Jump to content


Photo

Astro-Video Systems reducers on NextStar 8SE SCT

  • Please log in to reply
8 replies to this topic

#1 John59

John59

    Viking 1

  • *****
  • Posts: 512
  • Joined: 06 Nov 2011
  • Loc: Round Rock,TX

Posted 13 January 2014 - 10:08 PM

Hi all,
I received a new reducer that is configurable from Astro-Video Systems.
The reducer is specifically designed for the Astro-Video Systems camera so I cannot tell you how it would function with any other camera.
Essentially with a set of included spacers with the reducer I am able to configure several different reductions.
In the following posts I will show M42 taken with my NextStar 8SE SCT with a native F10 and the various reductions.
In all the following I was not trying to get perfect captures just enough to show the reduction settings.
It took me 6 hours in 40 degree weather to set up and tear down three different telescopes to collect all the video and stills to see how well this reducer worked.
For me this is definitely a must accessory with these cameras.
Sorry for the repeat. Just wanted everyone to get all the information in case they did not see the other posts with different telescopes.
This first is with native F10

Attached Files



#2 John59

John59

    Viking 1

  • *****
  • Posts: 512
  • Joined: 06 Nov 2011
  • Loc: Round Rock,TX

Posted 13 January 2014 - 10:12 PM

Here is .63

Attached Files



#3 John59

John59

    Viking 1

  • *****
  • Posts: 512
  • Joined: 06 Nov 2011
  • Loc: Round Rock,TX

Posted 13 January 2014 - 10:14 PM

Here is .45

Attached Files



#4 John59

John59

    Viking 1

  • *****
  • Posts: 512
  • Joined: 06 Nov 2011
  • Loc: Round Rock,TX

Posted 13 January 2014 - 10:16 PM

And last here is the last one at .28
It begins to show some slight comma but not enough to make it unusable.
This configurable reducer really breathes new life in my NextStar 8SE and I am really looking forward to using it more.

Attached Files



#5 GlennLeDrew

GlennLeDrew

    Voyager 1

  • *****
  • Posts: 10823
  • Joined: 17 Jun 2008
  • Loc: Ottawa, Ontario, Canada

Posted 14 January 2014 - 09:28 AM

Have you verified whether or not there is aperture reduction occurring for the more aggressive reduction setting? If this is happening, your f/ratio is not as fast as thought. For example, suppose that at a reduction factor of, say, 0.38X you are just hitting the threshold where aperture clipping commences. At further reduction ratios aperture clipping could possibly be keeping you at about f/3.8 (on an f/10 scope.) And so you would only be buying increased field, without a gain in image surface brightness.

There are different ways to check on aperture clipping.

The simplest? With the system at infinity focus, simply peer down into the front opening of the scope. What you're looking for is this... The center of the CCD *must* be visible all the way to the edge of the objective. On a Cat, this is the primary mirror. If the chip's center is hidden behind some baffle or other aperture stop *before* your sight line has reached the Morris's edge, aperture loss is occurring. The only 'difficulty' is estimating the CCD's center when part of it is hidden by a baffle.

You will want to use a flashlight to see down into that dark hole. :grin: And a finder scope or 1/2 a bino will magnify the view nicely, which becomes more desirable as system focal length increases. Note that be because the chip is at the focus, the objective collimates its image; your auxiliary viewer will have its own focus set to infinity--no need for a special close-focus device!

#6 KJL

KJL

    Ranger 4

  • *****
  • Posts: 343
  • Joined: 06 Jun 2012
  • Loc: Boston, MA

Posted 25 January 2014 - 11:00 PM

Is this equivalent to finding an eyepiece + extension combo that comes to infinity focus at the same point as the camera sensor, then using your laser/led test through the EP to directly measure the aperture reduction?

Maybe that would be easier to test for the OP.

#7 Dragon Man

Dragon Man

    Vanguard

  • *****
  • Posts: 2061
  • Joined: 07 Mar 2006
  • Loc: Snake Valley, Australia

Posted 26 January 2014 - 01:20 AM

The reducer is specifically designed for the Astro-Video Systems camera


How is this done? I wasn't aware that Optical companies would go to the trouble of designing and making specific optical items for other small Vendors.
Not saying you are making up stories or just giving advertising hype, but I find it interesting that an optical company would re-design, tool-up, and manufacture for small companies when some won't even change anything for large companies willing to place very large orders.

Or are they standard Focal Reducers chosen 'because' they perfectly match the AV camera?
I am interested, not nit-picking, because I make my own focal reducers.

#8 John59

John59

    Viking 1

  • *****
  • Posts: 512
  • Joined: 06 Nov 2011
  • Loc: Round Rock,TX

Posted 26 January 2014 - 02:35 AM


The reducer is specifically designed for the Astro-Video Systems camera


How is this done? I wasn't aware that Optical companies would go to the trouble of designing and making specific optical items for other small Vendors.
Not saying you are making up stories or just giving advertising hype, but I find it interesting that an optical company would re-design, tool-up, and manufacture for small companies when some won't even change anything for large companies willing to place very large orders.

Or are they standard Focal Reducers chosen 'because' they perfectly match the AV camera?
I am interested, not nit-picking, because I make my own focal reducers.

The creator, Matt, would have to give the exact details. I am only passing along what I know of them.
I am just an end user who is satisfied with the results that I am seeing.
I can tell you that I have another .5 reducer that shows a significant of comma when when I try to use it with this camera or my StellaCam III.

#9 Dragon Man

Dragon Man

    Vanguard

  • *****
  • Posts: 2061
  • Joined: 07 Mar 2006
  • Loc: Snake Valley, Australia

Posted 26 January 2014 - 04:37 AM

Thanks John.






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics