Refractor Madness

[steppenwolf]

The star colours were superbly strong and contrasty against really black space. Just how you want a refractor to deliver it

Sounds smack on to me, John!

[John]

If i ever win the lotto, i would have an obsy with a big Istar frac on a custom mount, i keep dreaming, till then i will make do with my 180 mak. Having owned the "spirit" Antares f15, my days of super long under mounted fracs are over

Mounting this one properly is going to be a real challenge Jules, I realize that. I'm not in a hurry though and I'm prepared to try different solutions to get the right one.

[Marki]

That looks absolutely magnificent John! Really looking forward to reading more detailed reviews in due course!

I saw that the F/10 was back up for sale Paul - bad luck that it didn't fit

There was a 150mm F/8 R30 anastigmatic as part of the same sale and that would have made sense for you, having CA levels of somewhere around an F/10.5. That got snapped up really quickly though. I wonder who bought the P2V 150 F/15 ?

I paid a visit to Paul on Monday, and concluded that the f10 was just about manageable for me, and I'm not space restricted (no obsy, just my back garden). No way I could have managed anything bigger though. I'm very impressed by the scope and I agree with what you say about the build quality on the Istar though - very robust indeed!

[swamp thing]

Very nice John. That deserves a nice wooden tripod

Time to dust those tools off eh?

[philj]

Congratulations John you have a nice scope there. I was most tempted earlier this year to go for one of these then I did some measurements and found that although my observatory mount (CGE) would take it with ease the length of the scope just made the practicalities in my observatory rather difficult. It's enough of a crush to run my 4" F15 in there let alone a 6". Look forward to some accounts of your views through it John

[F15Rules]

Congratulations, John, on a beautiful new scope acquisition .

I know the challenges of owning a 6" F12, and sadly my experience was cut short by the diagnosis of a double hernia (BEFORE I took delivery, how cruel is that!), but there is just something so "right" about a big, long frac.

For visual I'd have thought an EQ6 class mount should do unless it's really windy?..Maybe with an ADM saddle puck upgrade?

I always enjoy reading our scope reviews, can you save this one for the coming dark season when you can include Jupiter, M42 etc et please?

Full respect to you for pulling the trigger on this very individual scope. Just out of interest, how is the CA versus the older F8 6" you used to own?

regards

Dave

[John]

Congratulations, John, on a beautiful new scope acquisition .

I know the challenges of owning a 6" F12, and sadly my experience was cut short by the diagnosis of a double hernia (BEFORE I took delivery, how cruel is that!), but there is just something so "right" about a big, long frac.

For visual I'd have thought an EQ6 class mount should do unless it's really windy?..Maybe with an ADM saddle puck upgrade?

I always enjoy reading our scope reviews, can you save this one for the coming dark season when you can include Jupiter, M42 etc et please?

Full respect to you for pulling the trigger on this very individual scope. Just out of interest, how is the CA versus the older F8 6" you used to own?

regards

Dave

Sorry that your injury has curtailed your enjoyment of your large, long refractor Dave. I recall seeing the pictures of it and thinking it was very desireable indeed.

These are definitely niche instruments and not necessarily a rational choice

A number of folks have suggested an EQ6 so I will be looking into that if an alt-azimuth approach is unfeasible.

From the 2 sessions I've had with the scope, albeit on a limited range of targets, I'd say the colour correction is significantly better than the chinese 6" F/8's I've owned. I'd estimate that it's somewhere between the 5" F/9.4 and 4" F/10 achromats that I've owned in the past. I've yet to observe any planets with it though so I'll see how we fare on those in due course.

As the season / seeing conditions allow I'll happily post regarding the performance on DSO's and the planetary showpieces

[vlebo]

This might do the job and its on for a good price compared to TH at the moment http://www.explorescientific.de/twilight-giroiiiazimuth-double-mount-p-23960.html

[John]

This might do the job and its on for a good price compared to TH at the moment http://www.exploresc...nt-p-23960.html

Thanks for that. I believe I will need something quite a lot more substantial though. I already have a Skytee II and a Giro III type mount and, while they will hold the weight, they can't fully cope with the moment arm forces that the long tube generates.

Mounting really long scopes does throw up some unique challenges !

[alan potts]

Now you have gone and done it, I have not yerned for a 6 inch refractor for a while now, now you got me at it again. Nice scope clear skies to you!

Alan

[Marki]

A number of folks have suggested an EQ6 so I will be looking into that if an alt-azimuth approach is unfeasible.

Hi John - Similar problem. For info, given you are considering an eq6, this is the f10 on the AZEQ6GT in EQ mode.

Seems reasonably stable, wouldn't fancy it on anything much smaller. Definitely needs a pillar extention though.

Now waiting for some clear sky!

[John]

Was that Paul's 150 F/10 Mark ?

Nice setup !

My scope weighs not far off the same as the F/10 (according to the Istar specs) but is obviously that much longer. How does the AZEQ6GT compare with an EQ6 for capacity ?.

What I'm not going to do is rush into a mounting solution. I've got some "irons in fires" which may or may not pay off but I'm not really in a hurry and want to get it right, even if it takes some time to achieve

[Marki]

Yes, its the one Paul had. I think the AZEQ is rated to 25kg for visual, as is the NEQ6. I had to fit the extention bar to the counterweight bar to achieve balance. Cloudy here now .

I think your approach is sensible John; I'd describe this set-up as adequate, not optimal.

[philj]

Ah I thought the AzEQ would be a good contender for handling one of these. A pillar would bring the scope up a bit higher but that brings in more bending moment, I know Ive tried it with my 4" F15, HEQ5 and Tripod. I eventually built a higher beefier tripod which helped

[Damo636]

Fabulous scope John, many congratulations!

[John]

Fabulous scope John, many congratulations!

Thanks Damo although I still feel quite daunted by it as it stands in the corner of the dining room looking, as my Son says, like a discarded tank barrel !

I'm currently working on options for a more stable mounting arrangement - and trying not to spend much more than the scope cost to achieve that !.

This is a long term project though as I said above.

[anthony]

That is extraordinary! Very pleased for you, though you should have gone for the F15!

[John]

That is extraordinary! Very pleased for you, though you should have gone for the F15!

You are wicked Ant

I could only just fit the boxed 6" F/12 into my Volvo estate with all the seats down and the front passenger seat pushed fully forward !.

I'd have to strap the 6" F/15 to the roof rack

[John]

.....would that be a Crawmach focuser on it?.....

Sorry for the delayed response Jules. Having had a look at some of the Crawmach focusers now I'm pretty sure that these Istar focusers are made by Crawmach. This one has a 2.5" diameter drawtube. It's quite a nice unit from what I've experienced so far.

[emadmoussa]

Are you comet hunting??

[John]

Are you comet hunting??

Er, nope. Planetary, Lunar and binary stars will be the main "diet" of the scope. 

[emadmoussa]

Er, nope. Planetary, Lunar and binary stars will be the main "diet" of the scope. 

As a matter of fact you can climb on this scope to touch the moon, can't you?! Curious, how does it perform in comparison with your other refractors?

[John]

...... Curious, how does it perform in comparison with your other refractors?

I'll let you know in due course when I have it properly mounted. It's an entirely different "animal" to my other refractors so comparisons are going to be hard to make I reckon. 

[emadmoussa]

I look forward to that!

[John]

Well I've just collected a heavier duty mount for the big refractor. It's a Bray Tablet Alt-Azimuth mount on a Meade Giant Field Tripod. It's difficult to convey the size of this mount in pictures but, as a guide, the body of the Bray mount is 6 inches in diameter, the top of the tripod "hub" is 8 inches across, the top sections of the tripod legs are 3 inches in diameter and the bottom sections 2" in diameter. With the tripod fully extended (as in the pics) the altitude axis is around 5 foot 8 inches from the ground.

These pics were taken at my first "fitting" of scope to mount to tripod so I've not got everything adjusted optimally as I'm still finding my way around this big beast. Despite this the scope seemed a lot steadier than my previous attempts with a SkyTee II and, while there was still a little flex at the eyepiece end it seemed to dampen down quickly. I'm intending to add some counter weights to the other side of the mount (though the scope is stable without) and I may move to a Losmandy dovetail bar and clamp to remove the possibility of any flex in the Vixen style bar (albeit a heavy duty CNC one) currently in use. 

This is NOT a grab and go outfit - the tripod alone weights 50 lbs and the mount and scope take the whole lot to approaching 100 lbs  . I'm quite excited about the possibility of getting a proper "first light" with the scope soon