Travel scope on a budget

[Littleguy80]

I’ve already posted once on my intention to get a travel setup this year. I set an initial budget of £1000 to cover scope, mount, tripod and 2” diagonal. I had many great suggestions and felt settled on the idea of an 80mm frac. Basic requirements are for something that is airline transportable, can be used for widefield and that I could add an Herschel wedge tolo in the future for solar use. I have an one eye on the Mercury transit in November.  

What’s been bothering me is that I really love my 10” dob. I’ve looked through some really nice fracs (Taks) and always returned happily to my dob feeling like I had the better views. My dob only cost £400 so I started to question the value of spending £1000 on what will be my ‘B’ scope. 

I spotted an Opticstar 80mm F7.5 frac for £100 secondhand. Which made me think that I could perhaps getting something together for around £500. This doesn’t feel quite so extravagant and feels like a decent entry point. I’d perhaps be more inclined to invest in a better quality mount/tripod should I decide that I actually really like the little frac and would like something better quality. 

Am I alone in these feelings about fracs after only owning reflectors? The dob will never be airline transportable so a little cheap frac will be a definite improvement on no scope. I currently travel with 10x50 bins which are nice but I often feel like I want more. 

Would love to hear people’s thoughts as I’m driving myself crazy trying to figure out what I want or if all the doubts are just a sign that I don’t really need anything more than I have!

Many thanks

Mr Indecisive ?

[cloudsweeper]

80mm frac Neil?  I recently got an ES 80ED Apo Triplet.  It's extremely compact - needs both of the supplied extension tubes to reach focus, making the whole thing very light.  It's very wide field, with no hint of CA.  The stars are sharper in it than in the Dob and the Cat.  And the price would leave you plenty for other bits and pieces.

I like it so much that I'm thinking of getting the 127 version to replace my ST120.

This astro is defo a fun way of parting with your cash, isn't it?

Doug.

And - it has a DS R&P focuser - lovely!  I tried a Crayford once, and really didn't get on with it.

Did I mention the retractable dewshield?

 

[Stu]

I guess it depends what you want to achieve with it Neil. The OpticStars actuallybhave quite a good reputation, but the views and contrast wont be the same as through an 80ED. I would be more tempted to go down the 72ED route if you want to save budget and use a lighter weight mount. Stick that on an AZ4 or 5 or similar and you will be within budget.

To me to point of an apo refractor is not to compete with a dob, it won't ever do that head to head, but will offer something to complement the dob. Nicer stars shapes, no diffraction spikes, airline portable, widefield views, solar viewing etc etc. To me it has always been about the quality and aesthetic appeal of the views, so I prefer to stick to good ED (or fluorite ) doublets.

[Anthonyexmouth]

ED80 isn't what i'd call ideal for plane travel. William optics z61 or SW ED72 would be much better, my choice would be the z61

[Littleguy80]

12 hours ago, cloudsweeper said:

80mm frac Neil?  I recently got an ES 80ED Apo Triplet.  It's extremely compact - needs both of the supplied extension tubes to reach focus, making the whole thing very light.  It's very wide field, with no hint of CA.  The stars are sharper in it than in the Dob and the Cat.  And the price would leave you plenty for other bits and pieces.

I like it so much that I'm thinking of getting the 127 version to replace my ST120.

This astro is defo a fun way of parting with your cash, isn't it?

Doug.

And - it has a DS R&P focuser - lovely!  I tried a Crayford once, and really didn't get on with it.

Did I mention the retractable dewshield?

 

Your ES 80ED does look lovely, Doug. Where does it come in the pecking order of your scope collection now you’ve had it a few months? Do you mix up your scope usage much or are there definite favourites?

[Littleguy80]

12 hours ago, Stu said:

I guess it depends what you want to achieve with it Neil. The OpticStars actuallybhave quite a good reputation, but the views and contrast wont be the same as through an 80ED. I would be more tempted to go down the 72ED route if you want to save budget and use a lighter weight mount. Stick that on an AZ4 or 5 or similar and you will be within budget.

To me to point of an apo refractor is not to compete with a dob, it won't ever do that head to head, but will offer something to complement the dob. Nicer stars shapes, no diffraction spikes, airline portable, widefield views, solar viewing etc etc. To me it has always been about the quality and aesthetic appeal of the views, so I prefer to stick to good ED (or fluorite ) doublets.

I think you hit the nail on the head with the question of what I want to get out of it, Stu. Primary goal is something that I can travel with. We had a trip to Greece and a camping holiday in the Norfolk coast last year. Both times I enjoyed the binoculars but wished I’d had a scope with me. With Greece in particular, I wanted to explore Sagittarius more. See M6 and M7 at higher mags. 

Secondary goal is some widefield observing. I’m particularly thinking about the large diffuse nebula here. With my 130mm scope, I saw the Veil through an OIII with an exit pupil of 3.5mm. The SW 72ED with the APM HDC 20mm would give an exit pupil of 3mm which I think makes it feasible for this. Sky quality will be more critical though. I think my only question mark would be whether the weight of the APM eyepiece on an AZ4 would be too much. 

Final goal is something that would make a nice solar scope when used with a Herschel wedge. This feels less critical as the dob can be used for this purpose too. I think a frac is supposed to give better results for solar though? 

The SW 72ED on AZ4 looks like a great combo and an excellent suggestion. That would just leave me with a 2” diagonal to buy. There’s a SkyWatcher for around £90 or an Altair Astro for £100. Is there anything in particular to look for when choosing a diagonal?

Sorry for the 500 questions! 

[Littleguy80]

12 hours ago, Anthonyexmouth said:

ED80 isn't what i'd call ideal for plane travel. William optics z61 or SW ED72 would be much better, my choice would be the z61

This perhaps shows my dob roots and the general assumption that bigger is better when it comes to aperture. What makes you prefer the Z61 to the 72ED? I would think the increased aperture of the 72ED would give it the edge for visual use?

[cloudsweeper]

48 minutes ago, Littleguy80 said:

Your ES 80ED does look lovely, Doug. Where does it come in the pecking order of your scope collection now you’ve had it a few months? Do you mix up your scope usage much or are there definite favourites?

Well Neil, I'm still very fond of the Dob (aperture, mainly).  The ST120 frac doesn't get  lot of usage, mainly because the focuser is coarse and jerky.  (I put a Crayford on it, but that was less than useless.)  So the other popular approach these days is the ED80 and the 8SE Cat together, on the Skytee II - a great combination of sharp, widefield views, along with greater aperture and mag.

Although I only do visual, I went for a triplet because the price is not huge at that aperture, and I figured I might as well go for zero CA.  At larger apertures, there might be issues with weight and cool-down.  And cost, of course!

All good fun....

Doug.

[Anthonyexmouth]

25 minutes ago, Littleguy80 said:

This perhaps shows my dob roots and the general assumption that bigger is better when it comes to aperture. What makes you prefer the Z61 to the 72ED? I would think the increased aperture of the 72ED would give it the edge for visual use?

it its for visual then the ed72. the z61 has the edge on quality for AP i think. saying that, if its purely visual and just a travel scope the st80 is short and light. 

[Stu]

5 minutes ago, Littleguy80 said:

This perhaps shows my dob roots and the general assumption that bigger is better when it comes to aperture. What makes you prefer the Z61 to the 72ED? I would think the increased aperture of the 72ED would give it the edge for visual use?

At this size, even 11mm aperture increase makes a significant difference so for visual I would certainly go with the 72mm. I managed to get a TS 72mm from eBay for under £300 which has a nicer focuser and sliding dew shield so packs down shorter than the SW, but the 72ED would be cheaper is still very manageable. I tend to prefer ED doublets for visual because they are lighter and cool more quickly, but a triplet would offer a little better colour correction.

I've not used an AZ4 before, so others will be better placed to comment, I would expect it to be fine. You could consider an AZGTi which is pretty compact and gives you goto and more importantly tracking which is nice for solar and lunar, not really important for low power sweeping so you will probably prefer the simplicity of a manual mount. I have used giro style mounts for years, and a mini giro would likely work well with a 72ED but, I still reckon AZ4 would be best. One issue you can face is getting a good balance with short scopes and heavy eyepieces. You may have to use a longer dovetail to get things far enough forward.

Diagonal wise, I think any of the mid range ones would do fine. I tend to look for dielectric 99% reflectivity so you are maximising the light throughout from a small scope. You can go much more expensive but as ever it is reducing benefits and you are on a budget.

Another thought is that you could also pick up a Heritage 130P to use on the AZ4 as Mark at Beaufort does. Very different proposition to a frac, but for camping in the UK the extra aperture could be useful? They are actually very good little scopes.

[Littleguy80]

SkyWatcher 72ED, AZ4 (comes with tripod) and SkyWatcher 2” Diagonal for £532 shipped from FLO. Adding Lunt Herschel wedge and Baader Solar Continuum filter brings the total to £728. This feels much better. 

I think the lesson here is to get your budget right. Though I think the agonising over spending the money helped to focus my thinking on what compromises I was prepared to make. 

Many thanks for all the responses! Very helpful as always  

[scarp15]

That package looks like a good offer to consider Neil. My only suggestion would had been to consider looking out for a used TeleVue Pronto, 70.4mm aperture, F6.8, 480mm focal length. 

[Littleguy80]

8 minutes ago, scarp15 said:

That package looks like a good offer to consider Neil. My only suggestion would had been to consider looking out for a used TeleVue Pronto, 70.4mm aperture, F6.8, 480mm focal length. 

Good suggestion, Iain. I think I’ll try my luck with a wanted ad for that scope when payday comes around again. Everyone who’s mentioned owning one of the various models of little TV refractors seems to have high praise of them. 

[Littleguy80]

14 minutes ago, scarp15 said:

That package looks like a good offer to consider Neil. My only suggestion would had been to consider looking out for a used TeleVue Pronto, 70.4mm aperture, F6.8, 480mm focal length. 

On the assumption of dark skies, do these little scopes respond work well with narrowband filters? A 20mm eyepiece gives around a 3mm exit pupil which I think should be usable? 

[John]

My TV Ranger has the same optics as the Pronto. It's my travel / very-grab-and-go scope

 

[Littleguy80]

8 minutes ago, John said:

My TV Ranger has the same optics as the Pronto. It's my travel / very-grab-and-go scope

 

Your Ranger was one of the scopes that sprung to mind when Iain mentioned the Pronto, John. Based on your reports, it sounds like a great little scope  

Do you ever use with narrowband filters?

[Stu]

For comparison here is the TS on an AZGTi in solar mode. A bit chunkier than the Ranger, different proposition. Fpl-53 glass and a lovely R&P focused taking 2" eyepieces. I suspect you would prefer fully manual though, less hassle.

[John]

1 hour ago, Littleguy80 said:

Your Ranger was one of the scopes that sprung to mind when Iain mentioned the Pronto, John. Based on your reports, it sounds like a great little scope  

Do you ever use with narrowband filters?

I've not yet used filters with it Stu. Currently my filters (apart from the H-Beta) are 2 inch format. I'm thinking about getting a 1.25 inch Astronomik UHC to use with the Ranger.

 

[Littleguy80]

31 minutes ago, Stu said:

For comparison here is the TS on an AZGTi in solar mode. A bit chunkier than the Ranger, different proposition. Fpl-53 glass and a lovely R&P focused taking 2" eyepieces. I suspect you would prefer fully manual though, less hassle.

It’s a great looking scope and I’ve read that the FPL-53 glass is supposed to be very good. As you guessed, I would prefer manual although I did think about Goto for the tracking. I’m not sure if I’ll be lucky enough to get an eBay bargain like you but will be looking  

[scarp15]

2 hours ago, Littleguy80 said:

On the assumption of dark skies, do these little scopes respond work well with narrowband filters? A 20mm eyepiece gives around a 3mm exit pupil which I think should be usable? 

Yes it will do Neil, depending on the type of mount you intend to get heavier 2" low power wide field eyepieces will balance fine to.

[Littleguy80]

10 minutes ago, scarp15 said:

Yes it will do Neil, depending on the type of mount you intend to get heavier 2" low power wide field eyepieces will balance fine to.

Awesome. This is what I’m looking at for a mount and tripod.

https://www.firstlightoptics.com/alt-azimuth/skywatcher-az4-alt-az-mount.html

The scope is around £2kg. My 20mm APM HDC is 700g. Even with the weight of a diagonal this should be comfortably under 4kg with the mount rated up to 6kg. I think everything should play nicely together. 

[scarp15]

I notice that there is a Panoptic 24mm for sale in the used section which I understand is the choice for compact, lightweight low power wide field, complementing a wide range of mount types. To gain more extensive use with what you already have, when at least concerning the cost or potentially having eyepieces of similar focal length, is probably the best approach. 

[Stu]

Yes, the Pan works very well in a lightweight setup. You could combine with a Tak prism if you wanted a 1.25" option for air travel. Very good optically and not stupidly expensive.

[Littleguy80]

I still have my ES68 24mm which I believe is the same spec though not quite up to Televue standards. I think I’d still go for a 2” diagonal purely because all my filters are 2”. If I’ve understood it correctly, I can put the filter on the diagonal?

[John]

Yes, the filter can go on the end of the diagonal barrel. Some 1.25" - 2" adapters also are threaded for 2" filters but you need to make sure that the barrel of a 1.25" eyepiece will not contact the filter if you do it that way. Some eyepieces have longer barrels.