10" dob eq mount

Brycepj (Peter) · #1 11-02-2015, 09:19 AM

Hey everyone
I have a "crazy" thought as I'm prone to from time to time.
Is it possible, worth considering or just stupid.
I love my 10" dob and would really like to use it take high quality astro pix. Soon I will be moving to a new property( down sizing) and will be building a little flip top observatory so the scope will be set up all the time.
Is it possible to take the 10" dob and convert it to operate on a high quality eq mount? Of course it would all be used in a Goto fashion for tracking etc.
This would be a cost saving exercise of course.
Can the unit be made to fit using tube rings, as is or would some modification be needed? Are the wall of the tube strong enough.?
What would be the other issues I may encounter?

regards peter

rustigsmed (Russell) · #2 11-02-2015, 11:00 AM

hi peter,

I have heard of people doing it successfully before. the dob is solid and not flex tube right?

cheers

rusty

doppler (Rick) · #3 11-02-2015, 11:27 AM

I have mounted my 10" SW dob on an old eq pier mount. I left the mounts on the tube so I can still use it as a dob when required. I used GSO tube rings. I had to pad the inside of the tube rings as the SW tube diameter is smaller than the GSO and the SW rings were harder to get and a lot more more expensive than the GSO. I would recomend a long dovetail bar as balance can be a bit hard to get right and you will need to make adjustments for different parts of the sky. I am happy with my setup but one day I would like to get it on a computerised mount, single drive tracking is ok but hard to set up.

Cheers Rick

chuckywiz (Ben) · #4 11-02-2015, 02:03 PM

Yes definitely doable but wow its heavy to lug around even with mine being collapsible.. Ive since switched to an ED80 as my old back is struggling a little with the weight but heres a 10 inch on a NEQ6PRO for you. and it is balanceable and works fine. for e was mainly the weight was a problem.

Brycepj (Peter) · #5 11-02-2015, 08:06 PM

Rick, Ben & Rusty.
Good to know that this Is do able yes it's a solid tube.
The plan is to set it up once in a flip top observatory so I wouldn't need to move it again.
It sounds like tube rings and balancing is where the challenge will be.
The shopping list would be:
High quality Goto eq mount that can take the weight when fully set up with eye pieces camera etc.
Tube rings, dove tail.
Is their anything else I may need
Thanks for your advice

JoelyE95 (Joel) · #6 01-06-2015, 08:59 PM

Peter,

Here is my 10" dob on an AZ-EQ6. Works a charm with room to move.

Joel

P.s. Sorry for the orientation. iOS is terrible with orientation of photos on the phone.

ariefm71 (Arief) · #7 02-06-2015, 09:41 AM

Peter, I tried this before and decided to go back to the dob mount due to very uncomfortable viewing positions most of the time. I won't do this unless I have a way to rotate the tube easily. Parallax sells the rotating tube rings but they are pricey: http://www.parallaxinstruments.com/rings.html

cheers,
Arief

traveller (Bo) · #8 02-06-2015, 10:19 AM

Quote:

Originally Posted by JoelyE95

Peter,

Here is my 10" dob on an AZ-EQ6. Works a charm with room to move.

Joel

P.s. Sorry for the orientation. iOS is terrible with orientation of photos on the phone.

Hi Joel, can you confirm if you had to put an extension to the counterweight bar to your mount? Also, I see the counter weights are right towards the end. Have you tried to add any other gear (eg. Camera) and were you able to get balance with 2x5kg weights and added weight towards the front end?
Thanks
Bo

kens (Ken) · #9 02-06-2015, 12:24 PM

If you want to save cost for astrophotography that isn't the way to go. The bigger part of the cost is in the mount and for that size OTA you need a seriously good mount to take the weight. You'd spend less getting a smaller OTA and more modest mount.
The OTA would weigh around 16kg so you are looking at a 35-40kg class mount for AP

ZeroID (Brent) · #10 02-06-2015, 06:26 PM

The EQ6 will do it but ... balance is critical and you will need more weight or a longer bar. By the time you add other required accessories, guider, camera etc it will be very marginal for stability and vibration.

doppler (Rick) · #11 02-06-2015, 08:43 PM

Question? Is it the mount or the tripod that gives stability and reduces vibrations. I've found that most mounts improve a lot with a heavy duty tripod or pier, so controlling weight becomes a matter of balance (and shelter from wind in the case of large newtonians). Bigger aperture
= bigger image and with shorter exposure time.

cometcatcher (Kevin) · #12 03-06-2015, 01:10 AM

Quote:

Originally Posted by doppler

Question? Is it the mount or the tripod that gives stability and reduces vibrations. I've found that most mounts improve a lot with a heavy duty tripod or pier...

I think it's both. Extending the legs on any mount is a bad idea vibration wise, but it has to be done with refractors. I actually replaced the legs on my HEQ5 Pro with short legs. It has less vibration and a newtonian is still at a good height / angle.

However the thin shafts are the next point of weakness. I don't know why Skywatcher use such thin shafts in their mounts. Compared to my old Samson they look like a toy.

raymo · #13 03-06-2015, 01:36 AM

I feel that I can give an informed opinion on this subject, having been
around scopes and mounts for just over 60 yrs. In most cases it is the tripod. Wooden ones are generally much less prone to vibration than
any metal ones. The situation can usually be improved significantly by'
using vibration dampers under the tripod's feet, and/or suspending a substantial weight beneath the mount. In the case of larger Newtonians,
8" and up, on EQ mounts, another factor comes into play. Frequently, the tube rings/ dovetail plate assembly is not up to the job. Regardless of the ribbed construction of the dovetail plate, there is just too much overhang each side of the saddle. For example, my HEQ5 with a
90mm f/10 refractor aboard is rock solid. Vibes from a good tap are gone in a second or less. Put my 8" on it, and the same tap results in 4 to 5
seconds of frustrating wait. I can reduce it to around 3 secs by
moving the rings 50mm closer together. You can in fact improve on that
further by moving them even closer together, but then the OTA starts to
become more vulnerable to the wind, and just starts to distort a little under it's own weight.[The same overhang problem]. A custom made deeper and heavier duty dovetail plate can almost eliminate the problem. I just fitted an electric focuser[ sheer luuuxury]. That will have to do, I've rabbited on too much already.
raymo

JoelyE95 (Joel) · #14 03-06-2015, 09:45 PM

Quote:

Originally Posted by traveller

Hi Joel, can you confirm if you had to put an extension to the counterweight bar to your mount? Also, I see the counter weights are right towards the end. Have you tried to add any other gear (eg. Camera) and were you able to get balance with 2x5kg weights and added weight towards the front end?
Thanks
Bo

I am about to buy an additional counterweight for it considering that I am using the extension bar with both weights at the very end. And that is just the tube. I haven't hooked my camera or any thing else to it yet until I get the extra counterweight. It is fine at the moment for visual as it is only juuuust out of balance and the mount can handle it.

I also have a 13" losmandy DUP universal dovetail on it. It is a 75mm dovetail and is 20mm thick. Thick enough for the loads in my opinion so far. At the moment it is about centre down the dovetail for balance, so I have about 6" up or down to go when it comes time for cameras, as well as sliding the rings if needed.

I am also using Orion Rockstable Anti-vibration pads too.

I can post more photos if you are interested.