Category: Optics
Trixie's on the way
I bought a 13.1” f/4.5 mirror and matched 3.1” secondary today for $400. It used to be a Coulter red-tube Dob, but I’m just getting the mirrors. They will turn into the […]
Re: my first MaxDSLR photo run
On Feb 27, 2008, at 8:53 AM, Jimbo S. Harris wrote: > At 08:24 AM 2/27/2008 -0800, you wrote: >>> It seems to be able to do FIT, TIF, or RAW. If […]
RE: astrophotography
Hi Jimbo, Ahh, I am sorry, of course that doubleing the f/number is two stops difference! It must be this flue that is consuming my brain cells… 😉 Under one of your […]
Deep Sky / Gear / Long Exposure Photography / Optics
M42, The Great Orion Nebula
A ho-hum version of M42. The FOV on Pumpkin is really too side for this target (I had the whole Sword of Orion in the FOV. vertically.) but I was having fun […]
Astro knowledge / Deep Sky / Gear / Long Exposure Photography / Observing Reports / Optics
M42, The Great Orion Nebula
fullsize image I finally decided to try out Veronica (the 8” f/5 Newtonian) in the observatory, instead of the ED80. The reflector has two distinct advantages over the ED80; first, it’s about […]
Re: MPCC hyperbolic mirror overcorrection factor
Dear Mr. Harris, we are sorry but it is very unlikely that our MPCC will work for your telescope. At first it is not calculated for f3.3, maybe it is possible to […]
Astro knowledge / Deep Sky / Gear / Long Exposure Photography / Optics
M27, The Dumbbell Nebula in Vulpecula
It was this image that convinced me that I needed to do the filterectomy on the Nikon D70. According to S&T, The Dumbbell, The Coathanger, and Albireo form an equilateral triangle.
Re-2: MPCC hyperbolic mirror overcorrection factor
Dear Mr. Harris, if you decide to reduce your usable field to APS-sized CCD’s it may be ok with 38mm free lens diameter in terms of vignetting and with acceptable spot-size down […]
Re: scientific journal article
Some colleges or their libraries subscribe to sites that supply scholarly articles. I need a copy of the second article on the following list: http://scholar.google.com/scholar?q=Anastigmatic+catadioptric+telescope&ie=UTF-8&oe=UTF-8&hl=en&btnG=Search However, all I can get is an […]
Re: scientific journal article
Lemme know if this doesn’t help. D <http://scholar.google.com/scholar?q=Anastigmatic+catadioptric+telescope&ie=UTF-8&oe=UTF-8&hl=en&btnG=Search> — “Jimbo S. Harris” <jimbo@jimbo.net> wrote: > D, > > Do you know how I can find this… cheaply? > > Title: > Anastigmatic […]
RECENT UPDATE
Polar Alignment Calculations
Here’s a page that derives Polar Alignment Calculations. (update 5/2020: the original site is gone, so I found the text on Wayback and am inserting it below. This is by the original […]
Gear / Observatory / Telescope
Special Guest Star takes the mount at Hilltop O
The Astro Jedi needed somewhere to store his light sab—- I mean, bucket, and I was only too happy to accommodate him. I have decided that I need to come to a […]
General / Maintenance / Observatory
Dome shutter is motorized again!
I finally decided to bite the bullet and fix the shutter motor. Things went sideways last winter, and I’ve been opening the shutter manually (and tying it shut with rope, so we […]
Trixie 2017 – tube mods
I finally got around to cutting the MTA-UTA tubes to length; the only eyepiece that would come to focus with the focuser spacer in place is the Televue 55mm Plossl. If I […]
MOST COMMENTED
Observatory
Observatory 2.0 – Time has come today!
General / Maintenance
First Light, a deeper look
Mount / Observatory / Telescope
Observatory 2.0 – Result!
Observatory
Observatory 2.0 – The Pier goes in
Gear / General / Maintenance
Martin Farmer Wormblock installation notes
Deep Sky / Long Exposure Photography
NGC2244, The Rosette Nebula
Deep Sky / Long Exposure Photography
Another beautiful night.