My my if it aint another 4 inch scope......one of the classics Edmund's Astroscan (2001)

Seems like I have become a sucker for smallish scopes. How many 4" class scopes do I have now? Geeze. But when it came to this scope, I just could not resist, since it was one of the scopes I lusted after as a teenager, glossing over Orion's black and white catalogs back in the 80's. This is the ultimate "bomb" proof scope, the one scope that any kid can kick around and still look at the moon or stars afterwards. It has also been around for a long long time. Heck it is almost as old as I am. Edmund Scientific introduced this radical new design (which by the way won an "Industrial Design Award" when it was unveiled for the first time) in 1976, 4 years after I was born. Norman Sperling and Mike Simmons designed this scope to be ultra durable and superbly simple to use, the perfect introductory scope. We all know that in order for a scope to qualify as a perfect beginners scope, it has to meet several criteria:

• Sufficient clear aperture
• Ease of use
• Uncomplicated 
• Easy to maintain
• Most importantly portable so it can be carried anywhere (especially in this day and age of light pollution when we have to travel great distances to seek out darker pristine skies for stargazing!)

Enter the Astroscan. Looking more like a red bowling ball, one would not instantly recognize this as a telescope. However it is and its design is time tested and has remained unchanged since the mid 70's. The design has in fact been adapted for other higher end scopes, the MagOne Portaball.

Details details.....

"Astroscan with its metal stand, carry strap and my new prototype long focal length Orion 18mm eyepiece"

So what is the Astroscan? Well although it sure does not look like your typical newtonian reflector, it does in fact utilize the simple newtonian configuration.  It has a 4⅛" clear-inch (105mm) diameter f/4.2 aluminized, overcoated borosilicate parabolic primary with a focal length of 17½ inches (445mm) that is factory aligned, and there are no provisions for adjustment. Good or bad, it all depends. Most people would argue that in order for a scope this fast to perform optimally, one would have to collimate its mirrors ever so often for optimal performance at higher magnification. Since this was primarily designed for wide field panning (back in the 80's such scopes were called Richest Field Telescopes or RFT's), spot on collimation is not that much of an issue.

The scope I got only came with the metal stand and carry strap. It did not come with a finder. Many have judged this as an inconvenience, and the newer Astroscan's ship with a red dot unit finderscope (not the metal peephole finders from the days of yore). I did not find this as much of a hindrance as I could just ballpark the object and then scan around with my lowest powered ep (i.e. 24.5mm Meade SWA). That said this is not a scope for serious astronomy (i.e star hopping to faint galaxies). Even with a red dot finder I think it would be difficult as the movement of the ball is smooth in wide sweeps, but is not as smooth when it came to small precise movements. Maybe I need to wax the ball! Also with regards to actually using a finder on the Astroscan, I think a more suitable finder would be a Telrad (would try mounting the Telrad I got with my C8 OTA once I pry the finder base off the OTA!), or one of them tall Rigel finders as the profile would be higher and easier to use.

The focuser is crude but works surprisingly well. I have read horror stories of users turning the knob and the focuser tube (which is basically a metal tubing that is moved up and down via friction from the knobs) not moving. No such problems there. My model has what looks like teflon on the sides so movement is pretty smooth. The focuser tube also does not have setscrews so take extra care when using your heavier eyepieces. Speaking of heavier eyepieces, if you are viewing anything below 45 degrees, the scope has the tendency to nose dive, so you might have to cradle the bottom of the tube while you switch eyepieces.

Next comes the question when using the Astroscan......where do I set it up? Like all the other tabletop mini scopes, due to its low profile, you need some sort of table, car bonnet, etc. to raise the scope to a manageable height for viewing. I put it on the picnic table for some parts of the sky, and on the playhouse floor where the slides are located. Mounting the Astroscan was a problem on my Orion HD F2 as the quick release mounting shoe had a "too short" screw that would not tighten the metal base sufficiently to the shoe. It was easier to just rest the metal base on a flat surface. Now this is convinient if you have park benches nearby. If you out in the wilderness, you might have a problem. I find the scope cumbersome to use in seated mode on the floor as you have to really scrunch and contort your body in all sorts of weird positions to view through the eyepiece.

In the field

 "Down the barrel of the gun. Notice the metal ring around the primary that add's weight to the scope"

So how does this non collimatible scope work under the stars. I was actually anxious to see if my second hand Astroscan would be a great wide field scope, or a lemon. Since I got it for a lower price than what is currently available, I was half expecting the scope to be a lemon. Fortunately that was not the case. The scope performed brilliantly with the 24.5mm Meade SWA, operating at 18x magnification. Contrast was surprisingly really good too, throwing up much contrastier images than in my Orion SkyScanner 100, which is basically identical to the Astroscan in that its primary mirror is also a parabolic mirror in the 4" range, permanently set and has a very short focal length. Baffling must be better in the Astroscan!

The first object I looked at was the moon. My jaw dropped when luna came into view. Contrasty and sharp where the first two things that came to mind. The terminator region was just gorgeous. Even when I put in the 6mm Radian for 74x magnification (while cradling the tube as the scope nosedived the first time I inserted the ep) no issues with mushiness or smearing (a common problem in newtonian's with short focal length spherical mirrors).

Deep sky objects were nicely framed as well. As mentioned contrast was excellent despite the only fully coated optical window. This scope really excels for the larger sprawling objects such as the Andromeda Galaxy (M31), the Perseus Double Cluster (NGC869/884), the Pleiades (M45), the sword of Orion and M42, the great nebula in Orion as it shows these objects in context (even from light polluted skies!). It in effect acts like a giant monocular binoculars, but with the option of using filters and changing magnifications! I had the Astroscan side by side with the Orion StarSeeker II 130mm f/5, and while the StarSeeker went deeper, contrast was superior on the Astroscan. Will have to do a shootout between my Orion SkyScanner and Astroscan when I get the chance as they are virtually similar scopes!

Caveats? I had a look at old jove as it rose higher above the rooftops (initial views were terrible and the planet's disc would not focus down to a sharp image). As expected views were marginal at 74x magnification. I could make out the two cloud bands on the planets disk, but the planet never did come to complete focus. There was flaring's off the planets disk (worse than SkyScanner as Jupiter did focus down to a disk with no flaring's in the SkyScanner). Note that the flaring's was nowhere near as bad as what I had seen in the Celestron Firstscope mini dob or the Orion Funscope, both which have short focal length spherical mirror's. I need to confirm this by testing the scope on Jupiter when it is higher in the sky and not subjected to heat waves coming off the rooftops. That might have been the root of the problem here.

Conclusions

"Dewy scopes looking at old jove and the great nebula in Orion"

 

After 30 odd years of lusting after a telescope that looks more like a red bowling ball and finally getting one, I must say that the Astroscan did live up to my expectations, granted that I did not expect it to excel for high powered planetary views. I was surprised that the contrast was so good on my sample. The moon was super contrasty and sharp, even at 74x magnification. The views of Jupiter was underwhelming, but as mentioned, this scope was not built for high powered planetary views. It does give fantastic wide field views of deep sky objects and that's all that matters to me.