Posts Made By: Stephen Davies

Hello fellow astro enthusiasts!

I am currently building an observatory and am trying to determine the placement of my pier. The observatory is a 10' aluminum dome which will sit on top of an existing concrete block building which is roughly 13'x12'.

The pier is 88" high and the height of the block walls are 83". I am going to raise the base of the dome up about two feet above the 83" block walls to get better sight lines to avoid some obstructions in the view.

I am currently using an 8" LX200 with the equatorial wedge, but want this arrangement to be able to accomodate a different 'scope should I upgrade to a new telescope (larger SCT??).

Should the top of the pier be roughly level with (or maybe somewhat higher than) the base of the dome or am I mistaken? I will likely position the pier to be centered relative to the dome and will be constructing a subfloor at a convenient height(?) when I figure out the geometry I need.

I have not seen much useful information on positioning a pier within an observatory so any help would be greatly appreciated!

Thanks a lot, Steve

Hi Tom:

M$ Windoze associates the filename extension (ie, .jpg .doc .txt .gif) as "belonging" to a certain application, so that when you open any file with that extension, the associated application starts automatically. Unfortunately, sometimes that association gets changed from its original target program (the most common way this happens is that you install another program which can also open or utilize that type of file, and it "steals" the association).

The way you change it back varies somewhat with the version of windows you are using. Here is the Windows NT help text which describes how to change it back (in WIndows NT anyway).

Hope it helps, Steve
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To create or modify a file type

1 Double-click the My Computer icon.

2 On the View menu, click Options, and then click the File Types tab.
3 To create a new file type, click New Type.

To modify the settings for an existing file type, click the type, and then click Edit.

4 Specify a description for the file type and the filename extension associated with this type of file.
5 Click New to define an action for this file type.

If you are modifying an existing type, you can click the command in the Action box that you want to modify, and then click Edit.

6 Specify the action that you want to define, such as Open or Print, and the command that should run to complete this action.
7 Repeat steps 5 and 6 for as many actions as you want to define for this file type.

Short answer: I would go with the Oracle rather than a Pronto. Didn't have to think much about that! However, a TV76 is a closer competitor to the Oracle than the Pronto is.

The TV Oracle is a very nice 560mm f7.4 triplet apochromatic scope which has been out of production for many years. A number of years ago when this 'scope came out I really wanted one (but was a poor student so couldn't afford it).

The closest current TV scope would be the TV 76, which is also well colour corrected even though it is a doublet design, and has nearly identical aperature, but has a faster F ratio and shorter focal length (and the scope's OTA is quite a bit shorter than the Oracle also).

The Oracle had a thread-on dew shield, if I remember correctly, which is slightly annoying relative to other designs.

The Pronto on the other hand is not nearly as well corrected for colour as the TV76/Oracle, and has slightly less aperature.

My preference would be for a TV76, then the Oracle. I don't think I'd go for a Pronto as there are competitors out there (William Optical Megrez 80 series II, Borg 76ED, Tak FS60C/78 etc.) which offer either better performance, or better bang for the buck (IMHO). However, a Pronto is by no means a bad 'scope.

Steve

Tim:

Filter sizes (and locations) for the FS-102 are as follows:

67mm filter at the camera angle adjuster
48mm filter at the wide T-mount
48mm filter at the extension tube (2")
48mm filter at the diagonal mirror

This information is from the handy table hosted on the Anacortes site

http://www.buytelescopes.com/container.asp?dest=/manufacturers/takahashi/filter_selection.htm


Steve


Using Filters with Takahashi Refractors

Filters usable with the following models:
FS-60C 62mm filter at the objective cell
52mm filter at the camera angle adjuster
30mm filter at the C2X

SKY-90 95mm filter at the objective cell
48mm filter at the extension tube (2")
52mm filter at the camera angle adjuster
48mm filter at the wide T-mount
48mm filter at the diagonal mirror

FS-102/128N 67mm filter at the camera angle adjuster
48mm filter at the wide T-mount
48mm filter at the extension tube (2")
48mm filter at the diagonal mirror

FSQ-106 112mm for the objective cell

FS-152 48mm filter at the extension tube (2")
82mm filter at the tapered ring
82mm filter at the reducer
82mm filter at the flattener
82mm filter at the aux ring (prim focus)
48mm filter at the wide T-mount
48mm filter at the diagonal mirror

TOA-130 48mm filter at the extension tube (2")
48mm filter at the extender TOA 1.6x
48mm filter at the 35mm flattener
82mm filter at the 67 flattener
67mm filter at the F5.3 reducer adapter
48mm filter at the diagonal mirror
48mm filter at the wide T-mount

Common use: 28mm filter at the LE oculars; 48mm filter at the LE-50mm ocular; 48/49/52mm filters at the filterbox for the extender.

NOTE: Filters do not always fit as described due to the thickness of the anti-reflection coating on the screws.

Tim Carleton said:

I'm using the camera angle adjuster and the 5.9 reducer. What do i need to connect an Idas lpf to this setup? and I guess while I'm at it what size filter? Thanks, Tim

Rolando Chavez said:

These were taken with the C14.

Your planetary images and the animation of Jupiter on your link are terrific.

What camera are you using?