Ad Astra Observatory

Art Morton wrote:
> With a couple more moon nights you will have a perfectly calibrated G-11

I hope so; It really is a lot of new stuff to learn. Someday I’m going
to have to throw the Canon 300D into the mix, too. If I had enough
scopes to do it, I could in theory shoot 2 main images at once. I’ve
been wanting to do some piggybacked constellation shots…
> and the Newt is throwing stars that are in the ~ 1.72 4.x range for
> FWHM, or at least that is what I can get from the image you have sent me.
I’m not sure how good the FWHM in the original images are; The JPG is

stretched, unsharp masked, and most importantly resized (down) from the
original.
> That seems to be a fantastic improvement in focus …. at least the
> numbers are lower.
The focus distance between what FM came up with and my Mark II eyeball
was ~20 focuser step units. Effective.
> What size are the pixels on the Bayer matrix? It has to be large,

> 56 microns or so?
I think we’re both agreeing that the pixels are all 7.6mu, but that
since they come from a 2×2 square array and get interpolated, I’m
effectively using 15.2mu pixels.
> I am back to plotting angular resolution, point spread function,
> resolution….. and total madness.

I spent some time carefully measuring the focal distance from the MPCC
(and the WO FF/FR I got for the 66) to the CCD. Both flatteners are set
up for ~55mm (+/- 5%), and this is within tolerance of where I’m at with
both. I’m a little peeved at the curved field that I’m still getting
with the WO reducer; I might try adding a short spacer to see if that
helps. But the MPCC is really cooking. The field is *flat*.
> Why, a corrected newt 8” may be in order. I am quite excited to see

> that the stars in the corners of your images are quite round.
Did I send you the PNG? M51 is a tiny object; the corners of the JPG are
nowhere near the corners of the full frame. The stars at the corners of
the full frame are round, too, though. (:
> It is way to early in the season to have a scope so close to perfect
> for the new season…………… Don’t you need some more struggle.

More struggle, he says. 3 nights of fighting FM, trying to learn Max 5,
guider logs with 1” and 2” errors, building a lightbox for flats after
spending the afternoon cleaning optics, collimating in the middle of a
session… more struggle, he says. (:

So when are you coming down?

J