Skywatcher UWA Planetary eyepiece

[Stardust3]

Hi, I'm new to astronomy and seeking help.  I'm not new to the sky having watched Sky at Night for as long as I can, or want to, remember!  I have finally bought myself a telescope:  Skywatcher Skymax 127 Maksutov-Cassegrain.  With it came 10mm and 25mm eyepieces.  These, I know won't get me very far with planet viewing and so I was looking at the Skywatcher UWA Planetary eyepiece.  However, on doing the calculations re telescope focal length and eyepiece focal length this would take the magnification to 600x.  The upper limit power of this particular telescope is, again, according to the calculations 254x(mm) or 300x (in inches).  My question is: 

Would the UWA eyepiece work with my scope to produce reasonably sized and clear planet viewing? 

Also, apart from a 2x Barlow and perhaps a moon filter, is there anything else that you would recommend as a good start for viewing the planets and deep sky objects?

I also had a problem viewing Venus recently, although I didn't have the right eyepiece, the ones that came with it I understand are not useful for looking at the planets.  It was a clear night and Venus was easily visible, having checked its position before going out to make sure that the bright star in the sky was indeed Venus.  On looking through the scope I could see a bright white circle with a black centre, with some horizontal lines on the white disc.  There were also what looked like minute, transparent bugs on the white disc.  I've read a few posts that say that these are possibly floaters in the eye and you just have to get used to that?  When I refocused the lens the disc either went very blurred one way or to a small star like point the other way?  What was I doing wrong or was it because the 10mm and/or 28mm was useless for this purpose?

Your help would be greatly appreciated.

Thanks.

 

 

Edited February 9, 2020 by Stardust3

[johninderby]

Here’s the results running the Skymax 127 specs through the Televue eyepice calculator. The actual usable aperture of this scope is anout 118mm. It’s not actually a 127mm. 

Max usable mag is 279x

The second column gives the eyepiece focal length and the right hand gives the mag.

Edited February 9, 2020 by johninderby

[Stardust3]

Hi and thanks for the prompt response. 

Thanks for the information.  From what you've shown, the Skywatcher UWA Planetary 2.5mm eyepiece would not be any use for my telescope, is that correct?

[johninderby]

Yes the 2.5mm is simply too much. When I had a Skymax 127 found 7mm to be of more use as my high mag eyepiece and occasionaly a 5mm for the moon.

Edited February 9, 2020 by johninderby

[Ricochet]

6 hours ago, Stardust3 said:

What was I doing wrong

You were out of focus and essentially looking at the inside of your telescope. Always focus your telescope to make the object as small as possible. 

For your telescope I would guess that actually a 10mm is about optimum for planetary observation. A Baader Classic Ortho would be a good and relatively cheap upgrade over the kit lens, if you don't need glasses and can put up with the short eye relief. 

[John]

Your scope is at sharp focus when the target object is at its smallest size in the eyepiece view. Either side of that the image will expand to an increasingly large disk and when well out of focus you can see the secondary silhouetted against the disk and possibly any dust in the optical system (ie: the "bugs") as well.

The planets are generally surprisingly small when viewed through a telescope even at reasonably high magnifications.

 

[Stardust3]

Thanks to John, Ricochet and John (Moderator).  I'll just buy a Barlow then as then it will take the 10mm down to 5mm.  I assume that a Barlow lens and a 5mm eyepiece would be the same as using a 2.5mm in terms of upper power limit of the telescope?  I know what a Barlow lens does but don't understand how it works, i.e. does it just magnify the image after it's hit the mirrors, thereby not affecting the upper power limit of the scope, like using a magnifying glass on an image or does it count towards the magnification re  upper power limit of the telescope?  A bit difficult to explain this concisely but hope the above is clear?

Again many thanks for taking the time to read and help with the question.

[JOC]

If you are in the UK you might find that something given x200 and as an absolutely maximum x250 might be about all that's usable due to atmospherics.

[johninderby]

A barlow changes the focal length of the eyepiece so a 10mm eyepiece is effectively the same as a 20mm eyepiece with a 2x barlow.  It is mutiplying the magnification of the eyepiece. You could also think of it as dividing the focal length.

Edited February 10, 2020 by johninderby

[John]

Using a barlow does not overcome the limitations on useful magnification that the scope and seeing conditions impose. It's a device that is an alternative to using a short focal length eyepiece.

 

[Raph-in-the-sky]

2 hours ago, Stardust3 said:

Thanks to John, Ricochet and John (Moderator).  I'll just buy a Barlow then as then it will take the 10mm down to 5mm.  I assume that a Barlow lens and a 5mm eyepiece would be the same as using a 2.5mm in terms of upper power limit of the telescope?  I know what a Barlow lens does but don't understand how it works, i.e. does it just magnify the image after it's hit the mirrors, thereby not affecting the upper power limit of the scope, like using a magnifying glass on an image or does it count towards the magnification re  upper power limit of the telescope?  A bit difficult to explain this concisely but hope the above is clear?

Again many thanks for taking the time to read and help with the question.

If I were you I would invest in a decent eyepiece before a barlow. If the 25mm you got with the scope could be considered half (or a quarter) decent the 10mm is absolute dog sh*t. I think that an 8mm BST Starguider would be great with your scope

https://www.firstlightoptics.com/bst-starguider-eyepieces/bst-starguider-60-8mm-ed-eyepiece.html

[Stardust3]

Thanks again guys.  You've all been really helpful.  It would seem that I have a couple of choices, one to get a  6mm eyepiece or/and a 12mm and a 2x barlow to get me to my max usable magnification for viewing the planets.  As someone suggested BST starguider I may look at that.  I was looking at a 6ml plossl but as it's much less expensive around £24 at First Light Optics I wondered if it would be as good as a BST star guider 6mm?  Anyone have any experience of these with a Skymax MCT 127?

When, as suggested here, I reduce the focus right down until Venus is as small but in focus as possible I'm getting 'star shine/sparkle' and colouring, like a tiny rainbow blob coming out of the top left of Venus.  Does this suggest any fault anywhere, scope not collimated or lens not up to it?  The eyepiece I was using was a 10mm one that came with the scope, any ideas would be a great help.  So much to learn so little time!  

 

[Stardust3]

Hi again

Just looking at eyepieces.  There are so many to choose from, would this one be a good choice or are the skywatcher ones not as good as other makes?  The one I'm looking at is a 7mm.  The spec is below.   I don't want to get the wrong one and find it doesn't work as I would like, which is to see the planets with as much magnification and detail as my scope will allow.  Thanks again everyone, you're all great for taking the time to help us newbies out.  

Specification

• UWA Planetary series eyepieces are ideal when high magnification is required for the observation of fine planetary and lunar detail.
• Based on a modified Plossl design, these fully multi coated eyepieces are constructed with five lens elements, and are characterised by their wide 58 degree field of view, low distortion, high contrast performance and comfortable operation.
• Each model features fold down / screw off rubber eyecups and a generous 16mm eye relief, making them suitable for spectacle wearers.
• They feature the security of rubber grips and the eyepiece barrels are threaded for standard 1.25 inch filters.

[Raph-in-the-sky]

8 minutes ago, Stardust3 said:

Thanks again guys.  You've all been really helpful.  It would seem that I have a couple of choices, one to get a  6mm eyepiece or/and a 12mm and a 2x barlow to get me to my max usable magnification for viewing the planets.  As someone suggested BST starguider I may look at that.  I was looking at a 6ml plossl but as it's much less expensive around £24 at First Light Optics I wondered if it would be as good as a BST star guider 6mm?  Anyone have any experience of these with a Skymax MCT 127?

 

The plossl design for short focal lenght (ie. less than 10mm) have very short eyerelief which means that you will have to jam your eye very close to the lens making it uncomfortable to use.  The apparent field of view is about 50° with this design.

The BSTs have comfortable eyereleif and a 60° apparent field of view and are generally great value for money.

[Raph-in-the-sky]

3 minutes ago, Stardust3 said:

Hi again

Just looking at eyepieces.  There are so many to choose from, would this one be a good choice or are the skywatcher ones not as good as other makes?  The one I'm looking at is a 7mm.  The spec is below.   I don't want to get the wrong one and find it doesn't work as I would like, which is to see the planets with as much magnification and detail as my scope will allow.  Thanks again everyone, you're all great for taking the time to help us newbies out.  

Specification

• UWA Planetary series eyepieces are ideal when high magnification is required for the observation of fine planetary and lunar detail.
• Based on a modified Plossl design, these fully multi coated eyepieces are constructed with five lens elements, and are characterised by their wide 58 degree field of view, low distortion, high contrast performance and comfortable operation.
• Each model features fold down / screw off rubber eyecups and a generous 16mm eye relief, making them suitable for spectacle wearers.
• They feature the security of rubber grips and the eyepiece barrels are threaded for standard 1.25 inch filters.

This has routhly the same specifications as the BSTs but are considered by many (especially on this forum) as inferior in terms of quality of views. I have a couple of these and a couple of BSTs and I would say go for BSTs first and if you can't find the right focal lenght go for the Skywatcher... Again I beleive that an 8mm should be close to your max magnification but still usable on most nights (the max power will only be usable on the best nights, I would leave this for later))

[Steve Clay]

Thoroughly recommend the BST starguiders. I use them in a 127 MAK, ED80 and 150PDS newt. They give good views. Good eye relief and 60 deg FOV. They have a rotating eye cup and feel more expensive than they are. In-fact there are an 8 and 18 mm for sale in the classifieds.

I have the 8, 12 and 18 mm. I also have a good 2 x barlow which converts the EP's to 4, 6 and 9 mm respectively.

Another option price-wise is the OVL zoom EP . https://www.firstlightoptics.com/ovl-eyepieces/hyperflex-72mm-215mm-eyepiece.html  also add a barlow to this and you have a range of options covered.

I have that zoom and can say it is very good indeed. 

With the MAK being a slow scope it's not too critical on EP's 

Hope this helps

Steve

 

Here's the link to the classifieds;

 

Edited February 11, 2020 by Steve Clay

[Vicky050373]

Hi there, had this thread pop up in my notifications. Just letting you know that I have received a PM overnight stating interest in both BST EPs and asking for payment details. Just thought I'd let you know that these will both be sold once payment is confirmed. However, as an aside, as you can read in my classified post and in my signature that I am a huge fan of the BST eyepieces and have the full range in my case, along with a 2" 32mm Panaview for widefield viewing. I use the BST eyepieces with all my scopes (8SE, Equinox 80 and Prinz 660 vintage refractor) and I cannot fault the view they give in any of these scopes. I will comment again on this thread to advise if the BSTs are sold, or if they are still available. All the best, Vicky

[JOC]

Maximum theoretical magnification may not be what you get the best view with.  I have a 5mm in my box (1200mm focal length) giving me potentially 240 X magnification.  I try it and rarely succeed.  Many times smaller is sharper and far nicer to view the planets with.  If you haven't already done so I would commend the scrolling through of this thread and viewing the pictures on the first page:

 

[John]

19 minutes ago, JOC said:

Maximum theoretical magnification may not be what you get the best view with.  I have a 5mm in my box (1200mm focal length) giving me potentially 240 X magnification.  I try it and rarely succeed.  Many times smaller is sharper and far nicer to view the planets with.....

 

This is very, very true in my experience.

Theoretical maximums assume that a host of factors (including the seeing and other non-scope factors) are spot on. In practice they almost never are !

 

[Vicky050373]

Hi, just letting you know that both the 8mm and 18mm BST eyepieces have now sold. Vicky.

[Stardust3]

Thanks for all the replies to my questions and for the link to the 'What can I see'.  It's been very helpful and based on the information that I've gleaned and all the information given by you all and other posts on this website I've ordered an Vixen NPL 8mm for the planet viewing.  Once I've received it and had a chance to use it I'll post back.  I did sway for some days between the BST Starguider 8mm and the Vixen but decided to start with the Vixen as although it has a low eye relief the reviews were very good.  Time will tell.  

Thanks again to everyone.