Posts Made By: Alex McConahay

Directions for putting it back together (version 1):

Step 1: Get some cotton gloves.
Step 2: FInd a place to work with no dust, no static electricity, a clean soft surface (like a lintless paper).
Step 3: Thoroughly clean all optical surfaces.
Step 4: Order the lenses, spacers, and such in order of replacement from left to right. To determine the order, look at a picture from Televue website.
Step 5: Order the lenses right side up--and since you cannot tell which is the right side, please realize that you have 7 factorial permutations of this.
Step 5: Using the white gloves, pick up the first element, and place it, with spacer in the proper orientation in the lens barrel.
Step 6: Place any appropriate lens spacer (I don't know how to tell them apart!) in the barrel after the first element.
Step 7 through 19: Repeat steps 5 and 6 over again of the other lens elements.
Step 20: Screw retaining ring back onto bottom of lens barrel.
Step 21: Do a shake test. If something rattles, disassemble the unit and go back to step 2 and start over.
Step 22: If you have gotten this far, try the thing in a telescope. If it is not the same 27 Pan it was when you started, go back to step 2. If it works (ha, ha) you are done.

Directions if you want it to work (version 2):
Step 1: Call Televue, and arrange to have them do it.

They'll fix it for something on the order of $60 or $80 dollars....That price was from a few years back, though.

Alex

If you can skip the inverter, do so.

Every time you convert (or invert) energy, you lose something. SO, inverting a 12 volt from an RV, car, or special stand alone battery, into 110, and then back into 18, runs the battery down faster.

Of course, with a big enough battery, you can probably do one night easily whether you use a 110 inverter or not--but if you want to stay a few nights, etc. try skipping the 110.

Alex

Don't know if it is true--but it was on the internet!!

Alex

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE JACKSON KY
1145 PM EST FRI FEB 13 2009

...POSSIBLE SATELLITE DEBRIS FALLING ACROSS THE REGION...

THE NATIONAL WEATHER SERVICE IN JACKSON HAS RECEIVED CALLS THIS EVENING FROM THE PUBLIC CONCERNING POSSIBLE EXPLOSIONS AND...OR EARTHQUAKES ACROSS THE AREA. THE FEDERAL AVIATION ADMINISTRATION HAS REPORTED TO LOCAL LAW ENFORCEMENT THAT THESE EVENTS ARE BEING CAUSED BY FALLING SATELLITE DEBRIS. THESE PIECES OF DEBRIS HAVE BEEN CAUSING SONIC BOOMS...RESULTING IN THE VIBRATIONS BEING FELT BY SOME RESIDENTS...AS WELL AS FLASHES OF LIGHT ACROSS THE SKY. THE CLOUD OF DEBRIS IS LIKELY THE RESULT OF THE RECENT IN ORBIT COLLISION OF TWO SATELLITES ON TUESDAY...FEBRUARY 10TH WHEN KOSMOS 2251 CRASHED INTO IRIDIUM 33.

http://www.crh.noaa.gov/product.php?site=JKL&issuedby=JKL&product=PNS&format=CI&version=1&glossary=0

The rule is that off axis guiders are preferred when you have mirrors, and separate guidescopes are acceptable for fixed lens systems.

The problem with mirrors (either Newts or especially SCT's) is that the mirrors can slightly shift positions in their holders. This means that they are no longer pointing to exactly where the guidescope is pointed. If this happens while guiding, you have funny looking stars!!!!

You can have this problem with a refrator/guidescope combination when the mountings do not hold the respective scopes rigidly. It is called flexure. But with good mountings, it is not common. (You can also get flexure from inadequate focusers/drawtubes, heavy cameras, loose mounting screws, and whatever gremlins inhabit a system---Off axis guiding overcomes all types of flexure problems.)

In practice, with modern shorter exposures and very good mounting of the guide scope, the separate guidescope route is much easier to pull off. It also gets you a much wider selection of guidestars.

And many dedicated astro cameras have guide chips in the same head as the imaging chips, thus making the choice between Off axis guiding and separate guidescope unnecessary.

Alex

I really think that rather than add a new forum, appropriate questions should just be directed to the Equipment Forum up above.

If you make too many different Forums, you subdivide the audience to the point that it gets real small. And you won't find many people to answer.

Alex

Let's get a little more specific here--Just how big is this comet, from one end of the anti-tail to the other end of the tail?

I have been googling trying to figure this out, but the only number I have (and I do not know if it is accurate) is that the head of the comet is 20 arc minutes--which at one third of a degree sounds awfully large to me.....I'm wondering if they meant arc seconds.

Having said that-- I need to figure out which camera/tube (or camera/lens) combination to use on this thing.

Alex

That wasn't a modified Canon, was it?

Alex

Oh, I forgot to mention--I really liked the picture, also.

Alex

Could it be a substantially overexposed Saturn? The comet was near--although I do not think that near.

If you were to really stretch the comet, you would probably see the same blurring. However, since the comet is "blurry" in the first place, it would be hard to notice.

Alex

If you really want to go minimalist, simply buy the battery and connect a 12 volt receptacle to it. You can get the batteries that are the heart of the "Starter Packs" for about $20. Add the wires from a 12 volt receptacle (about $3-5), and a 12-14 volt wall wart (you probably have one around the house, but if not--$8-10). ANd you have it all for less than one of those starter packs. True, you do not have the all-in-one plastic case, but on the other hand, you are not taking up the extra room and weight.

Alex