Suggestions for a longer refractor for my next imaging scope

[900SL]

Hi

 

I currently have a Vixen SXD2 (payload 14kg max) and an ASI533MC Pro / Nikon D5600.  My longest scope is a GT71 with a 6AIII reducer/flattener

This is guided with an ASI Air Pro, 120MM Mini and a FMA 180 guidescope. 

I'm looking for a longer focal length refractor around 100 -120mm  aperture

Budget around €3500. I go for mainly DSO nebula, larger galaxies, some lunar.

Currently resident in Finland so will have to use European suppliers like TS Optics

The TS CF APO 102mm F7 FPL 55 (blue ring) has caught my interest with the 0.8 R/F and this should fit well with my set up but thought I'd throw this out there to the gallery to see what other recommendations you may have, as this isn't a big step up from my GT71.

   

 

 

[Cosmic Geoff]

Why a refractor? A SCT with f6.3 focal reducer could give you a much larger aperture and focal length with a €3500 budget.

[vlaiv]

https://www.teleskop-express.de/shop/product_info.php/info/p3041_TS-Optics-PHOTOLINE-115-mm-f-7-Triplet-Apo---2-5--RAP-focuser.html

[vlaiv]

This one as well (or other more expensive variants with different / larger focusers or FPL55 glass or whatever):

https://www.teleskop-express.de/shop/product_info.php/info/p6679_TS-Optics-PHOTOLINE-130-mm-f-7-FPL53-Triplet-APO-Refractor.html

but it is approaching max payload of the mount (add accessories and you'll be pushing 14Kg easily).

[900SL]

2 hours ago, Cosmic Geoff said:

Why a refractor? A SCT with f6.3 focal reducer could give you a much larger aperture and focal length with a €3500 budget.

Because, as stated, I'm looking for a refractor. I don't want the hassle of collimation, longer focal length, or having a waste bin hanging off my mount. But I appreciate your advice. 

[Elp]

Stretch for a Borg? What are you trying to achieve FL wise?

[900SL]

Elp, 500-600 after a reducer would be dandy. 

[900SL]

3 hours ago, vlaiv said:

This one as well (or other more expensive variants with different / larger focusers or FPL55 glass or whatever):

https://www.teleskop-express.de/shop/product_info.php/info/p6679_TS-Optics-PHOTOLINE-130-mm-f-7-FPL53-Triplet-APO-Refractor.html

but it is approaching max payload of the mount (add accessories and you'll be pushing 14Kg easily).

Thanks Vlaiv. That's pushing it but the 115 could fit the bill. Thanks

[Elp]

Esprit 120 native FL 840mm.

Explore Scientific 102 FL 714mm.

ES 127 FL 952mm.

A larger WO as you already know the quality with the GT71.

[raadoo]

I'll add to @Elp's list:

• APM LZOS SuperED - 800mm (slightly over budget)
• Takahashi FC-100DZ - 820mm (yes, it's a doublet but reportedly as good as a triplet)
• TS 106 FCD100 - 700mm
• Vixen AX103S - 825mm
• William Optics Fluorostar 120 - 780mm

[ONIKKINEN]

Since you're currently in Finland, have a look at this scope from a Finnish retailer: https://www.astroart-store.com/product/2170/founder-optics-106mm-f6-f636mm-triplet-refractor

Never heard of Founder optics but from the surface looks like a Long Perng scope in a different colour. 106mm/636mm and comes with a 1x flattener.

[Dan_Paris]

Do you firmly exclude reflectors ? A 200mm  f/4 Newtonian would have about the same focal length as refractors in the 100-120mm range, and  cut down dramatically the integration times. And is a good match to your mount.

The Lacerta Foto-Newton is well within your budget (about 2600€ with coma corrector)

Edited July 7, 2022 by Dan_Paris

[Elp]

1 hour ago, raadoo said:

Takahashi FC-100DZ

I refrained from adding a Tak as it bumps up the price just by mentioning the name... Same price territory as Borg though.

On a other note though personally I've found an added second scope is usually a different type, first it was a Newtonian for the aperture and FL, then an SCT again for the aperture and FL in a more compact form.

Edited July 7, 2022 by Elp

[raadoo]

5 hours ago, Elp said:

I refrained from adding a Tak as it bumps up the price just by mentioning the name... Same price territory as Borg though.

On a other note though personally I've found an added second scope is usually a different type, first it was a Newtonian for the aperture and FL, then an SCT again for the aperture and FL in a more compact form.

Understandable. I mentioned the FC-100DZ specifically as it's under budget (3k sans accessories), it falls under the "long focal length apo" category and Tak make a big deal out of this flavour of FC-100's photographical chops.

An Astrobin search yields some pretty good results. My only gripe with it would be that it's a long little doggy at 84cm. With a full image train you'll probably end up with a meter of skinny tube hanging off the mount, and wind is going to be a bit of a factor at that point.

[900SL]

10 hours ago, Elp said:

Esprit 120 native FL 840mm.

Explore Scientific 102 FL 714mm.

ES 127 FL 952mm.

A larger WO as you already know the quality with the GT71.

Thanks Elp

The ES scopes look interesting in FCD 100. I must admit I've not looked at them before. The carbon 127 is pretty light

My Skywatcher experience has put me off any of their products

I like the WO scopes, great fit and finish but they are re-badged with a flash paint job and patchy QA/QC at times (I read some wag say they made the worlds most expensive thermometer) so I'll be looking for something different this time.

 

[900SL]

9 hours ago, raadoo said:

I'll add to @Elp's list:

• APM LZOS SuperED - 800mm (slightly over budget)
• Takahashi FC-100DZ - 820mm (yes, it's a doublet but reportedly as good as a triplet)
• TS 106 FCD100 - 700mm
• Vixen AX103S - 825mm
• William Optics Fluorostar 120 - 780mm

Thanks Raadoo

Are the LZOS lenses still available? I assume you are referring to the 100/800 which looks like a great scope but a little slow for imaging

The Tak is f8 so looks like I'd need the 0.66 reducer too. Seems to be a great doublet and light

The TS 106 is in the frame, I have been comparing the two, some example images here:

https://www.astrobin.com/full/nub52x/B/   Looks like a bit of astigmatism in the full frame corners, which wouldn't phase me as I am APS-C max

The Vixen is an interesting design, FPL 53 triplet with an integral flattener built in and reducer available.

Some interesting choices there. Thanks

 

 

 

 

 

 

[900SL]

9 hours ago, ONIKKINEN said:

Since you're currently in Finland, have a look at this scope from a Finnish retailer: https://www.astroart-store.com/product/2170/founder-optics-106mm-f6-f636mm-triplet-refractor

Never heard of Founder optics but from the surface looks like a Long Perng scope in a different colour. 106mm/636mm and comes with a 1x flattener.

Been enjoying the heat wave Onikkinen!

I've used Astroart before, bought an ASIAirPro from them. I'll have a look.  

[900SL]

9 hours ago, Dan_Paris said:

Do you firmly exclude reflectors ? A 200mm  f/4 Newtonian would have about the same focal length as refractors in the 100-120mm range, and  cut down dramatically the integration times. And is a good match to your mount.

The Lacerta Foto-Newton is well within your budget (about 2600€ with coma corrector)

Thanks Dan. I was considering a Mak Newt earlier but eventually decided on a second Refractor as I will be driving to darker sky locations and setting up/taking down each time.  I've never owned a Reflector and the collimation side of things phases me. I do however like faster scopes, so will have a look

[Dan_Paris]

20 minutes ago, 900SL said:

I've never owned a Reflector and the collimation side of things phases me.

The key is to have the right tools for the job. I have the Catseye tools, and get consistently essentially perfect collimation in  few minutes. And it can be done during daylight.

Edited July 8, 2022 by Dan_Paris

[tomato]

Sorry to hear you had a bad experience with SW. The SW Esprit scopes from FLO in the UK can be supplied with an independent optical test for peace of mind on the quality of the scope. I use Esprit 150s, I can’t fault the performance/cost balance for an APO of this aperture.

[Elp]

Newtonians are easy to collimate, I guess it depends how super accurate you want to be.

[900SL]

37 minutes ago, tomato said:

Sorry to hear you had a bad experience with SW. The SW Esprit scopes from FLO in the UK can be supplied with an independent optical test for peace of mind on the quality of the scope. I use Esprit 150s, I can’t fault the performance/cost balance for an APO of this aperture.

Thanks Tom. I assume the scopes are better made than their mounts as there seems to be a lot of happy Esprit owners out there. However given that there are plenty of options I'll skip anything from SW in future. I tend to vote with my wallet

The quality of manufacture and the QA/QC was utterly abysmal.. I'm referring to my long gone SW Star Adventurer 2i. Pot metal junk.

 

[Adam J]

13 hours ago, 900SL said:

Thanks Vlaiv. That's pushing it but the 115 could fit the bill. Thanks

It is a good scope for the money. 

Adam

[Adam J]

45 minutes ago, 900SL said:

Thanks Tom. I assume the scopes are better made than their mounts as there seems to be a lot of happy Esprit owners out there. However given that there are plenty of options I'll skip anything from SW in future. I tend to vote with my wallet

The quality of manufacture and the QA/QC was utterly abysmal.. I'm referring to my long gone SW Star Adventurer 2i. Pot metal junk.

 

Esprit optics are for the most part good but stay clear of the 80mm version in my opinion as its the one that gives people issues for the most part. 

Adam 

[900SL]

On 08/07/2022 at 11:01, Dan_Paris said:

The key is to have the right tools for the job. I have the Catseye tools, and get consistently essentially perfect collimation in  few minutes. And it can be done during daylight.

Cheers Dan. I watched a few Utube guides on collimation, seems pretty straightforward on the Newtonian types with a Hotech laser

I was considering a Mak Newt earlier and the ES Comet Chaser MN152 f4.8 caught my eye, as well as the Intes Micro MN 56. The ES seems to be pretty well regarded for imaging, the Intes appears to have great optics but a small fully illuminated circle

 

 

Edited July 11, 2022 by 900SL