December 30, 2016: Year-end review, Part 1 – the Mak and the ‘frac

Because my plague of bad weather has now stretched on deep into a second month, I thought it would be a good time to take a look back at the past year – well, the past 14 months, actually – since I bought my Mak, and discuss both of my scopes, and my equipment with a longer perspective.   Instead of those “first look” reviews that are written after only a few weeks, this is much more of an actual review, after many months of use.

When my interest in astronomy rekindled into a bonfire last year, I was looking for the largest aperture scope that I could both reasonably move around and, of course, the largest I could afford.  It also had to be one that I could use in the light-polluted city so that it would help me locate objects.  I initially settled on an 8-inch dob – not too big or heavy for either my apartment or for lugging around.  The Apertura AD8 model had a huge appeal for me, as it would have digital setting circles that I could match up with a planetarium program, such as Stellarium, to help locate DSOs.

I soon figured out that I don’t quite have the chops for collimation – after learning about its existence as “a thing” for the first time in over 35 years of astronomy.  As a result, I decided against a newtonian, and set my sights on the Mak I have now, which was not only cheaper than the fully tricked out version of the AD8 I was looking to buy (with the setting circles and flocking), but was computerized as well.  Once I figured that out, and right after my neighbor Jason came by and put his Mak through its paces for me, I bought my Mak practically immediately.

As far as I’m concerned, the Mak itself has worked beautifully in the 14 months that I’ve had it.  It’s built like a tank, which I understand was Dmitri Maksutov’s plan when he designed it in the first place – a small, robust telescope that did not fall out of collimation if you looked at it funny.  The OTA is heavy at 8 pounds; I imagine that that’s not all just because of the extra weight of the meniscus up front, but a heavy mirror-moving mechanism to focus.

I often push the magnification with my 4mm Plossl to 385x on the moon just for grins and giggles.  I have no optical complaints, with the sole exception of the focuser.  Focusing causes the image to vibrate, because you are, of course, touching the scope.   This vibration makes it a little difficult to get a precise focus, because if the image is moving, it is difficult to tell if it is perfectly sharp.

Another drawback to the focuser is that it does not engage precisely as you go back and forth to dial in that perfect focus.  In other words, if you go past the perfect focal point turning the focus knob clockwise, you have to turn the focus knob counterclockwise past that point, past what you would think would be the right spot to get to that perfect focus again.  Minute adjustments to focus are therefore problematic.

One solution to this that I have not yet explored is an electric focuser.  The idea is that you attach it to the focus knob and you’re able to press a button on a remote so that the focusing is done without your touching the scope and inducing those vibrations.  But as far as I’m concerned, the problem isn’t that big of a deal to need this sledgehammer of a solution.

Obviously, as I’ve cataloged in this blog, the real problem with the Mak has been the SLT mount giving out twice in exactly the same fashion – with the clutch slipping and the handset being unresponsive.  I want to say that it’s because of the extra weight of carrying the ST-80 on it, which gets the weight to just over 12 pounds from about the 8 of the Mak tube itself.  But that can’t be the reason, as the first SLT mount I had (and returned) clunked out before I even bought the ST-80.  So the cause of failure remains a mystery.

One solution would be to upgrade to a better mount.  This one comes out of warranty in about 11 months, so that if it quits at some point after that time, I will have to get another mount.  The one mount that really sets me drooling is the iOptron Minitower Pro, which is normally $1148, but as of this writing, is on sale for $948.  This is an alt-az mount, which is just fine by me, since my interest in astrophotography is still close to zero, and because I also have no interest in polar alignment.

More important than any of that is that I absolutely adore the concept of the thing – it lets you mount two scopes at once on either side, like my Frankenscope idea, but implemented much more elegantly.  The weight capacity is much increased from the SLT mount’s puny 9 or 10 pounds or so; it’s rated at 33 pounds on one side for one scope, and another 10 pounds on the other side as a counterweight, even though I understand that those figures, or at least the 33 pound figure, may be overstated.

The problem with the iOptron is the mount itself – it gets a lot of complaints over at Cloudy Nights.  Yes, most people are satisfied with it, but there is a loud and vocal and significant minority who find the mount problematic.  It has a significant failure rate; it needs modifications in order to work properly.  Still, even with all that, and with no other alt-az mount out there that I know of that can do what it claims to do, it still gets me going.

Originally, I was looking to spend only about $500 on the Mak and accessories.  After all, the Mak came with 25mm and a 9mm EPs, and even though they’re only Kellners, the very long f/12 focal ratio makes any eyepiece look gooooood.  I also had 26mm and 9.7mm Plossls from my old scope, the dreaded Meade Bird-Jones, and a 4mm Plossl that I had bought to get me to the high magnifications I thought I could achieve with that scope.  But I knew with the Mak that I’d be spending another $100 or so on some accessories that I really needed – particularly: 1) a rechargeable battery pack, as this thing ate regular alkaline batteries like candy; 2) a 32mm Plossl to get the widest field of view possible – so that I’d be giving the goto the best chance possible to do its job properly; and, 3) a mid-magnification eyepiece, which turned out to be my 15mm Paradigm.

The battery pack continues to work excellently, even with its weird quirk of needing to be turned on to recharge.  It also has another weird quirk of needing around 12-15 hours to fully recharge, so if you happen to be blessed with 3 clear nights in a row, you definitely have to plug it in when you get back from observing, and not the next morning when you wake up.

The 32mm is my most used EP by far.  It’s always my finder EP, always sitting in the scope as the first EP to be used.  It remains a terrific EP, and it’s nice for “wide-field” views (well, as wide-field as a Mak can provide) of open clusters.  The 15mm gets some use on open clusters as well.  My stable of 9 and 10mm EPs (I have a 9, a 9.7, and two 10s – for binoviewing) – gets more use than the 15mm because if I’m not observing at low powers, I’m pretty much observing at high powers – on my more favorite objects, the moon and the planets.  I’m not really a medium power kinda guy.

With low, medium, and high-powered magnifications all covered, I was all set.  But was I?  Not really.  I decided I wanted to see what all this hoopla over wide-field observing was really all about.  I plunked down almost $250 on the used ST-80, a second diagonal, and a mount.  (The cost of the ST-80 itself came down to well below $100 once I had sold off most of the accessories that came with it, including the terrestrial diagonal, the finder, and a few EPs.)

The ST-80 is a quality refractor, not a toy in any way.  It’s almost entirely metal, a solidly-built, well-made piece of equipment.  The rack and pinion focuser knob is the only exterior piece of the scope that’s plastic, while the objective lens cell on the interior is the only other piece that’s plastic.  I know it’s well-built because I’ve dropped it twice – once because of my own stupidity, as it rolled off the bed onto the floor 3 feet below, and the other when I was carrying it slung over my shoulder, coming back from an observing session, when one of the bungee-esque straps from the Lyra Double-Double mount suddenly snapped.  It landed on the hallway carpet from about 5 feet up.  This scope takes a licking and keeps on ticking.

Beyond that, it puts up the nice sharp views you expect from a refractor.  The focuser s adjustable for tension, and works like a champ.  It is very easy to get perfect focus with, every time.  This results in the characteristic pinpoint refractor starfield.  At f/5, it throws up a bit more than its share of chromatic aberration, but it’s only on bright objects, and regardless, who cares?  A little purple haze never hurt anyone.

In use, I have a 25mm Plossl permanently placed in it, as opposed to a second 32mm Plossl.  I do this even though that sacrifices some field of view – from 3.92 degrees down to 3.25 degrees.  Why?  Because I’m at the mid-century mark in age, and the pupil of your eye opens less and less as you get older.  Supposedly, it starts out at about 7mm when you’re a kid, 6mm once you become an adult, and 5mm when you get to around my age.

In the ST-80 with its 400mm focal length, the 32mm has an exit pupil of 6.4mm, while the 25mm’s is 5mm.  What this means is that the cylinder of light coming out of a 32mm EP is significantly larger than the middle-aged (ahem) person’s eye’s ability to take it all in.  The result is that light get wasted.  Instead of entering into the eye’s pupil, this extra light hits the iris, the colored part of the eye that surrounds the pupil, and splashes off, never to be seen.  This means that the view is dimmer than it otherwise would be if the light were concentrated into a smaller exit pupil.  In my light-polluted location, I want every photon I can gather to hit my retina.

Of course, I love my Mak.  But buying the ST-80 was money well spent also.  Now I was up over $700, not $500.  And there was plenty more spending to come.

Next – Part 2 of the Year-End Review

 

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