12 replies to this topic

[Sreesha]

Hi,

 

I have the AM5 mount.  I am looking for APO triplet refractors in the range of 900mm for deepsky imaging, with a max of 8 kgs?  what options do we have?

i could not come across anything other than ES 127 ED FCD-100.

 

Thanks

[jrazz]

Go bribe someone and get a FC-100DL

[hyiger]

You can certainly go over 8kg with that mount. Example the AT130EDT is 8.6kg. I use it on my AM5

 

Edited by hyiger, 12 April 2025 - 09:05 PM.

[DeepSky Di]

Askar APO 120 is 840mm with its 1x flattener, also has a reducer, and weights 6.5kg according to specs.

[900SL]

Vixen SD115 SII. (Updated version). Doublet but well corrected. Weighs around 6kg including rings

Edited by 900SL, 13 April 2025 - 01:32 AM.

[Sreesha]

Vixen SD115 SII. (Updated version). Doublet but well corrected. Weighs around 6kg including rings

Thank you.  Would there be visible quality difference between imaging in Doublet vs Triplet?

Edited by Sreesha, 13 April 2025 - 01:44 AM.

[hyiger]

Thank you.  Would there be visible quality difference between imaging in Doublet vs Triplet?

For imaging you definitely want a triplet inside your budget range. 

[balcon3]

How about a Takahashi TSA-120? Triplet, f/7.5, focal length = 900. I have never used one, but they have a tremendous reputation. Weighs 6.7 kg.

[900SL]

Thank you.  Would there be visible quality difference between imaging in Doublet vs Triplet?

@Osbourne one-nil

@dave novoselsky

 

There's not much on AB but this image of M3 convinced me Vixen have got a great doublet here.

 

https://app.astrobin...115sii?i=tf528v

 

More here

 

https://app.astrobin...115sii?i=tf528v

Edited by 900SL, 13 April 2025 - 06:22 AM.

[Oldfracguy]

Askar APO 120 is 840mm with its 1x flattener, also has a reducer, and weights 6.5kg according to specs.

I have had two of those:

 

 

 

and they both were outstanding from an optical performance standpoint, unlike the smaller 103 APO I also tried.  The focusers on these scopes can be problematic, but they can be adjusted to make them work almost as well as the dual-speed rack-and-pinion focusers on the Kunming United Optics-made refractors, e.g. Astro-Tech, TS-Optics, Altair Astro, etc.  There is a thread here on CN about how to perform the focuser adjustments on the Askar 103 and 120 APOs as they share the same tube and 3.3" focuser.  Although these scopes do not have fully-rotating focuser assemblies, they do have really sturdy Camera Angle Rotators at the end of the drawtube with a nice 360° scale:

 

 

 

My Askar 120 APO loaded up with a 9x50 RACI, a 2" Baader Silver Mirror diagonal and an 18mm UFF eyepiece came to 17.4 lbs., or 7.9 kg.  I suspect that with a camera sensor, an EAF and a guidescope installed the overall weight would be very close to the same as far as the mount is concerned.  That 6.5 kg figure is for the OTA with tube rings and dovetail rail.

Edited by Oldfracguy, 13 April 2025 - 09:43 AM.

[DeepSky Di]

You can certainly go over 8kg with that mount. Example the AT130EDT is 8.6kg. I use it on my AM5

 

Ohh great to see the AM5 mounted on THAT tripod. I have one as well but have not gotten round to changing the threaded rod to make it work with other things.

 

The 8kg could be a personal limit rather than a mount limit :-)

[hyiger]

Ohh great to see the AM5 mounted on THAT tripod. I have one as well but have not gotten round to changing the threaded rod to make it work with other things.

 

The 8kg could be a personal limit rather than a mount limit :-)

Yep, as I get older, 8kg is starting to feel like 20kg when I was younger. 

 

The PE200 and M15 threaded rod combo works really well with that tripod. It's a very sturdy setup. 

[chvvkumar]

You could even go higher with the 140APO from Askar. You are limited to a wind of ~7mph with this.