Orion Optics 8" f8 Dob

[Stu]

Well I'm pleased to say that this all fits together nicely. I've wanted one of these for a long time, an Orion Optics 8" f8 1/10 wave and had picked up the tube cheaply a little while back but needed a dob base for it. Knowing that, despite all good intentions I was unlikely to get round to making one, when this one popped up for sale with an old f6 on it, it made sense to grab it, especially as OO no longer make the taller version needed to take the f8.

It is currently missing two of the PTFE bearings which is making the movement a little stiff but I have replacements ordered so this will be fixed soon. I just need to fit a Telrad to go alongside the Altair 10x60 RACI and that should be it sorted.

I plan to use it largely for lunar, planetary and doubles, and have a Watch House EQ platform it will stand on very nicely to give me tracking at high power. It is rather tall and skinny so this will help me keep hands off and enjoy the views.

First picture is of it with the f6 unit fitted, looking a little out of proportion, then with the f8 fitting very nicely.

[dweller25]

I had an excellent OO 8” F/6 that was great on the planets, yours will be better 👍

[John]

Excellent looking scope Stu - sure to be a wonderful performer as well

I used to have a Watchouse EQ platform as well for my 12 inch - they work very well. Pity that the company does not make them now.

 

[Stu]

Thanks John. Watch House EQ Platform seems to link to David Lukehurst so it seems like he may have picked up the designs and manufacture.

[Alan White]

I saw that f6 on ENS Stu, what you have done is super.
Know someone else on here who has similar and sings its praises.

[Geoff Barnes]

1 hour ago, Stu said:

just need to fit a Telrad to go alongside the Altair 10x60 RACI and that should be it sorted.

Looks the bees knees Stu!

I was reading up on the Altair finder, looks like the illuminator can cause problems with being too heavy.....

 

[Stu]

@Geoff Barnes yes, I ran into exactly that problem but did find a work around. There is a locking screw which let's the illuminator section swing freely, so I focused with this hanging downwards and it then no longer caused problems. It's a nice finder apart from that quirk.

I may need to add a little weight to the bottom of the dob to balance things up once I add the Telrad.

[Stu]

1 hour ago, Alan White said:

I saw that f6 on ENS Stu, what you have done is super.
Know someone else on here who has similar and sings its praises.

Thanks Alan. It was a piece of luck finding a dob base of the right proportions for the f8. I've no idea how it came to be with the old f6!

[Stu]

For anyone who hadn't seen it, here is a review of the OO f8

http://scopeviews.co.uk/OrionOptics200Dob.htm

[chiltonstar]

Fantastic scope Stu, and a good one for doubles - what does it weigh?

Chris

[Piero]

Congratulations Stu! Lovely scope.

It will serve you well

[NGC 1502]

1 hour ago, Alan White said:

I saw that f6 on ENS Stu, what you have done is super.
Know someone else on here who has similar and sings its praises.

 

Hi Alan, of course that’s me........

There’s one thing that bothers me however.  If you take a look at the pics shown earlier, you may agree with me that the mount is too narrow for its height.  When I first tried my OO 8” F6 it was a breezy night and I was bothered the whole scope could be blown over.  When I went indoors for a break and hot drink I lashed the mount to my shed door. I didn’t want to hear an expensive sounding thud whilst I was indoors.....

I’ve since extended the aluminium ground plate on the three feet to make the base much wider.  That makes it feel more stable when gently trying to pull it over.  I’m planning to lower the base when I have time.  The mirror end of the F6 tube clears the base when pointed at the zenith by several inches, this will allow it to work ok with a shortened base.

Lower and wider = more stable.

I can recall a more extreme example when OO made a 6” F11.   That really was tall and skinny..........and scary on a breezy night I’d guess.   The owner - moonshane ? -  added weights to the base, another way to help stability.

Ed.

 

[Rob]

11 hours ago, dweller25 said:

I had an excellent OO 8” F/6 that was great on the planets, yours will be better 👍

Ditto!. My OO SPX 8 f6 was fantastic too. Stu I'll bet yours will be jaw dropping!.. Nice one

[CraigT82]

That 8" F8 will blow your socks of on most targets to be honest!  

You may benefit from the cheap SW motor focuser.  With my 8.75" F7.5 the long tube makes tube vibrations pretty bad when focusing and the cheap motor makes things much easier and is easily adapted to most tubes/focusers.

[John]

It's a shame that there are not more of these longer newtonians available. An 8 inch F/8 with a modest central obstruction and a decent quality mirror is likely to perform as well as a 6 inch apo refractor I reckon, and better on DSOs but for a fraction of the price. 

 

 

[Stu]

12 hours ago, NGC 1502 said:

I’ve since extended the aluminium ground plate on the three feet to make the base much wider.  That makes it feel more stable when gently trying to pull it over.

I think I may do likewise Ed, or perhaps work out a mechanism to fix it to the EQ Platform.

[Mark at Beaufort]

I made an error selling my OO 6" f/8 1/10th wave Newtonian. It was a wonderful scope on the Moon and Planets.

[Stu]

1 hour ago, Mark at Beaufort said:

I made an error selling my OO 6" f/8 1/10th wave Newtonian. It was a wonderful scope on the Moon and Planets.

Ooooh, that looks very nice Mark. Very manageable and I bet pretty lightweight? I'm sure the views were excellent. I'm very keen I have my first proper look through mine!

[Stu]

Here it is tonight on the EQ platform which is working very well. A little bit of adjustment on the speed control and the moon is staying still at x128. Will up the power as it gets a little darker. Lovely detail showing up already.

Totally unprocessed snap with a phone.

[Mark at Beaufort]

Looking good Stu. I enjoy viewing Clavius and you have Blancanus and Newton in the shadows - very good.

[Stu]

4 minutes ago, Mark at Beaufort said:

Looking good Stu. I enjoy viewing Clavius and you have Blancanus and Newton in the shadows - very good.

Yes, Clavius is looking good too, plus Copernicus too.

[Rob]

Very nice Stu. Makes me miss my OO SPX 8 f6 even more.. nice to see they have not changed the lens cell!!.. Oh and swapped the focuser out on mine, had to re-size the hole for that. regret parting with - oh yes!

Edited July 12, 2019 by Rob

[John]

1 hour ago, Rob said:

Very nice Stu. Makes me miss my OO SPX 8 f6 even more.. nice to see they have not changed the lens cell!!.. Oh and swapped the focuser out on mine, had to re-size the hole for that. regret parting with - oh yes!

Just like a slightly smaller version of my 12 inch F/5.3 SPX Rob. Those curved secondary supports are quite disctinctive !

 

[Stu]

Very nice @Rob

I may think about upgrading the focuser on mine at some point. It has a single speed unit at the moment which is actually very good, same as John's had originally I think, but I do like my dual speeds! Perhaps a Baader SteelTrack might suit although I need to sort the balance out first.

The lens cell is well put together, plenty of room for air circulation which can only help.

I'm wondering whether binoviewing would work, will give it a try but I guess I should reach focus without the extension and I normally use a Barlow anyway which will push the focus point out.

Would love to try the circular secondary support too! Can't get them now though.

[Stub Mandrel]

very nice pitures Stu, I'm a sucker for pictures with blue sky in.