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80mm refractor vs 80mm reflector


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13 minutes ago, Navixc said:

I found a 80mm(F400) refractor and a 80mm(F800) reflector at my local astronomical store.

 

The aperture is same, so I am confused which one to buy.

I wouldn't buy either, especially not the reflector.  The 80mm f5 refractor will be best suited to low-power wide views.  An 80mm f10 refractor (suitably mounted) would be a better buy.  If your budget is very low, your money might be better spent on a pair of 10x50 binoculars.

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Generally, very small reflectors seem to be of poor quality, and as sunshine says the secondary obstruction can only be made so small, I would pass on that and get the refractor, unless you are prepared to look elsewhere, in which case I would highly recommend a look around on our sponsors website, First light optics

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1 hour ago, Sunshine said:

An 80mm reflector? I can't say I've seen such a small one, I would not look twice at such a small reflector once one considers the central obstruction, which ones are they?

They tend to be small, tabletop dobsonians. FLO have a Stellalyra one at 80mm, and there are few (such as the Celestron Firstscope) at 76mm. The latter is certainly targeted at children, and you have to think of the context in which they are offered. Simple to set up, simple to use and no need for the added expense of a wobbly tripod and mount at that price point. 

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In general I agree with the comments above. The refractor will be better for wider field, low power views whereas the longer focal length refactor should be more suited to mid and high powers. A lot depends on the manufacturer and quality though, so you know which make they are?

If you let us know budget and where you  are then people should be able to suggest some alternatives.

Just for reference, I have a tiny 65mm TAL Alkor, f7.7 reflector and it is excellent, quite amazing for its size.

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Do you have a astronomy club nearby you at all. 

It would help you immensely to go and chat with other astronomers, look at equipment and discuss what you want to achieve.

It could save you 1,000's of dollars/pounds/euros or whatever your chosen currency is 👍

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Getting back to the original question, l assume that the "local store" is the same Indian website that you linked to in a previous thread rather than a physical shop. Looking through their telescopes I see two options for a 80 / 800 reflector:

Star tracker 80 / 400 refractor 

KSON 80 / 800 reflector 1

KSON 80 / 800 reflector 2

The two reflectors ore the same telescope on different mounts so to start with lets just compare this refractor to this reflector. The refractor is the ubiquitous 80mm f5 and is well known. It will be best for low power, wide field observation of star fields. An achromat at f5 will show chromatic aberration on bright objects and so is not best suited to planetary observation, although a yellow filter should sharpen up the views. With the included 25mm kellner you are looking at a field of view of around 2.8° but if you add a 32mm Plossl you can open this up to around 4° which will make finding things in the sky easier.

With the 80mm reflector and the included 20mm kellner you have a much more restricted field of view of around 1.1°, and again with a 32mm Plossl you can open it up, but only to 2°, which makes finding objects much, much more difficult. I would be looking to add a 5° 8x50 RACI finder to a telescope with such a small field of view, but given the size a 6x30 might be more appropriate to compliment the red dot finder. However, once you have found an object, the 80 /800 reflector might give a better image as it will have no chromatic aberration, much lower field curvature, and due to the higher f10 focal ratio cheaper eyepieces will perform much better and add fewer aberrations of their own. At this price the mirror is likely to be spherical but at f10 this is unlikely to matter.

Moving on to the mounts, l suspect that all three mounts will be on the wobbly side and so you may want to find some way of bracing whichever one you choose. When comparing the two reflector mounts I think that the mount head on the more expensive option looks more substantial and also appears to have a standard vixen dovetail which would make switching telescopes and mounts easier in future, so I would go for the more expensive option if you choose the reflector. The tripod supplied with the refector looks more sturdy to me and the smaller telescope will exert less torque on the mount as well as being much les of a sail in the wind so this might be a more stable option than the reflector with the upgraded mount.

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15 hours ago, bomberbaz said:

Do you have a astronomy club nearby you at all. 

It would help you immensely to go and chat with other astronomers, look at equipment and discuss what you want to achieve.

It could save you 1,000's of dollars/pounds/euros or whatever your chosen currency is 👍

This  right here.  Best advice to take 

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