Category: Optics
Maintenance / Observing Reports / Optics
Re: RA driftage
Art Morton wrote: > All three of these images are fantastic and show that you are tuning > in. In either case here, your optics are quite good. The stars are > […]
Astro knowledge / ATM / Optics
big, fast, light
16” f/5 honeycomb mirror for $1500 According to the website, these optics are ~20% lighter than solid mirrors of comparable thickness. So this one might weigh only 20# instead of 26#. That […]
Gear / Maintenance / Optics
Pumpkin's field flattener — needs work
I bought a WO FF/FR for Pumpking, but I still need to figure out how to tune it. It’s still not quite right. Can’t use it as a widefield lens if the […]
Pumpkin – new field flattener
Pumpkin’s field flattener showed up last night. It’s a 0.8x reducer, too, which I didn’t really want, but I’m dealing with it. I didn’t do a great job at focusing (just eyeballed […]
Pumpkin field flattener / reducer?
I’m trying to decide if the curved field on the AT66ED is going to bug me or not. I think that it is. But the field flattener unit is also a focal […]
Pumpkin's huge FOV
It was clear last night, but the forest fires put up so much smoke that I couldn’t see anything in the way of stars. I just calculated Pumpkin’s FOV and compared that […]
Re: Pointing Model vs. Polar Alignment
Art Morton wrote: > > On Jun 9, 2008, at 9:13 AM, Jimbo S. Harris wrote: > >> Art Morton wrote: >>> I also have to find out how to handle that […]
Astro knowledge / Long Exposure Photography / Optics
Astrophotography: The "best" focal length
Astrophotography has a lot of legends and rumors floating around as regards focal length of scope. Since the focal length of the scope, size of the CCD, weight of the rig, and […]
Deep Sky / Gear / Long Exposure Photography / Optics
MPCC and coma correction
The MPCC is up there with the ST-4 as one of my Best. Astronomy. Purchases. Ever. My 8” f/5 Newt was almost worthless for DSLR photography before I added the MPCC. Now, […]
Astro knowledge / Deep Sky / Long Exposure Photography / Optics
Astrophotography in the slow lane
With most beginner astrophotography, a desire for fast optics (and the resulting short exposure lengths) is paramount. Unfortunately, fast optics necessarily mean wider FOV. This is not a problem when you have […]
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.