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Altair 8" f/4 Imaging Newtonian
Submitted: Tuesday, 19th April 2011 by Francis Milsom

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Altair 8" f/4 Imaging Newtonian

Paul Temple's recent review of the 8-inch f4 scope he purchased inspired me to write a review of mine.

I too have purchased one of these and from the description it sounds the same configuration with an internally baffled tube, mirror fan etc… just a different badge!

Mine was purchased from Altair Astro in the UK with the following specs:

  • Altair 200mm F4 Imaging Newtonian features:
  • Very fast f/4 focal ratio 200mm optics (800mm focal length).
  • Contrast-enhancing extended tube length with 15 internal baffles. 
  • Oversize secondary mirror to cover a 35mm CCD frame.
  • Built-in cooling fan for faster primary mirror cool-down.
  • 2" dual-speed Crayford focuser with 2" & 1.25" compression ring.
  • Light weight OTA - 8" of aperture weighing only 9.8kg (21.6 lbs).
  • Tube length only 32”
  • "No tools required" collimation knobs.
  • 8 x 50mm finder scope in a quick-release bracket.
  • Dual mounting rings.
  • Silicon dioxide mirror coating for extreme durability.
  • Lower-than-glass expansion B270 mirrors, free of internal stress.

I have mounted mine along with a WO ZS 80 EDII refractor, guide scope and a 135mm camera lens mounted on a Mintron camera, which acts as an electronic finder, all on an NEQ-6 goto mount and permanent pier.

It came well packaged and only required the collimation adjusting. I purchased mine as a photography only scope and obtained a Baader MPCC corrector/flattener with the scope.

The only negative (for me) I found was the length of the mounting saddle plate supplied with the scope. This was substituted very early on for a longer saddle plate (home made) giving a tube ring spacing of about half the overall tube length, and substantial enough to mount the other optics on the same saddle plate.

Everything else has been a plus.


Click to Enlarge
Altair 8" f/4 Imaging Newtonian

Click to Enlarge
Altair 8" f/4 Imaging Newtonian

I shoot using modified and standard Canon DSLR’s which I mount on the 8-inch and ZS 80 and focus using the live view feature on a laptop screen.

Collimation has been solid even given that I tend to flick from one object to another frequently making the mount do meridian flips.

The Baader MPCC corrector does exactly what it say’s on the box and stars are sharp right across the APS-C sized chips on the 450D and 500D cameras.

The image below is a full frame showing part of NGC 7000 shot on Saturday morning about 0300-0400 hrs and is a stack of 6 ten minute frames at ISO 800 using the modified 450D. All processing in PS CS-3.

My only other concern at the moment is that I intend starting to shoot LRGB images using narrow-cut filters and the need to use a coma corrector / flattener may cause back focus problems if I use a filter wheel - still researching this aspect.


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Review by Francis Milsom (ngc891). Discuss this review on the IceInSpace Forum.
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