A novice seeking advice.

[Soligor Rob]

I have a couple of 30yr oldish Refactor’s, a Helios Telescope D=120mm, F1000mm and a Soligor D=93mm, F1000mm.

Ok being a total novice I thought I could improve the quality by purchasing a better eye piece, currently I have a Plossl 25mm as attached photo, so I bought the Celestron X-Cel LX 18mm.

Using a daylight test of a tree some 150m away I’m not certain there is very much difference in image quality.

Have I just learnt a lesson that the scopes aren’t that good, the X-Cel doesn’t match the scopes, or that the Plossl eye piece is equal to the X-Cel.

Any advice appreciated.

[banjaxed]

Assuming that your primary mirrors are clean then you should see a difference between the plossl and the Celestron. Try them at night on a star or planet to get a better idea.

[wulfrun]

25 minutes ago, banjaxed said:

Assuming that your primary mirrors are clean then you should see a difference between the plossl and the Celestron. Try them at night on a star or planet to get a better idea.

Not clear what the second scope is (OP says a couple of refractors though) but the first one says "refractor" i.e. no mirrors to be concerned about (bar the diagonal?) 😉

Edited February 13, 2021 by wulfrun

[Waddensky]

I second the advice to try them out at night. What kind of difference in image quality did you expect?

[John]

Both these refractors are good performers. Their focal ratios (focal length divided by the diameter of the objective lens) are not particularly demanding on eyepieces so you probably won't see much difference between using the 25mm plossl and the more expensive Celestron X-Cel LX 18mm, apart from the latter giving a bit more magnification.

As has been said - get them out under the stars and they should both deliver some very satisfying views.

 

Edited February 13, 2021 by John

[Soligor Rob]

1 hour ago, John said:

Both these refractors are good performers. Their focal ratios (focal length divided by the diameter of the objective lens) are not particularly demanding on eyepieces so you probably won't see much difference between using the 25mm plossl and the more expensive Celestron X-Cel LX 18mm, apart from the latter giving a bit more magnification.

As has been said - get them out under the stars and they should both deliver some very satisfying views.

 

Thanks for that, I wasn't certain if a daylight test was the best option

Can you explain why Their  focal Ratios are not particularly demanding on eyepieces?

Would I be better quality Diagonal if there is such a thing help? or buying the X-Cel Barlow.

Thanks.

Edited February 13, 2021 by Soligor Rob

[John]

51 minutes ago, Soligor Rob said:

Thanks for that, I wasn't certain if a daylight test was the best option

Can you explain why Their  focal Ratios are not particularly demanding on eyepieces?

Would I be better quality Diagonal if there is such a thing help? or buying the X-Cel Barlow.

Thanks.

The focal ratios of these long refractors are F/10.75 for the 93mm (although I think that might really be a 90mm) and F/8.3 for the 120mm. These are considered relatively "slow" focal ratios by todays standards so the light cone they produce is not as steep as a "faster" scope would produce and this means that the optics within the eyepiece do not have to be too sophisticated / complex to deal with it effectively, ie: without adding optical issues.

Better quality accessories such as diagonals, barlows and eyepieces can improve things a bit but won't turn a poor scope into a good one.

Having used both the types of scope that you have, they are not poor scopes anyway. They actually perform pretty well.

You said in the earlier post that you learned a lesson that these scopes aren't that good - was that though your own experience of using them or from what you have read ?

Why not try them at night on astro targets and see how they perform then ?

 

 

 

 

Edited February 13, 2021 by John

[Soligor Rob]

18 minutes ago, John said:

The focal ratios of these long refractors are F/10.75 for the 93mm (although I think that might really be a 90mm) and F/8.3 for the 120mm. These are considered relatively "slow" focal ratios by todays standards so the light cone they produce is not as steep as a "faster" scope would produce and this means that the optics within the eyepiece do not have to be too sophisticated / complex to deal with it effectively, ie: without adding optical issues.

Better quality accessories such as diagonals, barlows and eyepieces can improve things a bit but won't turn a poor scope into a good one.

Having used both the types of scope that you have, they are not poor scopes anyway. They actually perform pretty well.

You said in the earlier post that you learned a lesson that these scopes aren't that good - was that though your own experience of using them or from what you have read ?

Why not try them at night on astro targets and see how they perform then ?

 

 

 

 

Again John thanks for the reply, the diagram explains a lot, in answer  to your question, I wasn't saying that either scope was of poor quality I was asking  were they of poor quality, I remember Soligor made some excellent camera lens in the 1980's so thought that might be ok, the Helios  having a  slightly larger diameter I assume will collect more light.

I have only been using them for a month and in that time only managed to get outside 3 times because of the skies, we live in a Bortle 5 area so not too bad for viewing, (have been reading lots) I purchased a Steve Richards book "Making every photon count" which is a fountain of knowledge, most of which is beyond me , I am at the start of a learning curve and well out of my comfort zone but eager to learn.

[John]

The Helios is the same instrument as the Skywatcher Evostar 120mm. The manufacturer (Synta) used the brand name Helios before moving to Skywatcher.  I think the Soligor refractor is made by GSO, Guan Sheng Optical in Taiwan.

 

 

 

Edited February 13, 2021 by John

[Soligor Rob]

17 minutes ago, John said:

The Helios is the same instrument as the Skywatcher Evostar 120mm. The manufacturer (Synta) used the brand name Helios before moving to Skywatcher.  I think the Soligor refractor is made by GSO, Guan Sheng Optical in Taiwan.

 

 

 

That's good information thanks so they are both fairly decent scopes for a beginner, hopefully we will have some clear skies soon.

Both are mounted on EQ3 mounts, the Helios on a "Sky Scan 2001"  don't know the Soligor mount, when I got the scope the mount was difficult to move but after stripping & cleaning it's movement is now fluid and precise.

[Tiny Clanger]

Hello and welcome.

The learning curve with observing is steep but worth the climb !

Soligor I remember that name from camera lenses ... 🙂

The two eyepieces you have are very similar in what they will show  you as far as magnification goes :  the 25mm plossl will give you 49x magnification and the 18mm 55.5x ( just divide the focal  length of your 'scope(s) 1000 by the eyepiece mm ) 

The slightly higher magnification more expensive celestron has a wider (60 degree)  field of view than a plossl ( usually the design is quoted as 50 degrees whatever the manufacturer) so the actual  view in the two will be very similar. Take a look at the field of view simulator at the bottom of this page, you can dial in your scope (or the present day equivalent John told you about  anyway) , delete the circles for all but your specific EP and add one for another manufaturer's plossl to see the difference on various targets

https://www.firstlightoptics.com/celestron-eyepieces/celestron-x-cel-lx-eyepiece.html

So if you expected a dramatic change in the field of view or magnification between the two, you won't see it. What you should see for your extra ££s on a clear night is sharper , better detail on whatever you point the 'scope at. If the telescope(s) are so forgiving that you cannot see a difference in quality, at least you have a good EP you can use if you upgrade at some point , and a plossl to bundle with one of the 'scopes if you sell 'em !

Fingers crossed you get the chance to use the kit at night  soon .

Heather

 

Edited February 13, 2021 by Tiny Clanger
added 'to use the kit at night' ,

[Soligor Rob]

15 hours ago, Tiny Clanger said:

Hello and welcome.

The learning curve with observing is steep but worth the climb !

Soligor I remember that name from camera lenses ... 🙂

The two eyepieces you have are very similar in what they will show  you as far as magnification goes :  the 25mm plossl will give you 49x magnification and the 18mm 55.5x ( just divide the focal  length of your 'scope(s) 1000 by the eyepiece mm ) 

The slightly higher magnification more expensive celestron has a wider (60 degree)  field of view than a plossl ( usually the design is quoted as 50 degrees whatever the manufacturer) so the actual  view in the two will be very similar. Take a look at the field of view simulator at the bottom of this page, you can dial in your scope (or the present day equivalent John told you about  anyway) , delete the circles for all but your specific EP and add one for another manufaturer's plossl to see the difference on various targets

https://www.firstlightoptics.com/celestron-eyepieces/celestron-x-cel-lx-eyepiece.html

So if you expected a dramatic change in the field of view or magnification between the two, you won't see it. What you should see for your extra ££s on a clear night is sharper , better detail on whatever you point the 'scope at. If the telescope(s) are so forgiving that you cannot see a difference in quality, at least you have a good EP you can use if you upgrade at some point , and a plossl to bundle with one of the 'scopes if you sell 'em !

Fingers crossed you get the chance to use the kit at night  soon .

Heather

 

Hi Heather, Thanks for the FOV simulator, I bought the Celestron eyepiece hoping I would get a more sharp and clear view I realise now that using it in daylight isn't a fair assessment.

Hopeful this bitterly cold Easterly wind will turn soon and we will get some clear skies.