Macavity

So that's the view of the sharp end of a Lunt80?! (I don't frequent these parts!) Despite the reflection teasing me (lol), do I see letters "ED" by any chance? I too have asked the question whether an ED doublet would be "better" than (even a FAST f/5) Acromat. But no one ever answers! lol Like @Stu I'm pretty certain... E.g. if I stop my ST120 down to f/7 it won't be "great" in the FAR Red spectrum. I also believe in more general "better build quality" arguments re. ED APOs too! I did TRY comparative measurements with WL + NB (HA, O3, CaK!) filters and it seemed to confirm that idea. But then, as ever, "clouds got in my way"... [JM] To echo the above, I suspect adapting a slower (f/10+) Achromat is reasonable. I won't show the ST120 Frankenscope here, because it's on test and until it's both proven optically *AND* mechanically, I won't be using it visually! Although I have a 90mm ERF + my Lunt50 Etalon, I want to TRY the established ED80 doublet. It's always good to find out what the "opposition" (VIS/IMG) are doing anyway!

Oops! ("Good old" Google... Or even Yahoo News to the rescue) https://www.yahoo.com/news/russia-reschedules-soyuz-launch-failure-blast-off-101640554.html (Anyway)

And, of course, it's also "telecentric" too? But came across this image: The back-focus of a Canon lens is about 40mm (IIRC!) so maybe it is a better clue than an "unknown" telescope? "I'm out" as they say on Dragon's Den. lol. But I hope you find a solution that works for you.

To a first approximation, once you have a working setup optically (visually), take a steel ruler or tape and measure the *optical path* as best you can. It's never easy to "get the right adapters" (at first go?) but it is possible...

Is it not possible to place a Quark *inline* with the telescope (perhaps after added extension tubes) and then introduce the diagonal / eyepiece after it [the Quark]? Looking at a weighty (and expensive!) optical "edifice" at right angles to the scope reminds me of past experiences of things hitting the deck... In fact, rather like this... Image of Sky Scout "dedicated Solar scope" (incorporating Quark)! P.S. See also: http://astronomynow.com/reviews/daystar_quark/tablet/index.html for a discussion of the possibilities...

While "researching" (lol) my Comedy Thread, I was reminded of one early childhood Laugh: Will Hay in "Oh Mr. Porter!". As Sir Patrick reminded us, a noteworthy Amateur Astronomer (Discoverer of a "White Spot on Saturn" way back in 1933!) A sucker for anything featuring *Historic Telescopes* me... Nowt to do with me! The Credits within the Youtube Video.

I finally understand now! (Long years of "wondering about such things" are now resolved)

Recalling days when folks used to build (tuned) *fireplace* chimney Horns?! I have to admit I have never understood how anything beyond "Class B" (push-pull) can successfully reproduce a *whole* audio SINE wave, but... Have fun with the Organ Music! If you haven't already bought/considered it: Widor's Toccatta and Fugue in F should "Blow the dust out" of things!

I love this "Meme"... Saw it elsewhere and recently? Someone who (at least) knew CATS! I laughed re. the recollection of a "runty" little kitten who persisted in pushing a HUGE Plant Pot off a table. Repeatedly, despite attempts to cajole / stop! Eighteen years of total love... and abject feline defiance?

I suppose the most perplexing thing about (many Lunt) solar scopes is the presence of these off-axis HALOS on the image? Rather than worry anyone (or myself!) I show a Gong example: Anyone know the WHAT/WHY of this particular phenomenon? I am extremely reluctant to start messing with the innards. lol However you describe it there is a left/right gradient (halo)! For me, this "feature" manifests when I "crank up" the gain to show the prominences. Maybe additional aperture *helps* with Signal to Noise ratio in eliminating them? But ALL the Pressure Tuned scopes might be potentially prey to this? As with most of my scope limitations, others might rush to demand exchanges, whereas I (as characteristically British) "make do & mend"? Our UK dealers are great! But we are (both) a long way from "Lunt Central". Exchanging "solar technology" seems a fraught and a lengthy process. I both admire and "resent" [teasing!!] our U.S. buddies on their third or fourth (e.g. Celestron C8) to ensure they get a "good one"! And whither the "bad" ones? To SOME extent, one has to be "pretty amazed" (reading the spec of solar scopes!) that such technology is available to Amateurs. Budget and Tolerance are coupled variables! At the cost of a Lunt 50 I am happy enough. For a bigger aperture Lunt I might not have been so accommodating? KUDOS to ALL fellow "Solarites"! I feel it is not an *easy* area of interest to pursue. My scope benefited from a fair bit of "tuning" and is certainly much improved compared to first light. Though ANY upgrade remains expensive...

Although reluctant to do so (Heheh) I sense that owners of 60mm Lunts seem to produce rather better images that I do. Or at least at less effort? The 60's more standard focuser makes it more versatile re. Barlowing etc.. Though I have never felt "ruined" by the latter. But I am (and still remain) of LIMITED budget re. Solar Scopes! In similar way, I LOVE my 66mm APO, but sense owners of 80mm APOs make rather better images. (Also a ratio of ~1.2x diameter). But I did buy a 66, 'cos it was a fair bit LIGHTER for Grab & Go! NO shame involved. But with these smaller apertures, I sense "every little helps"... *IF* you can afford it? I have always like to TRY a wide variety of (imaging) rather specialise (invest) in one particular field too.

Jus' bootiful...

Hahaha! The thought of a pocket punch up... "G'wan HIT him Robbo (my son)"! For me and & Leibniz? I have arranged bookshelves by "philosophical emnity"...

I MUST read this thread! I suspect it encompasses some/many of the issues of current concern here... That of being a "Generalist" - Too thinly spread? At the moment, I have divided my activities according to focal length - With specific scope and / or camera! My memory for "setups" ain't what it was! 2.6mm f/1.0 Computar + Watec 102N+ "All Sky" meteor/cloud Cam. (Remote VIDEO setup - Not really all-sky... coincides with rooftops!) 20-70mm Canon EF f/4 (non-stab) lens + EOS100D for Wide Field. (My current excitement! Constellation and "Open Cluster scope". Lunt 50Tha f=350mm H-Alpha scope + ASI120MM camera... The START of the rot! lol. Still need to work on Newton's Rings etc. Altair ED66 f/6 f=400mm (Sometimes wish I'd gone for an ED80) Currently White Light Solar with Lunt Wedge. Needs 1/2" Cam!!! TS 200mm F/4 (modded!) "Astrograph". My VIDEO Astronomy machine! Watec 910HX (Fully "remote"... focusser, HEQ5 etc.) Skywatcher MAK150 + Monorail Focus, Barlow(s) + ASI120MC for "Planetary" (Colour rather than RGB wheel, for simplicity?) Sometimes I wonder why I ever started this, lol! My ENTHUSIASM is still intact, but lack of clear skies, having a life, WEIRD neighbour(s) etc. etc. Determined to give it a few more seasons (Can I hire an "assistant"?) Aside: I also remembered this, which made me chuckle: Honourable mention for Skywater 102 + modded AZ3-2. "Pimped" + Monorail focusser! Envisaged for Astro Soc "Observation Nights" but...

I'm fairly decrepit, but once you've cut a path out with a half-moon cutter (you just STAND on that) digging out grass as "turves" was not too bad? The roots remain in place, but a so-called *WEED MEMBRANE* seems to have prevented grass regrowth? If the underlying soil/clay is solid enough, gravel worked for me. If you want to walk on it, I have found that "sharp" gravel (rather than pebbles!) binds to gives reasonable walking surface? Hard to say At the peak of my "powers", I could only lay 2'x2'x2" flags! lol I doubt I could even manage those these days. Never gets easier, right?

Video astronomy "Is what it is"? And DID "transform" my Astronomy. I do try tried to steer clear of the (to me surprising!) "controversies"? In retrospect here, my destiny was perhaps to be a "classical" imager... But local WEATHER (and life issues) severely limit multi-hour exposures? On BEST nights, I have VIDEO hopped from DSO to DSO and captured *some sort* of (stacked) image of 40+ Messiers, Caldwells, O'Mearas? Hardly "centerfold" material in Astronomy Magazines- But I like them. Having complete the "Marathons", I'm taking things EASY now on... Diversifying too? Personally I'm sticking with "internal integration", but! With the aid of ZWO ASI120MC and ASI120MM cameras, I'm exploring minimalist Planetary and Solar (H-Alpha) imaging. I do intend to revisit VIDEO Astronomy Targets. But maybe in a slightly less "frenetic" way! "It's all the same, only the names will change"? (Credit: BON JOVI!)

Maybe one of these might help? http://www.modernastronomy.com/product-category/accessories/finder-guider-adapters/ Though quite WHICH may take a bit of research? Personally I got my friend to "turn down" a standard 2" to 1.25" adapter, cut off an appropriate amount of finder tube (with angle grinder) and just "whacked it in"!... But I sense such things DO exist. Might be worth giving Bern @ Modern Astronomy a ring? (Not sure there will be room for a (unneeded?) Helical Focuser, without a fair bit of surgery!)

Might be of interest... (if you made a significant "profit" over Christmas!) Article in Astronomy Now (Jan 2016): "The Ultimate wide-field Refractor" The Canon EF 200mm f/2.8 L II USM + Canon cam, Starlight Xpress etc.

Ah, so that's where the focussing is hiding. (Doh!) Quite a nifty idea, given the limited back-focus... I'll have to see if merely "clamping" suffices.

Can I ask (generally) which microfocuser is being used? (Link, possibly) Aside: Rather going off the idea of fitting the (otherwise excellent) TS filter slide behind the Canon. Might be a good place for the focusser though! (At the moment extra slide deliveries keep receding into the future)

Heheh. Thus far, I love my (non-IS) f/4 70-200mm. Clearly, none of my scopes go below f/4 without (dubious!) focal reduction. Just learning m'self too, but: http://www.the-digital-picture.com/Reviews/Canon-EF-70-200mm-f-4.0-L-USM-Lens-Review.aspx I decide to forgo f/2.8. I didn't need the image stab. I think the PRICE dictated much of my choice tho! You could always stop down the f/2.8 aperture with an adapted *circular* 2" filter to avoid diffraction. Maybe you get the best of all worlds that way...

That is certainly the other (easier?) option! Baader make a variety of filter sizes... http://www.teleskop-express.de/shop/advanced_search_result.php?keywords=baader+filters&suchdas=OK (Idem more specialist optics firms?) if you were content to limit yourself to 2" aperture, filter threads seem to be universal? All you'd need is a stepper ring. Larger filter sizes seem to be square, are unmounted and rather expensive! But, with a little DIY, a cheap UV filter (with the glass removed) could adapt the camera thread to something you have lashed together yourself? Good question re. alignment. No doubt (to some limit) filter glasses will have to be orthogonal to the optical axis, optically flat etc. And a question to optics experts?

Finished "stealthed" ST102! My FIRST ever scope - Poor thing had been modded so much,.. So I felt she deserved a little TLC. Now with TS Monorail focuser and "Carbon Fibre" finish. Intended for the (vanishingly small) times local Astroc Soc "Observing Evenings" are clear!

As ever, we video astronomers do things a "bit differently"... The tube rings also provide a way of locking the focus. But I'm not totally convinced about the idea. But I did manage to focus with a (15mm) TS Filter Drawer System using the thinnest possible (10mm) T2 to Canon bayonet adapter: http://www.teleskop-express.de/shop/product_info.php/info/p6991_TS-CCD-Adapter-for-Canon-EOS-lenses-to-T2---only-10-mm-length.html I sense I should probably shim the system so the lens still focuses at "infinity". But I am probably not looking for the same perfection as classical imagers? I can always get plenty of brightness (increase camera gain!) so envisage a "mask" to aid focussing. (I did find a source of mini Bahtinovs somewhere). Or maybe something DIY will suffice. The RAIN isn't helping with progress.

Remembering my annual (Christmas Gift) Giles cartoon book: http://www.gilescartoons.co.uk/cartoon.asp?cartoon=266 Main sequence... know my place etc. etc.