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Can photographic gimbal mount be used to turn 3" or 4" APO telescope into a terrestrial telescope?

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#1 Spectrum805

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Posted 27 February 2021 - 03:41 PM

I wonder whether other amateur astronomers have the same thought about turning their APO telescopes into a high-end terrestrial view telescope and for birding near car when traveling on the road.  If so, what tripod head mount is suitable?  I would say my interest is broader, which make the traditional Alt Az telescope mounts potentially less suitable.  I wonder whether I can find a single tripod head, especially a heavy-duty gimbals (up to 5Lb weight is OK if I can get away with only one tripod head), that can be used to satisfy my varied needs (a) Terrestrial viewing using a 3" to 4" refractor telescope (8Lbs to 20Lbs), in lieu of a spotting scope, on a heavy tripod near my car (b) Birdwatching with 15x56 binocular on a travel tripod for hiking up to a couple of miles © Used as a regular ball-head equivalent for landscaping and travel photography.  (d) If eventually I do get a spotting scope for bird watching, be compatible with digiscoping as well.  One of the options I am considering is finding a heavy-duty photographic gimbal head to satisfy all these competing needs.  For example, ProMediaGear GK Jr Katana Pro gimbal head which only weighs 2.4 Lbs but can handle 50Lbs equipment.

 

I have Televue NP101is, when adding in all the accessories, can weigh up to 20Lbs.  I also have a much lighter Orion 80mm APO ED80T-CF which is only 8Lbs.  I have considered Televue Gibraltar HD5 or HD4, the great benefits are being top mounting and stable, but it's not something I want to pick up for a hike, or use for general photography.  I have also considered Stellarvue M2C mount which is much more compact but I have heard side-mounting a 20Lbs refractor with one hand while tightening up the saddle knob with the other hand requires great arm strength and can be a bit scary.  It is also not particular compatible with general photography with just DSLR camera and photographic lenses.  So I wonder whether photographic gimbal head can be used to handle telescopes?  Being top mount, it would be Televue Gibraltar HD4 equivalent and I can tighten the saddle knob while the weight of the telescope is resting on the saddle.  I know I need to produce my own custom converter by bolting a dual Vixen/Losmandy clamp onto a Arca Swiss plate.  Photographic gimbals almost always use Arca Swiss plate, which is slightly narrower and shallower than Vixen, can it really handle 20Lbs telescope securely?  Some of these gimbals are rated to carrier up to 150Lbs of equipment, although 50Lbs is more typical.  Some big telephoto lens can weigh 20+Lbs, so it gives me hope perhaps the same gimbal head can handle a 20Lbs refractor?

 

I just don't like the idea of carrying a Alt Az for telescope, a gimbal for heavy-lens, and a ballhead for photography.  Carrying three heads on the road is just too much.  What capability am I missing by just a single heavy-duty gimbal head (such as the 2.4Lb ProMediaGear GK Jr. that can handle 50Lbs)?  Is it much harder to change eyepieces while maintaining balance compared to the Televue or Stellarvue mount (because these two have either two disks or one disk with larger diameter to provide friction)?  My eyepieces are all relative heavy, from 1Lbs to 2Lbs.  What if I just lock the gimbal head tilt axis, change the eyepieces, then re-balance by sliding the adapter plate?  I like the idea that a full gimbal head can produce perfect balance in both tilt and pan, so the telescope can be pointed effortlessly  with a finger to any direction just like a telephoto lens.  The motion can also be damped by tightening the knob. Is such a set up really practical when it is a telescope mounted instead of a telephoto lens?  Why do I not hearing other people doing this?  There must be a blind spot in my thinking process.

 

A related question is spotting scope vs. telescope.  Other than being heavier, no zooming and not weather-proof, it seems a APO telescope will beat spotting scope in the field-of-view big time.  A spotting scope will NEVER match the 100 degree apparent field-of-view of Ethos eyepieces that I already have for my telescopes.  For example, Swarovski 95mm at 30x has a true field of view of ~1.9 degrees.  With my NP101is telescope at 32x (if hypothetically I use a 17mm Ethos eyepiece), I can get ~3.1 degrees sharp to the edge.  The viewing area is 2.7x bigger even at a slightly larger magnification!  I also don't like the idea of spending more and carrier more weight if the new equipment does not have better performance.  Why aren't more people using small telescopes in lieu of spotting scope for terrestrial applications?

Thanks!

Haibo


Edited by Spectrum805, 27 February 2021 - 03:42 PM.


#2 Gastrol

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Posted 27 February 2021 - 04:24 PM

A related question is spotting scope vs. telescope.  Other than being heavier, no zooming and not weather-proof, it seems a APO telescope will beat spotting scope in the field-of-view big time.  A spotting scope will NEVER match the 100 degree apparent field-of-view of Ethos eyepieces that I already have for my telescopes.  For example, Swarovski 95mm at 30x has a true field of view of ~1.9 degrees.  With my NP101is telescope at 32x (if hypothetically I use a 17mm Ethos eyepiece), I can get ~3.1 degrees sharp to the edge.  The viewing area is 2.7x bigger even at a slightly larger magnification!  I also don't like the idea of spending more and carrier more weight if the new equipment does not have better performance.  Why aren't more people using small telescopes in lieu of spotting scope for terrestrial applications?

Thanks!

Haibo

You know, you can use astro EP’s on some makes of spotting scopes......Kowa, Swaro, Meopta, Pentax.....  just to name a few.

I’m able to use all my 1.25” EP’s on my Pentax spotting scopes.

 

When I used to own a TV101 and a Pronto I briefly used the Pronto, and sometimes the 101 for terrestrial viewing, and it was fine.   I still have the TV 45* erect image diagonal somewhere...   But since using my spotting scopes with my astro EP’s I don’t think I’ll ever get the desire to use a small refractor for terrestrial use ever again.  They’re cumbersome, especially the 101, if you have to keep moving around.   Besides, seeing conditions rarely allow you to push high mags anyway.

 

I see you posed a similar question over at Bird Forum.   You’re likely to get a different perspective there.


Edited by Gastrol, 27 February 2021 - 04:41 PM.

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#3 AgilityGuy

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Posted 27 February 2021 - 04:50 PM

I tried to build a setup for a 92mm scope for wildlife photography and came to conclusion that I'll need to use a stable night viewing system even for daylight if I want to eliminate shakes and vibrations.  I purchased one of the most stable photography gimbals I could find (quoted load was about 40 lbs) but the moment arm of the 600mm telescope still made it quiver like a leaf - sent it right back because they are expensive.  If the telescope was balanced to keep it from nose diving one way or another there was just too much tube front and back of the gimbal saddle to control the motions induced at either end.  If you're just viewing maybe it will work but taking images - even though daylight photography allows a faster shutter speed - I prefer not to have my camera vibrating at a high frequency. 


Edited by AgilityGuy, 27 February 2021 - 04:54 PM.

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#4 WadeH237

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Posted 27 February 2021 - 04:59 PM

There is a person on the Astro-Physics user group who has some nesting bald eagles near (or on) his property.  He uses his 130mm AP refractor, with I think a DSLR, to image them, and the results are just plain spectacular.

 

I don't see how you could use a setup like that for birds in flight, but if you can steady the scope, I think that the optics on most astronomical telescopes are better than most DSLR lenses.  It turns out that star fields are pure torture tests for lenses.  If a set of optics works well for astrophotography, it will probably work very, very well for terrestrial photography.  Again, you need to have a suitable mount, and you need to manually focus, etc.


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#5 luxo II

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Posted 27 February 2021 - 06:30 PM

The main reason people don't use astro scopes for terrestrial is the high magnification they can achieve is un-necessary for terrestrial viewing; far smaller spotting scopes can deliver enough magnification perfectly well and be a lot more convenient in terms of bulk, weight and the mount required.

 

My little 70mm APO is about as big as you'd want on a photo tripod, and tats entirely capable of 200X which is more than any terrestrial observer is likely to use. Attempting to put say a 130mm APO on that kind of tripod is going to end in a disaster.

 

Another aspect to remember with astro scopes is whether the scope has enough backfocus to accommodate an image erecting prism of one kind or another - some do, some don't. You could get by with a 90 degree star diagonal, provided you're happy with the image being left-right reversed.


Edited by luxo II, 27 February 2021 - 06:32 PM.

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#6 Spikey131

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Posted 27 February 2021 - 09:47 PM

The Televue 60 is designed to function well as a spotting scope and astronomical telescope.  And it works very well.  Granted, it is not waterproof or as rugged as a dedicated spotter.  I have personally never used a spotting scope in the rain, but I imagine some people do.  So it all depends on how you use it.



#7 Tamiji Homma

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Posted 27 February 2021 - 10:51 PM

 

I also don't like the idea of spending more and carrier more weight if the new equipment does not have better performance.  Why aren't more people using small telescopes in lieu of spotting scope for terrestrial applications?

 

It is really up to your application and priority for the application.  I have both telescopes (50, 55, 60, 65, 71, 80, 92, 100, 102, 105, 130, 140, 152mm refractor) designed for astronomy as primary application and spotting scopes (50, 82, 88, 95, 115mm) designed for terrestrial viewing as primary application.

 

They may be used for the same application (viewing the same object) depending on your priority/compromise you (need to, have to) make for observing opportunity/situation.

 

When I need to carry and hike to observing site, my most telescopes for astronomy is not a good choice.

When I observe it in my backyard, telescopes can be a good choice for terrestrial viewing for static (not moving fast) object.

 

Regarding Gimbal head, I have RRS Gimbal head for photography use.  It works OK with small telescope (up to 80mm f/7-ish refractor) and staying around mid power (60-80x).  I have better luck with fluid heads.

 

Tammy


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#8 Spectrum805

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Posted 28 February 2021 - 11:09 PM

You know, you can use astro EP’s on some makes of spotting scopes......Kowa, Swaro, Meopta, Pentax.....  just to name a few.

I’m able to use all my 1.25” EP’s on my Pentax spotting scopes.

 

When I used to own a TV101 and a Pronto I briefly used the Pronto, and sometimes the 101 for terrestrial viewing, and it was fine.   I still have the TV 45* erect image diagonal somewhere...   But since using my spotting scopes with my astro EP’s I don’t think I’ll ever get the desire to use a small refractor for terrestrial use ever again.  They’re cumbersome, especially the 101, if you have to keep moving around.   Besides, seeing conditions rarely allow you to push high mags anyway.

 

I see you posed a similar question over at Bird Forum.   You’re likely to get a different perspective there.

Gastrol,  Thanks for the great info.  I did not know before that some spotting scopes can accept 1.25" astronomical eyepieces.  (Previously I was only aware some of the 100mm to 150mm scale big binoculars do.)  I took a quick look at Swarovski Optics website at their current spotting scopes, which consists of an objective module in 65mm, 85mm, 95mm and 115mm, to be mated with an eyepiece module in either ATX, STX or BTX configuration.  On the objective module side, the picture shows the final optics protruding out.  On the eyepiece side, the optics on the mating surface is recessed in.  Since all my 1.25" EPs (Ethos, Naglers) have the nosepiece protruding out, I couldn't envision how these 1.25" eyepieces can interface with the objective modules.  Does either Swarovski or a third party brand sell an interface module to allow the two to be connected together?  Or perhaps you are referring to an earlier generation of their scopes?  They also list ATS but I couldn't find info on how ATS eyepieces look like.  Then elsewhere in their website, it listed a 20-60x eyepiece module and a 25-50x W eyepiece module which do look like 1.25" astronomical eyepieces to some extent, with a protruding nosepiece.  Maybe they are intended for ATS?  It's not clear how it lock onto the objective module.  I have the same questing about 1.25" eyepieces, am I just going to loosely handhold the eyepiece or is there a locking mechanism for firm attachment?  Thanks!  Haibo



#9 Gastrol

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Posted 01 March 2021 - 12:12 AM

Gastrol,  Thanks for the great info.  I did not know before that some spotting scopes can accept 1.25" astronomical eyepieces.  (Previously I was only aware some of the 100mm to 150mm scale big binoculars do.)  I took a quick look at Swarovski Optics website at their current spotting scopes, which consists of an objective module in 65mm, 85mm, 95mm and 115mm, to be mated with an eyepiece module in either ATX, STX or BTX configuration.  On the objective module side, the picture shows the final optics protruding out.  On the eyepiece side, the optics on the mating surface is recessed in.  Since all my 1.25" EPs (Ethos, Naglers) have the nosepiece protruding out, I couldn't envision how these 1.25" eyepieces can interface with the objective modules.  Does either Swarovski or a third party brand sell an interface module to allow the two to be connected together?  Or perhaps you are referring to an earlier generation of their scopes?  They also list ATS but I couldn't find info on how ATS eyepieces look like.  Then elsewhere in their website, it listed a 20-60x eyepiece module and a 25-50x W eyepiece module which do look like 1.25" astronomical eyepieces to some extent, with a protruding nosepiece.  Maybe they are intended for ATS?  It's not clear how it lock onto the objective module.  I have the same questing about 1.25" eyepieces, am I just going to loosely handhold the eyepiece or is there a locking mechanism for firm attachment?  Thanks!  Haibo

Perhaps the astro eyepiece adapters made were for the previous gen Swarovskis.


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#10 Tamiji Homma

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Posted 01 March 2021 - 07:32 AM

 

Does either Swarovski or a third party brand sell an interface module to allow the two to be connected together?

 

Hi Haibo,

 

I have two Swarovski prism unit replacement made with Matsumoto EMS to make light weight binoscope with ATX 95 objective modules.

 

http://ems-bino.com

 

You can read about it here.  With EMS visual back in place, you can use large numbers of 1.25" and 2" eyepieces.

Some eyepieces don't come to focus to infinity due to lack of inward focus of the system (ATX 95 + EMS prism).

 

https://www.cloudyni...-95-binoculars/

 

Tammy


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#11 Jon Isaacs

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Posted 01 March 2021 - 09:20 AM

I use my 80mm Megrez II FD as a spotting scope.  I like the wide fields of view possible... Most spotting scopes are around 2 degrees, I can do up to 4.7 degrees. For terrestrial, it can be a big plus.. 

 

I mount it on a Bogen 3040, a 3046 tripod with a 3047 head and I mount it "sidesaddle" so it balanced... The scope is mounted alongside the scope rather rather than on top of it.  All that's necessary it to flip the top axis 90 degrees.

 

5917534-SideSaddle ST-80 #1.jpg
 
AT-72 on Bogen with eyepieces CN.jpg
 
5504986-Canyon de Chelley Francis.jpg

 

I use star diagonals.. Been doing it for more than 20 years.

 
Jon

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