[phpBB Debug] PHP Notice: in file /viewtopic.php on line 988: date(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected the timezone 'UTC' for now, but please set date.timezone to select your timezone.
[phpBB Debug] PHP Notice: in file /viewtopic.php on line 988: getdate(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected the timezone 'UTC' for now, but please set date.timezone to select your timezone.
[phpBB Debug] PHP Notice: in file /includes/functions.php on line 4284: Cannot modify header information - headers already sent by (output started at /includes/functions.php:3493)
[phpBB Debug] PHP Notice: in file /includes/functions.php on line 4286: Cannot modify header information - headers already sent by (output started at /includes/functions.php:3493)
[phpBB Debug] PHP Notice: in file /includes/functions.php on line 4287: Cannot modify header information - headers already sent by (output started at /includes/functions.php:3493)
[phpBB Debug] PHP Notice: in file /includes/functions.php on line 4288: Cannot modify header information - headers already sent by (output started at /includes/functions.php:3493)
Webster Telescopes Forum • View topic - Owner's Manual Secondary Mirror Holder Section
Webster Telescopes Forum
A Frendly Place for Serious Astronomers
It is currently Thu Mar 28, 2024 8:42 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 9 posts ] 
Author Message
 Post subject: Owner's Manual Secondary Mirror Holder Section
PostPosted: Fri Apr 15, 2011 3:42 pm 
Offline

Joined: Thu Jul 02, 2009 11:48 am
Posts: 80
Location: Detroit Michigan
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.

_________________
Eric Webster
http://www.WebsterTelescopes.com


Top
 Profile Send private message  
 
 Post subject: Re: Owner's Manual Secondary Mirror Holder Section
PostPosted: Fri Apr 15, 2011 4:09 pm 
Offline

Joined: Thu Jul 02, 2009 11:48 am
Posts: 80
Location: Detroit Michigan
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.


Attachments:
SECONDARY HOLDER START.jpg
SECONDARY HOLDER START.jpg [ 53.4 KiB | Viewed 11295 times ]

_________________
Eric Webster
http://www.WebsterTelescopes.com
Top
 Profile Send private message  
 
 Post subject: Re: Owner's Manual Secondary Mirror Holder Section
PostPosted: Fri Apr 15, 2011 4:26 pm 
Offline

Joined: Thu Jul 02, 2009 11:48 am
Posts: 80
Location: Detroit Michigan
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.


Attachments:
COWL.jpg
COWL.jpg [ 59.3 KiB | Viewed 11295 times ]

_________________
Eric Webster
http://www.WebsterTelescopes.com
Top
 Profile Send private message  
 
 Post subject: Re: Owner's Manual Secondary Mirror Holder Section
PostPosted: Fri Apr 15, 2011 4:36 pm 
Offline

Joined: Thu Jul 02, 2009 11:48 am
Posts: 80
Location: Detroit Michigan
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.


Attachments:
DEW-HEATER-DETAIL.jpg
DEW-HEATER-DETAIL.jpg [ 59.03 KiB | Viewed 11294 times ]

_________________
Eric Webster
http://www.WebsterTelescopes.com
Top
 Profile Send private message  
 
 Post subject: Re: Owner's Manual Secondary Mirror Holder Section
PostPosted: Fri Apr 15, 2011 4:41 pm 
Offline

Joined: Thu Jul 02, 2009 11:48 am
Posts: 80
Location: Detroit Michigan
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.


Attachments:
SECONDARY-MIRROR-IN-PLACE.jpg
SECONDARY-MIRROR-IN-PLACE.jpg [ 61.83 KiB | Viewed 11294 times ]

_________________
Eric Webster
http://www.WebsterTelescopes.com
Top
 Profile Send private message  
 
 Post subject: Re: Owner's Manual Secondary Mirror Holder Section
PostPosted: Fri Apr 15, 2011 5:28 pm 
Offline

Joined: Thu Jul 02, 2009 11:48 am
Posts: 80
Location: Detroit Michigan
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.


Attachments:
DEW-HEATER-INSERT.jpg
DEW-HEATER-INSERT.jpg [ 33.7 KiB | Viewed 11294 times ]

_________________
Eric Webster
http://www.WebsterTelescopes.com
Top
 Profile Send private message  
 
 Post subject: Re: Owner's Manual Secondary Mirror Holder Section
PostPosted: Fri Apr 15, 2011 5:30 pm 
Offline

Joined: Thu Jul 02, 2009 11:48 am
Posts: 80
Location: Detroit Michigan
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.


Attachments:
ASSEMBELED-SECONDARY-HOLDER.jpg
ASSEMBELED-SECONDARY-HOLDER.jpg [ 59.56 KiB | Viewed 11294 times ]

_________________
Eric Webster
http://www.WebsterTelescopes.com
Top
 Profile Send private message  
 
 Post subject: Re: Owner's Manual Secondary Mirror Holder Section
PostPosted: Fri Apr 15, 2011 5:32 pm 
Offline

Joined: Thu Jul 02, 2009 11:48 am
Posts: 80
Location: Detroit Michigan
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.


Attachments:
CONNECT-POWER.jpg
CONNECT-POWER.jpg [ 22.46 KiB | Viewed 11294 times ]

_________________
Eric Webster
http://www.WebsterTelescopes.com
Top
 Profile Send private message  
 
 Post subject: Re: Owner's Manual Secondary Mirror Holder Section
PostPosted: Fri Apr 15, 2011 5:35 pm 
Offline

Joined: Thu Jul 02, 2009 11:48 am
Posts: 80
Location: Detroit Michigan
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.


Attachments:
COMPLETED-INSTALLATION.jpg
COMPLETED-INSTALLATION.jpg [ 19.49 KiB | Viewed 11294 times ]

_________________
Eric Webster
http://www.WebsterTelescopes.com
Top
 Profile Send private message  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 9 posts ] 

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 17 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron
ClassyDark by ayasha : © 2007 Stargates Styles
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group