10 & 12 " dobsonians, goto and tracking

[PeterStudz]

On 24/02/2024 at 11:27, AstroKeith said:

The step up to a 'premium' Dobsonian comes with a significant increase in price and weight. A good solid basic Dobsonian on an EQ platform can be a good solution for some.

This sums up what I think too.

One of the things that I like about Dobs is how easy it is take everything apart with simple tools, modify and DIY, then get something that perfectly fits your personal preferences. But I understand that this sort of DIY isn’t for everyone. 

When I eventually upgrade from my 8” Dob (probably to a 12”, maybe secondhand) I’ll almost certainly make my own base. Having made one myself I’m now certain that I can make something superior to the ones sold with “standard” mass produced Dobs. 

I might be missing something but I can’t see the point of GoTo Dobs, when all you need is a mobile phone app. Maybe that’s a bit unfair as I’ve never used one. I do enjoy star hopping, but if I want to find something tricky I’ve been using the PushTo feature in an iPhone app called PS Align Pro. You need to sync to at least one known target, but it’s never failed to find something. After syncing on the sun (white light filter) I’ve even found the likes of Venus, Saturn and Jupiter in daylight. Oh… Mars too. When I did a little solar “outreach” with some kids finding/looking at Venus as an afterthought in daylight made a big impression. And if you get fed up with PushTo just move the Dob around in the traditional way. There’s no clutches etc to engage/disengage.

I also have a DIY EQ platform. Made following the instructions (linked to in the post above) on this site. Really simply, cheap and easy to make. Most of mine was literally constructed on the kitchen table with the only power tool being an electric drill. I think that these are great bits of kit and so simple that they do follow the Dob “principle”. In my garden I have the platforms position marked on the ground so all I do is plonk it down, plonk the Dob on top, switch it on and away you go. Sure, after an hour or so you need to “rewind” it but that’s the only extra fiddling. I don’t always use it, however, for outreach (for obvious reasons) it’s been excellent and in this situation I wouldn’t not use it.

[bosun21]

Well I'll be the odd one out. I have owned and used both 8" and 12" manual dobs , 12" dob on a David Lukehurst (RIP) EQ platform and now a 10" go to dobsonian. I was really content and happy with the 12" on the platform until I discovered planetary imaging. The constantly chasing the planet to keep it in the small ROI was both tiring and wasn't the least bit enjoyable. The EQ platform helped a great deal but still required corrections. The go to dobsonian keeps it nicely in the ROI while I capture away. Regarding the scope itself, it's smooth enough and the go to is accurate enough for my easily pleased self. With the Flextube I check the collimation before each session and tweak if it is required which is no big deal. I considered the 12" was just a bit too much as with the addition of the motors they are heavy. This is my sworn testimony in defence of go to dobs, I hereby rest my case 😂.

[PeterStudz]

I can see how the tracking part of a GoTo Dob can be useful for planetary imagining, but I was referring more to the actual Going-To a target stuff. 

I’m sure that the base is good enough, but after having built my own I’d find anything else just too annoying 😀

[Stu]

On 24/02/2024 at 11:27, AstroKeith said:

The step up to a 'premium' Dobsonian comes with a significant increase in price and weight

If you consider an Orion Optics dob to be premium, then the aluminium tube weighs significantly less than the steel alternatives.

[Flame Nebula]

8 hours ago, PeterStudz said:

I can see how the tracking part of a GoTo Dob can be useful for planetary imagining, but I was referring more to the actual Going-To a target stuff. 

I’m sure that the base is good enough, but after having built my own I’d find anything else just too annoying 😀

Based on my experience decades ago, if I recall, it was more the issue of tracking a planet at high magnification that I found a barrier to enjoyment. I could easily find jupiter and saturn, but as soon as the magnification was at high enough levels to be useful, I personally found it a pain. Now, that was over 30 years ago, but I swore never to buy a scope again without at least tracking. I have a skywatcher gti AZ-alt mount and certainly, my enjoyment of just sitting at the scope 80ed or 127mm mak) is definitely enhanced. But, I understand many people are happy to nudge their dobs. I'm interested in the DIY equatorial platform. I'll be looking into that! 👍

[PeterStudz]

Yes, I now always use the EQ platform for planetary. For me having a planet, especially Mars, stay in the FOV without having to nudge does help me see more. 

But unless I decide to do planetary imaging then I’m really unlikely to get a GoTo Dob. Although with this hobby it’s hard to predict the direction you’ll take! 

Edited February 26 by PeterStudz

[Kon]

My thoughts as an 8" (manual) and very new 12" Goto user. The 8" is excellent and it takes patience to do the manual tracking. With the 8" manual, I was mostly doing planetary and ISS imaging with it without any platforms etc. It is a nice size and you can push it to its limits when the weather is good. I have managed excellent details on ISS with individual modules and panels, Venus with fine details on its clouds, Jupiter and this year the northern polar hood on Uranus by doing a 20min hand tracking. The only planet that never looked good was Saturn in colour as dueto its low elevation I needed an ADC that is not easy to set with a manual telescope. Some images below with the 8".

 

But I wanted to get more out of my planetary imaging (and also challenge myself) so I recently got a 12" Goto flextube that was a bargain (I only had it for 2-3 weeks). First thoughts, it was a revelation to have Jupiter hanging in the centre of the camera without drifting; it kept in in the sensor for a good 5min using a tight ROI. I did not do 2 star alignment as I wanted to make it work for daytime imaging of Venus where there are no stars for alignment. I am sure I can improve for longer captures. But it is big and heavy. I lift my 8" fully assembled with its base  in/out in 2min. The 12" I have to take the OTA and base out in two trips. I am not sure about your observing/imaging spot but I only need to bring the base from my sitting room to the garden through the french doors. The base is not that heavy but it is awkward and bulky.  (I knew all that before I bought it). I need to find the best way to move the whole lot as a unit either using a dolly or a sack truck. 

[Flame Nebula]

50 minutes ago, Kon said:

My thoughts as an 8" (manual) and very new 12" Goto user. The 8" is excellent and it takes patience to do the manual tracking. With the 8" manual, I was mostly doing planetary and ISS imaging with it without any platforms etc. It is a nice size and you can push it to its limits when the weather is good. I have managed excellent details on ISS with individual modules and panels, Venus with fine details on its clouds, Jupiter and this year the northern polar hood on Uranus by doing a 20min hand tracking. The only planet that never looked good was Saturn in colour as dueto its low elevation I needed an ADC that is not easy to set with a manual telescope. Some images below with the 8".

 

But I wanted to get more out of my planetary imaging (and also challenge myself) so I recently got a 12" Goto flextube that was a bargain (I only had it for 2-3 weeks). First thoughts, it was a revelation to have Jupiter hanging in the centre of the camera without drifting; it kept in in the sensor for a good 5min using a tight ROI. I did not do 2 star alignment as I wanted to make it work for daytime imaging of Venus where there are no stars for alignment. I am sure I can improve for longer captures. But it is big and heavy. I lift my 8" fully assembled with its base  in/out in 2min. The 12" I have to take the OTA and base out in two trips. I am not sure about your observing/imaging spot but I only need to bring the base from my sitting room to the garden through the french doors. The base is not that heavy but it is awkward and bulky.  (I knew all that before I bought it). I need to find the best way to move the whole lot as a unit either using a dolly or a sack truck. 

Kon, 

I am impressed! You did a manual track for 20 minutes on uranus. A lot of patience needed. Your ISS, jupiter and venus images are superb, especially jupiter. I didn't think it was possible to get an 8" to give that much detail on Jupiter. What make of 8 " was it? And F ratio? 

[Kon]

Just now, Flame Nebula said:

Kon, 

I am impressed! You did a manual track for 20 minutes on uranus. A lot of patience needed. Your ISS, jupiter and venus images are superb, especially jupiter. I didn't think it was possible to get an 8" to give that much detail on Jupiter. What make of 8 " was it? And F ratio? 

Skywatcher 200P, F6.

[Flame Nebula]

2 minutes ago, Kon said:

Skywatcher 200P, F6.

I'd heard the 200p F6 was good, but you've really proved it! 

[PeterStudz]

I have a 200p Dob and still don’t know how  he’s managed to get such good images. Manually or otherwise!

As for carrying. I have a weak knee and carry my 200p in two parts anyway. It’s not the weight but the awkwardness, especially having to go over a step into my garden. Although even just carrying the OTA as-is was awkward. Which is why I drilled some holes and installed a sturdy carry handle. Personally I don’t find it any bother doing it that way. 

 

[Kon]

If you are considering the 10" goto, have a look at the excellent images from @Space Cowboy in the planetary imaging section.

 

[Kon]

23 minutes ago, PeterStudz said:

I have a 200p Dob and still don’t know how  he’s managed to get such good images. Manually or otherwise!

As for carrying. I have a weak knee and carry my 200p in two parts anyway. It’s not the weight but the awkwardness, especially having to go over a step into my garden. Although even just carrying the OTA as-is was awkward. Which is why I drilled some holes and installed a sturdy carry handle. Personally I don’t find it any bother doing it that way. 

 

Your last Jupiter with mobile was excellent and you are only limited by not having a planetary camera 😜. I know you don't want a computer but worth reconsidering at some point.

[Flame Nebula]

31 minutes ago, Kon said:

Your last Jupiter with mobile was excellent and you are only limited by not having a planetary camera 😜. I know you don't want a computer but worth reconsidering at some point.

Hi Kon, which planetary camera do you use? 

[Kon]

19 minutes ago, Flame Nebula said:

Hi Kon, which planetary camera do you use? 

For colour I use the asi 462mc and for mono (mostly for Venus) the 462mm. Both coupled to a 2.5x powermate so I have the correct sampling of 5x pixel size. The 462mc is discontinued as of last year but still an excellent camera. There are plenty of new ones with larger sensor etc etc. The 462mm is still one of the best for UV sensitivity.  I do not plan to change them anytime soon. The 585 seems to be popular amongst planetary imagers. You do not need an asi but qhy or uranus make similar ones.

[Flame Nebula]

1 hour ago, Kon said:

For colour I use the asi 462mc and for mono (mostly for Venus) the 462mm. Both coupled to a 2.5x powermate so I have the correct sampling of 5x pixel size. The 462mc is discontinued as of last year but still an excellent camera. There are plenty of new ones with larger sensor etc etc. The 462mm is still one of the best for UV sensitivity.  I do not plan to change them anytime soon. The 585 seems to be popular amongst planetary imagers. You do not need an asi but qhy or uranus make similar ones.

How would you rate zwo products? 

[Kon]

6 minutes ago, Flame Nebula said:

How would you rate zwo products? 

I had no issues at all. Stuart is using the equivalent of qhy 462. They all use the same sensor and it is the outer body that is different (irrelevant to the imaging capability).

[Flame Nebula]

58 minutes ago, Kon said:

I had no issues at all. Stuart is using the equivalent of qhy 462. They all use the same sensor and it is the outer body that is different (irrelevant to the imaging capability).

OK, I didn't know that. Do you know what the zwo equivalent of the asi 462 mc would be? 

[Kon]

5 minutes ago, Flame Nebula said:

OK, I didn't know that. Do you know what the zwo equivalent of the asi 462 mc would be? 

That's the zwo one 😉

[Flame Nebula]

30 minutes ago, Kon said:

That's the zwo one 😉

Oops! 🤪

[PeterStudz]

5 hours ago, Kon said:

Your last Jupiter with mobile was excellent and you are only limited by not having a planetary camera 😜. I know you don't want a computer but worth reconsidering at some point.

Thanks! I do enjoy trying to push the maximum out of what you can get from just using a mobile. And that includes the processing. Although it’s usually an addition to visual astronomy - I could not look through an eyepiece! It’s not just the camera, but the limited applications on mobile for doing this sort of thing. 

As you know I don’t want a computer. However, my daughter now has a laptop for “school work”. Well, it seems to be more gaming! I might just download some stacking and processing software and take a look. 

[Space Cowboy]

Just a point to make if this hasn't been mentioned. The 10" skywatcher flextube Dob has the same size mount as the 8". The 12" is a much larger beast altogether.  

I've had my 10" flextube for 13 years now and wouldn't swap it for anything. I keep it upstairs and it's light enough to carry up and down without trips to A & E 🙂 

[Flame Nebula]

14 minutes ago, Space Cowboy said:

Just a point to make if this hasn't been mentioned. The 10" skywatcher flextube Dob has the same size mount as the 8". The 12" is a much larger beast altogether.  

I've had my 10" flextube for 13 years now and wouldn't swap it for anything. I keep it upstairs and it's light enough to carry up and down without trips to A & E 🙂 

Hi Space Cowboy, is it a goto version? ( hopefully not an insulting question 😆

[Kon]

side by side comparison of my 8" and 12" Goto

[bosun21]

1 hour ago, Space Cowboy said:

Just a point to make if this hasn't been mentioned. The 10" skywatcher flextube Dob has the same size mount as the 8". The 12" is a much larger beast altogether.  

I've had my 10" flextube for 13 years now and wouldn't swap it for anything. I keep it upstairs and it's light enough to carry up and down without trips to A & E 🙂 

In two parts i presume. It's the awkwardness of them both together that poses problems. I still don't envy you manoeuvring the base up and down stairs.