Lightwave 0.6x reducer?

[Traingineer]

Hello, I've noticed that Altair Astro are selling a very inexpensive 0.6x focal reducer, has anyone used it for AP? Are the corners nicely corrected with a large APS-C sensor?

[Traingineer]

I also plan on using with a Celestron 80 ED and a Canon 7D. 

[Uranium235]

Unfortunately not im afraid. Trying to get an 80ED to reduce by 0.6x and get a perfect field on a big chip would be like trying to turn lead into gold, quite impossible.

You might get about 50 or 60% of your FOV as useable, but outside that you will start to notice radial distortion in the stars. By far the best reducer for the 80ED is the optically matched 0.85x flattener/reducer, which will deliver good stars right to the corners. Some have tried 0.8x reducers, but with mixed results (I tried a TeleVue 0.8x as well, didnt work).

Its going to be a case of trawling the internet for images taken with various reducers, inspecting the corners and deciding for yourself.

Edit: Need to add that the 0.85x is also a threaded solution (its attached directly to the drawtube) so its super solid. After going threaded you will never want to go back to thumbscrews or compression rings.

[Chris]

I have owned and used both the 0.6 and the 0,8 Altair reducers in the past with an ED120 and ED80. I found the 0.8 the best compromise but the 0.6 worked better than I thought it would !

Heres a link to a report I did on the 0.8 and i'll try and dig out a picture taken with the 0.6 for you

http://www.insideastronomy.com/index.php?/topic/530-altair-lightwave-08-reducer-mini-review/

If I was to have another reducer it would be the 0.8 Altair which would make it the third one I've owned

hth

Chris

[Chris]

Dug this out:

http://stargazerslounge.com/topic/206330-cone-nebula-xmass-tree/

Chris

I think its cropped just a touch which is worth bearing in mind. I found that the vignetting was quite bad with the 0.6x, this bothered me more than the eggy outer stars. its easy to crop eggy stars but difficult to get decent flats to rectify vignetting.

[Traingineer]

Unfortunately not im afraid. Trying to get an 80ED to reduce by 0.6x and get a perfect field on a big chip would be like trying to turn lead into gold, quite impossible.

You might get about 50 or 60% of your FOV as useable, but outside that you will start to notice radial distortion in the stars. By far the best reducer for the 80ED is the optically matched 0.85x flattener/reducer, which will deliver good stars right to the corners. Some have tried 0.8x reducers, but with mixed results (I tried a TeleVue 0.8x as well, didnt work).

Its going to be a case of trawling the internet for images taken with various reducers, inspecting the corners and deciding for yourself.

Edit: Need to add that the 0.85x is also a threaded solution (its attached directly to the drawtube) so its super solid. After going threaded you will never want to go back to thumbscrews or compression rings.

Thanks Uranium!, but about the 0.85x reducer you mentioned, would that focal reducer be the one Sky-Watcher sells for their ED 80? And a dumb question: How can you edit your own post?

I have owned and used both the 0.6 and the 0,8 Altair reducers in the past with an ED120 and ED80. I found the 0.8 the best compromise but the 0.6 worked better than I thought it would !

Heres a link to a report I did on the 0.8 and i'll try and dig out a picture taken with the 0.6 for you

http://www.insideastronomy.com/index.php?/topic/530-altair-lightwave-08-reducer-mini-review/

If I was to have another reducer it would be the 0.8 Altair which would make it the third one I've owned

hth

Chris

Thank you starfox for the help, those are some great images!

[Uranium235]

Thanks Uranium!, but about the 0.85x reducer you mentioned, would that focal reducer be the one Sky-Watcher sells for their ED 80? And a dumb question: How can you edit your own post?

Thank you starfox for the help, those are some great images!

Yes, its the Skywatcher 0.85x reducer. It should also work on the Celestron equivalent as it has exactly the same f7.5 lens cell.

You didnt mention which 80ED you had though, as there are many variants - the most common being the aforementioned SW and Celestron versions, for which the 0.85x will work. If its another variant, then you need to find its optically matched reducer - usually from the same manufacturer as the telescope, but if there is no match available then you are into the realms of guesswork.

Its a good reason to be very careful when purchasing an imaging telescope - first question should be "is there a matched reducer/flattener?".

In regard to editing your posts, you have a short grace period in which to make corrections to your last post if youve dropped a typo, or feel the need to elaborate on a technical point that you feel you havent explained well enough.

[Traingineer]

Yes, its the Skywatcher 0.85x reducer. It should also work on the Celestron equivalent as it has exactly the same f7.5 lens cell.

You didnt mention which 80ED you had though, as there are many variants - the most common being the aforementioned SW and Celestron versions, for which the 0.85x will work. If its another variant, then you need to find its optically matched reducer - usually from the same manufacturer as the telescope, but if there is no match available then you are into the realms of guesswork.

Its a good reason to be very careful when purchasing an imaging telescope - first question should be "is there a matched reducer/flattener?".

Thank you again Uranium, I have the Celestron 80 ED Astronomers without Borders sell, which I think is the same scope as Orion's ED 80 (and maybe Sky-Watcher's Black Diamond ED 80) But i've also seen that Orion's 0.8x reducer/flattener has worked pretty well with their ED 80 scope, and it's a lot cheaper than the Sky-Watcher reducer/flattener.

[Uranium235]

Ahhh yes, I forgot about the Orion version. Yep, thats the same optics as the other two.

But caution in regard to the cheaper reducers, as they rarely turn out to be better than the one specifically designed for the telescope (the 0.8x is a "catch all", so a bit iffy) - is that extra 0.05 speed boost worth sacraficing your corners for? Personally, I loathe eggy corners and I like to get the flattest image possible - otherwise I would be wasting expensive CCD pixels. Having the flattest field possible also helps a lot when attempting mosaics, as it makes the panes easier to stitch together.

[blinky]

Just bought the 0.8 Lightwave reducer to use with my ZS66, these look very well manufactured in Taiwan and seem to be getting good reviews. I had a Televue one as well but cant get quite enough in focus with it as it has a rather long nosepiece on it.

[Astronut1982]

I Previously had a Celestron ED80 / DSLR combo & I used an Altair Lightwave 0.8 reducer/flattener with it to great effect.

Here is an uncropped image taken with this combo :-

As you can see, there is only a slight warping of stars near the edge so it is a pretty good match with that scope. I also felt that the build quality was pretty good as well.

HTH,

Jeff

[Traingineer]

I Previously had a Celestron ED80 / DSLR combo & I used an Altair Lightwave 0.8 reducer/flattener with it to great effect.

Here is an uncropped image taken with this combo :-

As you can see, there is only a slight warping of stars near the edge so it is a pretty good match with that scope. I also felt that the build quality was pretty good as well.

HTH,

Jeff

That is an amazing image, Astronut! The 0.8x reducer/flattener does look like an excellent/affordable option. 

[Astronut1982]

Thanks very much Traingineer!

If you go with that combo, I'm sure you'll be very happy with it. I know I was.

Jeff