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Should I get a 102-127mm Mak-Cas or an 80mm refractor?


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I'm looking for a compact and lightweight setup. Around 4-8 pounds (2-4 kg) for the OTA (aiming for about 15-17 pounds for the whole setup), that will work on a heavy duty camera tripod with a good AZ mount. With the mount and two or three good eyepieces, my budget left over is up to $900 (560GBP) for the OTA only.

I've narrowed it down to a 102-127mm Mak-Cas or a 80mm f/6 -7 refractor. The refractors allow for 2" eyepieces and a wider field of view but push the limits of aperture at the higher powers. The Mak-Cas offer more aperture, and more focal length for moon and planets etc., but don't allow for 2" eyepieces or anything close to wide field views, and only seem to be available at a lower price/quality point.

I looked at the Synta Mak-Cas (Skywatcher, Orion, Celstron). In the UK these would be Skywatchers but here in the US they are Orion brand. The Celestron (and Meade's ETX as well) are only offered with full GOTO kits). The Orion is available as an OTA-only which I can setup as I like.

102mm is $309 (200GBP)

127mm is $409 (257GBP)

They come with a 45 deg. correct image diagonal that I would replace with a high-end 90 deg. star diagonal.

I also looked at the Vixen VMC110L modified Mak-Cas. It has an open tube design with a small meniscus corrector lens just ahead of the secondary mirror. This allows for faster cooling and less dewing issues. It uses curved spider vanes to give star images without the diffraction spikes the way we expect from a Mak-Cas. The diffraction is still there of course as with any central obstruction, just not patterned like a Newtonian. It also has a flip mirror that allows for right-angle or straight-through viewing for two eyepieces or an eyepiece and camera. I don't want to do any astrophotography but would consider using any Mak-Cas for terrestrial subjects. It does not have the flip-in viewer or barlow of the Questar. I also have some doubt the two ports would be parfocal but they might be. Unlike the Questar, the Vixen is a paltry $289 (180GBP) for the 110mm version. I would not be able to upgrade the mirror diagonal. Even though it's cheaper than the Synta, the Vixen seems to have better fit and finish and mechanical quality but for the price I can't expect the optics to be any better.

If there was a higher quality Mak-Cas in the $600-800 range, I would look at that but I haven't found one other than 150mm and 180mm which are too big and heavy and take a bigger and heavier mount and tripod which gets really too big and heavy. Because of the lower price, for the Mak-Cas I could afford better eyepieces like a pair of Naglers but a collection of huge Ethos would be too big and heavy and costs even more than the difference. I don't know how else I could try to hot-rod the Mak.

Some 80mm refractors are short and compact enough to fit my needs and may offer better optics than the relatively cheap Mak-Cas offerings. For examples, Meade's 80mm APO or a Skywatcher 80ED or a Stellarvue 80ED etc. The 90 and 100's start to get too long and too expensive, maybe even too heavy.

The 80's offer wider fields than a Mak-Cas and could probably do well at a higher magnification per aperture than a Mak-Cas so I think it's fair to compare an 80 to a 110.

So that's my dilemma, a good quality 80mm (but not a TV, Tak or something) refractor in the $800-900 range or the best quality Mak-Cas I can find for under $1000 which happens to be only $300-400 worth of optics but still quite a bit more aperture than an 80mm.

What do you think?

Edited by BenM
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Ben M

I would go for the largest aperture as then you will be able to see more objects visually but thats just me as I am a visual person!

I am sure some of the guys on here will confirm the best option from an astrophotography point of view. I suspect the answer will be FOV when taking CCD pictures and what you are going to be taking photos of..

Regards

Mark

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The 80mm refractors always seem to be one of the best general scopes around. A good one should take decent magnification.

Suppose that you are not on the East coast near NY?

NEAF is on pretty soon and they seem to often have bargins. Saw a post on CN about someone (well known but forgotten) bringing out a 60mm triplet. Seems that many on CN are looking forward to it.

Suppose that the Meg 90 is too heavy, have seen a new Meg 88 advertised by a Canadian retailer. Short tube so possibly just light enough, no price I could see. Otherwise Stella View (Vu ?).

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I will not do any astrophotography at all. It would be visual-only. I might use it for terrestrial photography but that's not why I'm buying it. It just happens that either of these types of scopes are easy to hook up to my 35mm cameras for snapshots in daylight. I'm not looking for anything for long-exposure celestial subjects. The rig won't be guided or even track very well (manual AZ mount).

Aperture is good but so is aperture free of obstruction and my experience is that higher quality optics can make up for aperture. I actually think it's optical quality that makes the difference more than the CO. I've had some 70mm binoculars that were optically very poor (Celestron). Good quality ones half their size easily blew them away in every respect but admittedly for four to fifteen times the cost.

I favor the Mak-Cas outfit because of the compactness for the aperture, but I'm wary of cheap optics. I believe a good APO (TV, Tak, A-P, WO) is quite comparable to a cheap reflector 150% the same aperture by diameter. A medium-quality refractor like the Meade or an ED, I'm not sure.

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The Meg 88 is a good example of a scope I'm fairly confident offers more than a $400 Mak-Cas. However, it's a bit too pricey -- about 40% over my budget. Besides simply affording the thing, I also need to be able to afford to knock it around in the field. The Meade 80 APO is almost half the price of a Meg 88. Stellarvue's achromatic 80's are also in range.

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