Which not-so light travel scope: TMB 92 vs TS Photoline 90 vs Primaluce Airy 90T?

[GTom]

I am looking for an airline-compatible APO. However, small size is not the only factor, I want it to be a great all-rounder, performing well for both visual and photographic deep-sky work and visual planetary.

I'd also use the scope for daylight birdwatching/photography. 

Currently I have an C5 omni XLT, which I feel limited (lack of contrast). I didn't carry around the c5 too much, but provided I pick up a lighter mount (astrotrac...) this bulk and weight should be OK.

Currently I have 3 candidates:

• 2nd hand TMB-92 Signature Series f/5.5
• 2nd hand TS Photoline 90mm f/6.6 (a bit heavier but cheaper )
• Primaluce Airy Black 90T or the equivalent but cheaper Technosky 90 (both should be Shaprstar scopes).

 

Which one would you suggest? As for mobility, the scope + mount head (sky adventurer??) must fit in a smaller hand luggage, the rest is not important, because I usually hire a car at the destination. 

 

[michael.h.f.wilkinson]

I have an airline portable APM 80mm F/6, but I ruled out the sky adventurer as being too light for it. The scopes you list are probably heavier. I have now snapped second-hand EQ3-2 (will pick it up next week) which should travel well enough in the hold, not hand luggage. I intend to make a light "counterweight" which I can fill with water or sand at the destination to save further weight. Not sure what the astrotrac weighs

[Cjg]

Worth having a read of http://alpha-lyrae.co.uk/, Matthew is @DirkSteele on here and has travelled with different set ups. Some lighter than others.

Good luck,

Chris

 

[GTom]

2 hours ago, michael.h.f.wilkinson said:

I have an airline portable APM 80mm F/6, but I ruled out the sky adventurer as being too light for it. The scopes you list are probably heavier. I have now snapped second-hand EQ3-2 (will pick it up next week) which should travel well enough in the hold, not hand luggage. I intend to make a light "counterweight" which I can fill with water or sand at the destination to save further weight. Not sure what the astrotrac weighs

I have actually two eq3's, none of them is airline portable. The complete astrotrack package is around 3-4kg. The scopes I listed are - except the longer+Aluminium tube TS Photoline - not really heavier than the typical 80mm unit. They are bulkier, except the TMB, which is <400mm packed.

2 hours ago, Cjg said:

Worth having a read of http://alpha-lyrae.co.uk/, Matthew is @DirkSteele on here and has travelled with different set ups. Some lighter than others.

Good luck,

Chris

Thanks Chris, I'll take a look.

 

One question, regarding optical performance, the TMB is quite a challenging design at f5.5, does anybody has first hand experience if the fast f-ratio hinders the scope's planetary "skills"? Unfortunately no one tested the sharpstar scopes AFAIK.

[DirkSteele]

By all the accounts I have read, the late Tom Back did a rather good job with the design of the TMB 92mm.  I recall reading a review of it in Sky & Telescope many years ago and it was a very positive review.  Kind of the spiritual successor to the Astro Physics Stowaway which was an even faster f/4.9.

It was the scope I hoped to hunt down before I purchased the APM TMB 105 f/6.2 which is also airline portable but tips the scales at more than 6kg for the barebones OTA.  Sadly with Tom passing away, finding one new was becoming hard and nothing was on at the second hand market at the time.  The LW version which has a smaller focuser is probably the better choice if you can get it so it puts less strain on the light weight mount you will be using.

[mikeDnight]

On 03/11/2016 at 16:12, GTom said:

I am looking for an airline-compatible APO. However, small size is not the only factor, I want it to be a great all-rounder, performing well for both visual and photographic deep-sky work and visual planetary.

I'd also use the scope for daylight birdwatching/photography. 

Currently I have an C5 omni XLT, which I feel limited (lack of contrast). I didn't carry around the c5 too much, but provided I pick up a lighter mount (astrotrac...) this bulk and weight should be OK.

Currently I have 3 candidates:

• 2nd hand TMB-92 Signature Series f/5.5
• 2nd hand TS Photoline 90mm f/6.6 (a bit heavier but cheaper )
• Primaluce Airy Black 90T or the equivalent but cheaper Technosky 90 (both should be Shaprstar scopes).

 

Which one would you suggest? As for mobility, the scope + mount head (sky adventurer??) must fit in a smaller hand luggage, the rest is not important, because I usually hire a car at the destination. 

 

That Airy Black 90T looks like a lovely scope! I think id be tempted by the 90T more than the others because of its lightweight tube, and also as a visual planetary scope due to its F6.7 ratio being preferable. And with its FPL53 objective you'll get that wonderful icey cold fluorite view that's so appealing when viewing the planet's.

Mike

[Highburymark]

6 hours ago, mikeDnight said:

That Airy Black 90T looks like a lovely scope! I think id be tempted by the 90T more than the others because of its lightweight tube, and also as a visual planetary scope due to its F6.7 ratio being preferable. And with its FPL53 objective you'll get that wonderful icey cold fluorite view that's so appealing when viewing the planet's.

Mike

Mike - I've been following your comments about the Tak FC-100 on CN - you write very eloquently and convincingly.... so much so that at the moment I'm trying to establish if it is airline portable - it seems if you unscrew the dew shield and minimise the focuser end the ota will (just) fit in cabin baggage - have you taken yours on board an aircraft before?

[Stu]

10 hours ago, Highburymark said:

Mike - I've been following your comments about the Tak FC-100 on CN - you write very eloquently and convincingly.... so much so that at the moment I'm trying to establish if it is airline portable - it seems if you unscrew the dew shield and minimise the focuser end the ota will (just) fit in cabin baggage - have you taken yours on board an aircraft before?

Mine fits in a Pelicase 1510 which is designed to be airline portable for those with the more generous dimension limits.

https://peliproducts.co.uk/products/cases/1510-protector-case-1030.html#

https://www.skyscanner.net/news/cabin-luggage-guide-hand-baggage-sizes-and-weight-restrictions

I noticed the other day that EasyJet have no weight limit for carry on baggage which is very useful if you want to take plenty of kit in the case too.

With the dew shield and focuser removed, the Tak FC100 is around 19" long, one reason I prefer it over the DL. It could easily be packed safely in a rucksack or other carry on bag. Note that I have yet to try this in anger but do plan to at some point in the not too distant future.

EDIT

Image added. The dew shield slides over the focuser end of the scope, and I put the lens cap over the obejective to protect it, bubble wrap stops any scratches.

From left to right along the bottom

Feathertouch focuser plus adapter

Giro-WR mount

then various filters and eyepieces.

With all this lot in it weighs quite a lot, but just the scope and mount are not too bad.

[mikeDnight]

10 hours ago, Highburymark said:

Mike - I've been following your comments about the Tak FC-100 on CN - you write very eloquently and convincingly.... so much so that at the moment I'm trying to establish if it is airline portable - it seems if you unscrew the dew shield and minimise the focuser end the ota will (just) fit in cabin baggage - have you taken yours on board an aircraft before?

To be honest I've never given it any thought! Stu's excellent reply to your question above seems to give you the answer. What I would like to add is that the FC100DC that I have differs fron Stu's FC100DF in its focuser arrangement. I understand the DF has greater travel on its R&P and so may be more airline portable. It's a shame the dew shield doesn't retract on any of the current FC100's, but Tak may make that option available in the future. As it stands, I'd imagine the DF version might be the better, though slightly more expensive option, as a travel scope. I've attached images of my focuser both fully extended and fully retracted and as you can see there isn't much in it. It's also worth being aware that the beautifully engineered lens cell of the FC occupies a significant portion of the dew shade, so removing it the 16cm long shade will only give you an 8cm advantage.

Mike.

[mikeDnight]

10 hours ago, Highburymark said:

Mike - I've been following your comments about the Tak FC-100 on CN - you write very eloquently and convincingly.... so much so that at the moment I'm trying to establish if it is airline portable - it seems if you unscrew the dew shield and minimise the focuser end the ota will (just) fit in cabin baggage - have you taken yours on board an aircraft before?

I forgot to say "Thanks for the complement." It's probably a good job my east Lancashire twang doesn't come across in my posts or any credibility I may have would likely dwindle rapidly. ?

Mike

[Highburymark]

Thanks guys for the replies - Stu I think your set up is so compact because you have a (removable) feather touch focuser. I've been in contact with Tak and they said the DF focuser should not be removed (unless obviously you are replacing it). They also said rather cryptically that part of the DC focuser can be safely removed for travel and reattached (as can the dew shield). That means both DC and DF models have a travel length of 534mm or 21". Right on the limit for cabin baggage. Much as I want to buy this scope, it has to be carry on portable for me - and I don't want to fork out for a feather touch focuser just for this purpose. 

But in a roundabout way, Stu has answered the op's question - the Tak 100 must be a contender for best airline travel apo. Just a question of whether it's possible without a new focuser

[Stu]

I can't actually remember which model mine is, it just says FC-100D on the focuser? I'll check the box I guess.

Mark, I don't think there is any need to upgrade the focuser. On mine it just unscrews from the OTA very easily, I can't see any reason for the caution from Tak? The FT is more compact but overall the OTA length with the focuser and dewshield removed will be the same. I had 19" in my mind but I'll check, perhaps it is 21" but either way it is still definitely airline portable and fits in the Pelicase.

[Stu]

Just did a bit of checking. Apologies to the OP if this is off topic, but I must admit I do think the FC-100 is well worth consideration as an airline portable scope.

With dewshield and focuser removed, both very easy things to do, the OTA is under 19", call it 18 3/4" to be safe, so it's well under the limit and can be packaged safely whilst remaining under. It is a very lightweight OTA too.

I've included a comparison shot between my (unused) Tak focuser and the FeatherTouch with adaptor. Note that I do need an extension tube most of the time unless using the Herschel Wedge or binoviewing, but there is no need to upgrade the focuser to be able to get the OTA under the hand baggage limit.

Stu

[Stu]

One further comment, and apologies again, but this has been a bit of a quest for me over the years, and I do genuinely think the FC-100 is the closest I've got to perfection.

The trouble with smaller, or rather faster scopes down at the f5.5 kind of range is the field curvature that you get. One reason for taking a scope like this to a very dark site is to get those beautiful widefield views, but if you stick a 21mm Ethos in and end up with defocused stars at the edge of the field then it defeats the object doesn't it? I have had this issue with a number of smaller (and still premium) scopes, but at f7.4, the Tak just doesn't really suffer from this to any significant degree.

I'll be quiet now

[Highburymark]

Stu - thanks so much for your help with this - it's really appreciated. Looking at the pics you have the DC model, which is the lighter one of the two. The DF has the heavier focuser and is more geared for imaging. Think you have proved that this is one of the very best portable, all round telescopes ever made. 

(Apologies to the op for taking this thread slightly off piste.)

[Stu]

5 hours ago, Highburymark said:

Stu - thanks so much for your help with this - it's really appreciated. Looking at the pics you have the DC model, which is the lighter one of the two. The DF has the heavier focuser and is more geared for imaging. Think you have proved that this is one of the very best portable, all round telescopes ever made. 

(Apologies to the op for taking this thread slightly off piste.)

That makes sense, I chose the lighter (cheaper) version knowing that I was going to swap the focuser straight away.

[lardy]

Tak FS60? Little scope big performance