Posts Made By: James McSheehy

An anastigmat is corrected for spherical aberration, coma, and astigmatism. It may have varying levels of correction for chromatic aberration and/or spherochromatism.

Well, there are those $10 refractors with 60 mm plastic objectives...a 16" Dob with a plexiglass mirror should be a real treat for the senses. 8)

The TEC140 would be my choice. You'll get essentially perfect optics and the oil-spaced triplet design means no collimation worries. For AP they offer a readily available field flattener, and TEC's new focuser is among the best out there.

(I've owned a TEC refractor since 2008)

Astrositall has such a pretty color -- like frozen honey.

Probably more than you ever cared to know about import tariffs:

http://hts.usitc.gov/

If you look around, you may be able to find one of the old Cave Astrola GEMs. The larger ones were made with heavy, solid axels and bearings and they had an electric clock drive for RA.

http://www.telescopebluebook.com/reflector/astrola8dlx.jpg

That is an interesting area and climate, and your photo shows how it transitions from sunny and humid coastal to dry, high desert in the space of tens of miles. We're you able to take in any tours of CTIO or the public observatory near Vicuña?

I faced this decision a couple of years ago and decided to pack only a DSLR and a small tripod where both would fit in a standard carry-on bag. For my "astro" fix, we scheduled a visit to a public observatory where they had Dobs, a 12" SCT in a dome, and knowledgeable, bilingual guides to show us around the unfamiliar skies. This worked out well, and not having to lug around or worry about an expensive, delicate OTA was a net plus because on most days when darkness fell we were too tired to do much observing.

An alternative might be to pack something really small like an ETX-90, or for wide fields, a pair if Canon's IS binoculars.

I had an opportunity to take a few more test images with the Celestron Nightscape OSC camera. These are all from ten-minute guided subs using a TV85 refractor, 0.8X reducer, and IDAS LPS-P2 filter. Conditions were not the best, with some high thin clouds and a waxing moon low in the West. I had the camera TEC set at -20C and outside of three program crashes (AstroFX still has rough edges), the session went well.

Some have asked about the color binning modes of this camera and I tried all three modes on a section of the California Nebula. In this setup with the TV85, the base resolution at 1x1 binning is about two arc seconds per pixel, which roughly matches the typical seeing. The color binning definitely "works", but some odd artifacts appear in the 4x4 image, and at 8.5 arc seconds per pixel, the stars are starting to get rather blocky.

These image data were all captured and processed (minimally) in AstroFX:

California Nebula, 2 x 10 min (to demonstrate color binning modes)

1x1:
http://db.tt/F6zjyGEZ

2x2:
http://db.tt/msMGrOga

4x4:
http://db.tt/cMLCGyjA


At 1x1 binning:

M81 M82, 5 x10 minutes:
http://db.tt/cU2Gqr3e

Rosette Nebula, 3 x 10 minutes:
http://db.tt/qIy5QebO

The height would be a range of values depending on your latitude and the RA angle. The folks on this Yahoo group can probably give you the specifics:

http://tech.groups.yahoo.com/group/ap-gto/