How-To's - South Florida Amateur Astronomers Association & The Fox Observatory
SFAAA is a registered non-profit educational amateur astronomy society located in Sunrise, Florida. Membership is open to anyone interested in any area of astronomy. See the Becoming a Member section for more information.
Fox Observatory
Area 51
Fakahatchee Strand
Kirby Storter
Websfaaa.com
SFAAA Newsletters
SFAAA Mar 2010...
SFAAA Feb 2010...
SFAAA Jan 2010...
Top Downloads
Polar Finder 314
SFAAA Observin... 290
SFAAA Membersh... 141

Home > Articles > How To's
Main Menu
How-To's

Have you ever put off learning or doing something that you know you should do because you were afraid to try it? Just curious about other guy's projects? How-to articles can show you how it's done - and they're written by guys who were exactly in the same boat you're in before they figured it out.



Loose Recticle in your Orion Polar Scope? PDF Print E-mail
Written by Charlie Hein   
Monday, 24 August 2009 20:33

Yes, if you have one of these things, we all do it - sooner or later, we loosen our polar scope recticle too much and it falls out and rolls around inside the polar scope. This makes polar alignment impossible - but it's very easy to fix! The trick is in understanding how the polar scope is put together... let's take it apart for a look.

The polar scope will easily unscrew from the mount. Once it's out, hold it vertically with the "eyepiece" side facing up and the "objective" side facing down, like so:



The "eyepiece" end of the polar scope unscrews. Remove it, and you will expose the loose recticle. At this point you can just empty it out into your hand if you'd like to have a closer look at it, although it's not necessary to completely remove it in order to fix your trouble unless for some reason the glass recticle lens itself has fallen out of its holder. More on this in a bit.

Here's a picture of the recticle itself:



Note that there's a larger "outside" ring that is the "holder" for the glass recticle, and a smaller ring that screws into the larger ring to secure the glass recticle lens in place. In the very unlikely event that this holder assembly has come apart, just drop the glass lens in place as shown and tighten the smaller ring into the larger ring with a small "jewelers" screwdriver until the recticle lens is snugly held in the metal "framework". Be careful not to over tighten the inside ring as you could shatter the recticle glass!

Just so you have an idea of what it looks like, here's a look at the back side of the recticle:



Now, the whole reason we're taking this thing apart in the first place is probably because we loosened one or more of the adjustment screws too much and the recticle assembly fell out as one piece. Fortunately this is an avoidable problem. The recticle is designed with a flange (or slot, or channel - pick the word you like) that will retain the recticle in place if we don't loosen it too much:



If you look down the disassembled polar scope towards the objective, it might look something like this:



In this case, note that one adjustment screw is way out (unscrewed) and one is not. This one screw was loose enough to allow the recticle to just fall right out. Notice that if it had not been loosened so far, the recticle would have still been held in place by the flange. Keep this in mind when you are adjusting the recticle for accurate centering later on.

However, now that the recticle *is* out, it might be prudent to loosen the other two adjustment screws so that they do not extend into the area that the recticle needs to fall into.

These adjustment screws require a 1.5mm allen key, by the way.

Once you've unscrewed the adjustment screws enough to clear the opening, just drop the recticle into the polar scope with this side facing you. Now that nothing is in the way, it should be pretty easy to get it right:



Now, tighten the adjustment screws up until the recticle is roughly centered in the housing. They should be tight enough to hold the recticle firmly in place, but definitely not "cranked down hard"! You could ruin your recticle if you over tighten it in this "holder"!

Once it's in place, it should look something like this:


Now that the recticle is back in its holder, you can thread the "eyepiece" back in, looking through the "eyepiece" and continuing to screw it in until the recticle is in sharp focus. Then just thread the whole polar scope assembly back into the RA axis of your mount. Problem solved!

Once the recticle is re-installed and we have the polar scope re-installed in the mount, we will definitely need to re-align the recticle to the RA axis of the mount. Accuracy is the name of the game at this stage - the more accurately the recticle is aligned, the better your chances are of getting really good polar alignments using the polar scope.

At this point, I could go through a discussion of the whole procedure for accurately lining up your recticle to the RA axis of your mount, but instead I'll direct you to one of the best explanations on the web for how to do this that I've ever found:

Instructions for aligning your polar scope recticle

Good Luck and Clear Skies!


Charlie

 
AutoStar Handset Repair PDF Print E-mail
Written by K.C. Kile, Sr.   
Saturday, 19 July 2008 10:00

Autostar Keypad Contact Repair
By K.C. Kile, Sr.

At some point in the life of your Autostar handset, it’s response to your input will most likely become less than desired. This may happen at the beginning when the unit is new, or appear after several years of use. The first instinct is to open the handset and clean the pads and contacts with alcohol. This is a definite NO-NO. Although your cotton swab will become black with material that you attribute to the problem, performance of the handset will be further degraded, as you have just removed the substance apparently used to insure good contact. I have found the most effective repair to be obtained from the Chemtronics CW2605 Rubber Keypad Repair Kit shown in Figure 1. This kit can generally be purchased from major electronic parts supply stores for under $15 and is of sufficient quantity to do approximately 20 handsets. The down side is that it only has a 72 hour pot life after mixing. DO NOT attempt partial product mixing to conserve!

Figure 1
Figure 1

Read more...
 
Wireless Telescope to Computer Interface - A Wi-Fi Based Solution PDF Print E-mail
Written by Monroe Pattillo   
Tuesday, 20 May 2008 13:11
Wireless Telescope to Computer Interface – A Wi-Fi Based Solution by Monroe Pattillo
President, South Florida Amateur Astronomers Association (www.sfaaa.com)

This is the second of two articles on wireless telescope to computer interfaces.The previous article focused on Bluetooth.This article focuses on a Wi-Fi based solution.

As in the previous article the goal was to replace the RS-232 computer to telescope interface cable with a wireless interface.The justification was to eliminate a cable trip hazard in the dark and to reduce, at least by one, the number of cables connecting the computer to the telescope (still currently need a cable to connect the camera mounted on the telescope to the computer, but I’ll get to that one eventually).By eliminating the telescope to computer interface cable set up and teardown times are also reduced since you don’t have to take the time to use a long cable so that you can route it carefully down to and along the ground to avoid the creation of a waist height trip in the dark hazard.

Read more...
 
Wireless Telescope to Computer Interface - A Bluetooth Based Solution PDF Print E-mail
Written by Monroe Pattillo   
Tuesday, 20 May 2008 13:03


Wireless Telescope to Computer Interface – A Bluetooth Based Solution by Monroe Pattillo President, South Florida Amateur Astronomers Association (www.sfaaa.com)

The goal was to replace the RS-232 computer to telescope interface cable with a wireless interface.The justification was to eliminate a cable trip hazard in the dark and to reduce, at least by one, the number of cables connecting the computer to the telescope (still currently need a cable to connect the camera mounted on the telescope to the computer, but I’ll get to that one eventually).By eliminating the telescope to computer interface cable set up and teardown times are also reduced since you don’t have to take the time to use a long cable so that you can route it carefully down to and along the ground to avoid the creation of a waist height trip in the dark hazard.

Read more...
 
LX-200 GPS Disassembly and Repair of the Right Ascension Gears PDF Print E-mail
Written by K.C. Kile, Sr   
Monday, 19 May 2008 17:23

LX-200 GPS Disassembly and Repair of the Right Ascension Gears

By K.C. Kile, Sr.

Two years after the purchase of my LX-200 GPS I began to have slippage on the R.A. slow motion control at various points of rotation. As there was no information available from publication on the Internet and the telescope was out of warranty, I was hesitant in doing or having repairs made. This was a mistake as things only became worse, and eventually the R.A. rotational stops failed. Realizing that this would cause subsequent failure of the wiring due to excessive twist between the base and the fork arms, I had no choice but to either send the scope back to Meade or attempt repairs myself. Due to shipping and potential repair costs, I chose the latter.

Read more...
 


Latest Downloads
SFAAA Mar 2010 New...
SFAAA 2010 Electio...
SFAAA Feb 2010 New...
SFAAA Jan 2010 New...
2010 Rise-Set Tabl...
Voice your Opinion!
Imaging or Visual?
SFAAA Events
Sat, Mar 20th, @7:00pm - 11:59PM
Saturday Night Public Viewing
Sat, Mar 27th, @7:00pm - 11:59PM
Saturday Night Public Viewing