Jump to content

Banner.jpg.b89429c566825f6ab32bcafbada449c9.jpg

Orion ED80T CF - first impressions

johnrt

By johnrt
in Member Equipment Reviews

Recommended Posts

johnrt

johnrt

Posted
Posted

So, what I should be doing tonight is adding the red & green channels to my M33 project - but the bank of cloud rushing in from the west has other ideas, so I'll have to make do with sharing my first impressions of the Orion ED80T CF.

I ordered the scope back on the 17th of August after considering my options in one of those "what imaging refractor" threads. The package advertised by SCS Astro was a very good deal in comparison to similar 80mm triplet refractors offered by other vendors. The package included; Scope, Dielectric diagonal & Flight case for £615.

The day after I placed the order I received an email back from SCS stating Orion had changed the price (new price £699) and removed the diagonal without informing them, but they were able to offer the scope & case at the original price.

Fair enough, I thought. I'm an imager only so have no use for the diagonal anyway, so I mailed back to say I was happy to go ahead. A week passed without any sign of the scope. I followed up with an email asking how my order was going. Another week passed, still no sign of anything and they hadn't charged my card.

Eventually I thought I'd give SCS one last chance and rang the shop in person - SCS said they had received no reply to their original email about the price change - lets give them the benefit of the doubt here and blame it on over zealous spam filters, as once we had confirmed via telephone, 48 hours later I had my hands on my ED80.

The ED80T CF is an 80mm / 480mm triplet with FPL-53 glass all housed in a carbon fibre body. Dual speed focuser & lovely long dew shield (with locking compression ring).

6110495408_0e61a38796_b.jpg

Front view.

6109949903_55fc761d89_b.jpg

I added a standard Skywatcher finder scope (from an ST80) and added it to my side by side bar in 90mm rings and we were ready for action!

In terms of build & finish quality I would place this scope above my previous imaging scope - a William Optics Megrez 72, but I have to say there isn't a whole lot in it. The focuser is smooth & robust, it feels like it will hold a whole lot more than my little Atik / filterwheel combo.

Optical quality and results on the other hand tell a different story. The Orion (with Atik 314l+) wiped the floor with the results I obtained from the Megrez straight out of the box.

Here is a 2 hour stack of 5 min Lum subs on M33 with the Orion.

The camera used was an Atik 314l+, Baader Lum filter & WO x0.8 reducer/flattener II - DBE & stretch applied in Pixinsight.

6110285169_ecc3c67c05_b.jpg

and secondly a 1 hour stack of 5 min subs with the Baader blue filter (same camera & reducer) - with DBE & a stretch applied to the stack in Pixinsight.

6113616427_abf9f031f6_b.jpg

Overall I'm really happy so far with both the price I paid for the Orion & the scope itself. :)

More to come - weather permitting.

Link to comment
Share on other sites
  • Replies 36
  • Created
  • Last Reply
Deneb

Deneb

Posted
Posted

Thats certainly looking very nice, congrats on your new scope john, its looking to be a really good performer. One thing would be nice, if it came with tube rings instead of the small shoe.

I too also would be interested in seeing the scope perform with a bigger chip size.

It would certainly add another choice in the 80mm field of scopes...

PS: How much does it weigh being CF.

Nadeem.

Link to comment
Share on other sites
MikeWilson

MikeWilson

Posted
Posted

Nice scope, John! Have you put any of the unflattened frames through CCD inspector? Nadeem did that with a similar 80mm triplet, the WO GT81 - and got some rather frightful results. Right, Nadeem?

Sent from my mobile using TapaTalk (so please excuse bad grammar & spelling!) :-)

Link to comment
Share on other sites
Deneb

Deneb

Posted
Posted

your going to need a flattener with it, certainly the GT81 needs some help with a flattener otherwise you will have some horrible effects with triplets, thats even with my AA115, especially if even your a tad out of focus, which the initial GT81 Test was.

Link to comment
Share on other sites
johnrt

johnrt

Posted
  • Author
Posted

My copy of CCD inspector was evaluation only and expired a long time ago I'm afraid.

Triplets are *more* prone to field curvature than a doublet so the flattener, even with the small chip is a must.

The "all in" weight of the OTA, rings, dovetail, finder, flattener, filterwheel & Atik 314l+ is 3.8kg.

Link to comment
Share on other sites
johnrt

johnrt

Posted
  • Author
Posted

Folks speak highly of the TV x0.8 flattener or you could give the Skywatcher version a try - I don't see why it wouldn't work.

What flattener would you chaps recommend for this scope?

The WO IV 0.8 reducer/flattener doesn't appear to be able to go down that far in focal length (480mm).

Link to comment
Share on other sites
MikeWilson

MikeWilson

Posted
Posted

I wonder if both might be an acceptable longer term solution. That way one would have 480mm focal length for the smaller planetaries and 384mm for the wider stuff.

I've asked SCS Astro if they can add one to my order.

I've got the last ED80T CF :)

All the best,

Mike

Link to comment
Share on other sites
Whippy

Whippy

Posted
Posted

Triplets are *more* prone to field curvature than a doublet so the flattener, even with the small chip is a must.

Where have you heard that? AFAIK, it's doesn't matter if it's a doublet or a triplet. Field curvature in refractors is detrmined by aperture and focal length, not the amount of glass in the lens cell. I can't remember the exact formula but basically the shorter the focal length, the more pronounced the curvature.

If you can find a WO FFII, it'd work a treat on this scope with a 314.

Tony..

Link to comment
Share on other sites
johnrt

johnrt

Posted
  • Author
Posted

Tony - I got this info from the knowledgeable chaps at FLO who posted this in Deneb's original GT81 first impressions thread. Here is what they said.

They are right Nadeem, the third lens is for enhanced colour correction. Triplet refractors typically exhibit more field curvature than a doublet, not less. For imaging it is normal practise to use a 'field flattener' or combined reducer/flattener. This is something we mentioned briefly HERE.

Hope that helps,

Steve

Cheers

John

Link to comment
Share on other sites
johnrt

johnrt

Posted
  • Author
Posted

Mike,

Congrats on the new ED80! You are going to love it!

I agree with Tony, if you can get your hands on a WO flattener II it does work a treat with this scope - it is what I've got and have used in the pics above. But getting hold of one might be easier said than done.

I don't use a focus mask, I just cycle 1 sec exposures and use the Artemis Capture focus aid tool which gives a FWHM & brightness readout on a star of choice.

John

Link to comment
Share on other sites
Whippy

Whippy

Posted
Posted

Ah, I see John. I'm no expert, but that what I've read. Maybe what FLO was getting at was that triplets are more prone to curvature becuase they can be made faster than doublets.

For example, an ED80 at f7.5 could have the same amount of colour correction as these f6 triplets but show less field curvature because they have a longer focal length. I'm saying they have, but that's how I understand it anyway!

Tony..

Link to comment
Share on other sites
MikeWilson

MikeWilson

Posted
Posted
Mike,

Congrats on the new ED80! You are going to love it!

I agree with Tony, if you can get your hands on a WO flattener II it does work a treat with this scope - it is what I've got and have used in the pics above. But getting hold of one might be easier said than done.

I don't use a focus mask, I just cycle 1 sec exposures and use the Artemis Capture focus aid tool which gives a FWHM & brightness readout on a star of choice.

John

Thanks John, I'm really looking forward to it. I haven't actually done any proper (>20 mins total, really!) imaging all Spring & Summer. I'm going to guide it using a 9x50 finder/guider so hopefully it will be a superbly compact and field-portable solution to my locally light polluted sky problem!

I'm using Nebulosity 2 which also gives max & avg brightness and FWHM on a selected star too - so I'll go with that. I've got an electronic focuser that I'm hoping to attach to the focuser (not sure how successful this will be or even if it's needed with such a lightweight refractor - the 150P with its single speed crayford really benefited from it though).

I'm looking for one of those flatteners but they're rarer than hens teen so have asked SCS Astro to add a TRF-2008 (!). Only once, I keep telling myself...

As for field curvature - the way I think about it is like this: camera lenses with shorter focal lengths have in general more curvature than ones with longer focal lengths. In the extremely small focal lengths <17mm, curvature becomes strongly apparent (fish eyed) whereas curvature is rarely a problem in the longer focal lengths >50mm.

Of course we're pixel-peeping here and so it doesn't surprise me that we can detect fairly strong curvature at <400mm whether it's a doublet or a triplet.

Whether triplets exhibit inherently more curvature than a doublet would be an interesting experiment. Maybe John can post some subs and we can compare with an ED80 owner (Nadeem?) - both scopes are made in the same factory with the same glass, aren't they? Could be an interesting test.

One other great selling point for the ED80T CT is that it makes a brilliant birding/terrestrial scope with practically no CA. A lovely long focal length telephoto camera lens :)

All the best,

Mike

Link to comment
Share on other sites
Deneb

Deneb

Posted
Posted
Whether triplets exhibit inherently more curvature than a doublet would be an interesting experiment. Maybe John can post some subs and we can compare with an ED80 owner (Nadeem?) - both scopes are made in the same factory with the same glass, aren't they? Could be an interesting test.

Nadeem

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.