Posts Made By: Thomas Davis

Butterscotch Life Saver?

Here is the wide field version (full frame) reduced to group rules size.

Tom

Robert,

I have one of the Baader 2" units, and it does have a shorter light path. After measuring it, it is only about 1/2" less, so I
don't know if that will be enough for your needs.

Tom

Jackie,

I owned a Vixen 115EDS last year. I eventually sold it when I got a larger refractor. My take was that it was an excellent telescope.

Only issue I noted was a slight shift of the color correction so that the red fell out a bit on bright yellow or red objects. Very
subtle, but there. Violet correction was such that I could see no discernible color. Overall, it gave excellent planetary and lunar
performance. I think the extra aperture would give an advantage over a Tak FS-102. Enough to be noticed. My point of comparison is
a TMB100/800 I own with an excellent test report from LZOS. The TMB has better color correction, but the extra 15mm gives the Vixen
a small advantage on planets. Going up to 130mm would make for a difference that would be clearly noted. A good used Tak FS128
might be a good choice. They come up for sale from time to time. There you would have a clear improvement over the 4", enough to
be worth the upgrade. Even though the 115EDS would show a noticed improvement over the 4", I think the extra inch would be enough
to make it worthwhile, with the 15mm possibly making you wish you had gone further.

The one advantage to the Vixen I liked was weight. It only weighs 9.7 lbs, making it useable on a relatively lightweight alt-az
mount. It made for a nice grab and go setup with my Unistar Deluxe mount. Now if portability and weight are issues, that could
make the 115EDS more desirable. I also understand that they now have a dual-speed focuser option on these scopes they did not have
previously.

Tom

Sounds like astigmatism. If the diagonal is not the culprit, looks like optics in the scope.

Jeff,

I used one with a Hutech modified Canon XS and an AP .75X focal reducer. I was very happy with the results.

I'm attaching a shot of M42 and the Running Man I took with it.

Tom

Jeff,

My AP130EDT F/8.35 had enough backfocus to use a binoviewer with no OCS. Where I see a problem is with the Optec focuser.
If the focuser has AP threads, this will all work, if not, the extra spacing on the reducer could create a problem. If the
distance is less, all you lose is compression. As you add spacing, the compression goes up, and the illumination goes down.
Might not be an issue with the smaller chip on the ST-10MXE, though. What I would worry about with that is how much it would
impact where you come to focus. My experience with other reducers (I had all the right adapters for the DSLR, so I did not
attempt to vary from recommended spacing), has been the focus point can change significantly with a difference as large as you
are discussing (close to an inch). I used the AP focuser with Feathertouch Micro adapter, and had zero issues nailing focus,
so if you found you needed to remove the Optec focuser from the mix, I don't think you will find it a real problem.

Tom

Mark Hansen said:

I've heard a rumor that I may get vignetting and distortion using an EOS clip-in filter and the Baader MPCC on my F/4 8" newt. Anybody using this or a similar setup without vignetting or other problems?

Thanks!

Mark,

I expect to get one delivered today. I don't have the Baader MPCC for my 8" F/4 Newt, but do have a TeleVue Universal Paracorr. I can hook up the filter up and see what I get with it. There is a possibility that vignetting occurs, as the light cone is steep at the F/Ratio.

Tom

Steve,

Very nice image. The galaxy resolves quite nicely.

Tom

Charles R Genovese, Jr MD said:

Light pollution limited exposures to only 3 minutes! FS 102 @f/6, 3minX10, moded XSI at 1600, unguided on my G11. Stacked in DSI, no flats or darks, then transferred to Registax 5, histogram streached and gamma curved, and only spent about 10 minutes processing!

Charles,

This is about all I can get without a filter from my place. A filter would help out enormously. I'm following up
this post with one I took last week with a similar scope (TMB100/800 at F/6 with an AP reducer) that will show what
an LPR filter can do. It allows for much longer exposures.

Tom