Regular achromat scopes are actually expensive!

[vlaiv]

Ok, let me first say - no, I'm not going to complain about prices of exotic ED glass - on the contrary!

I'm also going to do full disclosure here - I'm suffering cloudy skies syndrome at the moment - you know, have not been observing or doing anything astronomy related for months and I'm starting to fantasize about new scopes, different combinations, examining prices - making up needs and all those weird stuff we amateur astronomers do when we get this syndrome

It all started with focusers. I have M90 Monorail focuser that is leftover form an upgrade. I wanted to fit that focuser on My Evostar 102mm F/10 refractor for some time now but I can't seem to find suitable solution. While looking at other focusers and thinking about focusers - it hit me, most are quite expensive in comparison to cheap units that come on most entry level scopes.

You can't really find entry level refractor telescope with a decent focuser, and often, focusers themselves cost as much as entry level refractor scopes (achromat types).

For some reason I then started thinking about very cheap portable refractor type telescope that I would upgrade to make a decent scope (might have been prompted to this behavior by recent thread - "Show us your small refractor scope" ).

Say you take Skywatcher Mercury 705. I believe it to be decent glass, and with decent focuser, diagonal, maybe zoom eyepiece like Hyperflex 7.2-21.5mm - could make very nice portable / grab'n'go / quick peak package. I would also like retractable dew shield if possible.

Ok, let's see, how much would it cost? I'm going to quote here TS prices that are in euros and without VAT, so those are not final prices - but they do serve the purpose - comparison purpose.

OTA ~ 116 euro

Focuser  ~ 125 - 145 euro (125 is 1.25" model, and 145 euro and upwards are 2" models - all having 1:10 reduction. There are 1.25" and 2" single speed GSO crayford models that are for newtonian scopes but could be adopted - for about 76 euro each)

Adapter to mount focuser onto tube - at least 40 - 50 euro if not more.

Ok, lets add that up - OTA + 2" with 1:10 + adapter (cheapest estimate) = 116 + 145 + 40 = 301 euro.

On the other hand, you have something like this:

https://www.teleskop-express.de/shop/product_info.php/info/p1151_TS-Optics-70-mm-F6-ED-Travel-Refractor-with-modern-2--RAP-Focuser.html

And yes, it costs 301 euro and it has ED glass. Maybe not the best ED glass out there, but it will sure beat Mercury 705 in color correction and planetary views.

It has retractable dew shield as a bonus.

Moral of the story? Entry level refractors are actually expensive for what they provide!

[Alien 13]

Agreed but a well put together ST80 for example with decent focusser and premium eyepiece would be a joy to use on the right sort of targets..

Anyway God gave us small Maks, the perfect package to replace long achromatic s.

Alan

[Ags]

Nothing wrong with the ST80 focuser. I know it’s not fancy but replacing it with anything is probably at the bottom of my wish list. In fact it’s not even on the wish list. Replacing the basic focuser with a gleaming anodized doodad would kill the soul and charm of the telescope 😀

[vlaiv]

2 minutes ago, Alien 13 said:

Agreed but a well put together ST80 for example with decent focusser and premium eyepiece would be a joy to use on the right sort of targets..

Anyway God gave us small Maks, the perfect package to replace long achromatic s.

Alan

I agree. What replacement focuser would you put on ST80?

Maks are good the way they are, I would not replace anything on Mak and use it as is.

We could argue that Mak 102 mm and ST80 could combined replace single scope with ED glass.

Mak would excel at planetary / high power, while ST80 would be in charge of low and medium power DSO and wide field. Would we save money in doing so?

According to TS prices, we have:

ST80 OTA - for 120 euro

Mak102 OTA - for 206 euro

Together they add up to 326 euro. Add focuser to ST80 - that GSO one dual speed already has 86 ID flange, so it will be direct replacement - no adapter needed, it costs 145 euro.

Total of 325 + 145 = 470 euro

But then again, you have this:

https://www.teleskop-express.de/shop/product_info.php/info/p7169_TS-Optics-ED-APO-80-mm-f-7-Refractor-with-2-5--R-P-focuser.html

For 426 eueo and also this:

https://www.teleskop-express.de/shop/product_info.php/info/p8637_TS-Optics-Doublet-SD-APO-80mm-f-7---FPL-53---Lanthan-Objective.html

for 499 euro

First one probably has FPL-51 glass, while second is virtually perfect with respect to color correction with FPL-53 and lanthanum glass.

I suspect both would put up good fight against Mak102, which although has 102mm of aperture, has central obstruction, so it would be tough call on planets between those.

Both of these scopes would easily win versus ST80 on low / medium power for deep sky.

 

[vlaiv]

2 minutes ago, Ags said:

Nothing wrong with the ST80 focuser. I know it’s not fancy but replacing it with anything is probably at the bottom of my wish list. In fact it’s not even on the wish list. Replacing the basic focuser with a gleaming anodized doodad would kill the soul and charm of the telescope 😀

Well, certainly, if one likes the focuser - why change it.

I, on the other hand really like idea of having 2" capability, smooth action and 1:10 reduction. I added 1:10 micro focusing to my 8" F/6 newtonian and it is really nice feature to have on planets for example.

[John]

Back in 2017 the cost of ED glass was:

FPL-51 = 11x BK7

FPL-55 = 15x BK7

FPL-53 = 18x BK7

I believe the relative costs are similar today.

Given the above you would have thought that the glass used in the objective would be the principle determining factor on the overall cost of a scope

[Alien 13]

9 minutes ago, John said:

Back in 2017 the cost of ED glass was:

FPL-51 = 11x BK7

FPL-55 = 15x BK7

FPL-53 = 18x BK7

I believe the relative costs are similar today.

Given the above you would have thought that the glass used in the objective would be the principle determining factor on the overall cost of a scope

I doubt that the type of glass makes up much of the overall manufacturing cost of a scope apart from its availability.

Alan

[johninderby]

Always thought the Opticstar achros were a good buy as the optics were decent and had a good focuser for not a lot more than some of the basic achros from other places. 

http://www.opticstar.com/Run/Astronomy/Astro-Telescopes-Opticstar.asp?p=0_10_1_1_65

 

Edited December 9, 2020 by johninderby

[John]

1 minute ago, johninderby said:

Always thought the Opticstar achros were a good buy as the optics were decent and had a good focuser for not a lot more than some of the basic achros from other places. 

http://www.opticstar.com/Run/Astronomy/Astro-Telescopes-Opticstar.asp?p=0_10_1_1_90

http://www.opticstar.com/Run/Astronomy/Astro-Telescopes-Opticstar.asp?p=0_10_1_1_65

 

They look good but I've not been 100% sure about the quality of the objectives since reading Neil English's experiences with the 80mm F/5. He got a poor one unfortunately. He put the objective from a Skywatcher ST80 into the tube and then was much happier with the scope.

 

 

 

 

[vlaiv]

56 minutes ago, John said:

Back in 2017 the cost of ED glass was:

FPL-51 = 11x BK7

FPL-55 = 15x BK7

FPL-53 = 18x BK7

I believe the relative costs are similar today.

Given the above you would have thought that the glass used in the objective would be the principle determining factor on the overall cost of a scope

Could be that most of the cost of the scope goes into labor rather than materials?

Cost of transport, retailing costs, profits?

41 minutes ago, johninderby said:

Always thought the Opticstar achros were a good buy as the optics were decent and had a good focuser for not a lot more than some of the basic achros from other places. 

http://www.opticstar.com/Run/Astronomy/Astro-Telescopes-Opticstar.asp?p=0_10_1_1_65

 

They sure look nice, and that focuser looks like a proper unit. I think I read somewhere that people were not happy with such focusers.

This was not in relation to Opticstar scopes, but SVBony models that look remarkable like those of Opticstar, so I'm guessing that they might have same source factory?

Here is SVBony model:

and Opticstar

They might be decent units and at same level of quality as other focusers I have been looking at. This information came from Cloudy nights discussions on these SVBony scopes - some people report grinding feel to focusers, while others say their units are fine?

In any case - these sort of scopes come at right prices I would say? That Opticstar AR90S should be around 180 euro without vat - and that is rather nice price for 90mm aperture scope with 2" focuser with 1:10 micro focusing. There is also 90mm F/5.5 version (SVBony and also Omegon has it with single speed focuser).

I don't know if there is smaller version, though?

Above report of lens quality is something that also needs to be considered, however, as far as I've heard this AR90S model should be quite good optically?

 

[johninderby]

I had the AR90 f8.8 and the focuser was smooth and worked OK. Not a high quality focuser but what I would call adequate. Optics wee excellent and CA was well controlled for an achro. Felt very solidly built.

So all in all good value for money and good build quality. 

Edited December 9, 2020 by johninderby

[Chris]

lol I wondered where you were going with this story vlaiv but it's a very interesting point. 

Maybe it's more that the TS 70ED f/6 is crazy good value rather than the 70mm achro being particularly expensive if you upgrade it.  

[vlaiv]

34 minutes ago, Lockie said:

lol I wondered where you were going with this story vlaiv but it's a very interesting point. 

Maybe it's more that the TS 70ED f/6 is crazy good value rather than the 70mm achro being particularly expensive if you upgrade it.  

I thought so too, but, check this out

4" Evostar F/10 is listed at 300 euro with TS:

https://www.teleskop-express.de/shop/product_info.php/info/p2684_Skywatcher-Evostar-102---102-1000mm-Refracor---optical-Tube.html

Throw in another 150 for replacement focuser and 50 euro for adapter - and you have 500 euro refractor.

But, for that sort of money (516 euro), you can have this scope:

https://www.teleskop-express.de/shop/product_info.php/info/p4964_TS-Optics-ED-102-mm-f-7-Refractor-Telescope-with-2-5--R-P-focuser.html

Granted, it will have some color issues - but I think it will be less than 4" F/10 achromat. It will probably give equally good views of the planets and it will show wider field of view. It will generally be better all rounder scope than 4" F/10.

I think this is down to very strange situation on the market - some scopes are old stock, some are new, there is general market upset due to pandemic and I think that replacement focusers are probably overpriced because they are replacement units (well not overpriced as such, but same amount of overhead in transportation, handling and retail goes in both whole scope with focuser and focuser alone).

Some scopes have very strange prices probably due to demand. For example that Evostar 102mm is 300 euro, but look at this:

https://www.teleskop-express.de/shop/product_info.php/info/p3309_Skywatcher-Evostar-120-OTA---Refractor-120-1000mm-optical-tube.html

120mm refractor for 314 euro - only 14 euro more! I think that price of that 4" is very inflated. If we look at prices for F/5 versions (which are somewhat less money for some reason - as if it is easier to figure faster objective lens), we get "proper" ratio of prices. ST102 is ~200 euro and ST120 is ~280 euro.

Something tells me that if Evostar 120 is 314 euro and above F/5 versions have prices that they have, Evostar 102 is overpriced by at least 80 euro

I need to take a deep breath here, realize that I'm perfectly happy with 5 scopes that I now have and it's just time under stars that is the issue

 

[Chris]

Oh crikey that is over priced on the TS site! You can order the 4" f10 from FLO with the additional EQ3 mount for £349! I think you do need to factor in the 50mm finder and 2" diagonal etc but I'd pick the TS ED102 f7 all day long out the two. 

The prestige of owning something like a Classic f15 aside, I think it's getting harder and harder to justify achromat OTA's. As part of a beginner package with a mount and eyepieces sure thing, but as an OTA alone there are just so many great deals on ED glass scopes out there (stock issues aside).

Even triplets now, have you seen these latest offerings FLO have just stocked!

https://www.firstlightoptics.com/sharpstar-telescopes/sharpstar-61edph-ii-f5-5-triplet-ed-apo-telescope.html 

 

 

 

[John]

The obituary for the achromat has been written a few times over the past 20 years or so but they do seem to keep making a comeback

 

 

[vlaiv]

Anyone ever seen triplet with regular glass? I wonder how good such a scope would be?

[Chris]

45 minutes ago, vlaiv said:

Anyone ever seen triplet with regular glass? I wonder how good such a scope would be?

No, but in theory it should work right? One lens per primary wavelength? 

[vlaiv]

5 minutes ago, Lockie said:

No, but in theory it should work right? One lens per primary wavelength? 

It should, but those wavelengths that are not in focus - I wonder how much out of focus they will be.

Both ED and regular achromat are just doublets, and have two wavelengths in focus while others are out of focus. ED glass helps those out of focus wavelengths be just a bit out of focus - in some cases below what could be visually observed (but does show on long exposure photographs like slight violet halos around bright objects).

I wonder if regular glass types could achieve in triplet form what ED doublet achieves and why it was not attempted - or it was, but it did not do well?

[John]

The TAL Apolar 125 was a 6 element refractor that used a very novel optical layout and no ED glass as far as I know. It showed little or no CA when I tried one out:

https://stargazerslounge.com/topic/104408-tal-125r-apolar-apochromatic-refractor/

 

Edited December 10, 2020 by John

[mark81]

Clever Marketing...

Being a massive fan of the ST80, I havent had much to complain about. Its cheap and does good at what its supposed to.  BUT often i have thought about a focuser upgrade because when your sitting there waiting for the scope to settle after a re-focus you kind of wish it had a better focuser.... but that is about £180 so your £100 scope is now about £300 and all it can do it low/medium power.. as @vlaiv says, you add MAK for high  power and you may as well have got an ED80....

If you focus on one scope - like the ST120, You can get this on the AZ3 for about 280? And we all know that this mount is going to be poor with this scope sitting on it.... Yes, astro can be done but your soon going to become frustrated..... so you end up buying the AZ4 for £170 for a total outlay of £450 but of course in the first place you could have bought the 120 with the EQ3 (perfectly adequate) for £380!?   saving you £70.... clever marketing?

I guess that if we could all go back to the start of our astro journey, many of us would go straight in and buy our perfect scope and save loads of time and money although the outlay night sting a bit  ... and if you your just dipping your toe in, I guess we have to pay....

 

 

[Ags]

Forget upgrading cheap achros with better focusers etc... i would be happy with ED glass in a cheap ST80 OTA!

[F15Rules]

On 09/12/2020 at 19:12, vlaiv said:

Ok, let me first say - no, I'm not going to complain about prices of exotic ED glass - on the contrary!

I'm also going to do full disclosure here - I'm suffering cloudy skies syndrome at the moment - you know, have not been observing or doing anything astronomy related for months and I'm starting to fantasize about new scopes, different combinations, examining prices - making up needs and all those weird stuff we amateur astronomers do when we get this syndrome

It all started with focusers. I have M90 Monorail focuser that is leftover form an upgrade. I wanted to fit that focuser on My Evostar 102mm F/10 refractor for some time now but I can't seem to find suitable solution. While looking at other focusers and thinking about focusers - it hit me, most are quite expensive in comparison to cheap units that come on most entry level scopes.

You can't really find entry level refractor telescope with a decent focuser, and often, focusers themselves cost as much as entry level refractor scopes (achromat types).

For some reason I then started thinking about very cheap portable refractor type telescope that I would upgrade to make a decent scope (might have been prompted to this behavior by recent thread - "Show us your small refractor scope" ).

Say you take Skywatcher Mercury 705. I believe it to be decent glass, and with decent focuser, diagonal, maybe zoom eyepiece like Hyperflex 7.2-21.5mm - could make very nice portable / grab'n'go / quick peak package. I would also like retractable dew shield if possible.

Ok, let's see, how much would it cost? I'm going to quote here TS prices that are in euros and without VAT, so those are not final prices - but they do serve the purpose - comparison purpose.

OTA ~ 116 euro

Focuser  ~ 125 - 145 euro (125 is 1.25" model, and 145 euro and upwards are 2" models - all having 1:10 reduction. There are 1.25" and 2" single speed GSO crayford models that are for newtonian scopes but could be adopted - for about 76 euro each)

Adapter to mount focuser onto tube - at least 40 - 50 euro if not more.

Ok, lets add that up - OTA + 2" with 1:10 + adapter (cheapest estimate) = 116 + 145 + 40 = 301 euro.

On the other hand, you have something like this:

https://www.teleskop-express.de/shop/product_info.php/info/p1151_TS-Optics-70-mm-F6-ED-Travel-Refractor-with-modern-2--RAP-Focuser.html

And yes, it costs 301 euro and it has ED glass. Maybe not the best ED glass out there, but it will sure beat Mercury 705 in color correction and planetary views.

It has retractable dew shield as a bonus.

Moral of the story? Entry level refractors are actually expensive for what they provide!

Agreed 👍 - unless you trawl eBay etc and buy a well looked after old scope🙂..

Dave

[John]

I don't think I've ever bought a new achromat other than the TAL100R back in 1999 which at £250 with a mount and good eyepieces, delivered from Siberia was quite a bargain I think.

 

[DaveL59]

9 minutes ago, John said:

I don't think I've ever bought a new achromat other than the TAL100R back in 1999 which at £250 with a mount and good eyepieces, delivered from Siberia was quite a bargain I think.

 

I picked up the 100RS on an EQ5 with a set of eyepieces etc for £260 about 18 months back, lovely scope and I believe from the original owner, well cared for too. I consider it to have been a very good buy 🙂 

[nightfisher]

I guessed Tal would get mentioned in this interesting thread, and its such a shame that the 100RS is no longer for sale in the UK, it was an iconic scope that packed a punch well above its weight and always seemed to deliver sharp contrasty views