BGazing

1 minute ago, Steve Clay said:

Indeed Rowan do an adapter for a pier'/ az5. Or simply get an aluminium washer laser cut to adapt. If you want details pm me.

Wow, I see that...this looks really really good as I feel that my Uni 18 would be good enough...what a mount. Ideally with motors and tracking would be absolutely superb.

Rowan page suggests to use CW for scopes over 5kg...is that really true, the mount looks like CWs are not needed unless you are about to topple the tripod.

Disclaimer: I helped Oklop guys re fit and finish of SCT8 bags (they used mine to check it as they are based in Serbia) and got a free refractor bag for my Tak in return (actually the one they at the time advertised as a tripod bag).

Irrespective of that, my honest opiniong is that their products are of very good quality and practical, too. Tak has been transported thousands of kms without problems and I also ordered a custom bag for AYOII mount. Cases would have been overkill in both situations.

Thanx...very interesting, I was told by Beat that I can fiddle and adjust the second saddle myself but did not actually bother...

One more thing, is there any way to fit this mount onto EQ5 plate? Other than a EQ6 tripod, what are the other options, TPod plus some adapter?

On 03/04/2021 at 12:29, HollyHound said:

 

Only (expected) issue was the scopes weren’t aligned with each other, but I’ve ordered the adjustable saddle plate now to solve that minor problem. I do have the counterweight and bar too, so can use a single scope too 👍

 

That is a problem I have on my AYO...what's the adjustable saddle plate? Excuse my ignorance...

On 11/10/2020 at 17:22, banjaxed said:

The one thing I have learned from this hobby is patience is essential.

This. 

Wonderful prom, here's my smartphone shot, hand held, yesterday. Daystar Quark...the prom has dissipated today, not nearly as impressive.

Pretty interesting news here until the end of the thread.

17 minutes ago, merlin100 said:

I thought I noticed some CA at the edges of the disc, but I'm wondering if my eye was playing tricks with me, as I shouldn't be getting that with a Newtonian reflector!  I've seen that on the Venusian disc too!  What could be causing that?

If they are top and bottom (blue top red bottom, inverted in newton), it's atmospheric dispersion. If the target is low enough and your aperture big enough, it becomes visible.

Other orientations are chromatic smear due to poor seeing. You may get both of them together.

I've checked your Jup/Sat observing thread, dispersion is easily visible in the pictures you have taken...

5 hours ago, markse68 said:

Interesting. Seeing wasnt great here either last night- I guess all the heat from a very warm day didn’t help but I also noticed that very little correction was needed on the planets and it didn’t make any noticeable difference in the moon. I wonder if AD effects are inversely proportional to seeing quality? I guess if the ad is swimming around stirred by poor seeing then it’s not a fixed quantity to be fixed with a corrector? 🤔

Yes, you will occasionally see chromatic 'smear', when the chroma is smeared in the east-west direction, or when you correct with ADC and the top blue and bottom orange disappear and then you get chroma occasionally 'dancing around' the edges but as soon as the seeing settles it disappears.

But you can play around with it...return levers to 0 and suddenly there is unmistakable top blue bottom red. Tiny correction and it is gone and everything looks a bit better.

We talk about strehl this spherochromatism that chinese vs premium vs doublet vs triplet but what AD does on planets is that it basically smears those subtle Jove colors all over the place.

Played the whole night with ADC and binos on C8.

The amount of lever correction needed with 1.25GPC is tiny, but results in a detectable improvement. Moons are elongated dispersion dots and when corrected become dancing fuzzballs (seeing, meh) without dispersion. One can also see AD on the Moon this low, while cruising top part it has a sliver of blue fringe (very thin) and the corresponding orange sliver at the southern pole.

Seeing was not that spectacular, tbh, but what can one expect at 23 degrees in meridian.

2 hours ago, johninderby said:

Only once and thought it helped a bit but wanted to ba able to rotate it 180 degrees to see if it was better.

You can simply test it against the background...you will find the link in one of my earlier posts to a CN thread where the test and explanation to the test.

On 28/07/2020 at 23:41, Dantooine said:

What would be the highest magnification I could get on a good night with my 102ed f7 refractor? I’m asking as I’m considering a Barlow for those rare good conditions. Mainly for moon and planets. I normally max at 150x but have been up to 200x. 

150x is perfect for that aperture, 200x if seeing is really good, or even higher if the floaters do not bother you.

Fantastic prominence this morning...phone shot does not do it justice.

100 deg C and you have to heat them over 30 minutes, so it makes sense to get at least a few of them that need dehumidization.

9 hours ago, John said:

On a practical note, how much inwards focuser travel do the ZWO and Altair ADC's eat up ?

I've seen a figure of 57mm for the ZWO but that sounds a lot to me

Thanks

I did not measure, but then again when I use it in mono I use it with PM2.5 and I do not have to remove extension on Tak.

Just use some barlow or (ideally) PM2.5 with t2 connection to ADC...if you happen to have one.

Below f/10 you will get astigmatism. I would bump up even those f/9 scopes (DL?) although it just might be enough.

Essential? Well, having a scope and an EP is essential.

But really, in a small frac you might give it a pass...and in a bigger scope you will clearly see AD. It's one of those things when you remove it and you go 'a-ha!'. Sort of like when you go to your ophthalmologist and you think they got your prescription right and then they do the little astigmatism correction and it just gets better...

The cutoff altitude may vary by aperture. Jove at current altitude takes a particular AD hit, just the nature of the target.

Tried some more things last night - seeing was again meh, clouds came and went and distant flickering of the thunderstorms did not look like I will be observing much.

C8 was not used, again only Tak with binos, with and without ADC.

At around 100x in binos you can see AD. At around 150 it is not so pronounced (dimming, i guess, but it is still there). At 100x the moons have a bit of AD elongation. ADC clears that up and they become points. You certainly can use Tak without ADC and it is not overwhelming, but it is there and it blurs the picture. Also, the seeing  somehow appears better with ADC (this was also observed by the others). Jury is out there if seeing seems better subjectively with or without binos...there's certainly less eyestrain when viewing through the running water with both eyes.

More measuring stuff...when using binos without ADC I finally put the GPC in front of the diagonal to simulate 130x...and, believe it or not, it provides TOO MUCH back focus, I racked focuser out all the way with my extension and could not come to focus. It quite possibly would focus with the normal Tak extension (I use 47mm clicklock instead), or using normal diagonal with ep holder and 1.25 nose on Binoviewer, but at the expense of more magnification as per calculations above (approx 3.8x altogether). But if you are in dire need of backfocus, there's your solution, just put it in front of the diagonal and you are good to go.

4 hours ago, fate187 said:

You could be right there BG. The Gutekunst does not have this issue. Strehl including astigmatism and tilt 0.998.... 

BTW: Some were arguing the two levers of the ZWO unit. There is an ADC from Pierro Astro (Version 3) which has only one knob for tuning the ADC, so somewhat less "complicated", of course its more than the ZWO unit: https://www.teleskop-express.de/shop/product_info.php/language/en/info/p5992_Pierro-Astro-ADC-MK3-Atmospheric-Dispersion-Corrector-with-T2-connection.html . 

I would like to try out the ZWO and Pierro Astro device again, after I gained some knowledge in this field in the recent months.

best regards

Yes, MK3 PA looks very elegant except that it has been unavailable for quite some time.

I like the one knob adjustment. MkIV with a bubble level would be perfect.

1 hour ago, fate187 said:

No I had no barlows or PM back then. 

I just measured the height of the quick changer: 10mm. Add to that 5mm from the dovetail/bayonette part with T2 thread you get 15mm. However, in my bino the dovetail is similar to the one in Baaders Mark V/Maxbright II, which may reduce the optical path length. The Maxbright also comes with an T2 adapter to directly thread it on a male T2 adapter (like on their T2 diagonals).

 

Well your astigmatism was a factor of the f/l. You have to push it past f/10 to do away with astigmatism...

But yes, Gutekunst is a proper ADC for that scope.

1 hour ago, fate187 said:

I use the Gutekunst adc. See CN for some reports: https://www.cloudynights.com/topic/695135-gutekunst-adc/?view=findpost&p=10335854&hl=%2Bgutekunst

The astigmatism was seen with all my scopes I had at that time: SW120 equinox, LZOS 123 f/6 and I think the CFF185 f/6.8. Maybe the LZOS 130 f/9, I don't remember if I had this scope back then :D. Those are all but one not ideally slow scopes (frac wise), but the adc added little quality to the view. As others don't have this problem here, maybe I had a defective device?

You are probably right with the 15mm optical path (thats what Baader specified?!). Point is the easy way to connect the bino to another part via the T2 threaded bayonette system. In case of my set up I would need a 1.25" adapter on the diagonal, followed by the bino with 1.25" nosepiece. I regard this as less stable and probably also longer, especially the 1.25" adapter on the diagonal. Could be wrong though :).

Have you used barlow/powermate with your ZWO/ADC? I never used it with fracs without PM2.5?

I do not mind optical path and I love Zeiss/T2 system, it is just that Baader does not list if you are getting any additional optical path with it vis-a-vis the T2 coupling nut...  I am just curious...

36 minutes ago, fate187 said:

The bayonette system adds flexibility. I use it to quickly change between bino and mono, or other visual equipment parts, if necessary.

 

I know. I was wondering whether the 'default' bayonette system of Baader binos adds optical path in comparison with the 'default' T2 coupling nut solution.

The bayonette system I linked is 15mm optical path, that is for sure.

6 minutes ago, Moonshane said:

Totally off topic but I just noticed your avatar and loved Blakes 7 when I was a kid. In fact I was at an event in Manchester for the opening of a sci-fi themed night club called Fab Cafe  http://www.fabcafe.co.uk/  and Gareth Thomas was there as the VIP.

 

That was one of the first sci-fi shows shown in Yugoslavia, I think it was running on Monday nights. It was both great and awful. Used to make command screens out of plywood and take it to bushes to play. Bushes were starships, you know.

Yugoslav TV stations imported English shows in bulk, American imports were mostly reserved for the movies. Ask any Belgrade resident what his or her fav TV shows are and chances are half will say Monthy Python and the other half Only Fools and Horses.

Having trawled some threads for refractor measurement it appears that 2.6 GPC is around 2.46x when mounted on the diagonal and bino threaded directly on it and that the values are growing in a linear fashion with additional optical path, see here https://www.cloudynights.com/topic/397010-glasspath-magnification-factors-including-the-26/

For every 100mm of additional optical length between bino and GPC there appears to be 1.6 increase in magnification, approximately.

Mounting in front of BBHS T2 would add 48mm optical path, so 0.77 in plus, for a total of  3.23x.

Mounting in front of T2 zeiss prism would add 38mm optical path so 0.6 mag more, total 3.06x.

ZWO ADC body alone is 29mm, so 0.46 mag. If GPC is screwed into the diagonal, the magnification is 2.92x. Mounting bino on that ADC EP holder is probably around 17-18 additional millimetres, so around 0.28 more mag, altogether 3.2x. That's how it felt last night.   So mounting it in front of BBHS and in the default position with the ZWO brings to similar magnitude. If 2mm optical path male to male T2 ring is used instead of the EP holder this reduces magnitude to around 2.95x.

I do not know whether mounting via Zeiss bayonette adds anything in comparison with the T2 nut ring. This combination  https://www.teleskop-express.de/shop/product_info.php/language/en/info/p7744_Baader-2456322---Schwerlast-T2-Wechselsystem.html is listed as 15mm optical path, but it is difficult to know how much it adds to the default option and is in any event a different construction of bayonette than the one used in MBII. But if one wants to use it to connect ADC to diagonal and allow for rotation it would apparently add 0.24x.

Hope my math is correct, apologies if it is not.

12 hours ago, bomberbaz said:

Been flipping between this and a thread regarding binoviewing and if my understanding is correct that in a slow scope (F10 or F12)  if I wanted to use binoviewers I could arrange my kit in the following order.

Diagonal - ANC - Barlow - Bino/Eyepieces.

The reason I ask is that the increase in the focal train when using binoviewers means a 2x barlow is actually around a  4x increase. So if you then stick the ADC after the barlow you are probably up over x5.

Can anybody add weight to this as I am thinking of having a go with the frac and binoviewers. 

Yes, you can do it. I use ADC in mono on my SCT without any barlowing. I will use binos after ADC in SCT, but will insert 1.25 gpc in bino body for reducing focal length and possible aperture loss.

Once you hit f/10 with our run of the mill ADCs I think you're OK, you are trading one aberration for another at equal exchange rate. There's a good primer on that somewhere...

I tried ADC with binos last night in the Tak. Two photos attached, the first one where the diagonal remained as is, GPC inserted into 1.25 nose of the ADC (it won't go into ZWO ADC nose, had to swap it with the Baader one), then ADC and Bino mounted on top of ADC EP holder via quick coulpling (top is T2 threaded). This adds around 50mm of distance between GPC and bino and ups the magnification factor SIGNIFICANTLY. Not sure how much it was but surely way over 3x. I am not sure what is the exact figure.

Second picture is threading GPC on the T2 diagonal, then threading directly ADC on the diagonal, the rest like the first scenario (bino threaded on that EP holder), This merely reduces lever but the magnification remains the same. I did not have to remove one of the extensions on my scope. With GPC ZWO threads almost perpendicular and adjusting it to the horizon requires slight slanting. I had ample space tonight but that might be uncomfy during balcony operations...

I am waiting for a 2mm male-to-male T2 ring to arrive from FLO which will dispense with that long EP holder on ADC and reduce GPC magnification factor by a long margin.

Finally, another possibility (which I might try) is Powermate 2.5, T-Ring adapter, ADC then 1.25 GPC threaded into bino...Powermate would give about 2x at this distance from the focal plane and together with 1.25 GPC would come close to 2.5x magnification overall with good color correction and also (because of the PM) possibility to rotate ZWO in the clicklock 1.25 holder of the diagonal.

As for the visuals...it is better with the ADC. Requires only a slight correction (you can see that the levers are fairly close) but that is all it takes. I understand that the correction is dependant of the focal length and elevation, Jupiter was at 25 degrees for me here and the F/L was bumped to over 2000mm due to placement of the GPC. That is the same correction I normally use in C8 (similar focal length).

Next stop ADC with binos. I will try it the next couple of days. Now the trick is one has to get GPC before the ADC body, and the ADC body alone is 30mm, which will push 2.6 GPC in Tak to over 3x easily...and possibly more. This might not be that bad in itself.

But to use ZWO ADC body on T2 diagonal also means that I will have to use binos at an angle (because ADC when fully screwed is slightly slanted) or use ADC with 1.25 nose and inserted into diagonal with eyepiece clamp. That is 32 additional mms of backfocus, I think I have them but will check.

C8 same thing, except that I do not use GPC before ADC but in the binos (1.25) to bring bino forward and avoid aperture reduction. Here I will probably have to opt for slanted binos because 1.25 nose on ADC would add 100mm of focal length...and there's plenty of focal length to start with and the f/ ratio is already pretty high.

The only way to rotate ADC on T2 diagonal without eyepiece clamp would be this https://www.teleskop-express.de/shop/product_info.php/info/p7744_Baader-2456322---Heavy-Duty-T2-Quick-Changing-System.html but it saves just 15mm of optical path. Not sure if worth the hassle.