Posts Made By: Timothy Hornbeck

You can also get past posts by searching the fourms with your post title "First scope". I did and it returned a bunch of info.

Good luck.

Tim

Very nice job. I, too, am getting ready to start my 12.5" truss dob. It's an f/4.8, so it will be a little shorter. I like the mirror cell.

Thanks for the post and motivation.

Clear skies (and cold),

Tim H.

Have you replaced the battery recently? You can use a Zinc-Air battery to replace the "no longer" available mercury battery.

Here is a link to a great OM site:

http://www.mir.com.my/rb/photography/hardwares/classics/olympusom1n2/index.htm

Check out the message boards.

Good luck,

Tim Hornbeck

Thanks for all of the information. It sounds like the aluminum will work fine. The UO cell will be pretty much isolated from the frame that I am going to build. I was just concerned with the strength. The weight savings is always a plus.

Thanks,

Tim Hornbeck

I would have to question the 13 1/8" upper cage diameter. The program Newt or WinNewt says a tube diameter that size will vignette 75% of the ray at front aperture. The only reason this caught my eye is because I am also building a 12.5" truss. What is your focal ratio?

Here is the link to the software :

http://home.att.net/~dale.keller/atm/newtonians/newtsoft/newtsoft.htm

I would like to share some ideas, if you wouldn't mind. I am in the design phase.

- Tim Hornbeck

Found this from a Google search:

http://www3.telus.net/public/dfell1/astro/collimate.htm

SNIP ...
Some light will be reflected from each lens surface within the objective, although the reflection from the rear surface will probably be brightest. If the elements of the objective are accurately centered and collimated with respect to each other and have no wedge, all the reflections will coincide, forming one reflected spot. If there are multiple reflected spots, it is an indication of alignment problems within the objective. The collimator could then be used to diagnose and correct the inter-element misalignment.
SNIP....

This answers my question. I am going to try and rotate the objectives to get those two rings to join. I know someone with an auto-collimator device that aligns objectives. I may have them look at it too.

- Tim

Since you removed the focuser, you may want to check the collimation of the focuser to the lens, if you didn't already.

Clear skies,

Tim

If you do decide to purchase the CG-5GT and not stick with astrophotography, would you still find the CG-5 useful? In other words, would it have been a waste of your money? If no, then purchase it and give it a try. You have a wide range of astrophotography options i.e. prime focus, eyepiece projection, piggy back wide-field shots...

Dampen the legs with insulation foam and vibration surpression pads or replace with hardwood legs.

Experiment with them all and have fun. Learn with your Manual SLR and go from there. I am still in the learning stage too. I have produced some decent images and some not so good too. For example, I recently learned that 400ASA film through an f/3.5 lens at 150mm for 10 sec. exposure does not work. I'll never try this again after $12 in film and developing costs. Blew a whole roll.

Clear skies,

Tim Hornbeck

Awesome image! I love to count the back ground faint fuzzies. I lost track at 14+. Great details in the lower dust lane. You are one lucky guy to image at this facility.

More, more, more ....

- Tim Hornbeck

We must have been on the same wave length. You beat me to the punch. I hope this is correct.

Good luck,

- Tim Hornbeck