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First scope


gtis

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Actually I don't advise going for the 70ED. 

A large number of optics are sourced from Taiwan and China, which in itself is no bad thing; these companies (Long Perng, Kunming Optics) are the reason we can buy a sharp, unadorned apochromat for less than the price of Sky TV. The optics are generally good, but not equally so.

The 70mm series, in my experience, is a bit of a black sheep in the small apo market. They're nice for travel scopes, but honestly they suffer from an unusually great amount of chromatic aberration, specifically a green/purple halo around stars. 

The 72mm however, for some reason known only to whichever optician came up with the formula, fairs a lot better. Altair produce the 72ED-R which I heartily recommend, as it contains the same lens group as the William Optics Megrez 72 you see in my signature. It's the lightest scope I can image with, and it's at a nice quick f/6.

One thing; it's a doublet, so you will still see some residual halos around stars. Nothing much to worry about really, at small apertures CA is usually well controlled, but it won't stand up to a triplet on colour correction. I advise you to search on Astrobin for the scopes you're looking for, to see images made with them (make sure you're looking at the *imaging* scope, a lot of people with huge telescopes use a 72mm as a guidescope!).

The 80ED would serve you well, but as Ive said in another thread, I am not a fan of its focal ratio; f/7.5 for me is just way too slow.

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Actually I don't advise going for the 70ED. 

A large number of optics are sourced from Taiwan and China, which in itself is no bad thing; these companies (Long Perng, Kunming Optics) are the reason we can buy a sharp, unadorned apochromat for less than the price of Sky TV. The optics are generally good, but not equally so.

The 70mm series, in my experience, is a bit of a black sheep in the small apo market. They're nice for travel scopes, but honestly they suffer from an unusually great amount of chromatic aberration, specifically a green/purple halo around stars. 

The 72mm however, for some reason known only to whichever optician came up with the formula, fairs a lot better. Altair produce the 72ED-R which I heartily recommend, as it contains the same lens group as the William Optics Megrez 72 you see in my signature. It's the lightest scope I can image with, and it's at a nice quick f/6.

One thing; it's a doublet, so you will still see some residual halos around stars. Nothing much to worry about really, at small apertures CA is usually well controlled, but it won't stand up to a triplet on colour correction. I advise you to search on Astrobin for the scopes you're looking for, to see images made with them (make sure you're looking at the *imaging* scope, a lot of people with huge telescopes use a 72mm as a guidescope!).

The 80ED would serve you well, but as Ive said in another thread, I am not a fan of its focal ratio; f/7.5 for me is just way too slow.

Thanks somethink to think about

Neil

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Does it have to be refractor? There have been some amazing pictures on this forum from the 130pds especially from uranium(name escapes me but I'm sure it's something similar)

It's f5 and a cheap light bucket.

If your partial to refractors I'm a sucker for William optics.

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