Latest Discoveries and Developments
Imaging Comet 17P Holmes
I was too busy and too tired to set Brutus up, but I had a spectacular time watching the visual evolution of this bizarre comet. I learned how to take some afocal images through the Nagler 31 with my Fuji Finepix. Nothing to write home about, but my individual memorialization of this highly unusual celestial event.
More modifications to Brutus
(pending time to post--will document apodizing masks, repairs following the one near-fatal unloading accident from the Spring, a 'fix' to prevent a recurrence, and (hopefully) the end to the long-running saga of the erratically performing azimuth encoder -- which I understand from Rod Mollise never worked consistently even for the scope's builder. )
Some tweaks to Natasha (cue embarrassment now...)
Have been using this scope in my limited observing time, instead of Brutus. It is much easier to see the collimation adjustments (due to the shorter focal length), and is a superlative performer. I *did* discover by accident that when I installed the side mounted fans to blow a 'curtain' of air across the face of the primary, I actually installed them *backwards*. Obviously, that meant they were having no effect. Now they are generating some observable vibration-- the first time I've found this with any of my fan setups. Have to do some fine-tuning...
Report from the "Almost Heaven Star Party" -- for once, it lived up to its name!
After two mediocre nights, the final evening of our Club's star party was as good as it gets on the East Coast. Truly superlative dark skies, and the first time I ever ever seen clouds as 'dark holes in the sky' rather than illuminated gray/white masses. The margin of superiority over the G.W. Helicopter Pad (G.W. Helipad May 06) located some 30 miles east due to the lack of drive-by traffic (the bane of the Pad) is enough to convince me to re-think my philosophy of where to go on New Moon weekends, and 'stretch' for Spruce Knob more often. Here is my full report: AHSP 2007
UPDATE: to THE END OF MY AT-HOME OBSERVING???
ARGGHH! The restaurant is still at it as of November 2007. Will complain in writing this time (vice email) to the City. If that doesn't work, time to invoke VOLT (http://www.volt.org/) A local restaurant has decided to run four rotating searchlights at night. Although this establishment is fully two miles away from me by road and a full 1.5 miles 'as the crow flies', these lights oscillate far enough down from the zenith to cast beams that cover 80% or more of my sky. I've contacted the restaurant ("Vintage 50") that is running them, who said now that their grand opening orgy of optical excess is over they will only continue this un-neighborly behavior on undefined 'special occasions'. Whenever are dling this, it basically renders my telescopes inoperable-- and of course, they only pick the weekend nights when I do the sidewalk observing that constitutes 90% or more of my eyepiece time. I'll continue to highlight this kind of outrageous behavior in the public outreach I'll be doing for the National Park Service this year. Here is the link, with photos. Local Light Pollution Gone Overboard
Making my Scopes 'User Friendly' for outreach events
Using a product called "Astro-Glow" made and sold by an old observing partner of mine who now has a specialty astronomy business http://www.astronomy-shoppe.com/, I have been able to add passive illumination to the knobs, handles, ladder treads, and even some of the eyepieces I use at public events. It's cheap, versatile, and highly effective! See my applications of this stuff User friendly mods
Winter Star Party 2007
WSP 2007 This year I resolved to attend more events on site, which I did (one is better than zero!). Meeting and observing with folks like Al Nagler was a hoot, too. The lousy weather and the full week it takes to go to an event like this makes me question whether I'll do it again, though. Going to Spruce Knob or local star parties is probably a more efficient use of time, but everyone should consider going to this premier star party at least once!
Almost Heaven Star Party
Once again I will be a presenter and volunteer at our club (www.novac.com) star party, held from 9-12 August near Spruce Knob, West Virginia. This locale features some of the darkest skies east of the Mississippi-- check out a 'night face of North America' satellite image to see what I mean. (Spruce Knob is in the center of the dark mass eash of the Boston-Washington DC corridor.) I'll be doing a solar observing presentation and using my triple spectrum solar rig 'Uncle Beasley" ( Solar Observing) to showcase the sun. (Weather permitting-- the first year we hit a hurricane, and last year wasn't a lot better!). Hope to see some of you there!
Telescope Economics
Telescope Economics A back of the envelope calculation of light grasp gained per dollar spent on various large and medium Dobs, and a smattering of refractors. My homebrew scopes turn out to be cost-effective as well as good performers.
Getting back into Astrophotography
I'm beginning to play around with my recently acquired Fuji Finepix 5200 digital camera, trying my hand at night landscape shots, unmounted sky shots, piggybacked tracking images, and possibly some afocal/through the eyepiece work. Very much a work in progress... Astrophotos
Brutus is finished!!!
See Brutus Mods Rd 3. I've finally run out of things to tweak on this scope!
Natasha re-loaded
See Natasha Update. I've re-discovered the fun of using this optical gem, which occupied place of pride in my telescope kit until Brutus arrived on the scene. I've discovered that the simple device I made to help use the "Cats Eye" collimation system on Brutus (see Collimation tools--towards the bottom) also allows for more precise collimation of Natasha. The result on one memorable December night was pinpoint images that I would have thought were coming from a high end refractor rather than a reflector...
"Clash of the Dobs"-- a Christmas story
On a clear December night, I decided to set up Brutus, Natasha, the TV Ranger, and the (unmodified) ST120. The main event was comparing Brutus and Natasha. Natasha clearly had the sharper star images-- arguably the best I have ever seen from a reflecting telescope. Turning both scopes towards the M-42/Great Orion Nebula was enlightening. Both scopes clearly showed the "E" and "F" stars in the Trapezium. The views of the nebulosity through Natasha were fine... but those through Brutus were nothing short of ethereal. Both scopes are superlative performers, each in their own way. Brutus is the triumph of sheer size-- the largest scope I am likely to own that can be kept fully assembled and put in use within 5 minutes, and transported in a minivan. Natasha doesn't have quite the light grasp (OK, only 44% as much), but optically is 'as good as it gets'. There are a few mechanical issues with Natasha (vignetting of the secondary cage, mediocre accuracy of DSC's due to rocker box issues), but it is a potent package.
"Refractor shoot out"
A 70mm Televue Ranger, a dirt cheap ST80, and a cheap but highly customized ST120. All have their optical highpoints, and all have a distinct role in my observing kit bag. See Refractors for a performance comparison.
Meade 14 UWA-- teaching an old dog new tricks
The Meade 14 Ultrawide was one of my first premium eyepieces, acquired in 2001 or thereabouts. I believe I had tried it in the tunable top Paracorr early on with Frankenscope, but didn't see any optical difference. Maybe my eye is more highly attuned after all of these years of Big Dob observing, or maybe there is this much difference between an f/4 and an f/4.5 optical system (actually, both factors are likely true), but I notice a marked improvement in the parabola correction of the field of view of the 14 UWA when used in the Paracorr. It takes what were good star field images in Brutus and makes them almost distortion free to the very edge of the FOV. The same settings that work for the Nagler 20T2 apply to the 14 UWA. Wish I had known this years ago...
Observing at the G.W. National Forest 'Helicopter Pad'
Due to the unseasonably mild winter, I was able to drive to this mountain site much later in the year than usual (snow and this mountain road don't mix, at least for my minivan). In fact, I went near the New Moon in October, November, and December. Here is the combined observing report-- G.W. Pad rest of 2006
2007: my 'Year of Outreach'
In a typical year, I volunteer at a handful of NOVAC events (Astronomy Day, etc.) and Boy Scout Camporees. This year some friends and I will be adding regularly scheduled outreach sessions in a nearby National Park. (see SNP Outreach) I intentionally picked the weekend nearest the New Moon, so we may even have the chance to get some serious Deep Sky Observing in under dark skies once we have done our 'public duty' for the evening. I plan to use my 24" Dob to give the public a REALLY good look, and have outfitted it with a couple of expendable eyepieces to reduce my angst and personal exposure. I've also put a few dots of photo-luminescent green material on the focuser knob, the handles that move the secondary cage in manual tracking, and even a few strips around the perimeter of the main eyepiece (Clearvue 30mm) to guide the absolutely uninitiated user into looking in the right place. <g>
Acquiring 'cheap eyepieces' for public viewing
I've always lived somewhat dangerously, using my Nagler 31 on outreach observing sessions with hundreds of Boy Scouts. Now that I will be doing more public sessions in the coming year, it is time to stop this 'unsafe observing' practice before it comes back to haunt me. I have a Rini 62mm eyepiece, but this is too big (and throws away too much light) in Brutus. Although I owned one of the ubiquitous 30mm 2" RPD80 type eyepieces in the past, it seemed time to get another for use with the less discriminating --and less careful-- viewing public. I found a 'cherry picked' Clearvue optics version on Astromart (http://www.astromart.com), and was surprised at how well it performs in Brutus when used with the Paracorr. I also picked up a custom 20mm Plossl made from Zeiss binocular elements. In conjunction with the old Russell 2" 11mm and 13mm eyepieces which I've still got from my early observing years, I think I've got enough glass to put in front of the public, including kids with grubby, grasping fingers and indulgent parents. ;-)
Adventures in Tripod maintenance
Having customized my ST120 scope, I decided to bite the bullet and replace some of the Synta 'grease' (aka 'glue' to the Western world) in the EQ5 mount that I'll use it on. This mount usually houses my Budget Solar Trio and is used in modified 'alt az' mode, where I use the latitude adjustment screw instead of the right ascension axis to move the scope vertically. As a result, the RA pivot action was virtually as stiff as when I acquired the scope, unlike the declination axis that has had years of solar use to break down the viscous grease. I took the RA axis apart, trying to follow directions on the Web (http://www.astronomyboy.com/cg5/) that didn't accurately correspond to my mount. I got most of the old grease out and new stuff (my trusty Moly-graphite high pressure auto lube) in -- only to find that the two parts of the RA housing would not fully engage. After an hour of futzing I ran out of daylight and had to stop, worried that my fiddling had taken a functional tripod and rendered it useless. With some more daylight available to work with later that same week, I finally found a way to strip virtually all of the parts from the RA assembly-- and found the plastic friction 'button' that had indeed slipped out of place and prevented the successful reassembly of the housing. Now all is fine-- the RA action of the scope is now light enough to allow the ST120 to be slewed easily through the sky, instead of having to wrestle with it.
Starlight/Feathertouch saga
See Brutus Mods Rd 3, towards the bottom. I customized my old Feathertouch, only to find that it was old enough (15 years) that it suffered from mechanical wear and stood in need of a rebuild at Starlight Instruments (http://www.starlightinstruments.com/). Before I send it off, I'll purchase a discounted cosmetically blemished state of the art replacement Feathertouch and retire the rebuilt one to my spares bin.
No more Clement Focuser for me!
My experience with this focuser has been bittersweet, to say the least. I designed "Natasha" around its unique focus travel capability, but was plagued with equipment breakage from literally the first hour of use. This was compounded by what seemed to me excessive shift of the focal point as the focuser was racked in and out. On Natasha (focal length 72") this was nearly 3/4" that a laser collimator spot would shift across the primary. With Brutus (focal length 96") this shift was a full inch. This played hob with collimating the scope (wherever you had the focuser racked in its travel could cause you to erroneously re-collimate the secondary mirror, primary, and focuser tilt.) When the focuser came back from rebuilding by Don Clement, the maker, I confess I didn't even think to test for this, since he'd replaced some stressed and mis-installed hinges. Much to my surprise, the problem remained. Don, who I believe was as frustrated by this (or dealing with me!) as I was to have wasted countless hours pursuing false leads, graciously offered to refund my purchase price even though I'd had the focuser for far longer than the 30 day return period.
Left image: The Kendrick laser spot with the secondary collimated and the focuser racked out.
Middle image: All that has been changed is the focuser is racked in (~2.5" of its 3" travel, although most of the shift you see above occurred in the first inch of travel traverse). The laser aim point has moved a full inch across the primary. Since even a 1mm mis-collimation of the secondary to the primary can reduce an optically excellent mirror to below 'diffraction limited' performance, the implications are obvious.
Right image: a close-up of this image shift
