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Light, portable 102 refractor for portamount

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#1 AlienRatDog

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Posted 28 December 2012 - 05:18 PM

Well right now I have a 100mm f/9 ED refractor with a moonlight 2.5" focuser on it. On the Vixen Starguy mount, it is a bit wobbley (it is long). Are there any 4" (or close to it) that would sit better on the portamount (starguy)? What about a used 102ED f/7 scope? Or what about just dropping down to 80mm? This is for grab and go, I stopped using the 100mm on the CG5 mount because I could set up faster with my C8.

#2 Jon Isaacs

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Posted 28 December 2012 - 05:49 PM

An 102mm f/7 worked for me, an 80mm f/7 apo is more stable, an NP-101 is less stable but acceptable.

Jon

#3 Denimsky

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Posted 28 December 2012 - 07:28 PM

Abe, what is your budget limit?

#4 AlienRatDog

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Posted 28 December 2012 - 07:39 PM

I rather stay under $1000

#5 Larry Carlino

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Posted 28 December 2012 - 07:59 PM

You might try the KSON ED1026 refractor OTA. It's a 102mm, f/6 ED doublet with a carbon fiber tube, available in either red or dark gray. Optical quality is excellent, and the scope is quite light. There is a bit of c.a. at higher powers as one might expect from a scope that uses FPL-51 equivalent glass, but the overall performance is very satisfying. It comes with tube rings, a red-dot finder and one very nice 20mm wide-angle eyepiece. I have mine mounted on a Vixen Portamount, and it's pretty steady - a perfect grab-and-go set-up. Current price (new) is $899.
Larry Carlino

#6 Locoman

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Posted 28 December 2012 - 08:23 PM

I noticed on my StarGuy while using my 102 F/9.8 achro when I would nudge the scope up and down that there was movement in the azimuth part of the mount. I took the mount apart and tightened the bolt on the the bottom. After tightening it was a lot better, not completely solid but satisfactory for me.

#7 Jon Isaacs

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Posted 29 December 2012 - 04:57 AM

A couple of thoughts...

The Lunt 102 ED is about $750 at Anacortes...

I would be willing to bet your money that the Portamount mated with the 2 inch SS legged CG-5 tripod would solidify things to the point where your 100mm f/9 was plenty stable. Since you have a CG-5, you could try it, it might take some simple fabrication...

Jon

#8 Locoman

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Posted 29 December 2012 - 06:50 AM

I would be willing to bet your money that the Portamount mated with the 2 inch SS legged CG-5 tripod would solidify things to the point where your 100mm f/9 was plenty stable. Since you have a CG-5, you could try it, it might take some simple fabrication...

Jon [/quote]

He said he has the StarGuy so I would think the tripod (HAL130-SXG)would be sturdy enough.

#9 carlcat

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Posted 29 December 2012 - 12:28 PM

I keep my 100ED on a cg4. I keep the scope mounted and can easily take the setup out with no problems. It's very steady as well.

#10 Kon Dealer

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Posted 29 December 2012 - 04:14 PM

+1 for the Kson. Really light, great focuser.
Much better than a Megrez90 that was my
Previous G&G

#11 AlienRatDog

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Posted 29 December 2012 - 05:53 PM

Where do you guys get one?

#12 Locoman

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Posted 29 December 2012 - 07:29 PM

Kson

#13 Jon Isaacs

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Posted 30 December 2012 - 12:05 AM

He said he has the StarGuy soI would think thetripod (HAL130-SXG)would be sturdy enough



According to the original post, the mount is not stable enough. In my experience with the Portamount, that points to the tripod. I once mounted my Portamount head on my old Houston-Fearless tripod and it was rocksolid with my NP-101... My gut feeling is that the CG-5 tripod would be similar.

Jon

#14 Kon Dealer

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Posted 30 December 2012 - 08:23 AM

Kson OTA only weighs 5.6lbs and at f/6 is quite short.
Fits on my Synscan AZ goto mount perfectly and is
Pretty stable.
Also fits on my SE mount and with an extension tube in
The diagonal, can reach zenith OK.

#15 AlienRatDog

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Posted 30 December 2012 - 05:32 PM

The issue I have is the overall length adds quite the moment arm and the moonlight 2.5" focuser adds some heft to it...

#16 Gary Riley

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Posted 31 December 2012 - 12:29 AM

I have a 102mm f/9.8 achro on a CG-4 mount with the 1.75 inch dia. stainless steel legs and it carries it very well. If I have a fairly strong breeze blowing it will cause the OTA to shake at times slightly. Otherwise, it does very well.

#17 Locoman

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Posted 31 December 2012 - 09:19 AM

He said he has the StarGuy soI would think thetripod (HAL130-SXG)would be sturdy enough



According to the original post, the mount is not stable enough. In my experience with the Portamount, that points to the tripod. I once mounted my Portamount head on my old Houston-Fearless tripod and it was rocksolid with my NP-101... My gut feeling is that the CG-5 tripod would be similar.

Jon

The HAL 130 tripod is rated for 30 to 35 lbs. I tried my 102 F/9.8 with the "Mannys Bracket" and it was unusable. I took off the "Mannys Bbracket" and it was a lot better. I tightened the bolt on the azimuth stem and it was even better. In my opinion it is the mount itself and not the tripod. When I put my SLT mount on the HAL 130 with the 102mm F/9.8 scope it has less, much less vibrations than the porta mount on it with the same scope. My shorter scopes, ST120, C6-SCT amd C6-N which weigh more that the 102 F/9.8 are much more stable.

#18 AlienRatDog

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Posted 31 December 2012 - 08:28 PM

What's the ST120 like on it?

#19 Locoman

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Posted 31 December 2012 - 09:42 PM

ST120 is pretty solid. Damping times are minimal, a second or so if I remember correctly.

#20 AlienRatDog

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Posted 01 January 2013 - 08:14 AM

About how long is your ST120, I suppose if I get a refractor with similar dimensions, I would be set...

#21 Kon Dealer

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Posted 01 January 2013 - 10:45 AM

Had a ST120 and let it go for two reasons;
1 too much CA
2 too big for my SynscanAZ mount.

The CA has to be seen to be believed!!

#22 Locoman

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Posted 01 January 2013 - 03:18 PM

About how long is your ST120, I suppose if I get a refractor with similar dimensions, I would be set...

With the dew shield about 25" , without dew sheild about 19". This doesn't include diagonal.

#23 Locoman

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Posted 01 January 2013 - 03:34 PM

Had a ST120 and let it go for two reasons;
1 too much CA
2 too big for my SynscanAZ mount.

The CA has to be seen to be believed!!

I fail to understand why people make these kind of statements. The stated purpose for it is for deep sky objects. It is not meant for planets, moon or bright stars. It is a wide field scope. If I buy an F/15 scope then complain that it is a terrible wide feild scope on here people would laugh at me. I don't mean to be harsh but it is what it is! Also, isn't the Synscan basically the same as the SLT? The SLT mount can handle quite a bit on a heavy duty tripod!

#24 Kon Dealer

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Posted 02 January 2013 - 10:03 AM

Had a ST120 and let it go for two reasons;
1 too much CA
2 too big for my SynscanAZ mount.

The CA has to be seen to be believed!!

I fail to understand why people make these kind of statements. The stated purpose for it is for deep sky objects. It is not meant for planets, moon or bright stars. It is a wide field scope. If I buy an F/15 scope then complain that it is a terrible wide feild scope on here people would laugh at me. I don't mean to be harsh but it is what it is! Also, isn't the Synscan basically the same as the SLT? The SLT mount can handle quite a bit on a heavy duty tripod!

This is because I had read a few reviews that said the CA in a ST120 was "overstated" and that if it did prove troublesome was "easily addressed" with a fringe-killer, or similar.
Well it wasn't- in both cases.
Also the mount struggled with it, particularly in altitude.
What I learnt from this is that telescopes and one's views of them (and through them) are very personal. What works for one may well be unacceptable to another.

#25 Locoman

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Posted 02 January 2013 - 10:33 AM

I guess my ST120 may a good one because the other night Jupiter looked very good. I don't usually look at planets, moon and brighter objects with it but I wanted to try it on my SLT and it was a full moon night. Still, it is a great grab n go scope for the $ and if one sticks with dso's for which it was intended then CA is not an issue.






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