Lomo Astele 203

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Brand and Model:	Lomo Astele 203
Price ($USD):	1800
Type:	Maksutov-Cassegrain
Attributes:	Go-To PEC
Aperture:	203mm (8")
f Ratio:	f/10
Focal Length:	2030mm
Finder:	8x40
Electric Power:	N/A
Mount:	none
Tripod:	none
Weight (lbs):	28.6lbs
Dimensions (w/h/d):
Description:	Specs: Aperture - 203mm, Focal Length - 2030mm, F-Ratio - 10, Multi-Coated Optics, Weight - 28.6 lbs Comes With: 8x40 RA Finder & Bracket, 1.25" Star Diagonal, 1.25" 25mm Plossl Eyepiece, Photo Adapter, Lens Shade, Dovetail Mounting Assembly, Lens Covers

Vote Highlights

Lomo Astele 203

The first thing you'll notice is that the tube is longer than most f/10 cats. An initial impression looking at the tube alone is that it's likely an f/15. The reason is simple. Rather than opting for an f/2 primary to make the telescope as compact as possible, LOMO designers must have chosen to optimize performance over what might be considered a 'popular' trait.

In referencing "Telescope Optics", it's clear that minimizing the magnification factor of the secondary is recommended as the ideal approach to minimizing aberration. It's often said that slowing down the focal ratio of the primary is far more forgiving as well. Both can be accomplished by choosing the design parameters LOMO opted for. While I have not measured to be certain, rough estimates indicate the primary is likely an f/3-f/3.3, with the secondary having a mag factor in the same range (as opposed to the common f/2, 5x combination).

The telescope carries with it considerable weight when compared to most 8" catadioptrics. Removal of either cell reveals the reason for this. The tube is common thin walled rolled alum. It appears to be cast and machined, or perhaps even completely machined from billet. I did not appreciate, much less even realize any advantage to this until after mounting.

Like most, I've often felt that weight is a disadvantage. What didn't hit home until owning this observatory class instrument was this. If an increase in mass is a result of design geared toward stability, it will be well worth it for some.

In this instance, that superb stability has more to do with the telescope than the mount. Allow me to explain. Not having a heavier mount at the time, I opted to capture first light with what I was sure would be an overtaxed Losmandy GM8 (although it is about as stable as it could be with a Berlebach UNI tripod supporting it). I was surprised at how little shake was exhibited when focusing. The combination of a very smooth micrometer actuated focus mechanism, and a dovetail to tube attachment that eliminated tube flexure are the reasons why. Roland Christen's tube designs lept to mind as another example of rigidity to achieve superior performance.

A quick note on that dovetail. The angle is less inclined than most (much like some I've found on early model Takahashi's), and is Vixen style width. This results in having to expand a saddle a little bit wider, and contact only near the bottom of where the dovetail and saddle mate. I thought I would fit a Losmandy D style dovetail to this telescope, but the radiused and well secured V style works so well, I simply can't see any reason to change it. Yet another surprise.

The optics are first rate, with a snap to focus not found on most cats. I have not had superb seeing conditions, but have had good enough to believe the pattern presented is right in line with the claimed 1/8 wave PtV minimum standard. My experience with LOMO refractor optics and their claimed vs actual optical accuracy reinforces this evidence and resulting opinion. Focusing is smooth throughout the entire range of travel, with no image shift or tight spots. Image tone is a bit warm.

Primary mirror collimation adjustments are accessed by a removeable rear cover, which reveal a simple, yet very precise feeling push/pull arrangement. The discovery of beveled cell to tube rear mating surfaces explain why. Spot on collimation was achieved in the neutral setting of the primary cell, which speaks yet again to rigidity, and therefore orthagonality.

The corrector/secondary assembly is held in place by an ingenious series of spring steel leaf springs, which themselves are adjustable. This is important because that 'fine line' between too loose and too tight is all important for optical elements, and harder to accomplish as their mass increases. This telescope will not only gain, but also hold precise collimation as a result. This in incredibly important as well given that, while a Rumak, the secondary is glued to the corrector (and therefore, does not have provisions for collimation adjustments).

The LOMO 40mm finderscope is very good. A helical eyepiece focuser works well, bring both stars and crosshairs to focus simultaneously. There is a provision for an illuminator, although it's port is an uncommon thread size/pitch. The winged eyeguard is a poor fit. I am not the first owner of this telescope, so cannot speak to whether or not it is original. The finder's front cap snaps on securely, and is the same type of cap used on camera lenses. The domed telescope corrector cap fits very well too.

Cooldown was better than expected in a region where 35*F deltas(or more) are common, but not great. This is likely the only area where results met expectations. That was remedied with the addition of 2 small fans and a series of exhaust ports. It took some analysis and thought, but the recessed area under the removeable cover provided an ideal location for the low profile fans. A gap between the stout cell bevel and rear cap wall made for an ideal location for exhaust ports. The addition of foam insulation between tube wall and primary mirror have resulted in a Mak that takes design cues from the A-P 10", and cools extremely well because of it.

This telescope was an absolute bargain when compared to Questar, STF, Astro-Physics, TEC, or Takahashi cats. Those are great telescopes, but so is this. I waited years to find one. The wait was well worth it.

Overall Rating: 10
Optics:9 Ease of Use:9 Value:10
Weight: 1 (Unreliable Vote)
Date: 05/26/2013 02:42:13 pm PST
By: Anonymous (xxx.xxx.228.47)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=602858

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