Which 80mm APO?

[alexbb]

Hello all,

As the title suggests, I'm interested in buying a ~80mm APO 90% for imaging. I recently bought an ASI1600MMC camera and I still need to buy some filters, an EFW, figure out a better portable power source, etc. So I'm not in a hurry at all and I should save some months for this scope.

I have now some 300mm lenses at F/4.5 which should do fine for wide filed NB imaging, an 130PDS (the CC for it should arrive tomorrow). I'm looking for something to fill the gap from nothing to ~580mm (the 130PDS with the CC/reducer) in terms of colour correction and 300mm to ~580mm in terms of focal length. It could/should also replace the 300mm lens which is not colour corrected very well.

The budget should be around 1000 euros, +- a few hundred.

The options that I'm thinking of are:

1. SW Esprit 80 + FF at 400mm. F/5. ~1400 eur.
2. TS Photoline 80/480 APO Triplet + FF without reducer. ~1100 eur. And I can also buy later for this a 0.79 reducer or a Ricardi 0.75 reducer/FF, but this one is ~700 eur.
3. William Optics GT81. The combo WO GT81 + 0.8 reducer/FF is ~1500 eur. And, probably, the FR/FFs that fit the one above would fit this one too.
4. An Ascension 80ED triplet F/6. This one uses a FCD1 ED lens, but shouldn't it be easier to correct the optics if it's a triplet?! + FF is ~700 eur. Did anyone use this one? Did anyone use this one and one of the above to be able to compare it one to one?
5. The SW Evostar 80ED Pro. The combo + 0.85 reducer/FF is ~650 eur. The difference from 510mm to 480mm FL of the others is not to big, but it is already close to the ~580mm FL of the reflector. Shouldn't I better get the most out of the reflector before thinking of this one? Is there a cheap 0.75 reducer/FF that could go well with this scope?
6. Any other options? To be shippable to Europe.

The focusers should be all pretty good with the ZWO camera which is not too heavy. The rack&pinion ones should be better though.

Some say that the LOMO 80/480 triplets are one of the best optics, but they are very rare now. Stellarvue say that the new triplets with FPL53 should match the LOMO performance and I suppose that the TS and the WO have the some optics.

And I'm also open to SH market if I find one in good condition.

I read reviews about them, I saw pictures taken with them., The Ascension is almost an exception, I didn't see many reviews about them, neither pictures taken with them. There are some though. But not many.

I think that I can't fail with the Esprit, there were some issues at the beginning before the backfocus was figured out, but since then things were sorted out.

Opinions? Thoughts? Recommendations?

Many thanks,

Alex

 

[Highburymark]

I'm not an imager but the SW Equinox is often recommended in these threads - faster than the Evostar, same great optics. 

[geordie85]

If your quick there's a skywatcher  Ed80 just been put into the classifieds for a very decent price.

[Uranium235]

Take a look as one of the ES Reid checked Star 71's.  F4.9 @ 350mm, excellent colour correction and an all-threaded connection. It will cost a little more though... about 1200 quid.

https://www.firstlightoptics.com/william-optics/william-optics-star-71-ii-4-element-refractor.html

And being as its been pre checked by an expert, its quality will be nailed-on.

[alexbb]

31 minutes ago, geordie85 said:

If your quick there's a skywatcher  Ed80 just been put into the classifieds for a very decent price.

Thanks! Let's check this one first!

[ronin]

Have a look also at the ES apo's they are all triplets and come is a few variants. They have the Essential 80 and a newer FCD100 80 apo.

As they have a European site: http://www.explorescientific.de/index.php

It might be easier to get one to you.

[Commanderfish]

I have the Explore Scientific Triplet (aluminium, pre FCD100 version) and absolutely love it. Very sharp with pure colours.  Good stock focuser with 10:1 reduction. It has caused an expensive Apo addiction - but then I'm visual so I  need more aperture than you.  

Also comes in Carbon Fibre if weight is an issue.

Given your budget, whichever brand you choose I think you should go for a triplet, so I wouldn't personally go with number 5 above, as I'm pretty certain those are still doublets.

[alexbb]

22 minutes ago, ronin said:

Have a look also at the ES apo's they are all triplets and come is a few variants. They have the Essential 80 and a newer FCD100 80 apo.

As they have a European site: http://www.explorescientific.de/index.php

It might be easier to get one to you.

This one looks interesting too, thanks! I wonder if they can be pre-checked before sending.

[Highburymark]

The new ES FCD100 scopes are apparently extremely good

[ollypenrice]

I haven't tried any of them so how would I know? Paper spec is often only so much net fodder. What we do know, though, is that there are QC issues going as far up the food chain as Takaahshi so I'd be mainly concerned about the returns policy of the vendor. Saving 100 euros wouldn't get a look-in for me. Personally I'd be most tempted by an Esprit 80 from FLO but that's just me.

Olly

[alexbb]

Well, I have the FLO option for a Es Reid check for the Esprit. I admit that I'm an impulse buyer and I should resist somehow until Easter as I planned before buying the camera. I'm biased for the Esprit and it's also on the top in my list. My only concern about it is about its focal length, sometimes I think that is too short. The WO Star 71 looks nice too, but it has a too short FL.

[ollypenrice]

2 hours ago, moise212 said:

Well, I have the FLO option for a Es Reid check for the Esprit. I admit that I'm an impulse buyer and I should resist somehow until Easter as I planned before buying the camera. I'm biased for the Esprit and it's also on the top in my list. My only concern about it is about its focal length, sometimes I think that is too short. The WO Star 71 looks nice too, but it has a too short FL.

There are lots of great targets for short FLs...

Olly

[alexbb]

2 minutes ago, ollypenrice said:

There are lots of great targets for short FLs...

Olly

I agree with this, but this means that I will need 2 scopes. Please don't do this to me :))

[ollypenrice]

Only two? Don't do this to yourself...

Olly

 

[alexbb]

I'd like a longer FL if possible, something around 450mm, but I shouldn't spend that much for a 90mm or larger. For a shorter FL, there's a higher possibility of buying later a Canon L lens and use it for daytime photography too. I should avoid buying a lot of expensive stuff for a while, I spent many thousands this year and I'll be just 1 year old into astrophotography precisely the second day of Christmas. I should have better results before justifying the extra costs. Perhaps a newer car would be nice too

Alex

[rl]

For the last 12 months I've been running a s/h GT81 for which I paid £500 on ABS complete with the correct field flattener. I've been very pleased with it; 6 elements in total sorts out virtually all the optical nasties, at least on a 2/3 format sensor. R+P focuser is good as well; holds an 1100D in the vertical without slipping, and enough back focus to add filter wheels etc.  I don't know whether it's any worse or better than the other options but it's certainly worth a look. The handle/ bracket thingon top is more useful for a finder..I prefer my guidescope more solidly bolted down to the mount plate.

If you're buying new than Olly has a point; the after-sales service may prove more valuable than small differences in price and spec.

RL

[alexbb]

On 12/20/2016 at 13:56, moise212 said:

For a shorter FL, there's a higher possibility of buying later a Canon L lens and use it for daytime photography too.

As I expected, this happened. Got myself a sh 300 F4 L yesterday at ~500€. Now it's snowing.

I also wonder how it would behave with a 1.4 extender. 420 F5.6 would be nice too. But I'll wait to see how it performs at 300mm first.

So I hope I can avoid the need for the 80mm scope for a while.

Clear skies!

[alexbb]

Wait no more!

I really love the fov I get with my 300 lens. It's actually ~288mm. I found the fl perfect for framing many mosaics. However, I believe the IS element is not fixed when powered off and it causes me problems most of the time. I'm still looking for a Canon 300 F4 L non IS lens, but I ordered today the Esprit. I will have to shoot ~2x3 panels mosaics instead of ~2x2, but they will have greater resolution. And it seems that it's possible to attach a 0.79x TS fr/ff and get me to 316mm, F/4. That'd be great!

Now my hope is to get the clouds too only during the full moon.

Wish you all the others clear skies!

Alex

[alexbb]

It finally arrived! Clouds were already here so no change in this regard.

Lot heavier than I expected. Moreover, the case and the scope I think are heavier than my mount and tripod.

Tomorrow would be one year since I started the topic. I am very surprised I resisted that long.

Now.. let's see what it shows..