Webster Telescopes Forum http://webstertelescopes.com/forum/ |
|
Owner's Manual Secondary Mirror Holder Section http://webstertelescopes.com/forum/viewtopic.php?f=7&t=594 |
Page 1 of 1 |
Author: | Eric [ Fri Apr 15, 2011 3:42 pm ] |
Post subject: | Owner's Manual Secondary Mirror Holder Section |
Here is the rough draft for the Secondary Mirror Holder (SMH) section in the new owner's manual. Give it a read a make sure that it makes sense to all of you. Like always we welcome your comments and suggestions for improvement. |
Author: | Eric [ Fri Apr 15, 2011 4:09 pm ] | ||
Post subject: | Re: Owner's Manual Secondary Mirror Holder Section | ||
First start off with a clean, well lilt place to do your assembly. A kitchen table with a clean, light colored towel is ideal. Leave the Mirror itself wrapped up until you actually need it. We show an optional dew heater installation also, although many do not need one.
|
Author: | Eric [ Fri Apr 15, 2011 4:26 pm ] | ||
Post subject: | Re: Owner's Manual Secondary Mirror Holder Section | ||
The Cowl holds the mirror upside down over the primary. It has to fit just slightly loose as to not constrict the expansion and contraction of the Mirror, but not so loose as to let the mirror drop on the primary.
|
Author: | Eric [ Fri Apr 15, 2011 4:36 pm ] | ||
Post subject: | Re: Owner's Manual Secondary Mirror Holder Section | ||
Here is a detailed view of a typical Dew Heater. The Dew Heater has heating elements that touch the back of the mirror. Never use silicone glue to attach the heater to the mirror. Silicone is an excellent insulator and will block the transfer of heat (that is why those thin, silicone oven gloves allow you to grab a 450 degree pan from the oven without feeling any heat). The Secondary Holder Stalk has a slot to allow the wires to exit the Secondary holder: 1. One wire is the Black Negative, it threads onto one of the collimation knobs. 2. One wire is the Red Positive. 3. One is the Ambient Temperature Sensor - it reads the actual air temperature. 4. One is the power LED - it lights when the Heater senses the need for heat.
|
Author: | Eric [ Fri Apr 15, 2011 4:41 pm ] | ||
Post subject: | Re: Owner's Manual Secondary Mirror Holder Section | ||
Next we have the big moment, the installation of the mirror itself. Wash your hands and carefully unwrap the mirror. Slide it face up into the holder and nudge it all the way forward. Again, do not glue the mirror in place. It needs to have room to expand and contract freely without restriction.
|
Author: | Eric [ Fri Apr 15, 2011 5:28 pm ] | ||
Post subject: | Re: Owner's Manual Secondary Mirror Holder Section | ||
Next slip in the Dew Heater. Now add the Fluff. Adding the Fluff is a little of a black art. You need enough to hold the mirror in place, but not enough to introduce astigmatism. Large mirrors over 4.5" will also have a foam wedge to use up some of the void. An old rule of thumb is that if you carefully shake the assembled holder, and it just barely moves, you have the right amount of fluff.
|
Author: | Eric [ Fri Apr 15, 2011 5:30 pm ] | ||
Post subject: | Re: Owner's Manual Secondary Mirror Holder Section | ||
Put the Stalk into the Cowl and install the four Phillips screws. Make note that any wires cleanly exit out of the slot, with none of them binding between the Cowl and Stalk.
|
Author: | Eric [ Fri Apr 15, 2011 5:32 pm ] | ||
Post subject: | Re: Owner's Manual Secondary Mirror Holder Section | ||
Thread off the top nut and washer and install the holder into the spider. Connect the Red Heater Wire to the wire coming from the spider vane with the included wire nut. Avoid the temptation to solder the Red wire, because you will not be able to easily remove the secondary holder for service or storage.
|
Author: | Eric [ Fri Apr 15, 2011 5:35 pm ] | ||
Post subject: | Re: Owner's Manual Secondary Mirror Holder Section | ||
Finally tuck all of the wires out of the light path so they do not block any of the incoming light. Place the Red LED wire on the opposite side of the focuser, so it does not flood the eyepiece with red light.
|
Page 1 of 1 | All times are UTC - 5 hours [ DST ] |
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group http://www.phpbb.com/ |