Testing ST-80 and 60mm Refractors

January 19, 2006
9:30 pm – 10:30 pm
Mostly clear, 35-degrees, conditions average

I’m re-examining the equipment inventory and trying to decide what is worth keeping and what would be better sold and the money used for something else. My objective tonight was to see if I want to use the Orion ShortTube 80 as a personal “grab and go” scope – I have little hope for it in the program.

So I grabbed it and went over to the fence – an area of the yard that gives me a better southern horizon. I fooled around with the finder a bit, but it’s a straight-through 6X30 and awkward to use if something is high up. (Younger people may not give this a thought, but I twist and turn less easily these days and I don’t like kneeling on the cold ground to peer through a finder. ) Two possible solutions – get a RA finder which would probably cost half-again as much as I paid for the scope, or simply use the 40mm Celestron Plossl with it as the primary eyepiece. This gives me about 4.5-degree true FOV and a long with sighting along the tube made it fairly easy to quickly find things.

Test 1- Finding ability. Acceptable.

What can you see with it?

Star images are acceptable – not as sharp as I would like, but certainly as good as binocular star images.

I liked the way at 20X (simply 2X Barlow the 40 mm) it framed the Pleiades. This kind of wide field ( a little more than 2 degrees) surprised me when I swung it towards Saturn and found the Beehive (M44) in the same FOV. I’ve been looking at Saturn this season using more powerful eyepieces on “go to” scopes. I knew M44 was near, but never paid any attention. Anyway, it was kind of startling to see the planet floating so near such a rich star field and was a good example of how using a “go to” can take you out of context.

Using 16X (25 mm Plossl) before my eyes were dark adapted the Orion nebulae was disappointing – in fact, I had difficulty seeing the nebulosity. Fifteen minutes later it was quite satisfying. It became much more satisfying when I plopped in a 9mm Meade AR – certainly no fancy eyepiece, but it showed the nebulosity and the Trapezium very nicely. In fact, the view was good enough so that I went and got a stool so I could enjoy it more.

(Hmmm . . . maybe my best investment at this stage is more observing stools. We tend to undervalue these, but for me they are a critical part of the process if you are going to do any real observing, as opposed to quick sightseeing. )

I scanned around in the Big Dog some – it was in a gap in the tree and I usually don’t see it at all from my normal locations. In any event, using the 40mm I quickly stumbled across M41 and zoomed in on it with the Barlow and eventually the 9 mm. I can’t say I was overwhelmed. I was overwhelmed by M44 either. So I would rate it as acceptable on these objects.

As for Saturn, I could glimpse the Cassini Division at 80X (maybe 40X as well). The planet certainly showed nicely enough so that a newcomer would know they were looking at Saturn and would be excited by the view. And I could, of course, pick up Titan.

I also easily split Mintaka and two of the three stars in Sigma Orionis.

Test 2 - what you can see - The ST80 works nicely for showcase objects – M31, M42, M45, Saturn, Jupiter, and the moon. Beyond that it can provide some interesting wide field perspectives and acceptable, but hardlye xciting, image sof other objects. One area where it might fit well into the program is with the existing erect-image prism – which I did not use in this session. With this, it would give a power, erect-image view of the moon which would be helpful to the newcomer learning the seas and a few major craters.

Now the weak spot – the mount. I have it on a $100 Celestron Alt-Az mount with slow motion controls. This mount works OK in Az, but poorly in altitude. There now coarse tension adjustment accept the tightening of some bolts and this really is not acceptable. Also, it’s hard to mount the scope tightly enough to the head so that the scope doesn’t swivel when you want the head to swivel.

Maybe what I should do is keep this scope primarily for sessions introducing the moon. I could set it on an existing photo tripod, plus my old Orion head that gives some slow motion control. (I use this set up for the PST and it works.) I would then use the erecting prism system, Hmmmm…wonder how distracting the false color is?

And this does suggest a possible use for the 80mm F15 refractor This is a cheapy Orion model (I don;t see it on their web site any more) on a flimsy equatorial head with slow motion controls. I can use it to some advantage, but the beginner would be confused and frustrated by the equatorial mount and since it is not a very sturdy one, it is not worth the frustration it would cause. To date the main purpose of this scope has been to show people what NOT to get as a starter scope ;-)

But it can give some pretty nice, high-powered views. Bottom line? If I put the equatorial in alt-az mode and stick to low and medium power, the performance is acceptable on bright, showpiece objects with reasonable ease of use and dampening time.