New Eyepieces for a Skymax 127

[Lung]

A friend of mine died recently and left me his hardly used Skymax 127. His sister very kindly gave it to me yesterday, but the diagonal, Barlow and eyepieces were missing. Rather than bothering her or his mum to find them for me, I wondered what replacements might be worth getting instead? I have a Tal M scope that I'm renovating that has a 25mm Plossl and 15mm Kelner eyepiece set that I think I could use if I bought a diagonal. Other than those, what would people recommend? Is it worth going for a 2" adapter and eyepieces instead?

[Carbon Brush]

The '127 Mak is generally tolerant of eyepiece type.
I think first thing is to establish that the eyepiece/diagonal adapter, which screws in, is still there.
If you post a picture of the arrangement, that will guide your next move.

HTH, David.
 

[Grump Martian]

Hi,I would e-mail First Light Optics and ask them about which 1 1/4 inch star diagonal would fit your 127. The two eyepieces that you have would work well. Buy a 10 mm ,1 1/4 " eyepiece. This eyepiece would give you 150 x with your telescope focal length of 1500 mmm

 

[Lung]

57 minutes ago, Carbon Brush said:

The '127 Mak is generally tolerant of eyepiece type.
I think first thing is to establish that the eyepiece/diagonal adapter, which screws in, is still there.
If you post a picture of the arrangement, that will guide your next move.

HTH, David.
 

Adapter looks to be present.

[Cosmic Geoff]

Yes, that's what the adapter on the almost identical Celestron 127 Mak looks like.

You just need a 90 degree star diagonal - lots of choice there. I found that the diagonal that came with the scope worked just fine, so no need to spend a lot of money.  I had to buy a good quality 10mm eyepiece (£50+) to get the best out of the scope.

You definitely don't need a Barlow with a Maksutov of focal length 1500 mm.

You will also need a finderscope of some sort. It will mount onto the Synta finder bracket visible in your photo.

I wouldn't bother with a 2" adapter and eyepieces.  They cost more and the scope does not have a big hole in the rear.

Do you have a suitable mount for the Mak?

[Don Pensack]

I owned this scope for several years.  It is actually a 121mm f/12.7 Maksutov with a 1540mm focal length.  It's been made by Synta since around 2000-2001 and maybe before in non-USA markets,

and sold under at least 10 different marks (like Orion, Celestron, SkyWatcher, etc.)

It's actually 121mm in clear aperture because Maks need an oversized mirror to field the entire corrector's light, and they did not use an oversized mirror.

The Sky & Telescope test many years ago confirmed that.

When I had mine, I used it primarily for Moon, Planets, double stars and smaller star clusters.

 

The maximum field with 1.25" eyepieces is 1.04°, using a Baader 24mm Hyperion eyepiece.

The APM Ultra Flat Field 24mm (also available as Stellalyra and Altair Astro UFF in the UK) yields a 1.03° field.

A 32mm Plössl as a low power will yield 1.00° field.

The visual back that holds the diagonal has 10mm of useless thread on its outer end.  If you machine this off, the focal length of the scope with a 1.25" diagonal drops to ~1510mm.

This gains you so little in true field that it's hardly worth it unless you have the machine tools to do it.

 

An eyepiece set that is usable in the scope could start with the 24mm Hyperion, but also could start with a 32mm Plössl if you want a larger exit pupil.

From 32mm, the logical steps are 32mm, 22-23mm, 16mm, 11-12mm, 8mm

From 24mm, the logical steps are 24mm, 17mm, 12-12.5mm, 8.5-9mm.

The scopes generally don't perform great above 200x, for many reasons, which is a 7.7mm eyepiece.

 

If you get fantastically good seeing, the scope can give decent images with 6-7mm eyepieces, but I think it's more cost-effective to use a Barlow to achieve magnifications above 190x or so.

You need a finder scope, for sure, and a dewshield on the front of the scope (this can be home-made), or your observing sessions will be cut short by dewing of the corrector.

You also need a nice steady mount.  Due to the long focal length, look for a mount that can handle a 5" refractor.  Even though the Mak is lighter and shorter, vibration in the mount is more visible

due to the long focal length and large image scale.

 

 

 

 

[Lung]

4 hours ago, Cosmic Geoff said:

Yes, that's what the adapter on the almost identical Celestron 127 Mak looks like.

You just need a 90 degree star diagonal - lots of choice there. I found that the diagonal that came with the scope worked just fine, so no need to spend a lot of money.  I had to buy a good quality 10mm eyepiece (£50+) to get the best out of the scope.

You definitely don't need a Barlow with a Maksutov of focal length 1500 mm.

You will also need a finderscope of some sort. It will mount onto the Synta finder bracket visible in your photo.

I wouldn't bother with a 2" adapter and eyepieces.  They cost more and the scope does not have a big hole in the rear.

Do you have a suitable mount for the Mak?

Thanks, I'll look for the stock diagonal on eBay or similar. It came with a red dot finder, plus the goto mount and tripod, although it's the wrong tube for the mount (I've put a post in the scopes forum about that).

3 hours ago, Don Pensack said:

I owned this scope for several years.  It is actually a 121mm f/12.7 Maksutov with a 1540mm focal length.  It's been made by Synta since around 2000-2001 and maybe before in non-USA markets,

and sold under at least 10 different marks (like Orion, Celestron, SkyWatcher, etc.)

It's actually 121mm in clear aperture because Maks need an oversized mirror to field the entire corrector's light, and they did not use an oversized mirror.

The Sky & Telescope test many years ago confirmed that.

When I had mine, I used it primarily for Moon, Planets, double stars and smaller star clusters.

 

The maximum field with 1.25" eyepieces is 1.04°, using a Baader 24mm Hyperion eyepiece.

The APM Ultra Flat Field 24mm (also available as Stellalyra and Altair Astro UFF in the UK) yields a 1.03° field.

A 32mm Plössl as a low power will yield 1.00° field.

The visual back that holds the diagonal has 10mm of useless thread on its outer end.  If you machine this off, the focal length of the scope with a 1.25" diagonal drops to ~1510mm.

This gains you so little in true field that it's hardly worth it unless you have the machine tools to do it.

 

An eyepiece set that is usable in the scope could start with the 24mm Hyperion, but also could start with a 32mm Plössl if you want a larger exit pupil.

From 32mm, the logical steps are 32mm, 22-23mm, 16mm, 11-12mm, 8mm

From 24mm, the logical steps are 24mm, 17mm, 12-12.5mm, 8.5-9mm.

The scopes generally don't perform great above 200x, for many reasons, which is a 7.7mm eyepiece.

 

If you get fantastically good seeing, the scope can give decent images with 6-7mm eyepieces, but I think it's more cost-effective to use a Barlow to achieve magnifications above 190x or so.

You need a finder scope, for sure, and a dewshield on the front of the scope (this can be home-made), or your observing sessions will be cut short by dewing of the corrector.

You also need a nice steady mount.  Due to the long focal length, look for a mount that can handle a 5" refractor.  Even though the Mak is lighter and shorter, vibration in the mount is more visible

due to the long focal length and large image scale.

That's a lot of info, thanks for that! I had a quick look at the suggested eyepieces and the 24mm options are a bit pricey for now but the 32mm Plossl looks like a good option to start along with my Tal 25mm and 10mm.

The scope came with a dewshield and red dot, so that's sorted. It also has the goto mount, skyscan handset and tripod.

[RT65CB-SWL]

Hi @Lung

First off, my condolences on the passing of your friend. 🙏

I hardly bother with a Barlow lens with my C6/SCT or ‘re-modded’ ETX-105.

With regards to a star diagonal, I personally would opt for a 2” one with an SCT thread. Not sure whether your Mak has an SCT thread already. If not FLO and other dealers sell adapter rings to make the conversion. Also handy if you wish to add a ‘Crayford’ focusser at a later date. I have added an ETX to SCT adapter ring to my ETX-105 as per the images below. 

The ETX to SCT adapter ring and 1.25” visual back…

…and fitted to the backplate of my ETX-105……and with my 2” SCT star diagonal.

I also have a 2" SCT extension tube that gives me an 'extra' bit of focal length too, as shown below, and is also close/near enough to the same length of the ETX-105 specs, with the plastic rear end/flip mirror housing. Mine got damaged following a fall from mount and damaged two of three mounting points. The aluminium backplate is not a ‘Wegat’ one or other commercially available brand.
 

The aluminium backplate I designed/planned myself. After some rough sketches and plans on sheets of A4 paper, searching and enquiries of local engineering workshops close to my home, I found one that was prepared to make it. I left them the original backend as a template for the mounting holes, a hole for the focus shaft, and the threaded port, as per the original.

Edited March 25 by RT65CB-SWL

[Roy Challen]

On 24/03/2024 at 18:36, Don Pensack said:

 

The visual back that holds the diagonal has 10mm of useless thread on its outer end. 

I agree with everything in your post except this. Baader sell an inexpensive compression ring adapter that screws directly on to this thread, making a much nicer way of holding the diagonal. Looks nicer too!

Edited March 27 by Roy Challen

[Gonariu]

On 3/24/2024 at 5:17 PM, Lung said:

A friend of mine died recently and left me his hardly used Skymax 127. 

All of us amateur astronomers in the world are in fact one big family, thanks to the internet and also to SGL, we can hear each other all over the planet in the language that is now that of the whole world: English! Eternal memory to your friend!!!

[Scosmico]

Lung, If you want to embark on this hobby, something that was really valuable to me, in terms of eyepiece, was to learn how to differentiate a standard eyepiece from a good one. And no eyepiece gave me more understanding about contrast, sharpness, than  orthoscopic eyepieces. They are in the low budget spectrum, not because of the quality but because of the limited field of view. They are great for long focal length telescopes delivering a sharp planetary views. That is my advice about what type you could go first. All tips given before are very good.

Good luck.

[PeterC65]

I have a Skymax 127 (it was my first scope) and have made the conversion to a 2" visual back, fitted with a Baader 2" ClickLock. Mostly I use it with 1.25" eyepieces via a Baader 32mm prism diagonal that has a 2" nosepiece fitted to the scope side and a 1.25" Baader ClickLock fitted to the eyepiece side, but I also use the 2" visual back with a 2" mirror diagonal and a Baader Hyperion Aspheric 36mm eyepiece to gives me a 1.50° field of view. While the Skymax 127 is inherently narrow field, this does allow me to observe larger DSOs such as M45. I've not noticed any vignetting but haven't looked hard for it.

The Baader Hyperion Aspheric is pretty disappointing with faster scopes by the way, but with the slow Skymax 127 it works well and gives me a wider field of view than my (very much better) StellaLyra UFF 30mm.

[Louis D]

I just wonder if the Baader Hyperion Aspheric 36mm is enough better than the TS Paragon ED 35mm to justify the additional cost.  I have the latter, and it's pretty decent, but not great, at f/6.

[Don Pensack]

6 hours ago, Roy Challen said:

I agree with everything in your post except this. Baader sell an inexpensive compression ring adapter that screws directly on to this thread, making a much nicer way of holding the diagonal. Looks nicer too!

I was not referring to the threads on the back of the scope.  I was referring to the "visual back", the piece that threads onto the scope, into which the diagonal inserts.

On its outer end are 10mm of thread that do nothing other than to force the inserted diagonal to be 10mm farther from the back of the scope.

The thumbscrew that holds the diagonal is closer to the scope, in the solid, un-threaded, portion of the visual back.

Removing the 10mm of threaded section on the visual back, which was intended to be used with some obscure camera adapter,  allows the diagonal to move in toward the scope,

which shortens the focal length of the scope and yields a wider true field with every eyepiece.

The Baader adapter to which you refer, I believe, threads directly to the scope and replaces the visual back that comes with the scope.

[Don Pensack]

52 minutes ago, Louis D said:

I just wonder if the Baader Hyperion Aspheric 36mm is enough better than the TS Paragon ED 35mm to justify the additional cost.  I have the latter, and it's pretty decent, but not great, at f/6.

Don't waste your money, Louis.  I could see serious lateral astigmatism in the Baader 36mm at f/10 !.

[Don Pensack]

1 hour ago, Scosmico said:

Lung, If you want to embark on this hobby, something that was really valuable to me, in terms of eyepiece, was to learn how to differentiate a standard eyepiece from a good one. And no eyepiece gave me more understanding about contrast, sharpness, than  orthoscopic eyepieces. They are in the low budget spectrum, not because of the quality but because of the limited field of view. They are great for long focal length telescopes delivering a sharp planetary views. That is my advice about what type you could go first. All tips given before are very good.

Good luck.

IF the scope tracks.  And if the use is on planets.

But if the scope is on a manual mount, a long focal length instrument combined with orthoscopic narrowfield eyepieces require the scope to be pushed every few seconds.

And short focal length (10mm and shorter) Abbe Orthos require an extremely close eye position, which is uncomfortable even without glasses.

It works for planets, because you can simply pull your eye back, which narrows the field you see, and you can still see the planet well.

But pulling the eye back doesn't work as well for objects larger than planets (e.g. the Moon), and it means even more pushing of the scope to follow the turning of the Earth.

Well-made Plössls fall into the same category--nice and sharp, with good contrast, but uncomfortable in shorter focal lengths.

These are some of the reasons why wider apparent fields are popular, and why longer eye reliefs are popular (examples: Delites, SLVs, X-Cel LX, HD60, et.al.).

And even at high power in a tracking scope, wider fields with good lateral correction work are more enjoyable to use on the Moon.

[PeterC65]

1 hour ago, Louis D said:

I just wonder if the Baader Hyperion Aspheric 36mm is enough better than the TS Paragon ED 35mm to justify the additional cost.  I have the latter, and it's pretty decent, but not great, at f/6.

I bought the Aspheric 36mm thinking it would be flat and give a slightly wider field of view, but with my F6 refractor and F5 Newtonians (the indented use for this eyepiece) it was frankly terrible. Rather than admiring the wide star fields I was just noticing all of the seagull shaped stars. I can't imaging it would be better than the TS Paragon ED 35mm which is another eyepiece that I considered.

After much deliberation, and much frustration with the Aspheric, I bought the StellaLyra UFF 30mm which is fantastic as many others have commented, but its field of view is narrower than the Aspheric. I was going to sell the Aspheric but it does work well with the Skymax 127 and gives that extra field of view, but I wouldn't use it with any of my other scopes.

 

[John]

2 hours ago, Don Pensack said:

Don't waste your money, Louis.  I could see serious lateral astigmatism in the Baader 36mm at f/10 !.

So could I at F/12 !

I don't know what Baader were thinking with that one 🙄

 

[Roy Challen]

17 hours ago, Don Pensack said:

I was not referring to the threads on the back of the scope.  I was referring to the "visual back", the piece that threads onto the scope, into which the diagonal inserts.

On its outer end are 10mm of thread that do nothing other than to force the inserted diagonal to be 10mm farther from the back of the scope.

The thumbscrew that holds the diagonal is closer to the scope, in the solid, un-threaded, portion of the visual back.

Removing the 10mm of threaded section on the visual back, which was intended to be used with some obscure camera adapter,  allows the diagonal to move in toward the scope,

which shortens the focal length of the scope and yields a wider true field with every eyepiece.

The Baader adapter to which you refer, I believe, threads directly to the scope and replaces the visual back that comes with the scope.

The Baader adapter I had fits between the visual back and diagonal - see image below. The scope in the image is a 90mm but I believe the visual back is the same for the 127mm as well. I might be wrong on that though.

[Don Pensack]

I'm not clear on your picture.  Why isn't the diagonal simply inserted into the visual back?

The visual back on the 127 looks like this:

https://www.cloudynights.com/topic/624516-sw-127-mak-adapters-accessories/?p=8699550

And the external threads serve no useful purpose if a 1.25" diagonal is inserted.