Image of the day

Captured by
Douglas Rollain

M20 Trifid Nebula in LRGBHa

About Astromart

My Account

New to Astromart?

Register an account...

Need Help?

Posts Made By: Allen Tracht

June 6, 2005 07:41 PM Forum: Equipment Talk

Wide-field Complement to my C9.25

Posted By Allen Tracht
I appreciate all of your suggestions. In the meantime, however, I found a local FS-128 at a very reasonable price. I don't know if it complements the C9.25 or is just in a different league, but I think it will be great fun!

Just one item about it that bothers me: the straight-through finder. It's a great 7x50 finder, but it's nearly unusable more than 45 degrees above the horizon (even with my G11 tripod at full extension). Is there a reasonable right-angle replacment (even of lesser quality)?

Allen

June 14, 2005 03:42 PM Forum: Equipment Talk

Konus CG-5 mount and setting circles

Posted By Allen Tracht
I've only played with setting circles for a few hours some months ago, so take this with a grain of salt:

I'd bet that the locking ring tracks with the scope. In that was, it stays aligned with the stars. The second ring shows the position of the telescope relative to the stars.

So, I'd guess you aim at a known object and adjust the two rings until the 0/24 on one ring matches the RA of the object on the other ring. Then, lock the locking ring and don't touch the other. As you move the scope, the indicated RA should match the telescope's position.

Allen

June 14, 2005 03:45 PM Forum: Eyepieces

If I Already Have A Meade 32mm SWA Do I....

Posted By Allen Tracht
What is the maximum usable field of the C9.25 (unvignetted and vignetted)? Will the 40 suffer from vignetting?

Allen

June 28, 2005 03:06 PM Forum: Equipment Talk

Camera Mounts

Posted By Allen Tracht
Losmandy (a sponsor) has a dovetail plate that mounts to the top of the C9.25 to which you can mount camera mounts or rings, also available from Losmandy. I drilled and tapped holes in my dovetail plate for cleanly (without sticky tape) mounting my Telrad.

Allen

July 15, 2005 01:49 PM Forum: Equipment Talk

Shrinking a Telrad (long brainstorm)

Posted By Allen Tracht
After some careful thought (and thanks to all of your comments) I've got a plan:

1. Mount the pulser across from the dimmer control. There's just barely enough room and, even after trimming the circuit board, it still slightly (almost trivially) obstructs the lens. The details are gory, but it gets the bulky pulser out of the soon-to-be eliminated battery compartment. Almost done.

2. Replace the battery with a pair of coin cells in holders, one on each side of the optical path.

3. Shorten the Telrad and base to match.

4. Replace the pulser and dimmer controls with a custom microcontroller-based implementation. This should save power by eliminating resistive losses and give better control (eliminating the pulser's inherent 50% dimming).

Each of these steps is rather independent, so I can stop at any time. Step 4 is probably the most difficult, and the most fun.

July 15, 2005 09:12 PM Forum: Equipment Talk

Small multi-use refractor questions

Posted By Allen Tracht
My two cents:

Skip the finder. With such a small scope, and a reasonably low-power eyepiece, your FOV could easily be >4 degrees (maybe 6 or more).

Similarly, I'd skip the slow-motion controls. If the mount is reasonably smooth, they shouldn't be needed at reasonable magnifications.

For Astronomy:

I'd go for the larger aperture, if it otherwise fit my needs. 80 vs 66 mm gives almost 1.5x the light.

I don't know much about small mounts, but you should consider if a DSC like the compact Sky Commander can be fitted to it.

Allen

August 3, 2005 01:52 PM Forum: Equipment Talk

Finder Scope Blues

Posted By Allen Tracht
Consider a "dew shield plus" for the Telrad. The "plus" includes a mirror that allows right-angle use of the Telrad, eliminating the contortion, but it is a bit finicky to position correctly.

August 22, 2005 03:19 PM Forum: Equipment Talk

Telescope "buggy"

Posted By Allen Tracht
Whatever dolly you choose or build, you may also need a ramp to get it out of your garage or shed. My garage has a 1-3/4" lip (to keep the rain out) that is too far to let the mount drop when moving it out of the garage.

Allen

September 19, 2005 06:10 PM Forum: Equipment Talk

Low-profile tripod platform for an 8" truss dob?

Posted By Allen Tracht
I've seen an octagonal end table, from a thrift store, used as a base. The table's drawers and compartments were used to store accessories. It was bulky, but the owner had plenty of room in his van.

I didn't have so much room, so I rented a table saw for a day and built a stand from 1x3 firring strips. There were eight verticals between two octagonal rings, each made from 8 overlapping pieces. On my older Discovery DHQ, the rocker box was considerably smaller in diameter than the ground board, so my base could have the same OD as the ground board and have a large enough ID to nest over the rocker box for compact transport.

Sorry, but I don't have any pictures or drawings.

Allen

September 22, 2005 03:53 PM Forum: Pictures of Me and My Telescope and........

Re: Ugliest Scope Contest!

Posted By Allen Tracht
I just love that clock drive!

Funding Member

Sponsors


View all sponsors

Search