BGazing

10 hours ago, Moonshane said:

Does that mean that you have to readjust throughout the night with an eq mount but not an altaz?

Yes on the bubble. Also on altaz if your diagonal is slightly rotated to the left or right in your focuser.

Uh-huh lads, some long contraptions.

@Paz you may get 2.5 powermate to T2 adapter to significantly shorten that tower. Here https://www.firstlightoptics.com/barlow-eyepieces/tele-vue-125-powermate-t-ring-adapter.html

@johninderby there has to be a shorter way to that 😁 Actually you can screw on the bottom bit of the ADC directly to the T2 diagonal, it will be only a bit off horizontally so a bit of rotation of the whole diagonal will bring it level. (tried with ZWO version)

Enjoy! Washout here...

I know that water and soap are the norm for the mirrors. I gave my dob's secondary some cleaning but the fingerprints on the side are very stubborn to come off. Now they are nigh invisible but in the dark and under certain angle...

Everyone says do not use Baader fluid on mirrors, but Baader itself (and they are very conservative) say that you can in their advice. What gives?

Yes because the more parallel the rays are the less you have to compensate with ADC and bring in aberrations. It's a trade-off.

Has anyone tried using it visually on the Moon? Any results? I guess one would have to adjust it on a bright stare of comparable altitude...

4 hours ago, astro_al said:

Edit: I also saw on the FLO website that the recommendation for the ZWO unit is to get the ADC as close to the eyepiece as possible, which I wouldn't be able to do with a binoviewer. Eye placement when using binoviewers is also key for me. If I am not dead on it is easy to introduce unwanted colour so I may be chasing that with an ADC also.

Well that is something I intend to try. I think that the main issue with the correct sequence is to get a barlow in front and extend focal ratio, not sure whether having binos in the back would somehow spoil the functioning of the ADC. I initially thought it would, but then found quite a few reports of people using binos with ADC with success.

Have to wait for the skies to clear to try the effect.

19 hours ago, Highburymark said:

Hi Mike - I’m using Tak FC-100 DC.
Must say I find working out BV magnifications a little brainfrying at the best of times. Haven’t tried the two barlow combination yet on the Moon, so maybe my calculations are some way off, but I thought the standard 2x barlow screwed onto the nose of the Chinese BVs actually delivered that same increase in power. At least that’s what I recall with my old WO. Could be wrong. Maybe the Revelation is different?

My current (Baader) set up is more complicated, as I have 1.7x and 2.6x GPCs in the BV nose (which definitely don’t provide more than their stated magnification factors, in fact the 1.7x gives just 1.5x. Why Baader doesn’t call it a 1.5x GPC remains a mystery). But then placing a further barlow (Barcon) in front of the diagonal is supposed to provide another 2x leap in power - at least that’s what I read on CN. If correct this would mean Delites 18.2 would give about 200x in the F/7.4 Tak. Of course if I wanted more then I just add spacers to move the second barlow further from the eyepiece.

Would love to try a pair of pseudo Masuyamas one day. Interesting that you can use 7.5mm EPs comfortably in the Revelation. It is clearly a well collimated binoviewer - and a well collimated observer to be able to merge images at such high powers......😁

 

Not sure how you screw 2.6x into bino nose, unless I am missing something it either gets screwed into the 1.25 or 2in nose which is then attached to bino, or into the T2 diagonal in front of the bino. Alternatively, if you have T2 diagonal you can screw 2.6x in front and it gives around 3.13x if I remember. This would also allow stacking with other two GPCs in the bino nose. Baader says you should not do it because it introduces abberations, others report that they stack GPCs with no problem whatsoever.

I tried binoviewing with FC100DF on the Moon at around 150x (12.5orthos and 2.6GPC). It 'feels' like 200x mono in terms of brightness and detectable detail. I might try putting 2.6 in front which would give around 185x next time, not sure if it will work.

9 hours ago, johninderby said:

The Altair ADC uses CDGM's H-K9L glass instead of BK7 but apoarently it is the same formulation just a different manufacturer.

Should work well in the CC8” f/12. 🤔

It will work very well, indeed. Just make sure to check whether it's a righty or a leftie.

3 hours ago, markse68 said:

i think 40mm

Edit- sure i read that somewhere and thought it was too high but looking at specs of the ZWO unit i think it must be closer to 60mm. They say the body height is 30mm but then you’re shifting the ep out further with the ep adapter. Strange neither of them spec for this

I've read somewhere that it is approx 50mm. Useful info if you are using a PM or a barlow in front or a binoviewer after the ADC in order to calculate the resulting mags.

4 hours ago, bomberbaz said:

The Pierro Astro one isn't exacvtly cheap either

Yup but that MK3 looks fine with single button adjustment, makes me wonder whether it is easier to use than ZWO.

3 hours ago, johninderby said:

Look forward to finding out what apertures and focal lenghs get the greatest benefit from the ADC. 🤔

More aperture - more dispersion but I really do not thing it is user friendly in a dob. ZWO says get it over f/10, so PM 2.5 in Tak before ADC and without barlow in C8. The shorter the f/l the more astigmatism is introduced.

3 hours ago, Paz said:

There are a lot of very helpful contributions to this thread that have got me wondering if I've been using my ADC optimally, next time I'm out I'm going to try some different approaches and pay closer attention to what I'm doing.

If I've been using it incorrectly that will be embarrassing but on the plus side it would also mean I've got some more improvements in the views to look forward to!

Check out whether it is a left-handed or right-handed one. Here's a useful info on how to check your orientation (mine is right-sided but in a refractor and SCT with a diagonal the white knob goes to the left).

I find my ZWO essential on low Jupiter and very beneficial on low Saturn.  Without ADC, low Jupiter in C8 is a mess, and blurry in Tak. Borg can take them on without ADC. For UK altitudes anything but the smallest refractor is just too much dispersion for my taste. I am 7 degrees to the south of you and I find it obtrusive in the past two years.

A brief overview of my recent comparison of ADC vs bino here https://www.cloudynights.com/topic/717134-c8-vs-4-inch-frac-binomono-on-planets/

Next time I will try bino with ADC. Will certainly be more difficult to pull off than with Gutekunst, but worth a try. 

The bigger the aperture the more I need it. ADC beats aperture - I find it better to look through C8 and ADC on Jup then through 12 inch dob without ADC.

The amount of correction is dependent of the altitude and focal lenth of the scope. So Tak with PM2.5 in front of the ADC needs as much correction as C8 with ADC only.

Looking through some friends' dobs and through the one I recently acquired, I'd say that collimation and thermal management are the most important things. Nowadays most of the mirrors are at least decent, but even the best mirror will be worthless if not collimated and cooled actively.

My dob is built from scratch every time so I went for Farpoint combo (laser for secondary and cheshire for primary). I will probably do barlowed laser in the future for primary and just subsequent check with cheshire as it makes life easier collimating alone and not getting sore knees going up and down all the time. 

Using lasers requires relatively good focusers and registering laser in them the same way every time. I learned that lesson quickly. Stock focusers on dobs can be flimsy. Cheaper lasers are not that good and might misalign secondary if they themselves are not collimated.

Excellent in binos (white light) and mono in Ha around 95x. In white light there are a lot of tiny pores invisible on the screenshots, and plage in Ha still there. Finally a nice filament, too.

Too bad the Sun is clearing buildings on the east only around 9 and by that time is it already fairly high and the thermals are starting.

10 hours ago, Dantooine said:

Do you use it without a magnifying finder scope? have you ever used the Baader sky surfer v?

I use it without, not necessary at the mags and targets I normally do. Under dark skies, I use it with relatively low powers, in the city it is on the Sun (solar finder), the Moon and planets.

Never used V, but it is heavier and more expensive. 

Baader Sky Surfer III for me. Light, OK, good dew shield for prolonged observations.

6 hours ago, astro_al said:

Mine arrived last week.

Compared to my existing binoviewers I like:

• The rubberised panels
• The diopter adjustment
• The clicklock eyepiece holders
• The slightly shorter back focus requirement (1-2mm) now allows me to use the FC-76DC with the 1.7x (1.4x) GPC
• Slightly brighter image (left and right side are more evenly illuminated)

I dislike:

• The telescope side end cap was almost in two pieces 
• The bayonet adapter wasn't clean - grease and metal burrs
• The colour is off white but not in a good way to my eyes - pinkish white
• I can't seem to merge the image at 80x or above

The first three dislikes are minor but the last is a deal-breaker for me. I will try one more time tonight but it is likely that they will be going back for replacement. If the collimation was better then I would definitely be keeping them. Not having much luck with new kit at the moment.

 

Is this the first time you have problems merging? Which EPs did you use?

I found that I have problems unless EP has no eyecup or i pull it down. Once it is down it is fine for me, but until I figured it out I struggled with some of them.

I finally had a chance to try Quark with binos today through some holes in the clouds. Quite impressive.

Switched between mono and bino and here are some points:

- Binos dim the view a bit (duh!), I rotated Quark a little in order to get polarization dimming approximately the same in both eyes. There was a big prom and it looked even bigger. Everything looks bigger in the binos, when I went back to 32mm in mono mode it looked much smaller. I know it should not have looked smaller, but it felt like that for sure. The effect was quite pronounced.

- Merging was a problem at start but then I figured out that - for some reasons - the winged eyecups on my Baader 32mm plossls were bothering me. Once I folded them down there was no problem whatsoever.

- Mono view was brighter on the proms and, at the same magnification I saw additional details. Which probably means that I should dial magnification down to 40mm (which I tried, of which more below). The view in the binos was much more relaxing and, again, looked big and the narrow FOV looked somehow less constrained. Surface was easier to observe. Seeing was not that great anyway...

- I dug out one Vixen 40mm plossl that I regularly use with Quark and another, long forgotten, 40mm surplus plossl I got with C8 and somehow managed to use them and merge the image. The eye relief is much bigger on 40mm. I felt that promwise this is probably the optimum exit pupil for the binos, but I am not too keen on such big eye relief in binoculars. To order another Vixen 40mm or not and test it properly...or just stick to 32mm? Dunno.

- Balancing was a problem. On back end there's Quark plus bino plus eps, just over 1kg altogether, on the front there's DERF (over 500grams). I could have omitted DERF but the scope would have been even more unbalanced. AzGTi has 5kg load capacity so I tried to use AYOII, which did well (with balancing at all) until the sun started climbing and the barycenter moved with it too. Evolution would handle this with no problems. I am hesitant to put this on AzGti in either variant without DERF (and only internal ERF), straining the mount in handling a bottom heavy setup or with DERF (where it is better balanced) but comes at almost 6kg. Any tips are welcome...

8 hours ago, badgerchap said:

Nice - I forgot about M13. Used to be one of my favourites. Like a bad of diamonds strewn over black velvet! 

Again, if you want diamonds on velvet you have to cool it. We had, side by side, 12 inch dob and SCT 11 the other night. Dob mirror was cooled and M13 was spectacular, 215x and the picture was clear. C11 mirror was not...and it was not nearly as good even at 140x.

I use Lymax for my C8 and it cuts down cooling time a LOT. Either that or bring the C8 outside well in advance. If the temperature is falling down quickly you have to turn on Lymax once in a while...

Mmmmkay

Depends on what kind of sky you have.

I love my Lymax, keeps the thermals at bay. Consider it. Thermals are a killer on a SCT, if a mirror is catching up the whole night the image will be passable only on low power. Others use reflectix.

Solar system, Lymax again. Planets at the low altitude invite a lot of atmospheric dispersion, ZWO ADC to the rescue, consider it.

As for the DSO, there are PLENTY of them if you have dark enough skies. Especially edge-on galaxies can be quite good if you have dark skies. More important than the aperture, tried and tested.

Turn it on the globs, 8 inches is enough. At the same time, it is still small enough for some of the open clusters (they get worse with bigger aperture and smaller usable field of view).

SCT is great for low targets, would rather look at Skull in my C8 than with my 12 inch dob. Ergonomics 101.

Wow, you made me rewind the data. Eruptive prominence, lovely!

It's overcast here all the time with showers for the past week...and likely to continue that way.

16 minutes ago, bomberbaz said:

Actually nearer a half hour, the ten minutes is on top of the initial 20. Still good though.

Now your just bragging 😉

I have observed under skies of 21.85, I got lost because there were that many stars.

Thanks for the responses guys

'Fcourse I'm bragging LOL

Would you believe that I got lost, too. I was not sure which quadrangle is actually Hercules.

21.10 is good for 30 minutes drive, actually very good, wish I had it for short hops. This site is 2 hrs drive for us, luckily there is a house we are renting on the spot. Pefect place, if a bit wet at times. 21.2 site of another astro group (another direction) is another 2 hrs drive, it is just less brutal in winter, sort of reserve position.

On 30/04/2020 at 21:47, LRoulin said:

Thank you very much for the update, BGazing.

I'm glad you managed to solve most of your collimation issues, it is indeed a bit tricky on a Sumerian when you're used to "traditional" dobsonians.

As for the stabilisers, please do tell us if they help reduce vibrations when you'll be able to go to a dark site!

Take care!

 

Well, we finally went to our dark site. After two months of glorious skies since mid March (which we spent in quarantine at home) we could finally go, but the weather turned rainy and unstable. Still, Friday forecast gave about 50 percent chance that it will be clear so we took our chance, luckily. It was  clear night, SQM was 21.65 and we stayed for about 4 hrs (we were too tired to stay for more and it was fairly cold at 1000m elevation).

We used C11 and Alkaid, so it was plenty of aperture.

Alkaid did really really well. Before listing what went right, let me tell you what went wrong.

I came early and set up early. In doing so (and because i have not set up Alkaid for quite some time) I forgot to push trusses fully in. This meant that when I had to collimate, I was having all sorts of troubles, including running out of collimation screws (and primary holder going down) etc etc. I finally realized my folly when I saw that the bottom of some trusses is 'smeared' with whatever it gets smeared it when it is fully pushed down, i.e. I did not push them down and the whole secondary ring was offset. Once I naled that, collimation was great. But until that point, I was going back and forth (fortunately not in the dark) so many times that the next day my right knee locked. I also realized that barlow laser collimation is really something to consider in the future, so tuBlug will probably come.

Now for the good. Mirror got cooled down properly, shroud was on, startest showed excellent collimation and concentric circles except for the slighly quadratic rings due to the shape of the shroud.  We killed time until astro dark (22:30) by splitting some doubles, Algieba was particularly nice. Once it turned dark, I started galaxy hunting. Transparency was not that great and some of the favorite targets (e.g. Whale) were lower than necessary. M101 was relatively washed out. M51 was great with lower spiral clear in direct vision and hints of upper bridge. It was like 8 inches but everything better and clearer. Cigar was HUGE, galaxies were viewed mostly around 135-165x. Sombrero a bit low. Triplet was very nice. Black Eye at 200x was excellent, Whale at 165x, Hockey stick and whatnot. I planned a lot of targets but it turned out that the star of the show was M13. I turned to it out of curiosity and it was magical. I have viewed it through quite a few 11 and 12-inch scopes but this was the best M13 ever, no photograph I saw does it justice, jewels of black velvet, so many of them resolved already at 165x. 215x was even better and I was not even using Paracorr (still has not arrived). Mesmerizing. I have to say that this, in comparison with C11 (where I it was not as great) was due to thermal management. It was good collimation, good quartz mirror properly cooled.

In use Alkaid was fine. I pushed power until 215x and at that point tracking (nudging) was not jerky but was not completely smooth, difficult to describe. Stability was good, I was using light EPs (T6s and Pan 24). You cannot just slap the scope around because it is delicate, but treat it delicately and it will not rock around or lose balance. If I missed anything it was a good pair of IS binoculars to couple with the RDF, on some targets it took me a while. It does not help that in 12 inches there are so many galaxies popping out and confusing me and I was a bit lazy at times to go back to Pan 24 for low power finding...

But overall, it was a great night and I am glad I got that huge chunk of mirror. I did not use stabilizers, perhaps next time (June, hopefully).

On 21/05/2020 at 17:15, bomberbaz said:

Interesting answers and explains a lot too. I know of a place which on the face of it should be pretty rubbish but actually gives better results than it should. Mainly due to the fact most of the bad LP is northern, the southern aspect is clear. 

I mean really it should be obvious and I did expect last nights viewing to be affected by the LP, but not as badly as it turned out. 

It was gone midnight and above me the skies were super dark, inky black and I was struggling to spot some known stars as there were so many others, not bad considering there is no true astronomical twilight for my latitude at the moment.

However if I looked south it turned to dark blue, lightening to what almost felt like civil twilight by the horizon. Hence my nights viewing was cut short as half my list was in the south section. 

I am guessing an SQM-L pointed towards the southern skyglow would have given a pretty low reading and to be fair, it is that which I find the most important given that is where most of the DSO's are best viewed.

I have SQM-L and two of my friend have them, too. Most of the readings on lightpollution map in Serbia are done by us and the readings side-by-side are pretty accurate.

Over the years some things of note:

- When cooling it gives a slightly higher reading. So keep it ambient.

- Do avg of 3 readings at zenith, just in case.

- You can point it sideways to have a better idea of the quality further from zenith.

- Milky Way significantly affects it, easily 0.3 at dark place.

- SQM reading varies by season and atmosphere conditions. But it never lies. The BEST Swan I have ever seen was on a brutally cold and damp night in June on our dark site when fog was crawling in the gullies and we shivered, in C8 Swan literally burned our retinas. I kid you not. It was 21.77, the highest reading we recorded.

- SQM scale is logarithmic. Meaning that the difference between 21.0 and 21.1 is not nearly as big and pronounced as between, say, 21.5 and 21.6. Once you are over 21, every 0.10 will be a significant improvement and deserves a bit more hassle (i.e. driving).

- SQM cannot read transparency. There will be nights when the readings will be high but the views not as good as they were on nights of similar or even lower readings. 

We had a 21.65 night last Friday. It was magic.

1 hour ago, Rattler said:

Hi guys. Is 5v 2amp ok to power the Quark? Cheers.

Sure. Any phone charger rated 5v and 2amp is fine. Been using one like that for over a year.

Just now, Philip R said:

The filter I tend to use most often for planetary observing is the Baader Neodymium. I often refer to it as 'the Swiss Army Knife filter'. Jupiter or Saturn appear shade of pale blue. The last time Mars was at it closet opposition, it was having a dust storm, it appeared a pale violet. I could see a bit of surface detail with my C6/XLT-SCT. It is one of those Marmite filters; either you hate it or you love it!

 

+1, love Neodymium. Also doubles as UVIR cut for Quark. Swiss Army Knife indeed.

I love it on Jupiter and Saturn in C8 but on Tak I prefer them sans filter. Good on the Moon in any scope.