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Terry Wood

Jupiter (clearer) Nov 5th 2023 w/Mewlon 180c

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Posts Made By: John Biretta

August 3, 2010 12:28 PM Forum: Equipment Talk

Starting over - right approach questions...

Posted By John Biretta


I'd like something fairly portable.
I'd like something that I can share an experience with easily (my daughters are around 7).
I'd like something with at least an 8" aperture.
I'd like something that will track objects, but don't need GoTo.
Eventually...
I'd like to get into astro-photography.

Maybe something like a C8 on a CG5 mount. Purchased used, they would come
in well under your budget. For example,
http://www.astromart.com/classifieds/details.asp?classified_id=693598
http://www.astromart.com/classifieds/details.asp?classified_id=690421
I've used this setup and been fairly happy with it. I've seen good
and bad stuff from both Meade and Celestron -- don't think one
can decide much on the company name.




August 7, 2010 04:35 PM Forum: Solar System Observing

Learning Solar System Imaging

Posted By John Biretta

Spectacular! Keep it up!

August 8, 2010 08:32 PM Forum: CCD Imaging and Processing/Solar System

Jupiter 8 Aug 2010

Posted By John Biretta

Looks like my "average" seeing images, maybe better. Did you use some
sort of Barlow?

September 9, 2010 10:12 PM Forum: Digital SLR AstroPhotography

Milky Way Mosaic

Posted By John Biretta

This is really fantastic! Which version of the Nikkor 50mm is this?
F/1.4 AIS? AF? Its wonderful how all the nebulae stand out --
Veil, etc. You should post the full-resolution version somewhere.

September 10, 2010 10:44 AM Forum: Solar System Observing

First Jupiter with the new camera

Posted By John Biretta

Very nice! To get more detail on the planet, you'll want to
use a 2x to 3x Barlow lens. Focal ratios around F/25 to F/30
seem to work well.

September 13, 2010 12:22 PM Forum: Digital SLR AstroPhotography

Western Veil

Posted By John Biretta

Superb detail in the filaments! Fantastic!

September 13, 2010 12:35 PM Forum: Binoviewers

Are short imaging scopes better for binoviewing?

Posted By John Biretta

Binoviewer is going to need about 5.5 to 6 inches of back focus -- that
is the distance from the focuser at its inner most point to the focal
plane. Maybe 7 to 8 inches if you use a 90 degree diagonal (1.25 inch
or T type). Thats a lot of backfocus even for an imaging scope.
I don't think you can assume that a scope designed for imaging will
necessarily have enough backfocus for binoviewing. You really need
to check your binoviewer and then evaluate the scope specs.

There are lots of tricks to making binos work. Some eyepieces need
less backfocus -- that will help. A prism diagonal will help
(vs. a mirror model). You can pickup a few mm of backfocus by adding
clear filters or glass in the optical path. Weak Barlows help
-- 1.2, 1.4, 1.6x, etc. -- doesn't have to be 2x.

September 25, 2010 07:41 AM Forum: CCD Imaging and Processing/Deep Sky

M31 core

Posted By John Biretta

Beauty! Detail in dust lanes is striking. There's an obvious mosaic project here....

October 2, 2010 05:42 PM Forum: CCD Imaging and Processing/Solar System

I want to get started

Posted By John Biretta

Regarding the camera, I'd get the DFK 21, since it goes to
60 frames per second. The DFK 31 only goes to 30 fps which is
not enough in average seeing. I believe it also has somewhat
better noise performance. You don't really need the larger
DFK 31 chip unless you are planning to do mostly lunar
or solar observing. It takes more time to read the larger
chip -- mostly wasted time for planet observations. Only if
you have a large scope -- like 16" and excellent seeing,
would the larger chip become useful for Jupiter, etc.

As for computer, I'd get one with both USB and FireWire ports.
I tend to get the fastest frame rates if the images can be
stored somewhere that is not the internal main disk drive,
nor the same port the camera is atttached to. For example,
for a USB camera you might record the images to an external
FireWire drive. Some computers have the ability to attach
multiple internal drives, and that is another solution.
For example, some laptops have an expansion bay where you can
install a second hard drive for recording the images.

If you are going to process the images on the same computer,
you'll want a fast processor (dual core, 2 GHz or faster)
and lots of memory (2 GB or more). If you are just recording
with this computer, then somewhat less performance would be
OK.

It would also be best if the recording computer had as little
un-needed software on it as possible. If there are many
programs installed, there are probably many things running
in the background that will slow down the data recording.

Software: I like both Registax (free) and K3CCD (cheap)
for windows computers, but there are probably others that
work OK. My own experience is that K3CCD is somewhat better
at aligning the images, but Registax has more post-processing
features like wavelets. You'll also want some sort of
general image software like Photoshop for final adjustments,
etc. (Maybe you can find an old version of Photoshop
cheap somewhere. There are many other similar softwares
that work OK -- I sometimes also use Corel Paint Shop Pro
Photo.)

As for scope hardware, you'll want to run around F/25 to
F/30 which generally means some Barlow lens in front
of the camera. A flip mirror with cross hair
eyepiece (for centering the target) will also be extremely
helpful to have.

October 5, 2010 07:31 PM Forum: Refractors

Vixen Fluorite Design Question

Posted By John Biretta

I've star tested a bunch (5+) of the Vixen 102 FL, both the
Celestron and Orion versions. I can't say there was any
clear difference between the versions. All were superb.
I saw one or two of the Orion versions with some very minor
irregularity in the glass melt (i.e. striae or non-homogeneity
in the glass) that showed up in careful testing on an optical
bench, but not enough statistics to say if this is related to
Celestron vs. Orion versions. Would be happy to own any
of them. Very high performance per $$.