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Skywatcher 32mm SP Plossl for a Skymax 102 Mak?


jonathan

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Just wanted to get confirmation of what I think should give the 102 it's widest views, is it the 32mm Skywatcher SP Plossl or is there another option (without going silly on expense, want to keep it down if I can). 

I've been trying out the 102 today for bird watching with limited success, there seemed to be some stray light coming in (sun was to my back/right, had occasional red hues) so I'm going to try a dew shield, the 25mm plossl eyepiece I have (old Celestron one, came with my 8SE) worked well but at 52x it was at the top end of desirable magnification for locating and following moving birds.  Would the 32mm provide the optimum wide field in this 102 Mak, at 40x? (would be better closer to 30x for locating a target, but 40x is a good compromise for actually seeing more detail after getting the target in the eyepiece)

This scope will see plenty of astronomical use too of course, I'd just swap out the 45degree correcting diagonal for a 'normal' one, so the 32mm eyepiece will see some use for open clusters and the like too.

Thanks.

Edited by jonathan
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The 32mm Plossl will give the widest field possible with the 1.25" focuser on the 102. You can achieve a lower power with a 40mm Plossl but the true field of view will be identical to the 32mm, just at a lower power. Hope that makes sense.

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If it has the same rear thread as the 127 Mak, and you're willing to plonk down "silly" money, you can get the Mak to SCT thread adapter, a 2" SCT visual back, a 2" diagonal, and a widest field 2" eyepiece to vastly increase the true field of view with mild vignetting as seen below:

220226258_Max127MakTFOVComparison.thumb.jpg.fa1c73bddd25963f5af583532ef1f858.jpg

The difference is breathtaking at night when viewing rich star fields.

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4 minutes ago, Louis D said:

If it has the same rear thread as the 127 Mak, and you're willing to plonk down "silly" money, you can get the Mak to SCT thread adapter, a 2" SCT visual back, a 2" diagonal, and a widest field 2" eyepiece to vastly increase the true field of view with mild vignetting as seen below:

220226258_Max127MakTFOVComparison.thumb.jpg.fa1c73bddd25963f5af583532ef1f858.jpg

The difference is breathtaking at night when viewing rich star fields.

I was going to suggest that myself bu then couldn't remember if the smaller Skymax had the same thread on the rear or if the rear aperture was a wide as the 127.

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As far as I know, hole on Mak102 is smaller than that on Mak127. It is about 22mm if I'm not mistaken. According to one image online for Mak127 it is about 26-27mm

32mm Plossl works in my Mak102 but I have a few objections to that combination.

First is vignetting in daylight - I can quite notice it. Second is eye relief. It is by far the most eye relief that I had in EP/Scope combination and sometimes this bothers me. 32mm Plossl is otherwise very comfortable eyepiece for me, but with this scope - it is not so.

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1 hour ago, russ said:

The 32mm Plossl will give the widest field possible with the 1.25" focuser on the 102. You can achieve a lower power with a 40mm Plossl but the true field of view will be identical to the 32mm, just at a lower power. Hope that makes sense.

That's what I've read elsewhere too and seems like the best option.

I think given that the actual hole in the back of the 102 Mak is as vlaiv said, about 22mm, it doesn't follow in my mind that attaching a 2" visual back onto a 1" hole would be of much help, it's surely only going to produce considerable vignetting (particularly noticeable during daylight, and negates the effectiveness of the extra field of view) especially considering that the 102 Mak is quite a narrow field of view instrument in the first place.  At night it might make more sense, but for daylight use I think it would produce disappointing views.  Anyone actually tried this (in daylight) and can confirm?  I'm very likely going for the 32mm anyway at this point, but there's always room for more adjustments!  I'd be quite interested to see how the 32mm performs in my Celestron 70mm TravelScope as well.

Edited by jonathan
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1 minute ago, jonathan said:

That's what I've read elsewhere too and seems like the best option.

I think given that the actual hole in the back of the 102 Mak is as vlaiv said, about 22mm, it doesn't follow in my mind that attaching a 2" visual back onto a 1" hole would be of much help, it's surely only going to produce vignetting (particularly noticeable during daylight, and negates the effectiveness of the extra field of view) especially considering that the 102 Mak is quite a narrow field of view instrument in the first place.  At night it might make more sense, but for daylight use I think it would produce disappointing views.  Anyone actually tried this (in daylight) and can confirm?  I'm very likely going for the 32mm anyway at this point, but there's always room for more adjustments!

My nephew has the Skymax 90mm but we haven't used anything lower than 25mm. He uses it purely for the moon and planets. The 25mm is just a finder eyepiece.

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1 hour ago, Louis D said:

If it has the same rear thread as the 127 Mak, and you're willing to plonk down "silly" money, you can get the Mak to SCT thread adapter, a 2" SCT visual back, a 2" diagonal, and a widest field 2" eyepiece

For less money, just buy an ST80 as a daytime spotter. It works well, unless an object is silhouetted against the sky, when CA wrecks the view.

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The Skymax has a narrow field of view one just has to live with. I use an Astro Essentials 32mm plossl for the widest possible fov unless the scope has a rare home garden outing then a 24mm 65° UFF, but that cost as much as a used Skymax 102, and is like a hand grenade. So imho just not worth the purchase unless it's also being utilised by other scopes.

 

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39 minutes ago, Ags said:

For less money, just buy an ST80 as a daytime spotter. It works well, unless an object is silhouetted against the sky, when CA wrecks the view.

Which is a lot of the time when bird watching!  I already have the Celestron TravelScope 70 so I don't think the ST80 is going to give me much more in terms of magnification, the TravelScope has surprised me by the sharp views it gives for it's size and 'cheapness'.  The Mak didn't display any CA that I could notice when using it today in bright sunshine (sun behind me) as I followed a goshawk in flight above the treeline, although I think it maybe was tricky to tell with the heat haze whether or not I lost some sharpness, probably lost a bit of contrast compared to a refractor for sure.  I shall have to have both scopes out for comparison some day.

Edited by jonathan
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1 hour ago, Ags said:

For less money, just buy an ST80 as a daytime spotter. It works well, unless an object is silhouetted against the sky, when CA wrecks the view.

Never cared for my ST80 due to spherical aberration on top of the CA.  Views were never very sharp or contrasty.  My 72ED fixed both issues.

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Weeeeell I gave it a go, after a couple of sessions using the Skymax 102 with 25mm and 32mm eyepieces I'd probably classify it as 'a compromise' between price vs capability.  For sure it can't compete against the expensive and very high quality glass used in the dedicated high-end spotting scopes, but then at around £300 (including a good quality 45degree correcting diagonal and eyepiece) it's a fraction of the price of a Swarovski of similar potential power.  Comparing a Maksutov to an ED refractor is a little bit like comparing apples to pears, but with the compromise of narrower field of view and a heavier scope, I think the Skymax 102 certainly performs above the relative price difference between the two.  

One of the other handicaps is the tripod - I have the Horizon heavy duty tripod, it may be more than is required for the Skymax 102 but the weight of the 102 makes it feel a little more 'weighty' to quickly and smoothly pan to follow a bird in flight at high magnification, there's also some wobble from my shaky hand / arm control.  A lighter and smaller refractor should enable smoother panning and tracking.  I found that it also suffered from stray light entering the objective resulting in red hues in parts of the field of view depending on the angle, so a dew shield becomes a requirement on a sunny day.

As for the practicality of observing and identifying a bird in flight, if the view was a little steadier I don't think there was much of a problem there, I was able to successfully identify some key features of a Goshawk as it flew by over a distant treeline.  Contrast is undoubtedly not as high as with a good quality refractor.  The narrow field of view is definitely going to make finding the moving target more difficult, the Baader zoom eyepiece I have generates an even narrower field and only goes down to 24, giving a zoom of about 50x, typical spotting zooms go down much more than this and give a much wider field of view to ease the observer into the subject (a typical zoom level is about 42x, the 32mm eyepiece in the Skymax 102 provides this but does have some vignetting which could make observing more difficult).  Also the focus knob on the Maksutov design is inconvenient for refocusing on the fly, compared to the large integral focusing ring or feather touch dual focusing knobs of spotting scopes that are conveniently placed so that they can be used while the operator has one hand on the scope to steady it with the other hand on the pan handle.

I think I may just try using the Skymax 102 for astronomy for a while, get to grips with it's characteristics, and think about a second-hand spotting scope for the bird watching, however I will continue to try the Skymax for daytime spotting and may even give my 102 refractor a go from the garden just to see how that handles it. 

One final note - one of the attractive factors of a dedicated spotting scope is their compactness and ease of transport, especially when paired with a lightweight carbon fibre tripod and carry ruck sack; lugging the Horizon heavy duty tripod and Skymax 102 with eyepiece and diagonal (in it's storage bag) more than a few yards gets tiring very quickly.  I certainly don't regret buying the Mak, it'll make an excellent addition to my 'grab and go' collection!

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18 hours ago, jonathan said:

One of the other handicaps is the tripod - I have the Horizon heavy duty tripod, it may be more than is required for the Skymax 102 but the weight of the 102 makes it feel a little more 'weighty' to quickly and smoothly pan to follow a bird in flight at high magnification, there's also some wobble from my shaky hand / arm control.

Invest in a good fluid head normally used for videography.  The pan and tilt motions will be smooth and well dampened.

 

18 hours ago, jonathan said:

The narrow field of view is definitely going to make finding the moving target more difficult

Add a 6x30 straight through finder scope or similar to help get the scope quickly on target and then switch to the main scope's eyepiece.

 

18 hours ago, jonathan said:

Also the focus knob on the Maksutov design is inconvenient for refocusing on the fly

Can't help you there.  It's the nature of the beast.  I don't think there's room on the back for even a 1.25" Crayford focuser on a 102.

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