#1  
Old 05-03-2019, 12:07 AM
Astronovice (Calvin)
Saxon 200DS, HEQ5 Pro

Astronovice is offline
 
Join Date: Jun 2017
Location: Cairns Northern Beaches
Posts: 14
Refractor options

I am looking to buy a refractor and have narrowed my choice down to the following 3 options (unless something better second hand turns up on here at a similar price).

1. SkyWatcher ED 120 doublet
2. SkyWatcher Esprit 80 ED Triplet
3. Saxon 102mm ED Apo Triplet

All three come with a similar price tag but obviously the similarity ends there.

I currently own an F5 200mm Saxon newt on an HEQ5 Pro mount and am looking for something a bit more portable, albeit using the same mount at this stage.

I want to use the scope for both visual and imaging (deep sky rather than planetary). I will be using an unmodded Nikon D5500 for imaging and already have a T Ring adaptor.

I live in FNQ so some degree of humidity is usually a factor, as is a moderate level of light pollution at home.

All sage advice from members regarding best choice will be gratefully appreciated.
Reply With Quote
  #2  
Old 05-03-2019, 08:17 AM
AstroApprentice (Jason)
Registered User

AstroApprentice is offline
 
Join Date: Dec 2015
Location: Melbourne, Australia
Posts: 254
Ed120

I have an ED120 and it's a great visual scope. I have also taken very good lunar and planetary images with it using a Nikon D5500 and BackyardNikon. Nevertheless, it's not really an ideal deep sky setup for a number of reasons, particularly the mount demands due to its weight and length. If you're set on deep sky, then the Esprit 80 ED triplet has received many positive reviews and your HEQ5 will handle it comfortably.
Reply With Quote
  #3  
Old 05-03-2019, 10:52 AM
Saturnine (Jeff)
Registered User

Saturnine is offline
 
Join Date: Jul 2008
Location: Wollongong
Posts: 859
Would also recommend the ED120 , it will sit on an HEQ5, which will handle 10 / 12 kg easily. For deep sky , aperture wins, it will pull in fainter objects than smaller scopes. Will give good views for planetary and will work well for astrophotography . Not as well corrected around the edge of the frame as an triplet but it depends how obsessed you want to become. Can always upgrade to an triplet if and when you become more inclined to imaging.
Reply With Quote
  #4  
Old 05-03-2019, 11:52 AM
xelasnave's Avatar
xelasnave
Gravity does not Suck

xelasnave is offline
 
Join Date: Mar 2005
Location: Tabulam
Posts: 12,845
Hi Calvin
I went with the espirt 80mm and I think it is fantastic.
Easy to manage and I dont see any need to replace the focuser which often comes up.
The images I have obtained with it sees me using it and leaving my eight inch f5 in its box...if you are thinking of ever going narrow band you will be surprised what this little scope delivers.
Anyways in time you probably will add all the scopes on your list to your collection☺.
Alex
Reply With Quote
  #5  
Old 05-03-2019, 07:20 PM
Ukastronomer's Avatar
Ukastronomer (Jeremy)
Feel free to edit my imag

Ukastronomer is offline
 
Join Date: Jan 2019
Location: Llandysul, WALES, UK
Posts: 1,153
I have an Esprit and it is superb in finish and views

Can't beat a triplet

Mind you the doublet is nice I have the 72mm for Solar

As for Saxon, I'll stick with known brands for after sales service
Attached Thumbnails
Click for full-size image (P1050599.jpg)
45.6 KB15 views
Click for full-size image (P1060045.jpg)
104.9 KB18 views
Reply With Quote
  #6  
Old 05-03-2019, 07:22 PM
Ukastronomer's Avatar
Ukastronomer (Jeremy)
Feel free to edit my imag

Ukastronomer is offline
 
Join Date: Jan 2019
Location: Llandysul, WALES, UK
Posts: 1,153
Quote:
Originally Posted by AstroApprentice View Post
I have an ED120 and it's a great visual scope. I have also taken very good lunar and planetary images with it using a Nikon D5500 and BackyardNikon. Nevertheless, it's not really an ideal deep sky setup for a number of reasons, particularly the mount demands due to its weight and length. If you're set on deep sky, then the Esprit 80 ED triplet has received many positive reviews and your HEQ5 will handle it comfortably.
Reply With Quote
  #7  
Old 06-03-2019, 09:53 AM
skysurfer's Avatar
skysurfer
Dark sky rules !

skysurfer is offline
 
Join Date: Dec 2011
Location: 52N 6E (EU)
Posts: 1,043
Go for the ED120.

I have an ED110 for both visual and photographic use, with which I am very happy. I use it as a travel scope as well, I replaced the tube rings and the dew shield with lighter ones to reduce weight for airplane travel.
Most telescopes are not optimized for lightweight.

You can do the same with the ED120, if you think it is too heavy.
Attached Thumbnails
Click for full-size image (IMG_4721 copy.jpg)
211.2 KB25 views
Reply With Quote
  #8  
Old 06-03-2019, 10:21 AM
casstony
Registered User

casstony is offline
 
Join Date: Feb 2006
Location: Warragul, Vic
Posts: 4,134
Hi Calvin, if you haven't done any DSO imaging it's easier to start with a shorter focal length scope - you'll get good results more quickly and avoid frustration.

You can start with 30 to 60 second exposures but eventually you'll want to learn to guide to enable exposures of a few minutes.
Reply With Quote
  #9  
Old 06-03-2019, 11:44 AM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Posts: 5,284
Quote:
Originally Posted by casstony View Post
Hi Calvin, if you haven't done any DSO imaging it's easier to start with a shorter focal length scope - you'll get good results more quickly and avoid frustration.

You can start with 30 to 60 second exposures but eventually you'll want to learn to guide to enable exposures of a few minutes.
X2. An 80mm is a pretty good place to start, it gives you a nice field of view (like being able to get the entire Rosette Nebula). Look wider than the Skywatcher Esprit, as it's abit expensive compared to other well know 80mm triplet APO. At the very least check the Photoline scopes offered by Teleskop Services. If the cost doesn't concern you just buy from a local retailer. Get a reducer/corrector, unless your buying a dedicated astrograph type APO (which tend to have them built in). A reducer/corrector will give you a faster scope and slightly wider flat field). A scope like the one below is perfectly fine with just a flattener attached as it is fast for a triplet.

An example:

https://www.teleskop-express.de/shop...P-Focuser.html
Reply With Quote
  #10  
Old 06-03-2019, 11:59 AM
traveller's Avatar
traveller (Bo)
Not enough time and money

traveller is offline
 
Join Date: Aug 2011
Location: Melbourne
Posts: 2,116
+1 for the ED80 Triplet.
It has better colour correction than a doublet, shorter FL so easier on the guiding, plus it has a focal ratio of f/5 which cuts down imaging time.
Reply With Quote
  #11  
Old 06-03-2019, 01:45 PM
Astronovice (Calvin)
Saxon 200DS, HEQ5 Pro

Astronovice is offline
 
Join Date: Jun 2017
Location: Cairns Northern Beaches
Posts: 14
Quote:
Originally Posted by Ukastronomer View Post
I have an Esprit and it is superb in finish and views

Can't beat a triplet

Mind you the doublet is nice I have the 72mm for Solar

As for Saxon, I'll stick with known brands for after sales service
I think the Saxon is identical to the Explore Scientific 102mm F7 FCD100 triplet. The specifications and much of the scope description wording are identical on both Saxon and ES websites.

I would be interested in any comments regarding the Esprit 80 triplet vs the Saxon 102mm Triplet (Explore Scientific 102mm clone).

Last edited by Astronovice; 06-03-2019 at 02:29 PM.
Reply With Quote
  #12  
Old 06-03-2019, 03:52 PM
gregbradley's Avatar
gregbradley
Registered User

gregbradley is offline
 
Join Date: Feb 2006
Location: Sydney
Posts: 15,309
There is a bit of a scale of quality with refractors.

Here are some known good companies:

1. Teleskop Services. They have a broad range of scopes. A number of these are clones that are simply wearing their brand and you'll see the same scope elsewhere rebadged. But it seems like occasionally they demand a bit more from the same scope which is good.

2. Stellarvue. They have a good name. Their prices are probably a bit higher but you are less likely to have issues.

3. William Optics. They can sometimes be good. Check reviews though as I do read of the occasional dud.

4. Esprit. It seems these are quite high end triplets.

5. Astrotech - they often rebrand these same scopes as Teleskop Services, Skywatcher and others.


As a general rule triplets are better corrected for false colour than doublets although I see a lot of FPL53 (premium ED glass) and Lanthanum doublet scopes these days. How they perform is a bit hard to tell but from sample images some brands post they perform quite well.

Also keep in mind that the Q style refractors are more suitable for imaging than the straight triplets etc. Teleskop services lists their Q type astrograph refractors separately. They are often around F5 which is nice and fast and they should have more perfect stars in the corners.

As I understand it, a lot of these FPL53 triplets are lenses made by Canon iOptron and then they are fitted into various telescope bodies so the standard seems to be quite high.

APO refractors used to be extremely expensive and in the last several years they have come down a lot in price and the quality has risen.

To complete the list the high end scopes are:

1. Takahashi.
2. AstroPhysics.
3. TEC (Telescope Engineer Company).
4. APM.
5. CFF.

Astrophysics have a wait list so not that practical to list them but their scopes often come up in 2nd hand marts.

CFF would be my current top notch choice or Takahashi. APM used to be super high end but their strehl ratios are lower than Takahashi, CFF.
TEC are very good but optimised for visual so a bit weak in the red channel.

When considering a refractor I would;

1. Consider the brand as above.
2. Triplet is usually better than a doublet.
3. FPL53 is the premium glass and usually only 1 element is FPL53 and then the other 2 elements are some lesser glass. That is normal. If it were FPL51 I would be less interested.
4. Focuser. A good focuser is a must. It needs a micro adjuster as well.
Larger focusers are better than shorter ones.
5. How wide is the corrected circle of the scope? That means the circle where all the stars are round and not distorted.
6. Accessories - guide scopes, mounting rings, flatteners and reducers (a flattener makes stars round in the corners, a reducer makes the F ratio lower and the field of view wider making for faster imaging and wider views).

I hope that helps.

Greg.
Reply With Quote
  #13  
Old 06-03-2019, 04:15 PM
casstony
Registered User

casstony is offline
 
Join Date: Feb 2006
Location: Warragul, Vic
Posts: 4,134
Quote:
Originally Posted by Astronovice View Post
I would be interested in any comments regarding the Esprit 80 triplet vs the Saxon 102mm Triplet (Explore Scientific 102mm clone).
The Esprit is a safe buy and includes a flattener. It's a high quality scope.

The Saxon 102 FCD100 triplet would be better for double duty as a visual/imaging scope. The quality may not be quite as good. Astro anarchy (astro pete's) is a reputable dealer which sells both brands - ask them if the focuser is good enough for imaging and also ask if they can supply a suitable reducer/flattener.
Reply With Quote
  #14  
Old 06-03-2019, 08:12 PM
Ukastronomer's Avatar
Ukastronomer (Jeremy)
Feel free to edit my imag

Ukastronomer is offline
 
Join Date: Jan 2019
Location: Llandysul, WALES, UK
Posts: 1,153
Quote:
Originally Posted by Astronovice View Post
I think the Saxon is identical to the Explore Scientific 102mm F7 FCD100 triplet. The specifications and much of the scope description wording are identical on both Saxon and ES websites.

I would be interested in any comments regarding the Esprit 80 triplet vs the Saxon 102mm Triplet (Explore Scientific 102mm clone).
This is the problem when you don't have scopes lile this in the UK, even Explore Scientific are not "over" known, then you have no benchmark, as yet I have never seen an ES scope at a star party in the UK, just Skywatcher and better known ones.

You are probably 100% right and it is a good scope I would like to hear of peoples views on Saxon also

Thanks
Reply With Quote
  #15  
Old 06-03-2019, 08:13 PM
Ukastronomer's Avatar
Ukastronomer (Jeremy)
Feel free to edit my imag

Ukastronomer is offline
 
Join Date: Jan 2019
Location: Llandysul, WALES, UK
Posts: 1,153
Quote:
Originally Posted by gregbradley View Post
There is a bit of a scale of quality with refractors.

Here are some known good companies:

1. Teleskop Services. They have a broad range of scopes. A number of these are clones that are simply wearing their brand and you'll see the same scope elsewhere rebadged. But it seems like occasionally they demand a bit more from the same scope which is good.

2. Stellarvue. They have a good name. Their prices are probably a bit higher but you are less likely to have issues.

3. William Optics. They can sometimes be good. Check reviews though as I do read of the occasional dud.

4. Esprit. It seems these are quite high end triplets.

5. Astrotech - they often rebrand these same scopes as Teleskop Services, Skywatcher and others.


As a general rule triplets are better corrected for false colour than doublets although I see a lot of FPL53 (premium ED glass) and Lanthanum doublet scopes these days. How they perform is a bit hard to tell but from sample images some brands post they perform quite well.

Also keep in mind that the Q style refractors are more suitable for imaging than the straight triplets etc. Teleskop services lists their Q type astrograph refractors separately. They are often around F5 which is nice and fast and they should have more perfect stars in the corners.

As I understand it, a lot of these FPL53 triplets are lenses made by Canon iOptron and then they are fitted into various telescope bodies so the standard seems to be quite high.

APO refractors used to be extremely expensive and in the last several years they have come down a lot in price and the quality has risen.

To complete the list the high end scopes are:

1. Takahashi.
2. AstroPhysics.
3. TEC (Telescope Engineer Company).
4. APM.
5. CFF.

Astrophysics have a wait list so not that practical to list them but their scopes often come up in 2nd hand marts.

CFF would be my current top notch choice or Takahashi. APM used to be super high end but their strehl ratios are lower than Takahashi, CFF.
TEC are very good but optimised for visual so a bit weak in the red channel.

When considering a refractor I would;

1. Consider the brand as above.
2. Triplet is usually better than a doublet.
3. FPL53 is the premium glass and usually only 1 element is FPL53 and then the other 2 elements are some lesser glass. That is normal. If it were FPL51 I would be less interested.
4. Focuser. A good focuser is a must. It needs a micro adjuster as well.
Larger focusers are better than shorter ones.
5. How wide is the corrected circle of the scope? That means the circle where all the stars are round and not distorted.
6. Accessories - guide scopes, mounting rings, flatteners and reducers (a flattener makes stars round in the corners, a reducer makes the F ratio lower and the field of view wider making for faster imaging and wider views).

I hope that helps.

Greg.
Reply With Quote
  #16  
Old 06-03-2019, 09:18 PM
brian nordstrom's Avatar
brian nordstrom (As avatar)
Registered User

brian nordstrom is offline
 
Join Date: Apr 2007
Location: Perth WA
Posts: 4,358
Jeremy , Saxon is a big brand down here , your run of the mill Synta scopes but the 102mm triplet is not one , its a Kuming Optical I think and would be the sweet spot between these 3 scopes .

Brian.
Quote:
Originally Posted by Ukastronomer View Post
I have an Esprit and it is superb in finish and views

Can't beat a triplet

Mind you the doublet is nice I have the 72mm for Solar

As for Saxon, I'll stick with known brands for after sales service
Reply With Quote
  #17  
Old 06-03-2019, 10:53 PM
Astronovice (Calvin)
Saxon 200DS, HEQ5 Pro

Astronovice is offline
 
Join Date: Jun 2017
Location: Cairns Northern Beaches
Posts: 14
Quote:
Originally Posted by gregbradley View Post
There is a bit of a scale of quality with refractors.

Here are some known good companies:

1. Teleskop Services. They have a broad range of scopes. A number of these are clones that are simply wearing their brand and you'll see the same scope elsewhere rebadged. But it seems like occasionally they demand a bit more from the same scope which is good.

2. Stellarvue. They have a good name. Their prices are probably a bit higher but you are less likely to have issues.

3. William Optics. They can sometimes be good. Check reviews though as I do read of the occasional dud.

4. Esprit. It seems these are quite high end triplets.

5. Astrotech - they often rebrand these same scopes as Teleskop Services, Skywatcher and others.


As a general rule triplets are better corrected for false colour than doublets although I see a lot of FPL53 (premium ED glass) and Lanthanum doublet scopes these days. How they perform is a bit hard to tell but from sample images some brands post they perform quite well.

Also keep in mind that the Q style refractors are more suitable for imaging than the straight triplets etc. Teleskop services lists their Q type astrograph refractors separately. They are often around F5 which is nice and fast and they should have more perfect stars in the corners.

As I understand it, a lot of these FPL53 triplets are lenses made by Canon iOptron and then they are fitted into various telescope bodies so the standard seems to be quite high.

APO refractors used to be extremely expensive and in the last several years they have come down a lot in price and the quality has risen.

To complete the list the high end scopes are:

1. Takahashi.
2. AstroPhysics.
3. TEC (Telescope Engineer Company).
4. APM.
5. CFF.

Astrophysics have a wait list so not that practical to list them but their scopes often come up in 2nd hand marts.

CFF would be my current top notch choice or Takahashi. APM used to be super high end but their strehl ratios are lower than Takahashi, CFF.
TEC are very good but optimised for visual so a bit weak in the red channel.

When considering a refractor I would;

1. Consider the brand as above.
2. Triplet is usually better than a doublet.
3. FPL53 is the premium glass and usually only 1 element is FPL53 and then the other 2 elements are some lesser glass. That is normal. If it were FPL51 I would be less interested.
4. Focuser. A good focuser is a must. It needs a micro adjuster as well.
Larger focusers are better than shorter ones.
5. How wide is the corrected circle of the scope? That means the circle where all the stars are round and not distorted.
6. Accessories - guide scopes, mounting rings, flatteners and reducers (a flattener makes stars round in the corners, a reducer makes the F ratio lower and the field of view wider making for faster imaging and wider views).

I hope that helps.

Greg.
Thank you Greg,

Your comments are most helpful.

Am I right in assuming that Hoya FCD100 and Ohara FPL53 are broadly equivalent?

Calvin

Last edited by Astronovice; 07-03-2019 at 12:00 AM.
Reply With Quote
  #18  
Old 07-03-2019, 01:43 AM
Ukastronomer's Avatar
Ukastronomer (Jeremy)
Feel free to edit my imag

Ukastronomer is offline
 
Join Date: Jan 2019
Location: Llandysul, WALES, UK
Posts: 1,153
Quote:
Originally Posted by brian nordstrom View Post
Jeremy , Saxon is a big brand down here , your run of the mill Synta scopes but the 102mm triplet is not one , its a Kuming Optical I think and would be the sweet spot between these 3 scopes .

Brian.
I thought that may be the case, being well known there but not here

Reply With Quote
  #19  
Old 07-03-2019, 03:18 AM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Posts: 5,284
Quote:
Originally Posted by Astronovice View Post
Thank you Greg,

Your comments are most helpful.

Am I right in assuming that Hoya FCD100 and Ohara FPL53 are broadly equivalent?

Calvin
It depends on how broadly you want to define equivalent.

FPL-53 offers almost indistinguishable performance compared to Fluorite/CaF2, in an astronomical refractor, itís more stable, has better physical characteristics, cost far less, and it's environmentally better to work with. FPL-53 has an Abbe number of 94.99 .
FCD-100. The relatively new Extra Low Dispersion Hoya FCD-100 glass has an Abbe number of 94.66 compared to 94.99 of S-FPL53.
To most, if not all eyes using it visually, Flourite, FPL-53, and FCD-100, will appear to be the same. FCD-100 is more cost effective currently, but many astronomers buy on reputation, even if they cannot visually tell the difference, and Flourite and FPL-53 continue to sit at the top in people minds.
Reply With Quote
  #20  
Old 07-03-2019, 03:53 AM
Ukastronomer's Avatar
Ukastronomer (Jeremy)
Feel free to edit my imag

Ukastronomer is offline
 
Join Date: Jan 2019
Location: Llandysul, WALES, UK
Posts: 1,153
Quote:
Originally Posted by casstony View Post
The Esprit is a safe buy and includes a flattener. It's a high quality scope.

The Saxon 102 FCD100 triplet would be better for double duty as a visual/imaging scope. The quality may not be quite as good. Astro anarchy (astro pete's) is a reputable dealer which sells both brands - ask them if the focuser is good enough for imaging and also ask if they can supply a suitable reducer/flattener.
You see you get the FF free over there in the UK we have to buy it
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 06:35 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Advertisement
NexDome Observatories
Advertisement
Meade Australia
Advertisement
SkyWatcher Australia
Advertisement
Lunatico Astronomical
Advertisement
Celestron Australia
Advertisement
OzScopes Authorised Dealer
Advertisement
Bintel
Advertisement
Astronomy and Electronics Centre
Advertisement