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Neil English does it; should I?

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#1 Tristy

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Posted 17 May 2011 - 09:46 PM

In "The Story of a Journey: the Skylight f/15," the author and respected CN member Neil English writes that "[a]s a visual observer, I have developed a strong preference for simple, non-nonsense observing with minimum set up time. And while those wishing to carry out measurements of double stars will obviously want to mount this refractor on a sturdy motorised equatorial mount, I much prefer the elegant simplicity of a stable, yet portable alt-azimuth." He then goes on to state that the 4" f/15 Skylight proved to be "a good overall match" with the TV Gibraltar.

How is this relevant to me? I just acquired an 80mm f/15 refractor for high-magnification observations and I'm finding Neil English's rationale (that a long focus 'scope can be mated to a altazimuth mount and be suitable for tracking at high-ish powers) attractive.

Would a TV Panoramic be a passable choice for my refractor, or should I even go as far as to drop all this altazimuth nonsense and focus on a GEM only?

Your replies will be much appreciated,
-Tristan

#2 Jon Isaacs

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Posted 17 May 2011 - 10:01 PM

I like alt-az mounts but I also like fast scopes....

jon

#3 Midnight Dan

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Posted 18 May 2011 - 06:14 AM

For visual-only use, I'd go for an alt/az any day.

-Dan

#4 Doug76

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Posted 18 May 2011 - 09:02 AM

I used to lean that way too, alt-az for visual, but if you sketch at the scope tracking is more suitable, and frankly I've gotten where I just prefer the object to sit there in the eyepiece while I'm looking at it, without me having to adjust for movement constantly. But for my traveling scope, I do use an alt-az mount.

#5 la200o

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Posted 18 May 2011 - 11:11 AM

I'd go alt-az, but I'd skip the Gibraltar--I have one--and look at the Half-Hitch/Super-Hitch and the Discmount 4 and 6. Far better IMO.

Bill

#6 jrbarnett

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Posted 18 May 2011 - 01:05 PM

With all due respect to the esteemed Mr. English, opinions on this differ. I find the Televue Gibraltar to be scarcely adequate for moderately high magnifications when used with a TV-102 (much shorter than the 4" f/15 format). I'm with Jon on this one - alt-az mounts are great...with fast scopes (short tubes, wide fields, so-so prospects of high magnification, etc.).

I strongly prefer a driven mount for the inherently narrow fields of view that are a characteristic of long focus refractors. I honestly see significantly more detail in a stationary image than in an image I am chasing with periodic nudges and the resulting vibrations.

So not nonsense, but certainly not everyone's cup of tea. You should probably figure out if it suits you or rather you'd prefer a motorized GEM for 80mm f/15.

To dabble a toe in the alt-az ocean with that scope, I'd bypass the Televue mounts (unless you find a used Panoramic) and instead look at the Vixen Porta II (again, used - you're trying to figure out if you're an alt-azer or a GEMer). Use it for awhile, then sell it. Buy a used GEM (CG5-GT would be perfect for that scope), use it for a while, and decide if you like it or the alt-az better.

Regards,

Jim

#7 Astrojensen

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Posted 18 May 2011 - 01:45 PM

I'm with Jim here. I personally strongly prefer a german equatorial, and if used at high power, preferably one with motorized tracking. I have my 4" f/15 Antares on a modded EQ-6 with ADM dual saddle on a heavy Baader tripod and find it fine for visual use at most powers most sane people use. I am not sane, however, and find it somewhat lacking at 600x and 850x. An AP900 would be better.


Clear skies!
Thomas, Denmark

#8 Keith Howlett

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Posted 18 May 2011 - 02:31 PM

Yes, I think I agree with Jim and Jon.

My Gibraltar was brilliant for grab and go with a little Solarmax 60, very portable and very quick.

Stephen James O'Meara described his Gibraltar as 'steady as a rock'. Mind you, he was living on a volcano and may have had an atypical experience of 'steady as a rock'.

I sold mine when I got a 4 inch travel scope - it seemed to lose some of it's appeal at higher magnification. I think I would need much more patience to use it with a 80mm f15 scope at high magnification.

Cheers,

Keith

#9 ukcanuck

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Posted 18 May 2011 - 02:53 PM

I'd go alt-az, but I'd skip the Gibraltar--I have one--and look at the Half-Hitch/Super-Hitch and the Discmount 4 and 6. Far better IMO.

Bill


There's not many Discmounts in the UK, and I saw one for the first time at NEAF...I was really impressed. Tom makes a great mount (and he's a really decent guy).

#10 Doug76

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Posted 18 May 2011 - 04:44 PM

I have my 4" f/15 Antares on a modded EQ-6 with ADM dual saddle on a heavy Baader tripod and find it fine for visual use at most powers most sane people use. I am not sane, however, and find it somewhat lacking at 600x and 850x. An AP900 would be better.


Clear skies!
Thomas, Denmark


Your at least as sane as a mutual acquaintance of ours, who uses a 60mm at insane levels also! :lol:

#11 Jeff Morgan

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Posted 18 May 2011 - 05:21 PM

I strongly prefer a driven mount for the inherently narrow fields of view that are a characteristic of long focus refractors. I honestly see significantly more detail in a stationary image than in an image I am chasing with periodic nudges and the resulting vibrations.

So not nonsense, but certainly not everyone's cup of tea. You should probably figure out if it suits you or rather you'd prefer a motorized GEM for 80mm f/15.

To dabble a toe in the alt-az ocean with that scope, I'd bypass the Televue mounts (unless you find a used Panoramic) and instead look at the Vixen Porta II (again, used - you're trying to figure out if you're an alt-azer or a GEMer). Use it for awhile, then sell it. Buy a used GEM (CG5-GT would be perfect for that scope), use it for a while, and decide if you like it or the alt-az better.

Regards,

Jim



Agree. For under 200x alt-az is ok, especially considering the faster set-up time. Less desirable for high power work, and not as easy to star hop since the mount axes don't match the cardinal directions.

Nice to have both types, but the TV mount never impressed me either. The Disc Mount is awesome, should have never sold mine. If you can find a Vixen Polaris (or Super Polaris) it can operate in either mode.

#12 Tristy

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Posted 18 May 2011 - 05:31 PM

Thanks for the replies so far, guys.

The general consensus so far, it seems, is to shoot for a GEM (preferably motorized). The more I think about it, when considering that I will be taking notes, the convenience of non-manual tracking in an equatorial mount would be appreciable.

To buy a GEM would be a first for me, and I am looking for a new experience....

#13 Jon Isaacs

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Posted 19 May 2011 - 08:27 AM

Thanks for the replies so far, guys.

The general consensus so far, it seems, is to shoot for a GEM (preferably motorized). The more I think about it, when considering that I will be taking notes, the convenience of non-manual tracking in an equatorial mount would be appreciable.

To buy a GEM would be a first for me, and I am looking for a new experience....


One advantage of an alt-az mount is that it is easier to carry, you are not dealing with the counterweight so it is lighter and the counter weight isn't getting in the way going through doors. So a short refractor combined with an alt-az mount makes for a nice "out the door in one piece" type scope. A shorter scope is also easier on the mount so getting good stable views at 300x are possible with a moderately fast 4 inch apo and an alt-az mount. Of course, I am a big fan of fast scopes, if I am going to fool around with a 50 inch or 100 inch focal length, it's gonna have some aperture to support it.

But with a slow, F/15 scope, it's not going through the door mounted, the tripod is going to have to be quite tall for it to be at all comfortable and the mount will have to be more substantial just to handle it all. Add in the fact that it is not going to be good for low power widefield views, an EQ mount makes more sense, at least to me.

Jon






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