One Moon, One Gas Giant and Two Classic Refractors

[A McEwan]

Hi all,

I've finally got round to doing some extended observing with my two classic refractors. #1 is the 1964 Swift 839 60mm f13.5 achro with Takahashi achromatic optics, and #2 is a '81-'84 vintage Celestron 90mm achromat with Vixen optics, f14.4.

I've had "quick looks" with both over the last few weeks and have been mightily impressed with both scopes on Jupiter. The Swift 60mm actually amazes me with its sharpness and ability to resolve fine detail. The 90mm Celestron/Vixen, which hails from a time when the best Vixen optics were being housed in the Celestron tube assemblies, similarly impresses me, but with the addition of a truly sizeable tube - a true long refractor.

Tonight I was able to A/B them side by side under very good (not perfect seeing) while observing Jupiter and the Moon from my back garden. I had the Swift mounted on my modified AZ3 and the Celestron on an EQ3.

I started off with the Swift on the Moon. The terminator was very sharp indeed, with only the merest trace of blue fringeing at the limb visible. The Appennines, Plato, Conon, Hadley mountain area and southern highlands all displayed razor-sharp contrast, with plentiful detail within crater-floors. Try as I might, however I could not detect any craterlets within Plato with any surety.

Experimenting with various eyepieces I found that the scope was easily able to support 207x using a Siebert Starsplitter modified Ortho. That's a whopping 86.25x per inch of aperture, with focus easily found and maintained.

I then moved onto Jupiter and settled on 135x using a 6mm BGO. This revealed some structure in the equatorial belts, a storm feature in the NEB and some colouring at the north polar region. "Something" was hinted at below the SEB at this point but I was not sure about it.... so I set up the Celestron 90mm and lined it up too.

The view was easily brought to a fine focus at 185x using a 7mm BGO and the detail within the equatorial belts was increased over the 60mm view. The "something" below the SEB was now a distinct circular dot and I suspected it was a shadow transit. Checking online at this point showed that it was a transit of the moon Europa across the disc and I'd caught it right on the meridian! Nice timing. (Returning to the view in the 60mm and knowing exactly where to look, the dot of Europa's disc was more obvious and stayed visible more easily)

Swapping back and forth betwen the views I found them surprisingly similar. Both were excellent of course and held their focus very well. Sadly, there was some vibration from the motor drive on the EQ3 so I found the best views when I switched the drive off and let Jupiter drift across the view, in similar fashion to how the AZ3-mounted Swift was working. The view then was further improved with the detail within and around the belts being nicely sharpened.

I then decided to try the Celestron on the Moon, and unsurprisingly was rewarded with a super-bright razor-sharp tour of the terminator features again. Sadly the Moon was now over a neighbour's house and the seeing conditions were deteriorating, but I feel that if I was away from heat sources and had excellent seeing that this scope would be a lunar observer's dreamscope.

I love having these two long achromats and am thoroughly enjoying the observations they're giving me. The quality in both is easily apparent and they really do seem to punch above their weight. The 60mm Swift most noticeably, simply because it's easy to think of it as "just a 60mm"... until you look through it! The 90mm is more a case of "I expect that to be great... and it IS"

Clear skies everyone!

Ant

[nightfisher]

Wow Ant, thats a cracking and thorough review, sounds like you had a great night observing, through two lovely old refractors. I viewed Jupiter with my 100mm frac thae other evening and for the first time i found the false colour a bit of a pain, i guess i have been spoilt by the 180 pro.

So what of the 150 f8 ?

[AndyH]

Excellent !!

Your opinions of your 60mm mirrors mine, of my Carton 60/1000. Continually blown away with the views through the Japanese miricle worker.

Just shows what a super high quality lens can do, no matter how small. An extra bonus is that they seem to be able to 'punch through' poor wobbily seeing conditions.

Viva la mini scopes!!!

[Stu]

Very exciting. I've got a Carton 60/1000 arriving very soon and am looking to seeing what it can do. Based on these reports I won't be disappointed.

Which ep's work best?

Stu

[AndyH]

Stu - I usually just take out two eyepieces. A lower power/wide field eyepiece(40x-50x) and my speers waler 5-8mm zoom, giving me a range between 125x - 200x. So I can vary the mag to conditions and target.

If I still had them, this scope would be crying out for some nice sharp orthos to be used on it. Some orthos are on my wish list down the road.

Last time I had this wee scope it got me to thinking. Using a small scope is also a good way to train your eye to see detail. The details aren't being handed to you on a plate, they're there, but you really need patience to learn to concentrate on using your eye to eek out the detail. Makes you a better observer, in my humble opinion.

Andy.

[Stu]

Thanks Andy, that's very useful info.

I have a 3-6 nagler zoom which may be ok at the lower end of it's magnification range plus a 7mm nagler. Bit short of lower mag 1.25" ep's, though I do have a 40mm lanthanum which I have up for sale so may keep that, with a barlow it would give x50.

Will see how these go before thinking about anything else. Actually first thing I need is a .965 to 1.25" diagonal or convertor of some sort. Any recommendations?

Stu

[Stu]

Btw, totally agree on the observing bit. Have been trying to see more detail on jupiter through just spending more time looking and training myself to pick out the features.

I'm also interested in the effect of a smaller aperture in variable seeing, they do seem to cope better

Stu

[AndyH]

And they cool down quicker than a quick thing !!

As for an adapter, the only one that comes to mind is .........

ScopeTeknix ScopeTeknix 0.965" to 1.25" eyepiece adaptor

i'm sure there are other sellers out there too.

Andy.

[Stu]

Thanks Andy, and Ant for the original post. Will report back how I get on with it

Stu

[A McEwan]

Hi chaps.

Well I tried using a 0.96" - 1.25" adapter but found it a bit clunky opn an otherwise gorgeous looking scope so I ordered one of these: Antares 1.25" to 0.965" hybrid diagonal. It works very well and I have no issues with the quality.

I repeated the experience last night, though this time with the 90mm on my Vixen GP. Motor vibration was eliminated (though I did have to replace the batteries half-way through... sigh) so the view in the 90mm was completely steady.

Interesting point about the 60mm being able to punch through seeing. There were numerous pockets of bad seeing appearing from time to time, which showed themselves frequently in the 90mm as literally "bubbles" that seems to envelop the disc before wobbling away again. The 60mm was almost devoid of these, or at least was affected much less.

It is a very rewarding experience viewing through the 60mm as indeed it does train the eye somewhat. I was able to see all the main belts in the 90mm: NEB, NTB, NnTB and Polar region, as well as the SEB, STB, SsTB. The 60mm had those belts too but no detail in the polar regions.

Eyepiece wise I'm almost exlousively using BGO's at the moment, along with a 3.9mm Siebert Starsplitter and Explore Scientific 4.7mm UWA. I think my 5mm BGO needs cleaning though as the view was a bit grainy through it. It's such a TINY lens to clean though....

Ant

[AndyH]

Ahha, forgot about the hybrid diagonal. Good shout. I've got a 1.25" Crawmach crayford on mine.

[A McEwan]

Oh, and as for the 150 f8... well I hope to use it tonight. Has been overlooked slightly since the 90mm Celestron arrived, but now that that's been thoroughly tested I can get the Big Frac out again!

Ant

[Neil English]

Hi Ant,

I'm really enjoying your observing reports of late. The weather has finally settled down here and I've been enjoying some sublime views of Jupiter with my long refractors. My 60/1000mm has been delivering some really compelling views of the Giant planet and the perpetual waltz of the Medicean stars on the dance floor of Jovian space. I find a 9mm ortho yielding 111x to give the most satisfying views.

Of course, larger scopes show you much more, but all the essential features are there and calmly presented for study in the little 60mm.

I also managed to split Iota Cass last night with the 60mm. The system was pretty much at the zenith and conditions were good, despite a Gibbous moon. I managed to resolve the trio at 111x but was slightly easier on the eye at 166x.

It's amazing what fun you can have with these little scopes.

Keep up the great reports.

With best wishes,

Neil.

[Stu]

Thanks Ant, I'll give that diagonal a go.

I'll be interested to see the results. I must admit I've not seem much detail in the mak outside the two main belts this year, the seeing has generally not been very good when I've had the chance to use it. It picks up shadow and moon transits but I've struggled with the lower contrast features.

I was mainly thinking this carton scope would be fun for my children to use but the more I read, the more I think I'll be hogging it :-)

Stu

[A McEwan]

I'm sure it will be a great scope if it has a Carton objective! My opinion of "scopes for children" is that there should be no difference between them and "scopes for adults" - except in terms of portability and ease of use. What's good is good - period. Anyway, your family will get some great views all round!

Ant

[Stu]

Let's hope so :-) can only assume it had a carton objective.....

I agree with you about scopes for children, I guess the important thing is that they are affordable, fairly robust and easy to use but need to give good results to maintain interest

Stu

[MjrTom]

Great review Ant

I am a big fan of the Vixen optics and love my Vixen long tube achromat refractor. It sure turned a few heads at a recent star party.

They are the classic idea of what a telescope should look like

I like the optics so much I have ordered a flange so I can fit my Moonlite focuser to the OTA

[A McEwan]

Over the weeked I found an ideal lens-cap for the Swift 839. It was missing a cap and I'd been using a cloth elactic-banded over the dew-shield. This fits much better... Sweet, eh!

[Stu]

Anyone know where I can get some rings to fit my 60mm Carton? I want to try it on my giro mount. I am guessing maybe some guide rings but can't see any that are small enough

Stu

[AndyH]

I stuggled to find rings to fit the ota.

I started off using rings off a finder bracket. Unscrewed them from the bracket and put them on a dovetail. Needed some felt....

Eventually I was lucky enough to find a set of old, but nice rings that with only a small amount of packing, work well....

CrawMach make quality rings to suit. Telescope Accessories

Cheers,

Andy.

[philj]

I told you didn't I:)

That Swift works better than a 60mm should, testament to the tak optics and coatings.

I did a similar comparison with the moon between the Swift and my Towa awhile back and was most impressed. I found you could push the mags quite high on nights of good seeing.

I like the cap, I find cadbury's cocoa tub lids useful for the same reason.

Phil

PS just seen the Cadburys logo on the cap:-) I use the red ones less classy than the black one you have

[Stu]

Many thanks Andy, much appreciated.

Will put a wanted ad on here and see what I can find

Cheers

Stu

[philj]

Stu

I had a similar problem with a 76 mm scope, just couldnt find any rings. So I got some 90mm SW rings and made some adapter rings out of ali to drop the diameter to suit. It works well I'll post some pics when I get back tonight.

Philj

[Stu]

Thanks Phil :-)

Stu

[Merlin]

Regarding DIY rings for small refractors. I'm not a motorist but I use plated steel exhaust pipe rings for my 60mm and 70mm refractors.

They can be purchased at most car-supply shops. I think that one ring in its bracket costs about three quid.