Refractor Choice.

[bosun21]

I am looking at buying myself a new refractor shortly and I can't decide which way to go. The two contenders are the StellaMira 125 doublet with FCD100 and lanthanum glass and the Askar 140 triplet with one ED element (type not disclosed). I have been reading reports from owners of both and both are said to perform very well for visual. The 140 is bino friendly with a 3.5" R&P focuser as opposed to the 2.5" of the SM 125. It's the question of whether the better glass type of the doublet will be better than the supposed better correction of the triplet with one ED element. This being a considerable purchase for me I want to make the best choice possible. Any thoughts on the matter would be appreciated. Thank you.

Edited April 16 by bosun21

[Elp]

Difficult choice without looking through both at the same time. Both of these (My askar choice being a 103 or 120) are of interest due to providing a medium FL between my current scopes. For me it'd be the Askar because it's a triplet but that's because I image more than view.

[M40]

Have you considered the physical aspects of both? I.e. length and weight. The sm125 being about half the weight but slightly longer.  The height of my mount head is about 1700mm from the deck but the length of the sm125 makes visual near the zenith awkward but not impossible. Lifting the sm125 onto the mount at that mount height is not a challenge.

[John]

As purely a visual observer I would go for a doublet I think. There are quite a few very positive reviews out there of the 125mm Stellamira and the same scope under different branding. 

The weight of the Stellamira makes it appealing to me as well.

 

[IB20]

The Askar looks great but it’s a hefty looking OTA at >9kg. I feel that alone would put me off wanting to take it out and try to stick it on a mount, which I’d imagine would have to be fairly beefy itself.

I have the SM125 and I’ve no complaints so far. It’s knocked my socks off looking at M42. It’s excelled at nearly everything I’ve pointed it at. The only annoying thing is I’ve not had as many sessions with it as I’d have liked cos of the damn weather but I use it when I can because it’s so easy to handle.

I don’t feel much difference in weight between this and my 102ED-R. It’s quite a bit longer though but I don’t extend the dew shield til it’s set up. 
 

[bosun21]

1 hour ago, M40 said:

Have you considered the physical aspects of both? I.e. length and weight. The sm125 being about half the weight but slightly longer.  The height of my mount head is about 1700mm from the deck but the length of the sm125 makes visual near the zenith awkward but not impossible. Lifting the sm125 onto the mount at that mount height is not a challenge.

Yes I have been considering the physical aspects of both of them. I have just bought an AZ-EQ6 so the weight isn't a problem with either. My only concern is that I will probably require a pier extension to accommodate the length, and the 140 may prove to be cumbersome in conjunction with this. There is also the Askar 120 in this range to possibly consider. The SM125 has been on my menu for some months now, and indeed since its release. I basically want it for visual and a bit of EAA thrown into the mix. I've been searching for reviews of the Askar as the SM is a better known entity to me regarding performance etc. I will keep digging as I have about another month before I make the purchase. Thanks all.

[bosun21]

1 hour ago, John said:

As purely a visual observer I would go for a doublet I think. There are quite a few very positive reviews out there of the 125mm Stellamira and the same scope under different branding. 

The weight of the Stellamira makes it appealing to me as well.

 

Why a doublet over a triplet for visual John?

[John]

16 minutes ago, bosun21 said:

Why a doublet over a triplet for visual John?

Cool down time and weight / balance. Triplets can be front heavy and tend to be heavier overall. Also, it's been known for a good ED doublet to have better colour correction than a triplet 😉

I need all my setups to be as portable as possible so weight is important. 

Also, within a given price bracket, I reckon you have more chance of getting 4 good optical surfaces than 6. Probably me being pessimistic though !

 

 

[bosun21]

5 minutes ago, John said:

Cool down time and weight / balance. Triplets can be front heavy and tend to be heavier overall. Also, it's been known for a good ED doublet to have better colour correction than a triplet 😉

I need all my setups to be as portable as possible so weight is important. 

Also, within a given price bracket, I reckon you have more chance of getting 4 good optical surfaces than 6. Probably me being pessimistic though !

 

 

All good points you mentioned. Cool down time and weight being quite important to a lot of people myself included. Thanks.

[Elp]

If you're aiming for aperture and focal length why not a Newtonian?

[bosun21]

20 minutes ago, Elp said:

If you're aiming for aperture and focal length why not a Newtonian?

I already have a 10" go to dobsonian which fills that niche.

[900SL]

I'd go with the 125 doublet for visual.  Lighter, good colour correction, quicker cool down. The 125 f7.8 scopes (TS, Stellamira etc) have a good reputation. 

Askar fudge things like glass type and spot diagrams, and their QA can be flaky.. they know how to work with influencers though! I've been impressed with their machining, not so much their optics.

[Elp]

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.

Edited April 17 by Elp

[bosun21]

Thank you for your opinions. I am leaning firmly in the direction of the SM 125ED for several of the reasons already mentioned. I just need to add a pier extension to the shopping list now.

[IB20]

Just had a brilliant few hours on the moon with this scope. Managed to catch the Hesiodus crater ray thanks to the SGLers in the celestial heads up forum. Again, this scope has delivered, it’s completely colour free on the lunar limbs. It just keeps on impressing. 
 

[Doctor D]

The Askar's are okay but limited in their magnification due to some spherical aberration they often exhibit. This causes stars and planets to breakdown more apparently. 

[bosun21]

4 hours ago, Doctor D said:

The Askar's are okay but limited in their magnification due to some spherical aberration they often exhibit. This causes stars and planets to breakdown more apparently. 

Where did you read this? I have read numerous reviews stating that there's no aberration at    >  300x with the triplet Askars. I would like to read this report. I'm about 90% in the SM 125ED camp at the moment in any case.

[Doctor D]

11 hours ago, bosun21 said:

Where did you read this? I have read numerous reviews stating that there's no aberration at    >  300x with the triplet Askars. I would like to read this report. I'm about 90% in the SM 125ED camp at the moment in any case.

I usually do all my own evaluations with my observing group. Don't get me wrong, the Askar's are pretty good refractors, especially at such a low price point. Askar's are actually more well directed toward imaging rather than visual because the types of aberrations they exhibit during visual observations, which will not be an issue for imagers. Not sure what reviews you are referring to with 300x but happy to listen to you would like to share. Image quality is all relative and since not all views appear the same contrast at 300x, it depends on a number of factors that probably need to be discussed for better clarification, yes? Steady skies, ---daniel

Edited April 18 by Doctor D

[Elp]

Clarify please, are you generalising Askar quality in general, they produce at least three/four different ranges, they can't all have the same output. Sharpstar also produce scopes with their own name.

Edited April 18 by Elp

[MartianHill]

@bosun21

Between the two scopes you highlighted I would choose the doublet as it will cool faster and not be front heavy - the Askar 140 is a large triplet scope but may need to be mounted low in it’s tube rings to get correct balance so the eyepiece end will be low.

[Elp]

4 minutes ago, MartianHill said:

eyepiece end will be low

Won't this also apply to the SM125 as it's full length is 1000mm vs 870mm? Generally long refractors benefit from pier extension mounting unless if the pier/tripod is fairly high to begin with. Trying to see high altitude objects requires dexterity at times.

[MartianHill]

4 minutes ago, Elp said:

Won't this also apply to the SM125 as it's full length is 1000mm vs 870mm? Generally long refractors benefit from pier extension mounting unless if the pier/tripod is fairly high to begin with. Trying to see high altitude objects requires dexterity at times.

Yes to some degree but it’s not as front heavy being a doublet.

Edited April 18 by MartianHill

[fwm891]

I can't say what the Askar 120 APO's are like for visual use but I have 2 mounted as a dual set-up on my obsy mount and the optics (both 1x and the 0.8x) are superb with pin point stars right across the FoV.

Edited April 18 by fwm891
image added

[Doctor D]

54 minutes ago, Elp said:

Clarify please, are you generalising Askar quality in general, they produce at least three/four different ranges, they can't all have the same output. Sharpstar also produce scopes with their own name.

 

That's not the way it works with mass production on that level. One of the most common aberrations are zones in mass production and it's clearly evident when observing with the vast majority of these refractors as well as others. Most are coming from a few factories and being marketed with various names when we consider all the brands on the market. I'll give you a simple example of the issue. Go to YouTube and punch in "askar refractors". Pretty much everything you are going to see comes from beginner to intermediate users who mainly image. Imagers are an entirely different breed compared to visual observers and since the vast majority of users who inquire about Askar are imagers, most of everything you read isn't going to address the concerns visual observers have by comparison about these scopes.

There are various types of aberrations that annoy visual observers like myself who are going to be distracted by them while observing stars and planets at higher magnifications. Imagers won't see these aberrations at all the same way. As I mentioned though, Askar's are fine for most end-users and even some casual visual observing. Like I stated earlier, it's all relative, especially to ones level of experience behind an eyepiece.  Regards, ---daniel

Edited April 18 by Doctor D

[Elp]

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.