Uncle Rod’s Astro Blog

The primary wave digital setting circles weren’t much more accurate—if any more accurate—than the analog setting circles on an orange tube C8. All they did was offer you a readout in nice, big L.E.D.s that freed you from squinting at analog circles with a red light and a magnifying glass.

touch switchThen, as the 1980s ran out, “DSCs,?as us acronym-happy amateur astronomers began to call ‘em, started to change, to advance. In the hands of oldsters like a bit California company called “Tangent Instruments,?who were making a name for themselves in telescope electronics (for companies like Celestron, Jim’s Mobile, and others) DSCs were becoming real computers.

The primary benefit of the transition from readouts to computers was that the need for polar alignment became less exacting. The first DSCs were, again, just digital readouts, so, like analog circles, their accuracy was highly dependent on how closely the telescope mount was aligned to the celestial pole. The following generation of digital setting circles made that far less critical. By having the user “align?on one or two stars, the computer could figure out a polar alignment offset and yield decent push-to accuracy with no freaking drift alignment.

“What the hail is this ‘push-to?you retain going on about, Unk??If you’re a newbie, you could also be confused concerning the difference between goto and DSCs. Both goto mounts and DSCs require you to align on one or two stars, to center those stars in an eyepiece. It’s when you are aligned that things get different.

With a goto mount, you punch the variety of the item you wish to view into the hand control, push a button, and motors move the scope to that location. You enter your required object right into a DSC in similar fashion. There are (usually) no motors involved with digital setting circles, however. Instead, the DSC computer will indicate which way the scope needs to maneuver in RA/Dec or altitude/azimuth to achieve the target. You then PUSH the scope TO the item, watching the numbers on the DSC display decrease to zero as you approach it.

Did you notice the “alt-azimuth?above? That was the next big step up for DSCs after the polar alignment conundrum was solved. When DSCs were first catching on in a big way, within the late 80s, Dobsonian telescopes were also big (in popularity as well as aperture). Maybe as popular as they ever could be. Naturally, Dob owners, some of ‘em, wanted DSCs too, and it wasn’t long before all the names within the business, JMI, Lumicon, Roger Tuthill, and more (most of whom used Tangent’s electronic guts) were offering rigs that worked as well with alt-azimuth Dobsonian Mounts as they did with equatorials.

Just yet one more piece and the DSC puzzle can be complete. Even after adding computer horsepower, DSCs were awkward to make use of. First, you had to lookup the coordinates of your object in a fraking book. Then you definitely had to maneuver the scope until the R.A. and declination numbers on the display matched those of your target. Sounds easy, but ‘tain’t always so. As you move to the northern (or southern) area of the sky, them numbers begin changing awful fast on the readout, making it difficult to home in on ground zero.

Afore long, DSCs had object libraries. Want to take a look at M51? Punch up M51 on the pc and the DSCs would indicate the direction and distance you needed to push your scope to get to the target. DSC object libraries started out with a measly 110 (Messier) objects, but as the 90s came in and computer chips got cheaper, the highest of the road rigs were soon sporting the complete NGC and IC catalogs.

So, DSC owners lived happily ever after? Not quite. As goto scopes, the Compustars and the LX200s, and, soon, the NexStars and LX200 GPSes, hit the street, push-to users began to feel a mite ignored. Not only did the top tier goto rigs have hand controllers that contained many more objects than any digital setting circles computer, it was far easier to enter those objects right into a goto HC.

Whether you own an ancient Tuthill rig or the most recent Argo Navis or Sky Commander, one thing has remained constant: DSC computers make do with only a few buttons to perform many tasks. Almost all goto hand controllers have numeric keypads, but, as far as I know, no DSC computer does, not even the powerful Argo Navis. You wanna enter an NGC number? You do that with up and down and left and right cursor button pushes or, at best, by twirling a dial.

It could also be nice if DSC libraries contained more objects. While the mighty Argo Navis has 29,000 DSOs in its library, that number pales compared to the 145,000 the Meade Autostar II hand control boasts. The other players? Most are still stuck at the NGC/IC-and-a-few-more-catalogs level. Hell, if I want to take a look at PGC 15435, I wanna have a look at PGC 15435.

Luckily, there’s a relatively easy strategy to make digital setting circle computers easier to use and more full-featured. Almost from the start, DSCs have featured RS-232 serial ports that allow them to be interfaced to a PC. Why would you want to do this? Connected to a computer, you would select objects by clicking on them with a mouse, and you’d have the massive object library of the typical PC (or Mac) astronomy program available in your DSCs.

Alas, the primary time I saw a DSC hooked to a laptop, at the 1997 Texas Star Party, your old Uncle was not impressed. I had the great fortune to be arrange next to a friendly dude with a 30-inch scope. Well, it will have been fortunate if we’d had much in the best way of clear skies. We did get just a few so-so nights in the course of the week-long star party, however, and I was in a position to see how my new friend’s push-to rig, a JMI NGC Max and a laptop running TheSky planetarium software, worked.

In a way, it did fulfill a few of the promise Unk thought inherent in the mix. When Mr. Man wanted to go to an object, he clicked on it on TheSky’s screen. That object may very well be any certainly one of the many deep sky wonders in the program’s large library. That was the great. The bad was the way in which you had to push to your object. What you probably did was move the scope while watching a crosshair cursor on the program’s sky display.

There was a problem inherent in that. You had to have the pc close enough to the scope so you may watch the display as you pushed. In case you were moving the scope to a radically different position in the sky, you’d probably have to move the computer, too. For best results, you really needed to mount the computer on the scope somehow.

That was something that didn’t seem overly practical to Unk. Oh, maybe if you happen to were running a 30-inch Dob it is perhaps OK, but my old Toshiba Satellite, which weighed dern near 20-pounds, would have thrown my Dobbie of choice, Old Betsy, a 12-incher, seriously off balance, to put it mildly. I decided DSC + PC was an idea that wasn’t quite ready for prime time and thought no more about it for a very long time. I wasn’t alone. While I saw a number of amateurs using digital setting circles on star party observing fields, even the parents that had laptop computers with them rarely had their computers interfaced to the DSCs.

It didn’t much matter anyway, because it took a very long time for Unk to convince himself Betsy needed DSCs at all, whether computer interfaced or not. Betsy and i were perfectly happy running down objects using Sky Atlas 2000, Herald-Bobroff, a Telrad, and a 50mm finder.

We were, that’s, until Unk got his first goto SCT not long after the turn of the century. It was at the moment I decided I used to be more considering seeing objects than hunting objects. I wasn’t getting any younger, and i wanted to see as much of the nice Out there as I could in the years of observing left to me. In other words, goto had spoiled me, and i knew that if I were to continue using Betsy I’d at the very least should equip her with DSCs.

“Which DSCs??Was purty easy to determine. I crossed the Tangent-based units off my list. They were, in my view, tougher to align accurately than they must be, and their accuracy seemed to suffer in comparison to goto scopes. That left the Argo Navis, which had the advantage of numerous features and a high-powered processor, and the Sky Commander, which offered simplicity (and a lower price, which always gets Unk’s attention). Both were easy to align?point at two stars, you were done—and both offered goto accuracy comparable to my NexStar 11 GPS. I settled on the Sky Commanders, though I can see myself driving (sailing?) an Argo someday.

The Sky Commanders have worked great for me for over seven years. The truth is, their accuracy and Betsy’s still amazing reach at the 2009 Deep South Regional Star Gaze were what impelled me to undertake The Herschel Project. The Commanders just worked. They weren’t feature laden, however the features they had were usable and useful. Well, ever’thing except the RS-232 serial port. I had no idea how well that worked and did not feel moved to find out.

Oh, I knew what it was for, mind you. It had two purposes, upgrading the firmware and interfacing the DSCs to an astronomy program running on a PC. I did not need to do the previous and had little interest in the latter. Remembering the way back night where I’d watched that cursor crawl across the display of TheSky, I assumed I’d give it a pass.

Which returns us to last Saturday night on the PSAS observing field. After i finally got the mount squared away and had proved to myself that the binoviewer and StarSweeper focal reducer would work with the sting 800, and that my old eyes could still more or less handle a binoviewer, I got curious as to what Taras was up to with SkyTools 3 and his Dobbie.

What prompted my curiosity was him hollering, “IT WORKS! IT REALLY WORKS!?Unk strode over and enquired, “Calm down, son, what works??Taras informed me this was the first time he’d connected his laptop running SkyTools 3 (which purchase was my suggestion) to his Sky Commander (which purchase was also my suggestion). Looking at his laptop, I noted the screen was pointing away from the scope. “How the hell do you see where to move the scope for those who can’t see the screen??/p>

Taras informed your benighted old Uncle that he’d discovered you did not must see the SkyTools display to know the best way to push your scope to a DSO (or every other object). Click on an object within the ST3 observing list, mash the on-screen “push-to?button, and the item was sent to the Sky Commander computer, which showed you the way to maneuver the scope as per usual.

He also enthused about some sort of position indicator bars, and, further, said some English lady was a-telling him when he had his selected objects within the eyepiece. Some English lady, huh? Unk moved away slowly, back to his C8, Mrs. Emma Peel, and commenced messing with the binoviewer again. I was intrigued, however. Making all a million SkyTools objects available to the Sky Commander computer sounded like something Unk may be involved in. Dang tootin’.

Next morning, but not early the next morning, I took stock. If I wanted to hook my Toshiba laptop to the Sky Commanders, I would have to have a cable. A check of the pea-picking Internet turned up a few astronomy dealers who would sell me a Sky Commander computer control cable for 30 bucks. Call Unk a cheapskate, but 30 smackers for a roll of wire and a bit plastic DB-9 connector seemed high. So, I had a have a look at the pc cable that came with the Sky Commanders.

This cable, with an RJ plug on one end for the Sky Commander computer and a DB-9 adapter on the other to plug into a PC serial port, would obviously not work for controlling the Commanders with a computer. The Sky Commander end of the cable had a jumper across two pins, little doubt to put the computer in programming mode. It was also way too short to be practical to be used with a scope. Would Unk must shell out 30 bucks? He was not yet ready to resign himself to that awful fate.

Grabbed my trusty multimeter and the (decent) Sky Commander manual, and that i soon determined all I should need was a telephone extension cable—a phone extension that plugs into the wall, not a handset extension. Plug one end into the Sky Commander and the other into the RJ ?DB9 adapter that came with the programming cable, and i could be able to roll.

Me and Miss D. needed to stop at the home Depot for supplies as we continue cleaning up and clearing out the old Chaos Manor South, and that i seemed to recall the home improvement bigbox sold telephone accessories. They did indeed, just a few, anyway, sandwiched between cell phone geegaws. I discovered a 25-foot phone cord I assumed would serve. Cost all of five fraking bucks, which was a dern site better than 30—if’n it worked, in fact.

Last Tuesday night, we finally got some semi-clearing, and Unk decided to offer the DSC-computer trope a go. Old Betsy, my time-honored 12-incher, was in fine fettle—I’d spent the day cleaning both her primary mirror and her Dob body, since she’d been exposed to a good amount of dust in my initial clean-up of the shop. The only bad was the sky, which in typical midsummer fashion had gone from looking acceptable at sunset to nearly closed-down at dark.

Hokay, what can be can be, as Doris Day used to say. Lit a citronella candle to keep the skeeters away—I hate to use up the somewhat expensive Thermacell cartridges and pads for an informal backyard run. Set up the laptop, connected one end of my new cable to the USB serial adapter and t’other into and to the Sky Commanders?RS-232 port. Didn’t start SkyTools just yet, though. As with a goto scope, before you should utilize the computer, you need to do a standard alignment. If I could do a traditional alignment.

I always use Polaris as my primary DSC alignment star. This time of year, I’d probably pick Regulus as number two. Problem was, both were behind consarned clouds. I waited, as I did last week, hoping for the North Star to peep out, but it soon became evident that every one that was going to happen was that the sky was going to get progressively worse.

Vega was in sight, so that must be star one. Spica, almost due south, was also (intermittently) visible and could be my number two. I turned on the Sky Commander, entered the date (no time or location required), and centered the 2 stars in succession. Alrighty, then, computer time.

I launched SkyTools and selected the “RealTime?tab, which is where you do your scope interfacing and gotoing (or pushtoing). Next, I discovered “select/configure telescope?on the telescope control menu. All I had to do was choose “Sky Commander?and specify the baud rate I wanted to make use of for communications. Since, as I’d read in the Sky Commanders manual, the default within the DSCs is 9600bps, I told SkyTools ?600.?/p>

Taras had mentioned something about SkyTools talking to him in DSC mode, so I’d enabled voice in the program preferences. Still, I dang near jumped out of my pea-picking skin when a sexy-sounding Englishwoman declared, “TELESCOPE CONNECTED!?when i clicked the “connect to telescope?choice within the scope control menu.

Before I actually tried to do anything with the Sky Commanders, I assumed I’d better take a look at the “configure push-to indicators?menu I’d discovered. The one thing I did there was change mount type from EQ to alt-az. Time for the rubber meets the road thing, I reckoned.

I brought up the Messier list in RealTime, selected “M13,?and mashed the “push to?button. I was not as startled this time when “Audrey?told me to “Push telescope to focus on!?(SkyTools refers to its audio guide as Audrey, but I’ll probably just consider her as “Betsy?. At the scope, I had to mash the down cursor button to bring up the push-to indicators this first time, but that was all. I maneuvered the scope to M13 watching the Commanders?numbers count down just as always. When Bertha/Audrey intoned “Telescope on target,?I inserted the Happy Hand Grenade, my 16mm Zhumell 100-degree eyepiece, into the JMI NGF focuser and had a peep. Nuttin?honey.

A lookup showed why: Hercules was now a mass of clouds—I couldn’t make out a single one of many constellation’s stars. The scope did appear to be pointing in the right direction, but I wanted to be sure. What was available? The big Dipper was shining bravely, if barely, through the thickening haze to the northwest. I loaded my SynScan alignment star observing list and selected Mizar, which isn’t only bright but distinctive.

Pushed “push-to?again, Bertha told me to get out to the telescope and start pushing, and that is what I did. When the indicators on The Sky Commander was zeroed out, I peered into the Zhumell. There was Mizar centered in the sector. Yeehaw! My five-buck cable damn sure worked. I tried a number of more bright stars—Arcturus, Spica, and one or two others—and all were in the center of the field, convincing me all was well.

Since even the bright stars were now disappearing, I pulled the massive Switch, carried Bertha back inside the shop, and went within the house to provide Miss Dorothy the good news—I hadn’t let the smoke out of my DSCs. The cable and software worked perfectly; the Sky Commanders now had access to SkyTools huge database (including, importantly, asteroids and comets). And it was so much easier to click on objects on the ST3 display than to cursor to them with the Commanders?freaking little membrane keys.

Actually, the ST3-Sky Commander goodness doesn’t end there. Along with sending objects to the Commander so you need to use the traditional DSC readout to push the scope to focus on, SkyTools displays two large, red push-to indicators; one for altitude and azimuth. Push the scope till these red bands/graphs dwindle away to nothing, and you will be in your object. You may also tell SkyTools Interactive Atlas to display a reticle showing scope position on the map, but as with my buddy’s long ago TSP rig, I am not sure I’ll need to/need to do that.

Unk was one happy little camper as he sat with a draught of the Rebel Yell watching a late-night replay of Braves vs. Mets. Normally, I’d be right put out to be skunked this bad. I had not seen a single DSO after spending considerable time organising the scope in the recent stickiness of a Possum Swamp summer’s night (heat index hit 101 within the afternoon). But not this time. Not only did I now understand how good the mix of PC and DSCs can be, I may have given my much -loved twenty year old telescope an entire new lease on life, muchachos, and that can not be a bad thing.

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