Posts Tagged ‘telescopes’

I’m starting a new  a “Star Hopper”  education program for anyone who wants to learn about telescopes and how to find their way around the night sky with or without a computer. It will be run out of “Driftway Observatory”  – my backyard in Westport, MA, so obviously you need to be in driving distance and participation on any given night will be limited.  The way this works is invitations are sent out to the email list of participants on the morning of a night when the forecast is favorable.  Participants can then respond and space is reserved on a first come, first served basis.

You can use your own telescope, or use one of the telescopes here.

I see this also as an excellent parent/child shared learning opportunity, however, each child must be accompanied by an adult – one child/one adult, two children/two adults.

Other requirements for participants are:

1. That you purchase a copy of the excellent guidebook,  “Turn Left at Orion, ” which we will use for every observing session.

2. That before you attend any night observing session you complete a day-time workshop on telescope use in general, but particularly on the new line-up of telescopes at Driftway Observatory. 

3. That you have – or purchase – a pair of handheld binoculars suitable for exploring the night sky. 

The learning goals of this program are simple:

1. Learn your way around the night sky using the unaided eye and binoculars. (My “Prime Time” web site will be a major resource for this.)

2. Learn your way around the universe by finding examples of the major classes of astronomical objects (double stars, open clusters, globular clusters, nebulae, galaxies, etc.) with one of the telescopes at Driftway, or your own telescope if you have one and wish to use it instead. 

3.  Apply the classic advice of Sherlock Holmes – learn to “observe,” not simply to “see.”

My role will be to suggest appropriate targets (from “Turn Left at Orion”), have telescopes and large binoculars available for you to use, and coach you in their use.  Your role will be to read about your targets and how to find them before coming out to observe. You will find yourself involved in setting up instruments, using them, and putting them away when done. Most importantly, though, you will find objects on your own with some direction from me.

I hope you will find this approach very satisfying, but I’m not sure this style of learning is appropriate for everyone. You’ll have to decide if this is what and how you want to learn. If this interests you, please respond by sending me  email ASAP and ask to be added to the Star Hoppers list. If you know someone else who might be interested, please have him/her contact me.

I will schedule appropriate times for one or more persons to come here to learn about the telescopes in daylight. We will be using the three most popular types of astronomical telescopes – all relatively inexpensive models, by the way: A 12-inch Dobsonian (simple manual control), a 4-inch refractor on an Equatorial mount (mostly manual), and a 6-inch computerized, “go-to” catadioptric.   If you master those, I’ll be happy to show you how to do astronomical video as well.

You can find a copy of “Turn Left at Orion” at a local bookstore – Barnes and Noble has had it in stock – or at an online store, such as Amazon.com.  One caution. There are still several editions of this book available.  If you have an older one, that’s fine, otherwise get the most recent one (fourth edition 2011), and I suggest the spiral bound one because it folds flat and is easier to use in the field. Here’s the complete title of the book and a link to Amazon.

Turn Left at Orion: Hundreds of Night Sky Objects to See in a Home Telescope – and How to Find Them [Spiral-Bound]

Guy Consolmagno (Author), Dan M. Davis (Author)



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. . . such as they are.

I’m talking telescope powers here, and borrowing shamelessly, of course, from Wordsworth. But I really felt it this morning as I enjoyed about 90 minutes under a clear, but moon-washed sky. What did I feel? That I need another session with ASTROMARTERS ANONYMOUS. I’ve fallen off the wagon. The evil equipment junkie in me is loose again.

Oh, it started in a small way with the purchase of some nice 10X50 Pentax binos that I’m sure will prove useful. But that lead to a serious dallying with a 60mm Unitron Model 128 – the particular scope I used to dream about when I was a kid. But I dodged that bullet after I convinced myself that this was a unit built after 1980 – in other words “new!” – though Unitron apparently didn’t put serial numbers on these scopes and it’s difficult to be positive about dates because the Unitrons changed so little over decades.

But then suddenly, there I was grabbing at a Celestron NexStar SE4  – or is it 4SE? Doesn’t matter, it’s the smallest scope in the SE series and the only one that’s a Maksutov-Cassegrain and that’s what I have wanted to try for some time and this one came with a 9X50 finder and cost just $295. How could I resist?  So as I write this UPS is busy hauling it my way from somewhere down south. (Did I hear someone say this is a “go to” scope?  Isn’t that in  violation of my basic, star-hopping tenets? You bet. And it’s former owner has packed it in three separate boxes and the only one I intend to unwrap is the one with the optical tube in it. That optical tube  has a dovetail and will go right on the Voyager alt-az mount. And if it’s a keeper I’ll sell the go-to mount separately.)

But the point here is, I was on a  tear – yes, this is about observing – I’m getting there – please bear with me 😉 So when Larry Carlino, whose telescope reviews I’ve appreciated, decided he was divesting himself of all Chinese goods, I was smitten by the Orion 120 ED included in his “fire sale” ad  and after less than a hour of mulling the pros and cons, I offered him my SV80S Lomo as an even trade. I think subconsciously I was just stalling. But he might have accepted. The Lomo is a Russian lens, so it would get him out of the Chinese deficit/democracy issue that’s bothering him.

Fortunately, he said “no.” But see why I think I need to refresh my membership in Astronmarters Anonymous? No – it’s not because I’m busting the family budget. My habit is worse than a money thing.  I have a certain investment in astronomy toys and I keep it revolving. Purchases are always matched quite closely by sales. (That means I’ll be putting  an Orion ST120 refractor, an Orion 80ED with a two-speed focuser, and a 50mm Stellarvue “Little Rascal” on Astromart shortly  to compensate for recent purchases and to build up the PayPal account to take care of small temptations in the future. If any of those scopes interest you, ask me for the detail before I post them. I’d rather sell local.)

But as I say, this isn’t about money. This is about the amount of time I spend looking at the Astromart and Cloudy Nights classifieds in search of the equipment Holy Grail that I know either doesn’t exist, or is out of my price league. That’s not too disastrous a pursuit on cloudy nights and rainy days – but I could be building up my “to view” list instead. Or writing the April installment for the web site. Something productive. [b]But what really bothers me is the way it can co-opt my observing time.[/b] That’s where I feel the illness of my equipment obsession. William Wordsworth had it right two centuries ago when he wrote:

Getting and spending, we lay waste our powers;
Little we see in Nature that is ours;
We have given our hearts away, a sordid boon!

You bet, Bill! [b]And it is the heart I value most – or what I generally call being “rapt in awe” – or what Bob referred to recently as “getting your mind around” what you are seeing. Whatever you call it, I was doing none of that this morning.[/b] Instead I was wasting my time doing a side-by-side comparison of the SV80S Lomo and the Orion 120ST. Why the 120ST? Because it was the same size as the 120ED and so – I thought – might give me some experiential hints about how much  of a difference it makes to use 120mm vs 80mm – what was the real impact in terms of light grasp and resolution? [b]My conclusion, for what it’s worth, was not enough.[/b] Oh I know the numbers backwards and forwards, but when looking at the same objects side-by-side – the familiar M13 and Double Double and then M57 – well, the added light grasp (about 2X) and resolution just weren’t impressive. What was impressive was the pristine, high contrast view in the SV80S. That’s what I want. And yes [b]this was incredibly unfair.[/b] The 120ST sells for one-sixth the price of 80mm. It’s an F5 achromatic, versus an F6 apochromatic triplet.  And the 120ED would be significantly better than the 120ST. But still, what this did was convince me that I was lucky Larry hadn’t agreed to the trade and I was not going to buy the 120Ed outright and sell the SV80S to cover the cost – which it would, exactly. And in the final analysis that’s a subjective decision, but it was enhanced significantly by  some reminders  through real observing.

[b]The problem? Well, I didn’t really see any of these objects I was observing.[/b] I didn’t “get my mind around them.” I was not “rapt in awe.” I did try a little. I did sit back and try to give the various arguments about objective diameter, light grasp, focal length, coatings, baffles, etc. a chance to drift out of my mind.   I wanted to end the mental clutter driven by equipment details. I tried to land on these ideas gently, like a butterfly landing on a flower, as one of my meditation books suggests – and just nudge the thoughts away. And maybe I had some tiny success. But before I could see any of these objects for what they really are stratus clouds were covering a good deal of the sky, so I went in.

And that’s the real reason why I get mad at myself for wasting time “getting and spending.” That’s why I feel I need another session with Astronmarts Anonymous – an organization that’s just a figment of my imagination, of course – but when I consider that Larry rejected my trade offer because he already has a WO 80mm and a TMB 92 and in his current ad he’s selling four or five refractors – well, I don’t think I’m alone in this bad habit  🙄

What amazes me is how well Wordsworth saw all this so many years before the Web, before apochromatic refractors – heck, before most of what we know as modern society existed. Even  then, he felt these things closing in on us – and expressed it all so well.

The world is too much with us; late and soon,
Getting and spending, we lay waste our powers;
Little we see in Nature that is ours;
We have given our hearts away, a sordid boon!
This Sea that bares her bosom to the moon,
The winds that will be howling at all hours,
And are up-gathered now like sleeping flowers,
For this, for everything, we are out of tune;
It moves us not.–Great God! I’d rather be
A Pagan suckled in a creed outworn;
So might I, standing on this pleasant lea,
Have glimpses that would make me less forlorn;
Have sight of Proteus  rising from the sea;
Or hear old Triton  blow his wreathed horn.

Yes – not to mention being able to see M57 as the last gasp of a magnificent star and an indicator of the future of our Sun – or for that matter,  to even begin to appreciate what that simple, four-letter word, “star,” encompasses.

Ah well – more bad weather on  the way, but Saturday night is looking promising – and Friday, too, if you don’t mind the chill.


Oops – went out at sunrise to exercise and guess what – perfectly clear! Last night the CSC had said it would start clouding up by 3 am – and sure enough, that’s when I saw the clouds that drove me in. But when I checked the latest version of the CSC after writing this it said it would be clear this morning – and is. So I should have come in for a break, then gone out again – would have had clear skies and no moon! (It set about 3:30.) Can you ever predict our weather? And if you do, can you have enough sense to check those predictions in a timely fashion!)

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OK, I have been going around this bush for a month, exhausting my patience, thinking of, reading about, and trying various options.  Yesterday I made a decision – I bought a used Stellarvue 102EDT refractor. Here it is:


Simple, huh?  So what’s so special about this scope?

  • It’s short.
  • It’s good.
  • It’s rare.

First things first – short is good. See, right now I’m using an Orion 100ED on the parallelogram T-mount in the Observatory. Looks like this:


Frankly, I like this scope. The optical quality is excellent. The focuser is rather rough, but works fine for me. But, it is an F9 – that means the focal length is 900mm and what that boils down to is a tube that is about 36-inches long. Mounted on the T-mount the object end almost touches the dome and frequently the back of my head is touching the dome – or almost touching it – on the other end as I look through the scope. It simply crowds the observatory.

The Stellarvue 102EDT has the same objective diameter, but is an F6. That means the focal length is 612mm and the tube length will be about a foot shorter.

But – and this is a big but – the optical quality is NOT likely to match that of the 100ED. First, it’s simply more difficult to make a shorter focal length lens, so they cost more and dollar-for-dollar you can’t expect the same quality. This scope cost significantly more thant he Orion when it was made – it’s no longer in production – and while the optical quality is supposed to be very good, it’s really hard to tell without simply looking through it. Reviews of others can take you only so far. The Orion was a break through in price and quality and they sacrificed by keeping the tube and focuser fairly crude.

So what I expect this to come down to is a judgment call where I will weigh optical quality issues against length issues. I want quality – but I’m not a fanatic about it. I tried a really inexpensive F5 scope from Orion. The shortness was good – but it was outweighed by optical quality issues that bothered me. (I stress “me” because an awful lot here is in the eye of the beholder. Differences are measurable, but different people have a different sense of how important they are. )

My general feelings were confirmed and expanded upon when I asked about this on the Yahoo Stellarvue group. The comment most useful to me came from Clive Gibbons who sent me an email stating:

The 102EDT has color error roughly equivalent to an normal 4″ f/12 achromat. So, it’s quite good in that respect, but not in the same league as an ED100 doublet.

The objective lens was made by LOMO in Russia and uses “SP3″ glass.
LOMO makes very sharp, contrasty lenses. While it’s reputed to have a very flat field, you can expect it to be as typically flat as a normal 4″ f/6.1 optic. The triplet design is close-spaced. To obtain a flatter field, the rear element would have to be much closer to the scope’s focal plane. Of course, for visual use with typical eyepieces, the amount of curvature seen in a 4” f/6.1 lens won’t be an issue.

All-in-all, you should enjoy the scope a lot. It’s an excellent quality instrument.

I responded, asking permission to quote him here and making specific reference to mye xperience with inexpensive F4 achromats and Clive added:

Yup, the 102EDT will easily outperform any f/5 achro.
A 4″ f/12 achro has pretty minimal c.a., so for just about any object
(except the very brightest), spurious color would be a non-issue.

And what about point 3 – the rareness? Well, who cares? My understanding is this scope was made at apoint whent he market was rapidly changing and the price and availability of fancy glass was changing. SO a relatively small number of these were made – I don’t know if small means “less than 100” or “less than 1,000, but the SV102EDT is unusual. They seem to ocme up for sale on Astromart at the rate of one or two a year. For some reason I always seem to be attracted to the unusual – but I think that has very little to do with my decision in this case.  One warning I did receive from folks online is that the fine focusing mechanism on this scope is prone to breakage, so you have to treat it gently.  I’ll live with that, if all else falls into place. Scope should arrive in a few days, so in a week or two I should know.

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I’m going through another equipment exchange burst and I hope this will be my last. My problem is simple – I get obsessed with having just the right equipment which then detracts from true observing. This particular outburst was triggered by breakdowns in high-tech stuff that are driving me in the direction of low-tech solutions out of both frustration and a feeling – rationalization? – that the low-tech is really  a better choice.

My second problem is I just have too many telescopes – though I am seriously narrowing the field. They made sense when I had a lot of visitors – and when I really thought my visitors were going to use the telescopes. What I have found is they don’t. They tend to gravitate towards the telescope that I’m near. They don’t have enough training and experience to point the telescope on their own and they don’t have enough of either to do what I consider serious observing – that is, staying on a single target for at least half an hour and making drawings and/or notes. I could address these issues somewhat with computer-controlled scopes that tracked, but these involved too much set-up time for me.

Bottom line – at any given session for visitors I can handle two telescopes – maybe three – that’s it. To me, given varying observing needs, I need perhaps four telescopes. That also fits my personal observing habits.  In fact, I think I could be quite happy with a single, good refractor and an excellent set of eyepieces.  What I’m trying to build towards this time around is the following:

The 15-inch as the ultimate deep sky scope.

Two refractors for portable and general purpose use.

Perhaps a single 8-inch SCT with computer control, but I am favoring more and more the idea of using scopes without computer control and without tracking – primarily because it keeps life simple, but also because there are some serious advantages to NOT having a computerized scope. Of course this goes against the grain. Call me contrary 😉

I’m getting there. The main question I hope to resolve in the next couple of weeks is whether or not an achromatic refractor can do most observing tasks fine. In other words, is it really necessary to spend serious dollars on apochromatic refractors – or something that approaches them? I can’t bring myself to go for the top of the line type. I really do like very nice refractors that I consider semi-apo. But even there, tests may satisfy me that much less is fine. To that end if have on order an Orion ST-120. This is an F5 refractor suitable for use on my parallelogram mount. I want to compare it’s performance on two classes of objects in particular – double stars and open star clusters – with my best refractors, the Eon 80 and the 100 ED. I know it will show more stars – the question is, will it show pinpoint stars and will it give the high contrast I’ve grown used to?  Stay tuned.

I’ve also bought used a new p-mount – well, it’s an older variation of  the “t-mount” made by Universal Astronomics. It has a shorter arm and not as many degrees of motion as the parallelogram mount I’m using. I know it will mean a more comfortable fit in the observatory, especially when using either of the two larger refractors. (One advantage of the 120ST is it is an F5 and that means it’s about 11-inches shorter than the 100 ED and so will be steadier on either of the parallelogram mounts. ) The question is, will the T-mount be more stable than my current mount with any telescope? Stay tuned. This too I hope to resolve in a week or two.

The one part of the equation that is under control is the eyepiece situation.  I now have a complete set of Naglers for the refractors. Well, complete set of the ones that are light weight. I find the 22-mm “grenade” very nice, but too large for the parallelogram mount – switching between it and other eyepieces causes issues with balance that need to be addressed and that makes it inconvenient there. But my primary goal with that eyepiece was to make it the main low-powered eyepiece for the 15-inch – and that works fine.

For lowest power – and widest field – with the refractors I should receive soon a used 32mm Televue Plossl. I hope it’s better than the 32mm – cheaper – Antares Plossl I have. I don’t expect it to get much use. My primary starting point with the refractors will be the 13mm Nagler and that will be complemented by the 9, 7, 5 and 3.5 Naglers. (The 3.5 was just purchased and hasn’t arrived yet, so I use a 3.2 TMB instead – very nice, but narrower field.)

Why the Naglers? They’re excellent. If I put a double star at the edge of the field it looks as good as it does in the center of the field. And, of course, they have that huge, 82-degree field and that means – with no motors – that things stay in view longer. I don’t think I would need them if I were sticking with motor-driven scopes. (Again – more on this in another post.) I bought all the Naglers used for an averge savings of about 30 percent. I sold my 13mm Ethos. It’s a great eyepiece, but again, weight is an issue – just not enough advantage over the Nagler to justify rebalancing. )

This set of eyepieces is for personal observing and for use with experienced visitors. I have a second set of similar eyepieces – the Hyperions – which are 68-degrees, and all heavier – and all significantly cheaper. They’re very good eyepieces and I’ll use those as the primary eyepieces with visitors. Plus having a second set means it’s easy to keep two scopes going.

Big equipment question mark? What gets sold. Possibilities:

1. One of the two 8-inch catadioptrics. Either the Celestron or Meade. I’ll decide later, but one of these goes – possibly both.

2. Either the 100ED  goes or the ST-120 goes back to Orion as a return if it does not live up to expectations.

3. The mini portamount and probably the Unistar.

4. The binoviewers – I find myself using these rarely and only for the moon.

5. The Mallincam – maybe. Again, right now I am in no mood to deal with the complexity. It’s been a hit at star parties, but I am not at all sure it is worth the hassle of setting up.  More important, I’m not at all sure I really want people to watch TV when they’re out under the stars. There are some terrific advantages to it – and some huge disadvantages in my mind.  I never turn to it as a personal observing choice and that should tell me something – but just about my personal preferences.

6. One 21mm Hyperion I had bought for binoviewing, plus two or three red-dot finders and the Telrad. These are all battery operated and go hand-in-hand with the computer technology where all you need to do is spot a bright star. I much prefer the low-tech optical finder for alt-az, manual telescopes.

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