog, and some bug fixes.
Bernd Brinkmann mentioned that, when using this telescope with an hour angle setting circle, he'd prefer the "old" 24-hour convention. People with that situation can make a simple change to startup.mar to get hour angle to run from 0 to 24.