More Portable Scope - Sensible Choice?

[Roog]

Hi 

I have been exploring the skys from my back yard for nearly a year using my 10" Dobsonian and I think its great, but i have also been taking my 20 x 80 binoculars with me on my camping trips, (I have a very modest and old motorhome) and I have began to wonder if a portable scope might be more rewarding.

So looking through the ads for refractors I began to wonder whether I could kill two birds with one stone and get a physically smaller scope which I could use for direct viewing that might be suitable as a gateway into astrophotography in the future? accepting that I would need to get a suitable guided mount, laptop, software, camera, etc etc.

Sorry if this is a dumb question but is this possible or sensible? or am I asking too much from one scope?

I am wondering whether a 150mm Newtonian might  be a more sensible choice for dual use? I was looking to refactors in an attempt to keep the bulk down for travelling. 

I would appreciate your guidance,

Cheers 

[Zeta Reticulan]

Depends what you mean by portable.

[sorrimen]

Sorry if I’m being obtuse, but what’s stopping you from taking the 10” in the motorhome too? I could understand if you were just in a car or going by public transport but surely an unpowered scope with a dob base is exactly what you’d want for camping? Confused, but maybe I’m misunderstanding! 

When it comes to visual use, aperture really is king and downsizing should be avoided. A good quality frac will outperform a newt of the same aperture, but to get anywhere close to 10” you’re going to be spending a lot. 150mm newt needs a pretty sizeable mount and overall will only save you so much space. Add in powering, polar aligning and balancing the mount and I can’t see a world where this beats a 10” dob for camping. 

Portability certainly has its place and a good frac will definitely be suitable to get into ap plus do some visual, but it’s not going to come close to the 10” dob for the latter and I think with you having a motor home instead of a car I know what I would take with me! 

Of course, if you simply can’t fit the dob in the motorhome then your question is just scope versus no scope, where scope will win! A 150mm newt is going to be a harder  and more pricey start into AP than a small frac, but will be much better visually.

[Astro_Dad]

As I’ve posted frequently, (I’m not on commission!) my Heritage 150p Virtuoso GTi (The GOTO version) is for me an excellent  grab and go to complement my 10” Dob. It’s 6 inch aperture is very good for impromptu observing sessions, and can be used for getting into AP… look at the link below. Also fits into cars full of other gear !

I think many would advocate a small frac for getting into AP though, if that’s the clear direction… 

[Zeta Reticulan]

You'd be surprised what you can see with a 60mm ED refractor.

[Clarkey]

how about one of these?

U.K. Astronomy Buy & Sell (astrobuysell.com)

Small and light but also very good for AP. Should be just about small enough to sit on a star tracker.

[Stu]

I think trying to combine AP with a visual scope is likely to lead to disappointment in either or both goals. The best start for AP would likely be a 60 to 80mm apo refractor, but not even a hard core refractor nut like me would suggest that is going to give you a complete visual experience. Some very nice wide field views yes, and credible planetary and lunar performance, but you would be lacking a lot in resolution and light grasp compared with the 10”.

A lot comes down to your expectations obviously. One reasonable compromise might be a 130PDS  which would be nice and compact, could be put on a simple alt az mount for visual use but then you could add an EQ mount for AP. Somewhere on SGL there is a huge thread about AP with the 130PDS, it’s not ideal but certainly possible to get some good results from.

Much also depends on budget of course. A nice 4” f7 refractor could fit the bill if you couldn’t stretch to that, or possibly forget the AP aspirations and get a Heritage 150p. They are very compact so would go in your motor home easily, yet are surprisingly capable on a range of targets. That would probably be my preferred route, then get a proper AP rig if that is what you decide to do.

[Louis D]

I put together a 127 Synta Mak on an alt-az tirpod mount for my daughter to take camping.  It takes up a relatively small amount of space in the back of her Chevy Equinox, which is small by US SUV standards.  It wouldn't be good for AP, but it is decent enough for camping.  That, and its collimation takes the trip to the campsite very well.

[cajen2]

I've tried loading my 8" dob into and out of a motorhome a few times and it isn't as easy as you'd imagine. Most motorhomes have extremely narrow doors and rather unstable fold-out steps, and you're risking the scope (or your neck!) every time. A 10" is certainly not going to be any easier. One of the few situations where a panel van conversion is better.

I'd second a Heritage 150p for portability - I can lift my OTA and base with one hand - or I'd look for a short frac on a light mount.

[Roog]

Thank you everyone, so many responses I’m going to struggle to respond to each of you individually.
 

I take the point that I could transport my Dob in the motor home, but I think my wife might have something to say about it joining us! And getting it in and out through the narrow door with quite a drop would be a worry. 

I guess my anxiety is that having used a 10” Dob for visual I might be very disappointed  by a much lesser aperture for visual, ultimately I should seek to find a compromise and in the absence of personal experience it is a little of your wealth of knowledge I seek.

I have been watching videos of enthusiastic 150mm Newtonian owners managing to carry out AP effectively with this gear, but I have to confess it does look quite challenging as a travel rig. 
 

I think perhaps I need to prioritise future use for AP and accept that visual astronomy will be significantly compromised. I might be naive but I have a vision of a 80mm ED refractor in a case as a manageable travel scope.

[Astro_Dad]

7 minutes ago, Roog said:

Thank you everyone, so many responses I’m going to struggle to respond to each of you individually.
 

I take the point that I could transport my Dob in the motor home, but I think my wife might have something to say about it joining us! And getting it in and out through the narrow door with quite a drop would be a worry. 

I guess my anxiety is that having used a 10” Dob for visual I might be very disappointed  by a much lesser aperture for visual, ultimately I should seek to find a compromise and in the absence of personal experience it is a little of your wealth of knowledge I seek.

I have been watching videos of enthusiastic 150mm Newtonian owners managing to carry out AP effectively with this gear, but I have to confess it does look quite challenging as a travel rig. 
 

I think perhaps I need to prioritise future use for AP and accept that visual astronomy will be significantly compromised. I might be naive but I have a vision of a 80mm ED refractor in a case as a manageable travel scope.

There’s always a compromise - if you are visual first and AP second a compact grab and go 150 newt is entirely possible in the form of the Heritage Virtuoso - compact and capable. Check out some of the incredible images posted by others here using this. I’m also an imager second (very much so) but aspire to what is achievable with this modest set up having seen examples on this forum. 
Clearly if AP is top of the hierarchy it would likely be a small frac on a tracking mount that would do the job best. 

[rl]

Quote

I think perhaps I need to prioritise future use for AP and accept that visual astronomy will be significantly compromised. I might be naive but I have a vision of a 80mm ED refractor in a case as a manageable travel scope.

You might be able to get to some dark sites in a motorhome. I've had some very memorable views with a 80mm refractor from dark sites (Astrofarm in France being one of them). And a purpose built case that can take a certain amount of accidental abuse is worth its weight in gold in this sort of transport situation. I've got an Altair 60mm triplet in a small case that holds the diagonal as well as a couple of eyepieces that lives in the back of the car along with a star adventurer mount that's ready to go wherever I am.

[Astro_Dad]

4 hours ago, Zeta Reticulan said:

You'd be surprised what you can see with a 60mm ED refractor.

Lots I imagine, particularly on lunar and of course the pin point stars characteristic of high end refractors. I haven’t used one, but considering the well documented summation effect of a binocular view, I’d predict a 10x50 binocular would show slightly more or at worst similar  (1.4x aperture factor = approx 70mm equiv. ?) May be wrong and experience will tell otherwise but it again comes down to the hierarchy - visual v AP. 

[Zeta Reticulan]

1 hour ago, Astro_Dad said:

Lots I imagine, particularly on lunar and of course the pin point stars characteristic of high end refractors. I haven’t used one, but considering the well documented summation effect of a binocular view, I’d predict a 10x50 binocular would show slightly more or at worst similar  (1.4x aperture factor = approx 70mm equiv. ?) May be wrong and experience will tell otherwise but it again comes down to the hierarchy - visual v AP. 

I doubt 10x50 binoculars would show the Cassini Division, Galilean shadow transits, M27, or split many double stars. Let alone show surface albedo features on Mars.

[Stu]

8 hours ago, Roog said:

I think perhaps I need to prioritise future use for AP and accept that visual astronomy will be significantly compromised. I might be naive but I have a vision of a 80mm ED refractor in a case as a manageable travel scope.

If future AP use trumps visual as a priority then yes, an 80mm ED refractor would be a sensible choice. I’m observing with a 76mm apo currently and there is still plenty to keep interest. Even features on Mars are visible despite its small size currently. It’s a big step down from a 10” of course, but if used for its strengths ie widefield viewing, open clusters, doubles with lunar/planetary also being possible then it should be enjoyable.

[Astro_Dad]

7 hours ago, Zeta Reticulan said:

I doubt 10x50 binoculars would show the Cassini Division, Galilean shadow transits, M27, or split many double stars. Let alone show surface albedo features on Mars.

Not a hope! I imagine that just shows the quality of these smaller high end fracs… one day 😀

Edited September 1, 2022 by Astro_Dad

[Zeta Reticulan]

19 minutes ago, Astro_Dad said:

Not a hope! I imagine that just shows the quality of these smaller high end fracs… one day 😀

Which is why my original response depended on what the OP meant by portable. 

I'm consistently surprised just how much I can see with a 60mm refractor.

[Astro_Dad]

22 minutes ago, Zeta Reticulan said:

I'm consistently surprised just how much I can see with a 60mm refractor.

It is impressive - I’ve been curious for a while about how the summation rule (theory) with binos plays out in the real wirld - either way there is clearly no fair like for like competition with these high end fracs, even with a relatively small 60mm aperture. I’ve never used one so thanks for your info. 

[Zeta Reticulan]

4 minutes ago, Astro_Dad said:

It is impressive - I’ve been curious for a while about how the summation rule (theory) with binos plays out in the real wirld - either way there is clearly no fair like for like competition with these high end fracs, even with a relatively small 60mm aperture. I’ve never used one so thanks for your info. 

Refractors and reflectors are different animals. I think where most people go wrong is thinking that a 60mm refractor isn't much different from using a 50mm finder scope. I'm not familiar with the 'summation rule' but Patrick Moore once stated that a 4" refractor was roughly equivalent to a 6" reflector. Obviously the larger aperture has greater resolution, but I see what he meant. I have a 150mm Newtonian and a 102mm ED doublet (FPL-53/lanthanum). Although I seriously doubt a 40mm reflector would match a 60mm ED doublet or triplet. Admittedly a 60mm refractor has its limitations. The sheer portability makes up for many of them though.

Plus, a 60mm short tube ED refractor is great fun.

 

[Astro_Dad]

21 minutes ago, Zeta Reticulan said:

Refractors and reflectors are different animals. I think where most people go wrong is thinking that a 60mm refractor isn't much different from using a 50mm finder scope. I'm not familiar with the 'summation rule' but Patrick Moore once stated that a 4" refractor was roughly equivalent to a 6" reflector. Obviously the larger aperture has greater resolution, but I see what he meant. I have a 150mm Newtonian and a 102mm ED doublet (FPL-53/lanthanum). Although I seriously doubt a 40mm reflector would match a 60mm ED doublet or triplet. Admittedly a 60mm refractor has its limitations. The sheer portability makes up for many of them though.

Plus, a 60mm short tube ED refractor is great fun.

 

It’s a lovely ‘scope! My comparison wasn’t about reflector /refractor apertures but really between a 50mm binocular and a 60mm refractor. Binocular summation refers to the effect whereby two eyes deliver greater depth of vision and other subtle effects including visual acuity enhancement vs a monocular view. Some papers on this suggest multiplying a bino aperture by a factor of 1.4 to give a roughly comparable monocular aperture. So testing this, a 50mm high quality bino might deliver similar views to a 70mm refractor. I think you’ve suggested otherwise - in the real world…and of course it’s all theory and all things are never equal!

https://en.m.wikipedia.org/wiki/Binocular_summation

Of course the points you’ve made about reflector and refractor “equivalents” is still valid and of interest, just not the point I was making earlier. 

Edited September 1, 2022 by Astro_Dad

[Zeta Reticulan]

9 minutes ago, Astro_Dad said:

It’s a lovely ‘scope! My comparison wasn’t about reflector /refractor apertures but really between a 50mm binocular and a 60mm refractor. Binocular summation refers to the effect whereby two eyes deliver greater depth of vision and other subtle effects including visual acuity enhancement vs a monocular view. Some papers on this suggest multiplying a bino aperture by a factor of 1.4 to give a roughly comparable monocular aperture. So testing this, a 50mm high quality bino might deliver similar views to a 70mm refractor. I think you’ve suggested otherwise - in the real world…and of course it’s all theory and all things are never equal!

https://en.m.wikipedia.org/wiki/Binocular_summation

Of course the points you’ve made about reflector and refractor “equivalents” is still valid and of interest, just not the point I was making earlier. 

Oh right, stereopsis by another name lol. Yeah, I'm not totally sold on these theories. I believe binoviewing with a telescope is not true stereopsis. There are many arguments constructive discussions about this. I'm not sold on those either. 

[Roog]

9 hours ago, Zeta Reticulan said:

Which is why my original response depended on what the OP meant by portable. 

Of course you make a very valid point and for me it’s hard to define, I used to take my guitar in its case and a small practice amp with me on our camping trips buy that has been displaced by our two dogs and all of their stuff!
 

Ideally a 300 x 200 x 900mm case plus tripod, but in practice it will be what space is left for my “non essentials” so that will be as small as possible 

[Zeta Reticulan]

6 hours ago, Roog said:

Of course you make a very valid point and for me it’s hard to define, I used to take my guitar in its case and a small practice amp with me on our camping trips buy that has been displaced by our two dogs and all of their stuff!
 

Ideally a 300 x 200 x 900mm case plus tripod, but in practice it will be what space is left for my “non essentials” so that will be as small as possible 

I'd go with a small refractor. Or get smaller dogs.

[Stu]

Not sure why we are pushing a very small refractor here. I think an 80mm would have a lot of advantages and not be that much bigger. It would have a larger exit pupil at comparative mags, better resolution, still very much grab and go and not needing a huge mount.

I have owned and used a wide range of apos from 60mm through to 150mm (at least 15 of them). You can certainly have lot of fun with a 60mm, but they are still limited. 100mm gets a lot more interesting, but will be significantly larger so an 80mm makes a lot of sense, plus it works for starting off in AP too. You probably wouldn’t want a 100mm for AP, certainly not to start.

[RobertI]

Just to add another perspective to this thread (and hopefully not confuse the the OP!) it is possible to do basic astrophotography with a lightweight altaz mount. Below is a recent EEVA (Electronically Enhanced Visual Astronomy) session with my 66mm refractor on a SkyProdigy mount - very similar to the AZ-GTI or Virtuoso class mount I would think in terms of accuracy and load capacity. Exposures are typically 20 seconds. So you can do basic Astro Photography (AP) with modest altaz setups and get results which are better than eyeballing through a much larger visual scope. So as an alternative, how about a 150P Virtuoso for visual and then add a 60mm frac for basic AP?

And just a quick plug for EEVA, it's so quick and simple compared to traditional AP and shows you much more than visual. It's quite addictive....and cheap!  

 

Edited September 2, 2022 by RobertI