119 replies to this topic

[Nikguy]

Spot Diagram of the newest Askar looks pretty good!
 

[Bob_Huerbsch]

You can unthread the extension tube and make this scope airline portable, that’s huge benefit for those who travel! I’m waiting on real world tests

[kevinkiller]

Here's an in-person review, but it's in Chinese and there's no sub-title translations

 

https://www.youtube....estarryskyworld

[kevinkiller]

I chose the 120APO since it has 1.44x the light gathering power, better (tighter) spot diagrams than the 103APO, and pairing it with the Starizona APEX-L focal reducer gives me:

 

 

F7 / 840mm / 0.92" /  1.6° x 1.07°  -- (flattener),
F5.6 / 671mm / 1.15" / 2° x 1.34° -- (0.8x reducer),
F4.4 / 530mm / 1.47" / 2.54° x 1.7° -- (0.63x reducer).

 

Compare that to the 103APO at:

 

F6.8 / 700mm / 1.11" /  1.92° x 1.29°  -- (flattener)
F5.4 / 560mm / 1.38" /  2.4° x 1.61°  -- (0.8x reducer)
F4.3 / 400mm / 1.76" / 3.05° x 2.04°  -- (0.63x reducer).

 

 

These F-ratios are all large enough to avoid band-shift problems with ultra narrow band filters like the Antilia 2.5nm series (for mono) or the Player-One Anti-Halo Pro Dual-Band Ha(3.7nm)/OIII(3.2nm) filter (for OSC) which is super important for me living in a bortle 7 location.  The resolutions support seeing 2.76" FWHM seeing (120APO) and 3.33" FWHM seeing (103APO) which is pretty good and can be halved with 2x drizzling for those rare occasions I take my scope to the top of a mountain for several days of imaging.  

 

 

I spent some time on https://telescopius.com looking at the Framing of the various nebula with the above focal lengths and except for a couple nebula which would require more mosaic-ing with the 120APO (like the Cygnus Loop and the  Lambda Orionis ring) everything else would fit equally in both scopes.  Given this, I went for the bigger/1.44x light gathering power of the 120APO.  Also, the 120APO is better at 840mm for smaller targets like galaxies and planetary nebula and it's smaller sampling can support better seeing.

  

Note: both scopes support Full-Frame sensors with the flattener and the 0.8x reducer with tight round stars right to the corners (see https://www.youtube....el=NebulaPhotos and https://www.youtube....estarryskyworld) while the Starizona APEX-L is limited to APS-C sensors.    If you go to the first link and look in the description you'll see this link https://drive.google...mbbrKxCScsIDLAa to actual images captured by the 4 scopes he tests (which includes the famous SkyWatcher Esprit 100). 

 

 

To my eye and needs the images are virtually indistinguishable from each other.

 

 

Interesting enough a full-frame camera with 0.8x reducer covers almost exactly the same field-of-view as the 0.63x sensor with APS-C.   I looked at the price of a full-frame camera $4300 vs the price of the Starizona reducer with a custom threaded focuser adapter for the M84 Askar scopes ~$540 and decided I'll stick with my APS-C camera for now and when I upgrade I'll sell the Starizona reducer.

Edited by kevinkiller, 28 September 2023 - 12:55 AM.

[Nikguy]

Thanks for the link!

 

The corners in full frame look very good!

[gul1337]

I can't wait to see how it works with binoviewers

[denis0007dl]

Look very nice!

Fantastic is its binoviewers friendly, and light weight for 120mm triplet class.

Denis

[Nikguy]

A real competitor to the ESPRIT 120, especially if it can also do full-frame.

[Doug Culbertson]

Look very nice!

Fantastic is its binoviewers friendly, and light weight for 120mm triplet class.

Denis

Yeah, since none of my telescopes are binoviewer friendly, I am about this ** close to preordering one of these. 

[denis0007dl]

Yeah, since none of my telescopes are binoviewer friendly, I am about this ** close to preordering one of these. 

Yeah, finally more and more companies realise binoviewers users need more backfocus, hopefully it will become standard for most telescopes in future.

 

BTW, price of Askar 120mm is apealing!

[Doug Culbertson]

Yeah, finally more and more companies realise binoviewers users need more backfocus, hopefully it will become standard for most telescopes in future.

 

BTW, price of Askar 120mm is apealing!

It's about the same price as the TS-Optics Doublet SD-APO 125 mm f/7.8 - FPL-53 / Lanthanum once I do the Euro/USD conversion, but then I am looking at pretty high shipping rates plus 8% duty. The Askar doesn't specify glass types, but those spot diagrams sure do look good. 

[denis0007dl]

I doubt Askar will reveal glass type they using...

[Bob_Huerbsch]

I doubt Askar will reveal glass type they using...

Most likely HK-61 / FPL-51

[Doug Culbertson]

Most likely HK-61 / FPL-51

Given the price point for this triplet, that sounds reasonable. They don't even give a clue in their advertising blurb in the Vendor's section: " Askar 120APO adopts a triplet air-spaced APO lens design, including one piece of ED glass."

 

Another thing that caught my eye is the schematics that Askar posts for this particular model. They show an OTA diameter of 110mm. So, if I'm looking at it correctly, they are sticking a 120mm diameter objective on a 110mm tube. Obviously I am no optical expert, but wouldn't this cut down on the effective aperture right off the bat? Maybe I'm not as enamored with this scope as I was when I got the email from Agena. 

Edited by Doug Culbertson, 06 October 2023 - 08:42 AM.

[gul1337]

 

Another thing that caught my eye is the schematics that Askar posts for this particular model. They show an OTA diameter of 110mm. So, if I'm looking at it correctly, they are sticking a 120mm diameter objective on a 110mm tube. Obviously I am no optical expert, but wouldn't this cut down on the effective aperture right off the bat? 

I was thinking that maybe it is wider at the dew shield? At F7 light cone should be around 110mm diameter after about 70mm of travel.

maybe that's why dew shield seems so big and wide, it also has some taper, maybe for the light cone?

[Doug Culbertson]

I was thinking that maybe it is wider at the dew shield? At F7 light cone should be around 110mm diameter after about 70mm of travel.

maybe that's why dew shield seems so big and wide, it also has some taper, maybe for the light cone?

Yeah, that makes sense too. At first glance that odd looking dew shield was the first thing that caught my eye. Still, the ability to remove a section for binoviewing may keep me considering it. 

[Nikguy]

[andylast]

I doubt Askar will reveal glass type they using...

They won't comment on any tech info (any stated aim of wavefront error, Strehl ratio etc). I have asked them (Sharpstar) and they have declined to offer any info. They just pointed to their website which is just marketing. That's a turn off for me. They are not even willing to discuss these issues. In my view its never wise to become an early adopter for products like this. If they circulate and info emerges that they are of good quality, consistently, then great. Otherwise, I will wait. I am looking around for a refractor of between 110mm and 125mm. As it is nearly impossible to "try before you buy" with astro scopes, I have two choices - Rely on certification offered, or wait till the product has been around long enough to get good feedback.

[Nikguy]

I have so far used Askar FRA 300 and 600 and PHQ 107 for astrophotography and have had no problems.

 

I tested all with APS-C (ASI 2600MM Pro) and full format (NIKON Z6 II) and also the edges and corners were ok!

For astrophotography it makes no sense to use "better" telescopes in my region (Central Europe) because the seeing (>1.5") is not perfect. So you don't need an apo with Strehl > 98 for good astrophotos.

Askar has now brought out a "healthy" focal ratio with the APO series and with the 120APO a real competitor to the ESPRIT 120.

 

justmy2cents.

BTW: I have pre-ordered a 120APO :-)

[andylast]

I have so far used Askar FRA 300 and 600 and PHQ 107 for astrophotography and have had no problems.

 

I tested all with APS-C (ASI 2600MM Pro) and full format (NIKON Z6 II) and also the edges and corners were ok!

For astrophotography it makes no sense to use "better" telescopes in my region (Central Europe) because the seeing (>1.5") is not perfect. So you don't need an apo with Strehl > 98 for good astrophotos.

Askar has now brought out a "healthy" focal ratio with the APO series and with the 120APO a real competitor to the ESPRIT 120.

 

justmy2cents.

BTW: I have pre-ordered a 120APO :-)

Yes you can get away with lower quality for astrophotography, but I like observing and if I buy an APO I want a reasonable Strehl. I would be very surprised if the 120 APO is .97 or better. We shall see. If it is, consistently .97 or above, it will do me fine.

[Booney3721]

Askar120.jpg

can I get a ELI5 on this? (Explaon like I am 5), what does this chart mean? I have been back and forth on this one or the 103APO

[Bob_Huerbsch]

If you can afford it and mount can handle it, more aperture is nearly always better, I’d get the 120

[Starlancer]

Saw the 120, had already ordered the 103 with the .6 reducer, of course it's been clouds since then.  I will say the .6 reducer for the 103 is a chunk of glass!  If I didn't want to carry everything all assembled I have considered the 120.  I'd be more interested in a 130 now but the AT130EDT would pretty much fill that role.

[akdwivedi]

Another thing that caught my eye is the schematics that Askar posts for this particular model. They show an OTA diameter of 110mm. So, if I'm looking at it correctly, they are sticking a 120mm diameter objective on a 110mm tube. Obviously I am no optical expert, but wouldn't this cut down on the effective aperture right off the bat? Maybe I'm not as enamored with this scope as I was when I got the email from Agena. 

that caught my attention as well. It seems that 103APO and 120APO share the same OTA and focuser. The width of the tube and focuser size is same in diagrams of both the scopes on aliexpress. 

 

Not sure if just like Askar V series (60mm and 80mm), there is some shared componentry between 103 and 120APO.

[Starlancer]

The focuser on the 103 (and assume 120) is excellent!  I actually like it better then my Stellarvue focuser since to rotate the Stellarvue you have to rotate the focuser controls/EAF with it but the rotator is after the controls on the Askar.  I did not have any tilt or slop in the focuser, auto focus curve was textbook.

 

They also sell a really nice backfocus adjuster that I purchased at the same time that allows 2mm of adjustment in either direction, it replaces the end of the focuser so the spacing stays the same.

 

I know this thread is for the 120 but since they are similar and question of which to get here is the first light for the 103 with the .6 reducer.  I am happy!