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Istar apo

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#1 telescopemullet

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Posted 14 July 2013 - 11:34 PM

Purchased a forfax apo yesterday from Mike at the SCAE: This is one incredible scope. Photos and details to follow. First night was an eye opener.
 

#2 mikey cee

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Posted 15 July 2013 - 10:29 AM

Mullet you obviously didn't hear a word the critics have said. That scope can't be any good. :whistle: Mike
 

#3 Kunama

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Posted 15 July 2013 - 05:57 PM

Mullet you obviously didn't hear a word the critics have said. That scope can't be any good. :whistle: Mike


??????

Looking forward to seeing the pictures and report on this one.
 

#4 NHRob

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Posted 15 July 2013 - 06:37 PM

need 1st light report!!
 

#5 Kunama

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Posted 15 July 2013 - 07:01 PM

Pics ...... where are the pictures ! :question:
 

#6 telescopemullet

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Posted 15 July 2013 - 10:16 PM

Scope is acclimating now, this is a brand new 140 forfax.

This is a very well built scope, solid. Focused is an IStar as well, no complainants there, not a FT but still good. Report to come tomorrow.
 

#7 jrbarnett

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Posted 15 July 2013 - 10:47 PM

What are the specs on the scope (doublet or triplet? glass types used? focal ratio? etc.). Also are there any spot diagrams for the optic? I didn't see a "Forfax" listed on the Istar website. Is it maybe a discontinued or a newly introduced model? 140mm is a nice portable, but still large (for a refractor) aperture.

- Jim
 

#8 telescopemullet

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Posted 15 July 2013 - 11:47 PM

Moon...there was a very slight yellow tint on the edge of the limb when using celestron eyepieces, the pre luminos versions, i forget their names. When switched to televue naglers, absolutely color free views, a very bright moon against a very dark background. Color free down to 9mm which is where I stopped on the magnification. Shadows were very dark and crisp. I did not press the issue with my planetary eyepieces as the atmosphere is still not allowing more magnification.

This scope is easily handled by the g11, vibrations well less than 1 second, focusing manually not an issue.

The triplet is very heavy, but again, g11 is taking this scope in stride.
 

#9 Kunama

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Posted 15 July 2013 - 11:53 PM

What are the specs on the scope (doublet or triplet? glass types used? focal ratio? etc.). Also are there any spot diagrams for the optic? I didn't see a "Forfax" listed on the Istar website. Is it maybe a discontinued or a newly introduced model? 140mm is a nice portable, but still large (for a refractor) aperture.

- Jim


Istar used to do a 140mm F12 (LTT140 ?) I think there was a review on CN last year, I assume this is the same scope.
Very long at 1680mm FL so would have quite a moment arm and need a solid mount.
There was one on Astromart for $2500 last year from memory.
Good luck with your new scope Mullet.

Number of Elements: 3
Type: Super Apochromatic Triplet
Lens Coating: Full Multi-Coated
Clear Aperture: 140 mm (5.5 inches)
Lens Diameter: 144 mm
Focal Ratio: f/12
Focal Length: 1680mm
OTA Weight: 13.9 kg - 30.6 lbs. (including focuser reduction and cap)
 

#10 telescopemullet

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Posted 16 July 2013 - 12:09 AM

That is the model I purchased. Moment arm is not that big of a deal, but then I have been using my 150 f15 for a while now and this apo is much shorter.
 

#11 timps

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Posted 16 July 2013 - 04:16 AM

I contacted Istar earlier this year, enquiring about their
Apo's. They told me Istar no longer make Apo's.
 

#12 SteveG

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Posted 16 July 2013 - 05:34 PM

Here's a thread from last year regarding the Forfax:
http://www.cloudynig...5680526/Main...
 

#13 telescopemullet

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Posted 17 July 2013 - 11:17 AM

I have been observing Saturn last two nights and comparing the view with my CPC1100. The atmosphere has been pretty sloppy here so I was only able to get down to my 7.5 Tak LE on the APO. Tried to employ a 5mm Mono but it was too much. Saturn is crisp and no false color at all. Colors seen on planet are exact as seen in the CPC 1100, details are plainly evident and comparable to the CPC being that the CPC does not take magnification as well as the refactor.

Going to get some deep sky next.
 

#14 mgwhittle

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Posted 17 July 2013 - 01:37 PM

When you say the CPC doesn't take magnification as well as your new Istar, what exactly do you mean?
 

#15 telescopemullet

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Posted 17 July 2013 - 02:35 PM

My CPC cannot handle very high magnifications, especially under poor skies: Last night I could not get past a 22mm eyepiece in the CPC while the refactor took down to a 7.5mm. Make sense?
 

#16 Tapio

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Posted 17 July 2013 - 02:56 PM

Something is not right with that CPC.
 

#17 telescopemullet

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Posted 17 July 2013 - 03:02 PM

It works just fine, I can typically use down to a 12mm but that takes good skies...this is on planets mind you...
 

#18 Gord

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Posted 17 July 2013 - 03:09 PM

Colors seen on planet are exact as seen in the CPC 1100, details are plainly evident and comparable to the CPC being that the CPC does not take magnification as well as the refactor.


And more specifically, this IStar apo is only performing the same as a poor performing C11? :question: 127x (22mm) in a C11 is loafing along. Is the collimation out?

Clear skies,
 

#19 telescopemullet

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Posted 17 July 2013 - 03:13 PM

The views are comparable because I could not push the magnification on the CPC, the image was blowing out given the atmosphere and the cool down factor of the scope being in my observatory all day. I was steering clear of stating that a small APO was providing more detail that an 11-inch refactor, the views were comparable given the magnification level with the CPC.
 

#20 fred1871

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Posted 17 July 2013 - 07:06 PM

Mullet, you appear to have a problem with your CPC1100 if the 22mm eyepiece (127x) is the limit sometimes, and 12mm (233x) is your planetary limit. I have a C9.25 and it does better than that; in the past I had regular access to a C14, and it was loafing at 120x (the C9.25 isn't pushed at that level either). Around 240x on either of them, including for planets, is no big deal.

On the C11 a power of 233x is a 1.2mm exit pupil. That should not be the limit for planets if the seeing is even half-way reasonable.

So comparing what seems to be a C11 with problems with any other telescope is not informative, because that C11 appears to have problems and isn't performing at a normal level for a C11.


 

#21 RGM

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Posted 17 July 2013 - 07:45 PM

I live under the jet stream in central Ontario. My Tak FS78 can put up better images than my C8 or 10" dob on certain nights. For those that observe under relatively steady skies, you are lucky! I do not know where telescopemullet lives, but it could explain his comments. My 3" and 5" refractors serve me well and are my most used.
 

#22 telescopemullet

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Posted 17 July 2013 - 10:12 PM

There is nothing wrong with my cpc, it kills when atmosphere is steady. The view with the 22 last night was perfect, more magnification and the atmosphere took over. It is perfectly collimated, it's an atmosphere and lack of cooling time issue. The views the istar are simply spectacular, crisp, clean, and detailed.
 

#23 timps

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Posted 17 July 2013 - 11:40 PM

Yes. It is common knowledge that SCT's are more sensitive to atmospheric conditions.
 

#24 Kunama

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Posted 18 July 2013 - 01:12 AM

Post deleted by KWB
 

#25 Tapio

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Posted 18 July 2013 - 01:54 AM

If using same magnification in refractor/sct I dont' understand why SCT's would be more sensitive to atmospheric conditions. Even less if you can use larger (in mm) eyepiece in SCT (because of bigger fl) to get same magnification.
I understand that cooling (and tube currents) can have an effect but not seeing conditions.
 






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