johnturley

Had another go with my ZWO ADC coupled with a Baader Neodymium filter last night, despite a significant breeze, viewing conditions were much improved on the previous evening, and through my 14in Newtonian I can't recall previously having seen so much detail on Jupiter when it was so low down, the great red spot was obvious, and I also observed the Ganymede occultation.

Like Chris, I didn't mess about attaching a camera and running the camera through Firecapture or Sharpcap to obtain the optimal setting as per the instruction manual (I don't have an astro camera anyway, just a digital SLR). I simply pointed the telescope horizontal, and then rotated the ADC so that the spirit level (on the top) indicated horizontal, and then when viewing adjusted the 2 levers by an identical amount so as to minimise the amount of false colour due to atmospheric dispersion, I think in the case of Jupiter it was somewhere between 0.5 and 1 on the scale.

I also tried out the ADC through my Esprit 150, in this case the effect was more marginal, and the optimal position with the levers was less than 0.5. I therefore get the impression that larger reflectors benefit more from an ADC than smaller refractors, and that they will probably be of limited benefit in the case of 4 in or smaller refractors.

John 

2 hours ago, CraigT82 said:

Just had a thought... if you haven't done so yet, it's worth checking if your ADC is a righty or lefty (I.e. which way the prisms are stacked) as this will dictate whether you have the null point pointing left or right.

Nice and easy test for this here...

https://www.cloudynights.com/topic/525563-for-users-of-the-new-zwo-adc-important/

I just assumed that the spirit level on my ZWO ADC was intended to be on on the top of the unit when is use (which makes sense), which then puts the levers on the right, and is the way I have used mine.

I had more success with it on Jupiter last night (when atmospheric conditions were poor) through my 14in Newtonian, using it in conjunction with a Baader Neodymium filter, I simply moved the 2 levers in opposite directions until the false colour caused by atmospheric dispersion virtually disappeared.  I ended getting a more pleasing view of the planet through the 14 in, than through my 150 mm Esprit, normally the smaller refractor gives a better view when atmospheric conditions are poor, I didn't however try the ADC with the Esprit. 

The Baader Neodymium filter helps in particular on Jupiter through the 14 in, as otherwise the bright image tends to wash out some of the detail in the cloud belts.

John 

Observed the comet for the first time in over a week last night, superb view through my 15 x 70 binoculars, although the comet had faded a bit this was not by much as predicted, and it was still just visible with the naked eye. The tail appeared to have grown from about 2 to 4 degrees, virtually filling the field of view of my 15 x 70 binoculars. 

John 

24 minutes ago, George Jones said:

 

Be careful. As a general statement, your first sentence is FALSE.

I assume by local noon Corncrake meant the time when the sun transits (i.e. noon as indicated by a sundial), rather than local noon which would still be affected by the equation of time.

John 

1 hour ago, johninderby said:

The 2” nosepiece may be a good idea. 😁

 

Fitting a 2" nosepiece, as I have done with my ZWO ADC, will reduce the light path (i.e. the amount on in travel required) by about 10 - 12 mm, useful for Newtonian Reflectors where limited in travel on the focuser is available.

John 

On 12/07/2020 at 13:12, markse68 said:

I’ve been playing with my Atmospheric Dispersion Corrector the last couple of nights and getting the clearest views I’ve ever had. I’m coming to the conclusion that it is an essential piece of equipment for planetary observing- at least while they’re low. Jupiter and Saturn were incredible last night with it-  very very sharp. Mars is looking more like a planet than an orange blob and the icing on the cake was Venus rising- without the adc a rainbow crescent but with it a tight crisp mini moon bar the wobbly atmospherics. It’s really been quite an eye opener! 

I guess the extra glass must take something away from the image but if the image is already blurred by AD then what it subtracts is more than made up for by what it corrects. Mine has uncoated prisms  so with my 18m bco on Jupiter I get 4 reflected jupiter’s around the edge but the glass being planar and angled these are off to the edge so don’t affect the important central image. I guess coated prisms would be better. shorter fl eps the reflections are out of view anyway. I’m using it with a 2x barlow.

Mark

Do you have the ZWO version (the Altair version appears similar), or one of the much more expensive Gutekunst versions.

I find that my ZWO helps a bit on Jupiter, in particular through my 14in Newtonian,  but would not say that it makes a dramatic difference, although possibly I'm not setting it up correctly. I also find that a Baader Neodymium filter helps on Jupiter, as otherwise the very bright image through my 14in, washes out a lot of the detail in the cloud belts.

John 

Attach one my best images from last night (11.07.20), I needed to go to a nearby sports field in Dronfield to get a suitable north east horizon.

After almost a week of cloud and rain, I first spotted the comet the previous evening (10.07.20) with my 15 x 70 binoculars, superb tail extending several degrees. Returned last night with my Canon camera and tripod expecting the comet to have faded slightly, but to my surprise, and against the predictions, it appeared slightly brighter.  On 10.07.20. I could barely spot the comet with the naked eye, but last night it was quite obvious, this may however have been due to the sky being a bit clearer and the comet slightly higher in the sky. I estimated the magnitude at between 1 and 2. 

Canon 6D 24 - 105mm zoon lens at 105mm f5.6, 5 seconds exposure at ISO 1,600. 

Definitely best comet since Hale Bopp, although it did not compare with the latter, or Comet West in 1976 and Comet Bennett in 1970. 

1 minute ago, JeremyS said:

Yes, that's correct John. There's an N26 listed on Widescreen's website, as was discussed above. But the price tag is huge (of course, for this sort of eyepiece), so I never contacted them to check if they had it in stock.

 

I would also be tempted by a 26mm T5 Nagler if I could find a good second hand one at a reasonable price, but like you don't want to pay £579 even if the Widescreen Centre still have one in stock.

John 

19 minutes ago, JeremyS said:

So I went for a Nagler T5 20mm and 26mm in the end.

As I said elsewhere, I'm done with the eyepieces now 🙂

 

I assume you managed to find second hand ones, as far as I'm aware they're no longer available new.

John 

11 minutes ago, DeathWarpedUp said:

Cheers, just didnt know what to call them. Don't offer them in the UK the shipping is close to £12!!

I think Opticron in the UK stock some lens caps, not sure what sizes are available.

John

I have some thoughts of upgrading the focuser on my Esprit 150 to a Feathertouch, but worried as to whether retro fitting one could affect the collimation, especially as when Es Reid checked mine, he told me that it was one of the best he had tested.

John 

15 minutes ago, gorann said:

I have two Esprits, 100 and 150 and I love them, so I am sure the 120 would be an excellent scope. However, an alternative from which I have seen great images is the 130 from TS. You can see on Astrobin what "pete xl" https://www.astrobin.com/users/pete_xl/ can do with it, very impressive, and it comes at a very reasonable price. 

 

I think that this is very similar to the Altair version, but the TS version is cheaper, and uses FPL53 rather than FPL51 glass. 

John 

Rother Valley Optics website says everything normally in stock, and the Wide Screen Centre does not state whether items or in stock or not, and for example they still list a couple of Nagler eyepieces that were discontinued some time ago.

As an alternative there is the Explore Scientific 127mm FCD 100 Refractor, which according  Harrison Telescopes website is in stock at £1,890, it is quite good optically (I have one), but build quality is not as good as the Esprit.

The Altair Wave Series, which I think are sold under several different brand names with minor variations, have quite a good reputation, the 125 EDF f7.8 FPL 53 is listed at Harrison Telescopes at £1,699 and the 130 ED f7 at £2,299, the latter uses FPL51 glass so colour correction maybe not quite as good. However both these scopes are currently listed as being out of stock.

John 

3 hours ago, bomberbaz said:

blooming heck that's a beastie for a 127, never realised they were quite that big. I am so glad I resisted the temptation to got for one a while back. 

I think it partly depends on the angle from which the photograph was taken, in this photo my ES  127 on an AZ-EQ5 does not appear quite so large.

Had my first view of the planet this apparition early yesterday morning (26 June), not much detail visible but south polar cap very distinct.

John 

1 hour ago, JeremyS said:

I’m afraid I can’t answer that. All my 2-inch eyepieces work but none has a 1.25-inch barrel

I've never seen the point of dual 2in/1.25in barrels, the eyepiece ends up being a lot bigger and heavier than it need be.

John 

On 21/06/2020 at 08:37, dweller25 said:

I gave up on Ebay and Paypal when someone got access to my credit card details - that only PP had - to steal £1500 from me.

I got it all back but it was worrying.

 

Someone hacked my wife's PayPal account recently (I don't have one and don't intend to either) to buy 2 bottles of champagne, fortunately she was able to get the money back, and has since closed her PayPal account.

Yet PayPal try to make out that its more secure than bank transfer. 

John  

12 minutes ago, Timebandit said:

 

 

A lesson to be learnt here I think

LEAVE YOUR MIRROR ALONE 

I have never washed or cleaned my mirror. Its been in the scope for years. And I read an article some years ago about the mirror coatings are so so easily damaged. So unless your mirror is in really terrible condition then personally I would not clean it 

 

 

Personally I don't agree with this, obviously it is best to try to avoid the mirror getting dirty in the first place and reduce the need for cleaning to a minimum, but Newtonians or scopes where there isn't a corrector plate or optical window sealing the tube, will eventually need cleaning at some point, unless one is prepared to put up with significantly reduced performance. I agree with John, and think that the problem in this instance may have been a poor quality coating in the first place.

Most coatings you get these days seem to last a lot longer than they used to, I can remember in the 1970's it was normal to have a Newtonian mirror re-aluminised every 3 to 5 years, nowadays they seem to last much longer. I last had my 14in Newtonian re-aluminised in 2013, and opted for the Hilux coating from Orion Optics UK, and it it is still in very good condition after 7 years, much better than would have been the case with traditional aluminising 40 years ago. I usually give my mirror an annual clean, using first soapy water, and then a first surface cleaner such a Baader Wonder fluid, finally rinsing off with distilled water, care is however required at every stage.

John 

4 hours ago, greg110902 said:

Update:

So in the end, I threw caution to the wind. I figured there's a chance this mirror is useless now, and I found I can buy a new one for ~£30. So, I rinsed it under deionised water, and cleaned away marks with a dishcloth. It looks okay, everything looks sharp and I popped it back in the tube and checked it out with some terrestrial viewing, everything looked up to standard. Looks like it could be a clear night here tonight-we shall see (or maybe I won't)

I don't think you've ruined the mirror, it just may need re-aluminising, the coating possibly wasn't in very good condition in the first place.

John 

As forecast, completely clouded out in most of the UK, and its now raining where I live.

John 

Unfortunately weather outlook not great from the UK.

John  

Sometimes you need to increase the manual exposure time to see an image on the live view screen, then after focusing reducing it the appropriate setting.

John 

4 minutes ago, johnoelliott said:

Everyone has their own opinion of which ones work best so my solution to the problem was to buy a 5 position manual filter wheel and put in UHC, Deep Sky, Hb and Oiii filters leaving one empty.

I can quickly go back and forth comparing them to see which ones work best for the target I'm looking at

This is exactly what I did as well.

John 

3 hours ago, Chriske said:

I

Another thing, I do have a well equipped workshop. Among the many tools I have, also many drills. The smallest drill is 0.1mm. It goes up by 0.1mm per step, ending at 10mm. After that it continues to go up with 0.5mm per drill.

 

I can't imagine a drill bit as small as 0.1 mm, what does it look like, and what is it used for, my smallest drill bit is 1.5 mm, and that is very delicate.

John 

14 minutes ago, Ibbo! said:

When i was lad in my first job out of school, woking in the lab at a coke oven plant some of you might of heard of -Orgreave (Choke and Chemicals as it was commonly known) we had to measure something in grains /hundred cubic feet as that was what the old tables listed.

Thing is we could not get gas meters that measured in cubic feet and the tests were done in SI units and instead of converting the tables we had to convert the result.

 

I remember the old Orgreave Coking Plant well, used to sample the effluent there initially on behalf of Yorkshire Water Authority, and then later the National Rivers Authority.

I expect that you also used to measure the strength of the caustic soda in degrees twaddle.

John