Unconvinced by mount/clamp for my Tak

[Highburymark]

Hi all, 

Last year I bought a 4" Takahashi frac with a vixen type dovetail, along with an Ercole mini and a 'luxury' clamp (from Teleskop Service in Germany). Very happy with the Ercole, but I don't like the all-metal clamp (pictured). It's difficult to tighten, or to know whether it has been fully tightened, particularly if outside on a cold night, and once I felt the scope starting to slip when observing at the zenith - even though the ota only weighs 2.8kg. (Another annoyance is that the dovetail on my smaller Equinox 80ED doesn't fit into the new clamp for some reason - but that's a side issue.) So my question is: what would be a better, safer, stronger choice of clamp to hold a lightweight 4" refractor with a vixen dovetail? All suggestions gratefully received.

[John]

I use ADM 2-knob clamps on all my mounts now, including the ones that I use my Tak with. My Tak has the same dovetail bar arrangement that yours is using. The ADM clamps seem very secure to me.

 

[Highburymark]

10 minutes ago, John said:

I use ADM 2-knob clamps on all my mounts now, including the ones that I use my Tak with. My Tak has the same dovetail bar arrangement that yours is using. The ADM clamps seem very secure to me.

 

Excellent - thanks John. I deliberately chose a pricier clamp first time round thinking it would be worry free but as ever, should have asked SGL first .....

[Knighty2112]

I'd go with John too with the ADM saddle. Much easier to feel when fully tightened down, even when hands are cold. I did also get another clamp (can't remember the manufacturer at the moment) which had excellent knobs to tighten up, but didnt have the springs on them like you get on the ADM saddle to make it easier to take out the scope from the saddle. 

[Knighty2112]

Just remembered the other saddle I have too; Farpoint. Nice chunky knobs to lock, but like I said no springs to aid opening on the saddle when removing and attaching the scope, so prefer the ADM saddle better. 

[Highburymark]

51 minutes ago, Knighty2112 said:

Just remembered the other saddle I have too; Farpoint. Nice chunky knobs to lock, but like I said no springs to aid opening on the saddle when removing and attaching the scope, so prefer the ADM saddle better. 

Thanks Knighty - definitely no springs in mine either

[Stu]

I would never try to argue against using ADM kit (why would you?), but I do use a different option on my Giro-WR which has always provided a solid connection. I was looking for something which matched the black, round style of the built-in clamp and which was strong but not too heavy. The negative side of this clamp is that it does not have a non-marring plate, but I often find these hold the dovetail more securely anyway.

http://www.teleskop-express.de/shop/product_info.php/info/p1772_Starway-Dovetail-clamp-DX---GP-standard---for-high-loads.html

Another option I have used, which is along similar lines is this Berlebach clamp. This one has the advantage of a non-marring plate and has a nice big plastic knob to make tightening up in the cold easy.

http://www.teleskop-express.de/shop/product_info.php/info/p3788_Berlebach-deluxe-dovetail-Clamb---Vixen-level---surface-pressure.html

I think much depends upon how portable and lightweight you want the mount to be. For travelling I prefer the smaller clamps, if that is not an issue then the dual clamp ADMs are a very good bet.

[GavStar]

Ok I'll argue against using ADM kit ? But only a little bit. I think the official losmandy dual clamp as per the attached link is better than the ADM one. This is because the knobs are easier to turn but also more importantly the plate is cut in two and each knob presses its own plate down separately (unlike the ADM one where both knobs work on the same level plate). I think this gives just a little bit more protection against changing temperatures causing the plate to move. 

http://astrograph.net/epages/www_astrograph_net.mobile/en_GB/?ObjectPath=/Shops/www_astrograph_net/Products/AGLOSUNIV

I use the Losmandy on my t-Rex for my bigger refractors. However on my smaller refractors such as my Tak fc100df I do use adm clamps!

[Highburymark]

Thanks Stu and Gavin. Lots to chew over. It's the only part of the whole set up I didn't research in some depth - am sure all  your suggestions would be a significant improvement.

 

[GavStar]

This is the adm clamp I use for my portable setups (although the knob is not as shown in the picture but rather the same as the ones used for the adm dual clamps)

https://www.firstlightoptics.com/adm-dual-type-dv-series/adm-dual-dv-series-dovetail-adaptor-takahashi.html

[Paul73]

ADM Duel clamp for me too.

Although the Tak's are surprisingly light..... But, if I felt that baby starting to slip, I'd be going for it Belt and brace with the clamps!!

I haven't tried the Losmandy offerings. They sound expensive but good).

Paul

[John]

The Losmandy dual clamp looks great but surely a bit OTT for the Tak 100 F/7.4 on a Mini-Giro mount ?

I think Mark's original spec was "... to hold a lightweight 4" refractor with a vixen dovetail ...."

If he had a 6" F/12 going onto a massive EQ or Alt-Az might have suggested something else !

 

 

[Highburymark]

10 hours ago, Paul73 said:

ADM Duel clamp for me too.

Although the Tak's are surprisingly light..... But, if I felt that baby starting to slip, I'd be going for it Belt and brace with the clamps!!

Indeed Paul, it was only a tiny movement, but heart stopping nonetheless 

[moriniboy]

I have no problems with the Altair clamp on my grab n go set up. For anything heavier than 3kg I would go for an ADM dual knob version.

For comparison the bearing surface (i.e. the bit that clamps on the dovetail) is a useful 100mm wide, the ADM is 150mm and an original Skytee 2 clamp is only 80mm

[Alien_Photons]

I drilled out my rail and added two bolts either side of the clamp and far enough away from the centre of gravity to alow some adjustment. The bolts protruding enough to stop the rail from sliding out. 

[JG777]

Mark,

I had a side issue similar to yours with the Equinox 80 and it would not fit into the Altair clamp, so I added a dovetail as in the pics. Two bolts keep it rock solid.

 

[iPeace]

I assume yours is on the left. I do like that one, but you do need to slide a Vixen dovetail bar in from either end as it won't fit in from the side. The top one has always felt most secure, double clamps and nice deep groove. The Berlebach is at bottom, very nicely engineered and probably my favorite - I have several of these. At right the ADM, enough said.

All of these fit perfectly on the Ercole Mini.

[mikeDnight]

I've always found the Tak clamshell to be perfectly adequate, holding the scope solidly and firmly in position, even when the scope has been loaded with heavy eyepieces or binoviewer. It's also easier to quickly rebalance the scope in the clamshell when using heavy kit than in rings. If I felt the scope was slipping, and the clamshell was tight, I'd consider simply adding another layer of felt to the inside of the clamshell. Every clamshell I've ever used on my own and other Tak scopes has held the scope perfectly well. It's strange that yours does not!?

A small square of green felt and a can of spray on carpet glue and the problem will be solved in minutes, and you'll retain that classy Takahashi look to your scope. I know CNC rings are popular but when I had them on my FS152 I hated the look of them as they detracted from the Takahashi theme. Sad I know! To me it was like putting furry dice on a Porsche! 

Another alternative would be to inform your vendor of the problem and ask for a replacement clamshell.

Mike

[Stu]

8 minutes ago, mikeDnight said:

I've always found the Tak clamshell to be perfectly adequate, holding the scope solidly and firmly in position, even when the scope has been loaded with heavy eyepieces or binoviewer. It's also easier to quickly rebalance the scope in the clamshell when using heavy kit than in rings. If I felt the scope was slipping, and the clamshell was tight, I'd consider simply adding another layer of felt to the inside of the clamshell. Every clamshell I've ever used on my own and other Tak scopes has held the scope perfectly well. It's strange that yours does not!?

A small square of green felt and a can of spray on carpet glue and the problem will be solved in minutes, and you'll retain that classy Takahashi look to your scope. I know CNC rings are popular but when I had them on my FS152 I hated the look of them as they detracted from the Takahashi theme. Sad I know! To me it was like putting furry dice on a Porsche! 

Another alternative would be to inform your vendor of the problem and ask for a replacement clamshell.

Mike

I don't think it's the clamshell that's the problem Mike, it is the clamp/dovetail which is not giving a secure connection.

[mikeDnight]

9 minutes ago, Stu said:

I don't think it's the clamshell that's the problem Mike, it is the clamp/dovetail which is not giving a secure connection.

Oh! Yes I've had that problem too. It arises from the Tak Mewlon dovetail being slightly too  narrow compared to most other dovetails. I resolved it by gluing a brass strip to the inside of my clamp. It was more of a problem with my AZ4 than with my Vixen GP, but easily resolved in minutes.

Mike

 

[Alan White]

Another ADM vote from me, just bought one for my new Giro Ercole and the ADM clamp is a very solid grip and very well made, the most solid my ED100 has ever been held to date.

 

[astro_al]

I don't have a problem with the clamp on my Castor mount, but I have loosened it instead of one of the alt-az knobs a couple of times. Scared myself with my own stupidity ?. I always make sure I have a bolt or something bigger in the dovetail above and below the clamp. Has been a good investment for me ?

 

[Highburymark]

On 12 May 2017 at 08:50, JG777 said:

Mark,

I had a side issue similar to yours with the Equinox 80 and it would not fit into the Altair clamp, so I added a dovetail as in the pics. Two bolts keep it rock solid.

 

Great advice - thanks!

[Highburymark]

On 13 May 2017 at 09:05, iPeace said:

I assume yours is on the left. I do like that one, but you do need to slide a Vixen dovetail bar in from either end as it won't fit in from the side. The top one has always felt most secure, double clamps and nice deep groove. The Berlebach is at bottom, very nicely engineered and probably my favorite - I have several of these. At right the ADM, enough said.

All of these fit perfectly on the Ercole Mini.

Thanks Mike - yes, mine is the one on the left. Good to have your comments

[Stu]

On 13/05/2017 at 14:09, astro_al said:

I don't have a problem with the clamp on my Castor mount, but I have loosened it instead of one of the alt-az knobs a couple of times. Scared myself with my own stupidity ?. I always make sure I have a bolt or something bigger in the dovetail above and below the clamp. Has been a good investment for me ?

 

Good to see someone else has arrived at the same sort of solution for counter balancing a giro mount  works very well, doesn't it?