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Posts Made By: Ron Oehlert

March 9, 2010 10:41 PM Forum: Equipment Talk

How to setup my cg5 mount

Posted By Ron Oehlert

When I just now entered a search for *dual dovetail* via google dot com (I then immediately selected *dual dovetail mounts* from their expanded subject-variety list), the very ninth return (the 1st 8 returns were for rifle scope mounts) directed me to Astromart where a Losmandy-brand dual dovetail is presently listed under the Mounts, Drives, Tripods catagory in the Classifieds here. IOW most any astro mount or astrophotograply dealers have such items, which BTW are also called Tandem bars; Anacortes supplies them. You might also want or need a pair of adjustable-aim Rings to mount a scope to the dovetail bar to easily aim both scopes to the same spot (or to piggy-back one scope to the other eliminating the need for a Tandem bar). You can also just Manually guide by watching thru the other scopes' eyepiece (attach a DIY pointer in the eyepieces' field stop & de-focus the guide star = no illiminated crosshairs needed) & making drive corrections via the hand controller to your drive; that is how I did it back in the days of film photography. And depending on desired image scale (even for deep-sky), the C6 could be your photo instrument with the other scope as the guider (you'll quite likely interchange both). A book or two on the subject of astrophotography & digital processing will tell you what you need to know & help you get started (see Software & Publications catagory in the Astromart classifieds or vist Anacortes looking under Astronomy & then Books).

March 26, 2010 05:26 PM Forum: Equipment Talk

Best Year's For Cave Astrola's Mirrors And Scope's

Posted By Ron Oehlert

From Sky & Telescope, August, 1994: Along with Thomas Cave Jr's own superb mirror-making reputation, Alika Herring was perhaps one of Caves' finest opticians upon whom the Companys' reputation was built; Herring was with Cave Optical from 1953 thru 1960. The Astrola line of telescopes began in 1954. During the 1960's top-notch opticians like Bob Crawford, Ed Beck, & Walt Depampalis were hired & Herring returned in 1969 after his career with the Arizona Lunar & Planetary Laboratory. In 1979 Thomas Cave Jr became critically ill which spelled the demise of Cave Optical Co which after almost 30 years was no more by 1980.

April 4, 2010 05:10 PM Forum: Deep Sky Observing

Marking up a star atlas

Posted By Ron Oehlert

Altho I've made my own such charts when I 1st started out, now I'd recommend you just get a chart that already has such objects Accurately plotted. Petersons' Field Guide (or likewise the Bright Star Atlas mentioned in another reply) & Tirions's larger scale Sky Atlas 2000 have served me well for decades. Orion's Deep Map 600 is convenient for my 7X50 Binocular or grab & go small scope use & folds like a Road Map. There are plenty of other detailed pocket & larger-scale field charts & some have companion indexes with complete object info.

April 19, 2010 11:28 AM Forum: Reflectors

odd optics

Posted By Ron Oehlert

The coating (regardless of who did it) is not the problem, but rather the optical surface of the mirror is not a true & smooth parabola. It is *stepped* with the outer zone & central zone each coming to focus at a slightly different place. This mirror was a Dud from day one & refiguring (or replacement) is the only solution. I've run into this same situation while making & testing my own mirrors. Meade is primarily an Importer/rebrander (always was) plus the people in their Customer Service Dept do not make mirrors so that is why they could not properly advise you on this issue.

April 19, 2010 09:44 PM Forum: Reflectors

another mirror cleaning problem

Posted By Ron Oehlert

Basically you need to remove a cured Rubber film. I'm not sure acetone or other solvents will have any effect. 'Twere me (& I've worked in a plant that originally distriburted & used G.E. Silicone adhesive since it 1st hit the industrial market) I'd simply rub the rubber film off via a thumb or finger & finally clean the surface area with WD-40 followed by a soapy water cleaning. If you are gentle & patient (don't rush the process) you may get away without a recoat. A hard silicon monoxide overcoat can also sleek, so do not bear down too hard with the finger rubbing trying to achieve quick results. But once an edge starts to lift, it should go easier as it rolls off. As previously advised, repeat your problem on a piece of window glass & trial/practice the removal technique.

April 20, 2010 02:14 PM Forum: Equipment Talk

2x Barlow (not a shorty) question

Posted By Ron Oehlert

You can fashion a tube liner from black felt or construction paper, (roll it up, tape together & slip it in) to eliminate sidewall reflections. You can also remove lens from cell & blacken the sides of lens itself with a felt-tip permanent marker to further address stray light if the lens is not already edge-blackened. This works well for visual use, too.

May 2, 2010 05:11 PM Forum: Refractors

spacer question in 76mm refractor

Posted By Ron Oehlert

Likely there exists what is termed Wedge with respect to one of the two elements. IOW one element was produced at a slight angle to the optical axis. Unequal original spacers attempted to correct this example anomoly by tilting one element with respect to the other thus aligning the optical axes of both elements. Of course, without that 3rd spacer (of appropriate thickness) the two elements could now *rock* on the axis of the remaining two spacers upsetting their alignment, or worse rest glass-to-glass at that 3rd spacer position risking damage to the rear elements' softer surface. So, replacing that 3rd spacer as originally assembled is recommended. Rotating one lens element with respect to the other also alters wedge effects & performance in general, so ALWAYS apply index marks to the edges of both lens elements for same prior alignment when reassembling. At this point, you'll need to make several trials with different element rotations (respective to each other) to discover the correct alignment with 3 spacers. Use temporary lead pencil index marks until satisfied, then index mark with a permanent felt tip marker.

May 2, 2010 11:00 PM Forum: Equipment Talk

Spots?

Posted By Ron Oehlert

IOW, per the other replys, those spots are NOT in your scope but rather in your Eye(s).

May 3, 2010 09:06 PM Forum: Telescope Making

bonding plate glass for mirror blank.

Posted By Ron Oehlert

Perhaps bond some glass spacers inbetween the two discs. Such a sandwich blank should have greater stability both physically & thermally, yet still with low weight & cost.

May 5, 2010 06:20 PM Forum: Meade

Meade QX lens sequence

Posted By Ron Oehlert

Hi, in lens terminology, *flat* is refered to as Plano, so your convex-flat is a plano-convex lens. Given the lens elements you listed, it would seem the 32mm QX is an Erfle variation design with perhaps a Barlow as your field lens; the 20mm & 15mm QX are classic Konig designs with an added Barlow. I'd apply the plano-convex as the eyelens with flat side towards eye, the thinner achromat plano-convex doublet in the middle with its' flat side towards eye & the thickest achromat double-convex doublet as the actual Field lens with its' greatest curved surface facing the curved surface of the middle achromat, followed by the Barlow that you assumed was the field lens. That arangement should place the thinner spacer between the eye lens & middle lens with the thicker spacer between both doublets, but their curved surfaces will inform as to correct spacer placement; reverse the orientation of that double-convex achromat Field lens if spacer or performance dictates.