Refractor Choice.

[MartianHill]

The more cost effective Askar telescopes may well fall into the areas Daniel is discussing. Spherical aberration immediately comes to mind which can be an issue for visual observers at high powers for doubles and the planets but not for imagers.

 

Edited April 18 by MartianHill

[Elp]

Depending on the scope isn't it also more likely to be an issue the larger the aperture of the refractor?

[dweller25]

@bosun21

I know it’s not on your list but for almost the same price as the Askar you could get a 4” Takahashi…..

https://www.firstlightoptics.com/takahashi-fc-100-series-refractor-telescopes/takahashi-fc-100dc-f7-4-doublet-fluorite-apo-refractor.html

[Elp]

24 minutes ago, dweller25 said:

@bosun21

I know it’s not on your list but for almost the same price as the Askar you could get a 4” Takahashi…..

https://www.firstlightoptics.com/takahashi-fc-100-series-refractor-telescopes/takahashi-fc-100dc-f7-4-doublet-fluorite-apo-refractor.html

Funnily enough (though it is an imaging comparison):

https://youtu.be/grH0O3RekgU?si=Q4hM1fYv3DtFfNv7

 

https://youtu.be/1ZCSPwM5_Hg?si=hpIJpRHGA5v5bWC1

 

[dweller25]

2 minutes ago, Elp said:

Funnily enough (though it is an imaging comparison):

https://youtu.be/grH0O3RekgU?si=Q4hM1fYv3DtFfNv7

 

https://youtu.be/1ZCSPwM5_Hg?si=hpIJpRHGA5v5bWC1

 

Yes, but does not bring an answer for visual as images get a lot of processing.

[Elp]

Watch the live feed videos

[dweller25]

11 minutes ago, Elp said:

Watch the live feed videos

Yes, good idea

The SM looks a little better than the Tak in the live videos but to me that’s mostly as the SM image is brighter.

[Elp]

That's the issue with the video feed, the exposure duration will have been lowered so that surface detail can be captured in better detail. Take it with a pinch of salt. Visually it should be much brighter in both scopes than the video shows, but you can ascertain the resolution capacity a little.

[John]

28 minutes ago, Elp said:

Funnily enough (though it is an imaging comparison):

https://youtu.be/grH0O3RekgU?si=Q4hM1fYv3DtFfNv7

 

https://youtu.be/1ZCSPwM5_Hg?si=hpIJpRHGA5v5bWC1

 

The poster of those is a long standing member here. Perhaps he can chip in personally ? 🙂

Maybe he actually looked through the scopes as well ?

[Doctor D]

3 hours ago, Elp said:

The issue is you've generalised the quality of a whole company's product in one post. You can't compare a doublet/triplet/petzval etc and lump them all into the same quality category, some are purely imaging instruments where some can do both imaging and visual, a lot of them aren't even in the same price brackets. I take the point about production, they're not Astro Physics scopes by any measure, but they're also not AP prices.

I think you'll find imagers are just as, if not more critical of optical quality where a lot of it can be measured and is quantifiable, not subjective to an observers opinion and also based on the quality of their vision and also utilised eyepieces which can make a massive difference. Though as you say the quality criteria for either discipline may be different.

I think either scope will be good but until one actually uses one for their intended purpose, this is the unknown to the individual.

 

 

End-users always generalize about brands, no different than you generalized about Astro-Pysics being a top tier brand. Have you ever tested a bad AP, Tak, TMB or TEC? I have. The problem today is end-users want what they interpret to be facts. Facts based on what experiences of the end-users themselves? What experiences do people or end-users with those concerns have to bring to the table other than just some more images of DSO's? Most of the end-users who insist on optical authenticity of quality struggle to even understand what they are looking at and since most of them don't even observe in the first place, it's going to be even harder. So in essence, they don't  know what they don't know.

There's also this idea by many end-users where they seem to believe that because they see something on a computer screen, that somehow means they are seeing hard facts. Just because end-users look through an eyepiece does not mean an issue is treated with any less care or can't be confirmed, in fact, quite the contrary. Some people are just horrible observers and depend on computer screens while others are excellent observers. Observing is a skill learned over time. For example, some people choose to look through microscopes while others choose to use digital screens. For refractors, both methods can achieve excellent results while both methods can also achieve bad results depending on the aberrations they are concerned about. 

Yes, there most certainly are differences with refractors better intended to be used for visual while others are better suited as astrograph's. Most of the confusion with that topic stemmed from the imaging community though, not the visual community. The reason this happened is because imagers were mixing their own concerns with the visual community. Most who were starting out, didn't know any better and huge amounts of misinformation were posted by the imaging community in particular. This is why I have advocated on numerous occasions in another forum that there needs to be two separate refractor topic threads; one for imaging refractors and another for visual refractors. Yes, with the increase in aperture, they inherit greater challenges that are pretty specific. 

 

 

Edited April 18 by Doctor D

[900SL]

On 17/04/2024 at 22:24, Elp said:

There's a few people on here and CN whom already own the 103 and 120 Askar triplets and majority think they're great both visually and photographically which is far more testing. Don't know if anyone has a 140 though.

For visual a doublet will cool down quicker though.

https://www.astrobin.com/forum/c/equipment-forums/askar-140apo/chromatic-abberation/

My personal view is that Askar have good mechanics, but cut costs on glass, polish, assembly and QA/QC. Smaller objectives are more tolerant of such an approach than larger objectives.  Objective pinching at low temperatures is another area where some of these budget scopes fall flat. 

Askar also ensure 'A' grade well corrected samples are cherry picked for influencers. Their marketing is hard to fault, and the price/performance ratio is good, assuming you are not in the %age that gets a duffer.

Software will deal with minor issues for imaging, and as noted above, visual observers have different priorities to imagers.

I'm not anti-Askar. Just pointing out the facts. They are priced very competitively, and Askar (or should I say Sharpstar) have improved their products over the years, and I have to say that the 120 APO is an outwardly attractive proposition to me.  But at these prices, something has to give. And thats likely glass and consistency outside of the first run.

 

Edited April 19 by 900SL

[Doctor D]

The other thing that comes into play is the history and reputation of the ones making the claims about Askar's visual performance. What else have they compared in order to make well rounded decisions? What are their seeing conditions like? Are they mostly imagers? What is their level of experience on interpreting aberrations such a zones, under-correction etc, acclimation, color perception, diagonal selection, observing platform. What did they see specifically when they observed stars and planets? 

This is why I care greatly about who writes these reviews. People love to get data, but the problem with data is end-users obviously struggle to differentiate theory from observation itself. Anyone who has an Askar can do a review. It doesn't mean they are seasoned enough to know what they should be looking for. The other side of the coin is it may be good enough for them and that's perfectly fine, in fact, that's great. The real issue though is if they are going to set a claim on real world performance, I like to hear more specific information about the observation, knowledge and experience of the observer. 

The internet is plagued with imagers and theorists who do nothing but read about optics and sadly there are not enough observers doing real world observing by comparing telescopes who have a long history behind them. Those are the details I look for because too many beginners are just pontificating the same stories about optics and glass again and again. 

[bosun21]

This is one of the threads on CN which has several contributors some of whom appear to be very well experienced visual observers. They have used several higher end refractors visually as well. It was from this thread and others that I gleaned the visual performance of the 120/140 Askars was good. Have I been reading this thread through a pair of rose tinted glasses? Thanks.

https://www.cloudynights.com/topic/900932-askar-140-apo/

Edited April 19 by bosun21
Add link.

[dweller25]

18 minutes ago, bosun21 said:

This is one of the threads on CN which has several contributors some of whom appear to be very well experienced visual observers. They have used several higher end refractors visually as well. It was from this thread and others that I gleaned the visual performance of the 120/140 Askars was good. Have I been reading this thread through a pair of rose tinted glasses? Thanks.

https://www.cloudynights.com/topic/900932-askar-140-apo/

I just read that thread and here is my take.

The one person who bought the Askar 120 said it was visually outstanding and then sold it quite quickly !

 

[Elp]

Maybe if you get the Takahashi, all the bashing will stop :)...

[Mr Spock]

Just now, Elp said:

Maybe if you get the Takahashi, all the bashing will stop :)...

That's a bit unnecessary. I'm sure all scope owners, no matter what they have, can get along 

[Mr Spock]

I'm sure the 125mm will be excellent. You can't really tell from images though. I'll stick to my 100mm. Apart from the quality there's the size issue. It's small, light and convenient.

[Elp]

I think either will be good. Even a 4 inch makes for an excellent scope like my Starfield which is good for both imaging and visual.

[Doctor D]

41 minutes ago, bosun21 said:

This is one of the threads on CN which has several contributors some of whom appear to be very well experienced visual observers. They have used several higher end refractors visually as well. It was from this thread and others that I gleaned the visual performance of the 120/140 Askars was good. Have I been reading this thread through a pair of rose tinted glasses? Thanks.

https://www.cloudynights.com/topic/900932-askar-140-apo/

 

I'm assuming it must be a specific post since the OP appears to be discussing imaging. 

[bosun21]

1 hour ago, Doctor D said:

 

I'm assuming it must be a specific post since the OP appears to be discussing imaging. 

The OP jonbossley is a visual observer as per his first light report. He returned the scope due to image shift at high magnification. This apparently can be rectified by adjustment screws on the focuser, although this shouldn't need to be done with a new scope.

[900SL]

19 hours ago, dweller25 said:

I just read that thread and here is my take.

The one person who bought the Askar 120 said it was visually outstanding and then sold it quite quickly !

 

I think Askar hide their sins in the large spot sizes, judging from the comments in that thread?

[dweller25]

16 hours ago, bosun21 said:

The OP jonbossley is a visual observer as per his first light report. He returned the scope due to image shift at high magnification. This apparently can be rectified by adjustment screws on the focuser, although this shouldn't need to be done with a new scope.

Sorry, you did say you were considering the 140mm and my response was for the 120mm !

[bosun21]

1 hour ago, dweller25 said:

Sorry, you did say you were considering the 140mm and my response was for the 120mm !

I was, but on looking deeper I have decided on the StellaMira 125. It seems that this is the best option for visual!

[dweller25]

15 minutes ago, bosun21 said:

I was, but on looking deeper I have decided on the StellaMira 125. It seems that this is the best option for visual!

Yes, a 125mm refractor is a good size and there are quite a few out there now 👍

[Mr Spock]

The 125 SL is fast gaining a reputation as a good scope. Plus it's no where near the size and bulk of a 130 despite only being 5mm different. I wouldn't mind one myself (inner me say no - you have too many already lol).