Good all round refractor for astrophotography

[Skooby]

Hi guys I'm looking at getting a refractor for a 2nd scope for astro imaging use I've been looking at the William optics 71ed but it's over £350 my question is what can I get for around £150 to £200 that is close to the 71ed in performance scope only! as I've got a neq6 pro mount or shall I just hold out for the Williams optics 71ed? What is the SkyWatcher Startravel-102? Decisions decisions any help will be much appreciated thanks.

Kevin.

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[ronin]

For £150-£200 there isn't really anything.

Simply refractors at that cost will be achromatics and they will show chromatic aberration on objects. Another consequence is that they tend to have a less well defined focal plane so are a bit "softer" which means less well defined.

The ST's are f/5 so will have CA present, something like an f/7 achrom should be better, but they are slower and there are very few around, as in none really.

Imaging scopes thend to start off being ED scopes, then you move to apo triplets. Many use the Skywatcher ED 80, but you might need a flattener reducer.

Occasionally the WO Megrez 72's come up for sale, usually just over the £200 mark and they are popular for starting off in imaging. They do however tend to get sold quick

Best suggestion is the used side of things, ABSUK and here, if you do then check 2 or 3 times a day. Problem with imaging is that the equipment tends to be costly for anything good, however people start out with an ED 80 then if they stay move on to an apo, or they abandon it (imaging takes lots of time up) so either way scopes appear for sale.

[ollypenrice]

I agree with Ronin. There is nothing remotely satisfactory for refractor imaging at the budget you mention, other than second hand - and even then you'd need some luck. ED and full apo refractors are popular because they give tight images fairly quickly and very easily. Achromats cannot do that. Their false colour is overwhelming because cameras pick up more of the extreme violet than our eyes do. ST series scopes give stars with huge blue bloat and lots of coma.

The budget alternative is a small SW Newtonian OTA. Some wonderful results have been posted recently with one of these.

Olly

[GuillermoBarrancos]

I think this is pretty much the cheapest APO you can buy for imaging really:

http://www.firstlightoptics.com/equinox/skywatcher-equinox-66-apo-pro-ota.html

But I would rather add another 30 pounds and go for this:

http://www.firstlightoptics.com/pro-series/skywatcher-evostar-80ed-ds-pro-ota.html

Reason simply, because the 66 has only a 1.25inch focuser (too limiting if you ask me), while the 80ED has a 2inch focuser and supports a flattener/reducer.

PS. What camera are you planning on using with it?

Did you end up buying that second hand QHY8L?

[Skooby]

I think this is pretty much the cheapest APO you can buy for imaging really:

http://www.firstlightoptics.com/equinox/skywatcher-equinox-66-apo-pro-ota.html

But I would rather add another 30 pounds and go for this:

http://www.firstlightoptics.com/pro-series/skywatcher-evostar-80ed-ds-pro-ota.html

Reason simply, because the 66 has only a 1.25inch focuser (too limiting if you ask me), while the 80ED has a 2inch focuser and supports a flattener/reducer.

PS. What camera are you planning on using with it?

Did you end up buying that second hand QHY8L?

st what I thought I think I'll get either the 71ed or one if these 2 what are these to scopes like compared to the 2"William optics 71ed what would you choose? No I didn't get that qhy8l but I'm going to get it new instead hence this refractor so if you could help me choose thanks guys.

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[GuillermoBarrancos]

I would definitely go for the SW 80ED. It's a true and tested scope and most widely used, with consistent performance.

I read a lot of reports around the WO 66 and 71 doublets that they don't correct very well and show a lot of bloat on bright stars.

[Skooby]

I would definitely go for the SW 80ED. It's a true and tested scope and most widely used, with consistent performance.

I read a lot of reports around the WO 66 and 71 doublets that they don't correct very well and show a lot of bloat on bright stars.

thanks Guillermo I will probably go for the sw 80ed then and sorry didn't see when you asked about camera I'll use the canon 600d until I get the ccd thanks

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[LukeSkywatcher]

Refractors are expensive. I paid about 350 euros for my 90mm refrac about 7 yrs ago. As Olly has said, a small(ish) reflector such as the SW Explorer 130P is about on budget and many people use them for imaging.

[Alien 13]

I think the ED80 and WOZS71 are both good starter scopes the ED80 has slightly better control of the blue part of the spectrum but the ZS71 is much faster and has a much better focuser, price wise there is not much in it the ED80 tube is cheaper but when both are packaged with the FF/FR the WO comes out the best value.

The choice realy comes down to what are the important factors to you and the upgrade route in the future.

Alan