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Old 21-11-2018, 01:32 PM
Placesinthedark (Stephen)
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10 or 12 inch dob

Hi all,


I currently have a 90mm refractor that uses wifi and an app to move to a target. It's been great fun, but I'm really thirsty for a scope I would move myself as I like the idea of just looking about the sky. (The alignment process fails more often than not so that also has turned me off using it)


I've done some research and have found Andrews to have the best overall deal for a 10 or 12 inch solid tube dob, with 4 extra eyepieces overall plus a fan/RA finder/ 10:1 focuser that the other brands don't have.



Is Andrews a good company that take care with shipping and are those extra worth the $130+ in shipping or should I just go to a Brisbane store (2 hours drive) and see if I can get some kinda deal as the Skywatchers I see don't have all those eyepieces and extras?



I really like that Andrews seem to give a dam about it's products but what are actual customers' experiences?



I think the portability of a 12 inch is not too much issue and already plan to get either a dolly or a trolley to wheel out from the shed to my lawn. But is there a big difference with 10 to 12 inch in terms of moving it around. I'm 38 and fairly fit and strong.



My town has some light pollution but probably a 3/4 on the bortle scale. Do you think it's still worth going for the 12 inch or maybe just go with a 10 inch due to the light pollution in my town. I own a Kia Rio at the moment and worry a 12 inch won't fit if I ever want to take it out to some darker skies.



Cheshire or laser collimator for a first time dob user?



Sorry for all the questions, thanks for any and all help!



Steve.
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  #2  
Old 21-11-2018, 02:04 PM
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JeniSkunk (Jenifur)
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Hi Steve, obvious question: What make/model of scope do you have?
A decent goto scope should have a manual free roam mode.
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Old 21-11-2018, 02:25 PM
gaseous (Patrick)
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Hi Steve, and welcome.


Those Andrews deals are good, and the 30mm superview eyepiece is a pretty good performer for the price. Andrews have a generally good reputation - they've always been very prompt whenever I've dealt with them, but like anything there are always going to be a few people who may have had less than optimal dealings with them.


Dunno how big a Kia Rio is inside, but a 12" GSO dob is 1500mm long, which is really going to take some squeezing in, particularly when you need to put the base in separately somewhere, plus whatever else you may want to bring (table / chair, etc) if you decide to travel with it.



Regardless of the light pollution / sky darkness, the viewing difference between a 10" and a 12" is probably not going to be significant, but providing you can fit the larger scope in your car and lug it around, you might as well get the bigger scope.


A solid tube dob should hold collimation reasonably well, particularly if you're mainly using it at home and not bumping it in a car for extended periods of time. A laser collimator was fine for the first few years of my collapsible 8" dob, but a cheshire gives that extra bit of accuracy if that's important to you - I tend to use both now. Others may have differing opinions on collimation.


Good luck - either way you should land yourself a good deal.
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Old 21-11-2018, 02:32 PM
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mental4astro (Alexander)
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Hi Steve,

to IIS!

A 10" dob is a BIG scope. A 12" scope is and even BIGGER scope. A solid tube 12" dob will be a challenge to fit into most cars, such as a sedan or small hatchback. A 10" while a little easier to handle loses a lot in terms of aperture compared to a 12". I have owned a solid tube 12" scope, but it wasn't an issue for me to transport because I have an SUV. Like Patrick said, a 12" solid tube scope is a BIG unit A 12" solid tube scope may fit down the whole length of the passenger side of a Kia Rio.

If you have the space at home, and car, I honestly would suggest going for a 12". This aperture size begins to allow you to resolve the arms of the larger spiral galaxies. A 10" won't. And that's what it comes to in astronomy - the bigger the aperture the better.

In so far as dealing with Andrews Communications, I can recommend them 100%. Give them a call and ask if they could give you some idea on the dimensions of a solid tube 10" and 12" scope. Or someone here could. Either way, Andrews Com are very approachable and knowledgeable.

Cheshire or laser? I say BOTH! A Cheshire will actually allow you to do the whole collimation process, secondary mirror and primary. A laser is ONLY for the primary mirror, it will not sort out the secondary mirror. In the collimation process for Newtonians, the secondary mirror NEEDS to be dealt with FIRST to make sure that it is centered and square with the focuser and then in relation to the primary, and only after the secondary has been sorted do you look at tweaking the primary mirror.

This is something that is not mentioned anywhere enough. Retailers cannot be expected to know your proficiency at collimation, so if you just purchase a laser that's all they care about. And many retailer themselves do not know how to collimate a Newt, so they would not even be clued up enough to ask if you do.

I started out with a cheshire eyepiece, but sold it to get a laser. No one told me about the above collimation process, and I too mistakenly thought a laser would do it all. And it took me six months of frustration to work out something was not going right, and then I looked at the secondary mirror through the draw tube and saw that it was WAY off. It was then that I worked out that the laser was not the fix-all took I thought it was. I then got another cheshire, use it with the laser, and never looked back.

Alex.
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Old 21-11-2018, 03:47 PM
Placesinthedark (Stephen)
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Quote:
Originally Posted by JeniSkunk View Post
Hi Steve, obvious question: What make/model of scope do you have?
A decent goto scope should have a manual free roam mode.
It's a 90GT Celestron "Cosmos".

For me, fiddling with the phone and app after connecting is just not fun and you can't look through the red dot finder and move the scope at the same time as the buttons on the app are not intuitive and give no feedback! Those buttons often freeze, even on different phones.

I really wish I could just manually move the scope but it only allows me to move it up and down.
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  #6  
Old 21-11-2018, 03:51 PM
Placesinthedark (Stephen)
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Quote:
Originally Posted by mental4astro View Post
Hi Steve,

to IIS!

A 10" dob is a BIG scope. A 12" scope is and even BIGGER scope. A solid tube 12" dob will be a challenge to fit into most cars, such as a sedan or small hatchback. A 10" while a little easier to handle loses a lot in terms of aperture compared to a 12". I have owned a solid tube 12" scope, but it wasn't an issue for me to transport because I have an SUV. Like Patrick said, a 12" solid tube scope is a BIG unit A 12" solid tube scope may fit down the whole length of the passenger side of a Kia Rio.

If you have the space at home, and car, I honestly would suggest going for a 12". This aperture size begins to allow you to resolve the arms of the larger spiral galaxies. A 10" won't. And that's what it comes to in astronomy - the bigger the aperture the better.

In so far as dealing with Andrews Communications, I can recommend them 100%. Give them a call and ask if they could give you some idea on the dimensions of a solid tube 10" and 12" scope. Or someone here could. Either way, Andrews Com are very approachable and knowledgeable.

Cheshire or laser? I say BOTH! A Cheshire will actually allow you to do the whole collimation process, secondary mirror and primary. A laser is ONLY for the primary mirror, it will not sort out the secondary mirror. In the collimation process for Newtonians, the secondary mirror NEEDS to be dealt with FIRST to make sure that it is centered and square with the focuser and then in relation to the primary, and only after the secondary has been sorted do you look at tweaking the primary mirror.

This is something that is not mentioned anywhere enough. Retailers cannot be expected to know your proficiency at collimation, so if you just purchase a laser that's all they care about. And many retailer themselves do not know how to collimate a Newt, so they would not even be clued up enough to ask if you do.

I started out with a cheshire eyepiece, but sold it to get a laser. No one told me about the above collimation process, and I too mistakenly thought a laser would do it all. And it took me six months of frustration to work out something was not going right, and then I looked at the secondary mirror through the draw tube and saw that it was WAY off. It was then that I worked out that the laser was not the fix-all took I thought it was. I then got another cheshire, use it with the laser, and never looked back.

Alex.
Thanks for the info, I think Cheshire will be the way to go honestly.


By the sounds a 12" will ensure my girlfriend won't fit in the Rio with the dob. Since she has the purse strings I'll have to consider a 10" and think about moving up to a 14" in the years to come.
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Old 21-11-2018, 03:53 PM
Placesinthedark (Stephen)
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Quote:
Originally Posted by gaseous View Post
Hi Steve, and welcome.


Those Andrews deals are good, and the 30mm superview eyepiece is a pretty good performer for the price. Andrews have a generally good reputation - they've always been very prompt whenever I've dealt with them, but like anything there are always going to be a few people who may have had less than optimal dealings with them.


Dunno how big a Kia Rio is inside, but a 12" GSO dob is 1500mm long, which is really going to take some squeezing in, particularly when you need to put the base in separately somewhere, plus whatever else you may want to bring (table / chair, etc) if you decide to travel with it.



Regardless of the light pollution / sky darkness, the viewing difference between a 10" and a 12" is probably not going to be significant, but providing you can fit the larger scope in your car and lug it around, you might as well get the bigger scope.


A solid tube dob should hold collimation reasonably well, particularly if you're mainly using it at home and not bumping it in a car for extended periods of time. A laser collimator was fine for the first few years of my collapsible 8" dob, but a cheshire gives that extra bit of accuracy if that's important to you - I tend to use both now. Others may have differing opinions on collimation.


Good luck - either way you should land yourself a good deal.
Thanks Patrick!


I really like the way Andrews come across in their website material and it just seems like a no-brainer to get the GSO. However, I might pop into a local store and have a look at some scopes and see if they can do me a deal.
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  #8  
Old 21-11-2018, 04:06 PM
gaseous (Patrick)
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Ahhh, girlfriend vs dob - the age-old dilemma...


You say your celestron's goto capability is giving you grief, but a decent goto dob is pure viewing pleasure. It costs a lot more than the non-goto version, but for me at least the extra $$$ has been well worth it. Horses for courses though, as they say.
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Old 21-11-2018, 05:30 PM
Startrek (Martin)
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I had a Bintel 10 solid tube dob for 2 years and enjoyed every minute star hopping across the night sky.Then recently purchased a Skywatcher 12 GoTo Dob which was a quantum leap in terms of finding objects and resolving the dimmer objects. You can use it as a manual nudge push as well as goto
Id recommend a 12 goto if its a stay at home Scope
Mine is in the garage and only have to move it 12 metres using a Bunnings parcel trolley. Im nearly 60 and a light build 72kg. No issue for me to move it

My 2 cents .....
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Old 21-11-2018, 06:08 PM
astro744
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I recommend going to a store as you will see up close how big the different telescopes are and whether each will likely fit into your car.
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Old 21-11-2018, 06:41 PM
raymo
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In case you might want to attach a camera to your scope, if you go for the GSO, make sure it has sufficient back focus to allow this; many GSO Newts do not, whereas all Skywatchers do. I would go for the collapsible every time,
unless you have a tray back vehicle.
raymo
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Old 21-11-2018, 06:44 PM
Placesinthedark (Stephen)
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Originally Posted by astro744 View Post
I recommend going to a store as you will see up close how big the different telescopes are and whether each will likely fit into your car.
Thanks for that!


Yup, already planning a trip to Brisbane to see the Dobs in person and go from there.
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Old 21-11-2018, 10:10 PM
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Deeno
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Hi Steve
I have both an 10" and 12" GSO dobs.
The 10 is now almost 13 years old and the 12 would be ten.
I can't vouch for the quality of today's GSO mirrors but, a decade ago it was hard to find a bad 10", anything bigger was a little bit hit and miss.
I still love my 10. Its had the primary recoated, the tube 'flocked' and the base has been rebuilt in marine ply. I don't observe as much as I use to but, the 10 is the goto scope when we go camping or just setting up in the backyard and its easier for the kids to have a look through. Plus the tube will lie across the back seat of a Corolla....

I may have been unlucky with the 12 as it never offered the nice pinpoint stars the 10 did. Its light gathering abilities far surpassed the 10 though, and was great for galaxy hunting.

Cheers
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Old 21-11-2018, 10:13 PM
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AndyG (Andy)
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Quote:
Originally Posted by Placesinthedark View Post
It's a 90GT Celestron "Cosmos".

For me, fiddling with the phone and app after connecting is just not fun and you can't look through the red dot finder and move the scope at the same time as the buttons on the app are not intuitive and give no feedback! Those buttons often freeze, even on different phones.

I really wish I could just manually move the scope but it only allows me to move it up and down.
Hi Stephen,
I believe the Celestron Cosmos mount is similar enough to the rest of the "Astro-Fi" line. I too experienced all the frustration that you have described with my Mum's Astro-Fi SCT. I improved this in a few ways:

1. Check that the Mount firmware was up to date. My Old Girl's Astro-Fi was, but check anyway. https://www.nexstarsite.com/Firmware...FiFirmware.htm
2. An update to the Celestron phone app late 2017 made a huge difference to the dropouts.
3. Using the mount in "infrastructure mode", as opposed to Ad-hoc helped again. Only good if your home WIFI signal is good, maybe counterproductive for if not.
4. Update to the paid SkySafari 6 App. Now is the time (thanks Julian) Version 6 uses a neat phone tilting method to move the scope in all directions manually. As you know, you can't feel the buttons on screen, which is frustrating.
5. I ended up buying a cheap Celestron SLT mount and Nextar AZ hand control from eBay. Some LA based sellers were flogging off thousands of (I suspect) store return stock. The mount and hand control was $160 delivered. I ended up pier mounting the SLT, so no waste there. The hand control makes the Cosmos mount a standard light duty Nexstar AZ mount.

Personally, I think the 12" Dob (transport allowing), will be the best thing you can do. I hope the above helps you experience some satisfaction and value from what you've already spent however.
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Old 22-11-2018, 07:58 AM
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NorthernLight (Max)
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Get the 12”! They are similar in size and won’t have to wonder whether you hshould have gone bigger. Bigger is always better
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Old 22-11-2018, 09:14 AM
Placesinthedark (Stephen)
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Quote:
Originally Posted by AndyG View Post
Hi Stephen,
I believe the Celestron Cosmos mount is similar enough to the rest of the "Astro-Fi" line. I too experienced all the frustration that you have described with my Mum's Astro-Fi SCT. I improved this in a few ways:

1. Check that the Mount firmware was up to date. My Old Girl's Astro-Fi was, but check anyway. https://www.nexstarsite.com/Firmware...FiFirmware.htm
2. An update to the Celestron phone app late 2017 made a huge difference to the dropouts.
3. Using the mount in "infrastructure mode", as opposed to Ad-hoc helped again. Only good if your home WIFI signal is good, maybe counterproductive for if not.
4. Update to the paid SkySafari 6 App. Now is the time (thanks Julian) Version 6 uses a neat phone tilting method to move the scope in all directions manually. As you know, you can't feel the buttons on screen, which is frustrating.
5. I ended up buying a cheap Celestron SLT mount and Nextar AZ hand control from eBay. Some LA based sellers were flogging off thousands of (I suspect) store return stock. The mount and hand control was $160 delivered. I ended up pier mounting the SLT, so no waste there. The hand control makes the Cosmos mount a standard light duty Nexstar AZ mount.

Personally, I think the 12" Dob (transport allowing), will be the best thing you can do. I hope the above helps you experience some satisfaction and value from what you've already spent however.
Thanks so much for this info. I'll have to check the firmware on the telescope and I love that app feature for moving the scope.

Sadly, I'm trying to sell the 90GT to help fund the Dob so won't pull the trigger on the app.

I thought about upgrading it using a control system to bypass the phone as it's more fiddly than it's worth. Hopefully I can move onto the Dob and see what the future holds for GoTo systems and me.
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Old 23-11-2018, 01:22 AM
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AndyG (Andy)
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No worries Dude,

All this phone muckabout with the scope was not much fun for me either. It's a nice idea, but like many, I couldn't beat the tactile feedback of the Nexstar handset.

You can however, control the mount from a PC as well (despite indications that it's IOS/Android only:
https://www.cloudynights.com/topic/5...scom-it-works/

I have done this, and can confirm it works. I plan on making a remote controlled scope/camera combo, for late night EAA viewing indoors.

Regarding SkySafari, I bought and used, version 5, for 6 months before I even owned a telescope! It really is that good, as an educational, and planning tool. I can't recommend it highly enough.

Be excellent to yourself
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