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Grab and Go Refractor

equipment refractor tripod LP
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#26 f74265a

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Posted 24 November 2020 - 02:45 PM

I have never used an eyepiece tray in the centre and have never had a stability problem, not even close and that includes on uneven ground ! They are definitely not required but they were put there to give the worriers a sense of security. So they can sleep peacefully, lol !


Well if you do ever decide to use the triangle tray it is a total pain to screw in the wing bolts in the dark. It does add some incremental vibration reduction. To obtain stiffness, the bolt holes intentionally don’t line up so you have to force it a bit which adds tension. As mentioned, I opted to upgrade to a light duty wood tripod- yes for more money and more weight-for added vibration suppression which is helpful when using heavy eyepieces

#27 LDW47

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Posted 24 November 2020 - 03:01 PM

Well if you do ever decide to use the triangle tray it is a total pain to screw in the wing bolts in the dark. It does add some incremental vibration reduction. To obtain stiffness, the bolt holes intentionally don’t line up so you have to force it a bit which adds tension. As mentioned, I opted to upgrade to a light duty wood tripod- yes for more money and more weight-for added vibration suppression which is helpful when using heavy eyepieces

When I first started into this great hobby I used the trays, that soon went out the window never to return when it was evident they did nothing for me in every sense of the word !   PS:  When you are viewing, you are supposed to be very refined in your movements, very easy and soft should be your fingers on the focuser wheels, vibration should be avoided at all costs ! Thats the way I operate and it works for me !



#28 gwlee

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Posted 24 November 2020 - 03:52 PM

Who in their right mind is going to pay hundreds of $’s more, carry more weight and bulk to try and eliminate a bit of shakiness because many times they are pushing the scope well beyond its magnification limits, its capabilities if you will, in the first place ? Now I said in their right state of mind, lol !  PS:  And they forget that most nites the skies won’t let them, like it or not !  I guess its all in the name of astronomy ?

I don’t often use any of my scopes at high power: magnifications that result in exit pupils below 1mm. If I anticipate needing  more magnification, I usually select a larger scope.

 

I have a 72mm refractor that I occasionally put on a very light mount/tripod for extensive tree dodging or when I need to carry it a mile or two to view a celestial event that I can’t view from my home.

 

In light configuration the 72mm weighs less than 15# ready to observe, but its a bit shaky at 62x, so I normally use it on a heavier tripod. In heavy configuration, it weighs less than 20# and has no noticeable shakiness at 62x.

 

My 92mm scope is on a heavier mount/tripod, and it weighs less than 30# pounds ready to observe with 2” accessories, so it’s light enough for grab-and-go use at this site, and also doesn’t have any noticeable shakiness at 175x, which is twice the magnification than I normally use with this scope. This mount/tripod is adequate for up to a 4” refractor, but the weight increases to 35#. 

 

Of course you are right, mounting a scope well enough that it doesn’t shake costs more and weighs more than under mounting a scope, but a I prefer a rock solid mount for a grab-and-go scope, and I can handle 35# easily enough on this site. 
 



#29 cupton

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Posted 24 November 2020 - 03:52 PM

Well if you do ever decide to use the triangle tray it is a total pain to screw in the wing bolts in the dark. It does add some incremental vibration reduction. To obtain stiffness, the bolt holes intentionally don’t line up so you have to force it a bit which adds tension. As mentioned, I opted to upgrade to a light duty wood tripod- yes for more money and more weight-for added vibration suppression which is helpful when using heavy eyepieces

Agree on that! Both my Porta II and my old EQ3 mount both use those dang tray with those screws and wing nuts. Even though I dont use the trays anymore I did end up taking the screws and measuring them at Home Depot so I could confirm what type there were and find replacements. I ended up getting replacements with a knurled head and no more wing nuts. Work great for the trays I dont even use and I was out a total of like $10.  ;)



#30 Ps191

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Posted 25 November 2020 - 09:23 PM

Why did you feel that an 80 mm restricted your abilities?  Too small of an aperture?  Something else?

I have a 8" reflector and wanted something a little easier to use for short sessions. You know the whole "the best telescope is the one you use the most". I really enjoy and like a small(er) refractor: no cooling, no collimation, easy to deploy, crisp views with no fuss, etc.

 

Aperture was maybe a small part. I enjoyed pushing 80mm and seeing all I could from that aperture - it made me a better astronomer.

 

I think image scale may be a bigger part. The scope I had was only f/6 so I ended up buying a 3.2mm eyepiece to achieve the views I desired with the brighter objects.

 

Finally I'm always dreaming and looking to optimize. I think a 4" refractor can still fit my definition of portable, no cooling, no collimation while give me a little better view then the 3".



#31 Ps191

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Posted 26 November 2020 - 12:53 AM

I haven’t used a 4” refractor, mount, and tripod yet that I consider adequately mounted that weighed less than about 35#. It’s easy to go lighter if you can tolerate some shakiness in a scope though. 

I'll have to admit that I don't have real life experience supporting 4" refractors - although I'm planing to  gain some soon.

 

My weight calculations come from 4" f/7 scope like the AT102mm ED (9 lbs), alt-az mount like the Stellarvue M002 w/ column (6.5 lbs), and carbon fiber photo tripod like the Robus RC-5558 (5.5 lbs). This leave around ~ 5 lbs for visual accessory’s. Simple red dot finder and 1.25" diagonal and eyepieces should theoretically squeak the whole shebang in around 25 lbs - in theory blush.gif

 

In reality 35 lbs would still be fine by me. In the end I find the shape and placement of the weight while moving more important the final weight.

 

I'm always willing to learn more, please share the set up that you find adequate support for a 4" scope. I think this would be useful knowledge for me and the OP. If they're seriously considering a 4" they may need to flex their max weight requirement.

 

Best,



#32 gwlee

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Posted 26 November 2020 - 06:59 PM

I'll have to admit that I don't have real life experience supporting 4" refractors - although I'm planing to  gain some soon.

 

My weight calculations come from 4" f/7 scope like the AT102mm ED (9 lbs), alt-az mount like the Stellarvue M002 w/ column (6.5 lbs), and carbon fiber photo tripod like the Robus RC-5558 (5.5 lbs). This leave around ~ 5 lbs for visual accessory’s. Simple red dot finder and 1.25" diagonal and eyepieces should theoretically squeak the whole shebang in around 25 lbs - in theory blush.gif

 

In reality 35 lbs would still be fine by me. In the end I find the shape and placement of the weight while moving more important the final weight.

 

I'm always willing to learn more, please share the set up that you find adequate support for a 4" scope. I think this would be useful knowledge for me and the OP. If they're seriously considering a 4" they may need to flex their max weight requirement.

 

Best,

I had my TV NP101 on a DiscMounts DM6 and DiscMounts wooden tripod for a few years. It’s more mount than necessary for a 4” scope, but I also used it with Tak Mewlon 210 (8”).

 

My current 4-inch class mount is a DiscMounts DM4. DiscMounts recommends a Berlebach UNI-18 wooden surveyor tripod for this mount. Tom Peters designed the DM4 for a 4-inch refractor. 

 

I found it pays to be very skeptical of published weights because they are often more aspirational than actual.

 

To me, the potential for a wide field of view one of the most attractive features of a small refractor, so I use heavier 2-inch accessories with mine.

 

A 4” refractor often needs an extension column between the mount and the tripod to allow scope to point at the zenith before it hits the tripod, which adds about 3#.

 

I would be wary of using a photo tripod under a 4” refractor unless I had prior personal experience with it and knew it was capable of solidly supporting a scope of similar weigh AND length. 

 

Unquestionably you can assemble a 4” refractor, mount, and tripod that weighs 25#. The question is whether the scope will work well enough to satisfy you. When I slew my scope to a target and remove my hand, I want the scope to stop instantly without moving or shaking, and the image shouldn’t jiggle while I am focusing. For this kind of performance, I think 35# is a more realistic minimum weight budget, but I think it might be possible to take a few pounds off with a high-end carbon fiber tripod like a Gitzo Series 5, but I haven’t tried it yet. 
 


Edited by gwlee, 26 November 2020 - 07:39 PM.


#33 Paul Sweeney

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Posted 28 November 2020 - 06:19 PM

When kids are involved, I would only get a scope that I am not going to cry about when it ends up in the mud.

For me, grab-&-go means it is always assembled and ready to use. It has to be light enough to pick up with one hand, and it has to be robust. Mine is a 70mm f/5 on an az3 mount that I bought used for $25. It is super light and delivers sharp images and a wide field of view. There is a lot of blue, but it is spread over the whole fov so it is not that noticable. If I was buying new, I would go with an 80mm scope, and not necessarily an ED. It will cost about $300, and if it gets damaged, it's no big loss.
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